更改

====Obtaining free energy ====

====Obtaining free energy ====

获得自由能

获得自由能

Bernal said on the Miller–Urey experiment that <blockquote>it is not enough to explain the formation of such molecules, what is necessary, is a physical-chemical explanation of the origins of these molecules that suggests the presence of suitable sources and sinks for free energy.<ref>{{harvnb|Bernal|1967|p=143}}</ref>

Bernal said on the Miller–Urey experiment that < blockquote >it is not enough to explain the formation of such molecules, what is necessary, is a physical-chemical explanation of the origins of these molecules that suggests the presence of suitable sources and sinks for free energy.<ref>{{harvnb|Bernal|1967|p=143}}</ref>

</blockquote>

< /blockquote >

Bernal said on the Miller–Urey experiment that <blockquote>it is not enough to explain the formation of such molecules, what is necessary, is a physical-chemical explanation of the origins of these molecules that suggests the presence of suitable sources and sinks for free energy.</blockquote>

Bernal said on the Miller–Urey experiment that < blockquote >it is not enough to explain the formation of such molecules, what is necessary, is a physical-chemical explanation of the origins of these molecules that suggests the presence of suitable sources and sinks for free energy.< /blockquote >

伯纳尔Bernal在 Miller-Urey 的实验中说，

伯纳尔Bernal在 Miller-Urey 的实验中说，

</blockquote >仅仅解释这些分子的形成是不够的，需要的是对这些分子的起源作出物理化学解释，表明存在合适的自由能源和自由能汇。

 

< blockquote >仅仅解释这些分子的形成是不够的，需要的是对这些分子的起源作出物理化学解释，表明存在合适的自由能源和自由能汇。

</blockquote >

</blockquote >

协同学这门学科研究的是物理系统的自组织。Hermann Haken在其《协同论》一书中指出，不同的物理系统可以用类似的方式处理。他举了几种类型的激光、流体动力学（包括对流）中的不稳定性以及化学和生化振荡作为自组织的例子。他在序言中提到了生命的起源，但只是泛泛而谈。

协同学这门学科研究的是物理系统的自组织。Hermann Haken在其《协同论》一书中指出，不同的物理系统可以用类似的方式处理。他举了几种类型的激光、流体动力学（包括对流）中的不稳定性以及化学和生化振荡作为自组织的例子。他在序言中提到了生命的起源，但只是泛泛而谈。

<blockquote>

< blockquote >

The spontaneous formation of well organized structures out of germs or even out of chaos is one of the most fascinating phenomena and most challenging problems scientists are confronted with. Such phenomena are an experience of our daily life when we observe the growth of plants and animals. Thinking of much larger time scales, scientists are led into the problems of evolution, and, ultimately, of the origin of living matter. When we try to explain or understand in some sense these extremely complex biological phenomena it is a natural question, whether processes of self-organization may be found in much simpler systems of the unanimated world.

The spontaneous formation of well organized structures out of germs or even out of chaos is one of the most fascinating phenomena and most challenging problems scientists are confronted with. Such phenomena are an experience of our daily life when we observe the growth of plants and animals. Thinking of much larger time scales, scientists are led into the problems of evolution, and, ultimately, of the origin of living matter. When we try to explain or understand in some sense these extremely complex biological phenomena it is a natural question, whether processes of self-organization may be found in much simpler systems of the unanimated world.

</blockquote>

< /blockquote >

<blockquote>

< blockquote >

In recent years it has become more and more evident that there exists numerous examples in physical and chemical systems where well organized spatial, temporal, or spatio-temporal structures arise out of chaotic states. Furthermore, as in living organisms, the functioning of these systems can be maintained only by a flux of energy (and matter) through them. In contrast to man-made machines, which are devised to exhibit special structures and functionings, these structures develop spontaneously—they are ''selforganizing''. ...<ref>{{cite book |last1 = Haken| first1= Hermann | title=Synergetics. An Introduction. |year=1978 | publisher=Springer }}</ref>

In recent years it has become more and more evident that there exists numerous examples in physical and chemical systems where well organized spatial, temporal, or spatio-temporal structures arise out of chaotic states. Furthermore, as in living organisms, the functioning of these systems can be maintained only by a flux of energy (and matter) through them. In contrast to man-made machines, which are devised to exhibit special structures and functionings, these structures develop spontaneously—they are ''selforganizing''. ...<ref>{{cite book |last1 = Haken| first1= Hermann | title=Synergetics. An Introduction. |year=1978 | publisher=Springer }}</ref>

</blockquote>

< /blockquote >

</blockquote>

< /blockquote >

In recent years it has become more and more evident that there exists numerous examples in physical and chemical systems where well organized spatial, temporal, or spatio-temporal structures arise out of chaotic states. Furthermore, as in living organisms, the functioning of these systems can be maintained only by a flux of energy (and matter) through them. In contrast to man-made machines, which are devised to exhibit special structures and functionings, these structures develop spontaneously—they are selforganizing. ...

In recent years it has become more and more evident that there exists numerous examples in physical and chemical systems where well organized spatial, temporal, or spatio-temporal structures arise out of chaotic states. Furthermore, as in living organisms, the functioning of these systems can be maintained only by a flux of energy (and matter) through them. In contrast to man-made machines, which are devised to exhibit special structures and functionings, these structures develop spontaneously—they are selforganizing. ...

当讨论生命的起源时，对生命本身的定义是最基本的。由于不同的生物学教科书对生命的定义不同，所以对这个定义存在一定的分歧（虽然遵循相同的基本原则）。詹姆斯 · 古尔德James Gould:

当讨论生命的起源时，对生命本身的定义是最基本的。由于不同的生物学教科书对生命的定义不同，所以对这个定义存在一定的分歧（虽然遵循相同的基本原则）。詹姆斯 · 古尔德James Gould:

<blockquote>

< blockquote >

Most dictionaries define ''life'' as the property that distinguishes the living from the dead, and define ''dead'' as being deprived of life. These singularly circular and unsatisfactory definitions give us no clue to what we have in common with protozoans and plants. <ref “Gould”>{{cite book| last1 = Gould | first1 = James L. | last2 = Keeton | first2 = William T. | year = 1996| edition = 6 | title = Biological Science | location= New York | publisher = W.W. Norton }}</ref></blockquote>

Most dictionaries define ''life'' as the property that distinguishes the living from the dead, and define ''dead'' as being deprived of life. These singularly circular and unsatisfactory definitions give us no clue to what we have in common with protozoans and plants. <ref “Gould”>{{cite book| last1 = Gould | first1 = James L. | last2 = Keeton | first2 = William T. | year = 1996| edition = 6 | title = Biological Science | location= New York | publisher = W.W. Norton }}</ref>< /blockquote >

Most dictionaries define life as the property that distinguishes the living from the dead, and define dead as being deprived of life. These singularly circular and unsatisfactory definitions give us no clue to what we have in common with protozoans and plants.

Most dictionaries define life as the property that distinguishes the living from the dead, and define dead as being deprived of life. These singularly circular and unsatisfactory definitions give us no clue to what we have in common with protozoans and plants.

大多数字典将生命定义为区别于活人和死人的属性，并将死人定义为被剥夺了生命。这些奇异的循环和不令人满意的定义，没有给我们提供任何线索，让我们了解我们与原生动物和植物的共同之处。

大多数字典将生命定义为区别于活人和死人的属性，并将死人定义为被剥夺了生命。这些奇异的循环和不令人满意的定义，没有给我们提供任何线索，让我们了解我们与原生动物和植物的共同之处。

<blockquote>

< blockquote >

whereas according to Neil Campbell and Jane Reece <blockquote>The phenomenon we call life defies a simple, one-sentence definition.<ref “Campbell”>{{cite book| last1 = Campbell | first1 = Neil A. |  last2 = Reece | first2 = Jane B.| year = 2005| edition = 7 | title = Biology | location= Sn Feancisco | publisher = Benjamin }}</ref></blockquote>

whereas according to Neil Campbell and Jane Reece < blockquote >The phenomenon we call life defies a simple, one-sentence definition.<ref “Campbell”>{{cite book| last1 = Campbell | first1 = Neil A. |  last2 = Reece | first2 = Jane B.| year = 2005| edition = 7 | title = Biology | location= Sn Feancisco | publisher = Benjamin }}</ref>< /blockquote >

whereas according to Neil Campbell and Jane Reece <blockquote>The phenomenon we call life defies a simple, one-sentence definition.

whereas according to Neil Campbell and Jane Reece < blockquote >The phenomenon we call life defies a simple, one-sentence definition.

然而，根据尼尔 · 坎贝尔Neil Campbell和简 · 里斯Jane Reece 的说法，

然而，根据尼尔 · 坎贝尔Neil Campbell和简 · 里斯Jane Reece 的说法，

</blockquote>

< /blockquote >

The phenomenon we call life defies a simple, one-sentence definition.

The phenomenon we call life defies a simple, one-sentence definition.

我们所说的生命现象，不符合一个简单的、一言以蔽之的定义。

我们所说的生命现象，不符合一个简单的、一言以蔽之的定义。

</blockquote>

< /blockquote >

This difference can also be found in books on the origin of life. John Casti gives a single sentence:

This difference can also be found in books on the origin of life. John Casti gives a single sentence:

在关于生命起源的书籍中也可以找到这种差异。约翰-卡斯蒂John Casti给出了一句话：

在关于生命起源的书籍中也可以找到这种差异。约翰-卡斯蒂John Casti给出了一句话：

<blockquote>By more or general consensus nowadays, an entity is considered to be "alive" if it has the capacity to carry out three basic functional activities: metabolism, self-repair, and replication.

< blockquote >By more or general consensus nowadays, an entity is considered to be "alive" if it has the capacity to carry out three basic functional activities: metabolism, self-repair, and replication.

根据现在更多的或普遍的共识，如果一个实体有能力进行三种基本的功能活动：新陈代谢、自我修复和复制，那么它就被认为是 "有生命的"。

根据现在更多的或普遍的共识，如果一个实体有能力进行三种基本的功能活动：新陈代谢、自我修复和复制，那么它就被认为是 "有生命的"。

</blockquote>  

< /blockquote >  

Dirk Schulze-Makuch and Louis Irwin spend in contrast the whole first chapter of their book on this subject.

Dirk Schulze-Makuch and Louis Irwin spend in contrast the whole first chapter of their book on this subject.

阿尔伯特·莱宁格Albert Lehninger曾在1970年左右指出，包括糖酵解在内的发酵是生命起源的合适原始能源。。

阿尔伯特·莱宁格Albert Lehninger曾在1970年左右指出，包括糖酵解在内的发酵是生命起源的合适原始能源。。

<blockquote> Since living organisms probably first arose in an atmosphere lacking oxygen, anaerobic fermentation is the simplest and most primitive type of biological mechanism for obtaining energy from nutrient molecules. </blockquote>

< blockquote > Since living organisms probably first arose in an atmosphere lacking oxygen, anaerobic fermentation is the simplest and most primitive type of biological mechanism for obtaining energy from nutrient molecules. < /blockquote >

由于生物体可能首先是在缺氧的环境中产生的，因此厌氧发酵是从营养分子中获取能量的最简单、最原始的一种生物机制。 </blockquote >

由于生物体可能首先是在缺氧的环境中产生的，因此厌氧发酵是从营养分子中获取能量的最简单、最原始的一种生物机制。 </blockquote >

  | doi = 10.1016/0079-6107(95)00004-7

  | doi = 10.1016/0079-6107(95)00004-7

<blockquote>. . . depict LUCA as anaerobic, CO₂-fixing, H₂-dependent with a Wood–Ljungdahl pathway, N₂-fixing and thermophilic. LUCA's biochemistry was replete with FeS clusters and radical reaction mechanisms. Its cofactors reveal dependence upon transition metals, flavins, S-adenosyl methionine, coenzyme A, ferredoxin, molybdopterin, corrins and selenium. Its genetic code required nucleoside modifications and S-adenosylmethionine-dependent methylations."  

< blockquote >. . . depict LUCA as anaerobic, CO₂-fixing, H₂-dependent with a Wood–Ljungdahl pathway, N₂-fixing and thermophilic. LUCA's biochemistry was replete with FeS clusters and radical reaction mechanisms. Its cofactors reveal dependence upon transition metals, flavins, S-adenosyl methionine, coenzyme A, ferredoxin, molybdopterin, corrins and selenium. Its genetic code required nucleoside modifications and S-adenosylmethionine-dependent methylations."  

..说明LUCA是厌氧的、固定二氧化碳的、依赖H2的、具有Wood-Ljungdahl途径的、固定N2的和嗜热的。LUCA的生物化学中充斥着FeS簇和自由基反应机制。它的辅助因子揭示了对过渡金属、黄素、S-腺苷蛋氨酸、辅酶A、铁氧化还原蛋白、亚钼嘌呤、柯啉环和硒的依赖性。其遗传密码需要核苷修饰和S-腺苷蛋氨酸依赖的甲基化"。

..说明LUCA是厌氧的、固定二氧化碳的、依赖H2的、具有Wood-Ljungdahl途径的、固定N2的和嗜热的。LUCA的生物化学中充斥着FeS簇和自由基反应机制。它的辅助因子揭示了对过渡金属、黄素、S-腺苷蛋氨酸、辅酶A、铁氧化还原蛋白、亚钼嘌呤、柯啉环和硒的依赖性。其遗传密码需要核苷修饰和S-腺苷蛋氨酸依赖的甲基化"。

  | pmid = 7542789

  | pmid = 7542789

</blockquote>The results depict methanogenic clostridia as a basal clade in the 355 phylogenies examined, and suggest that LUCA inhabited an anaerobic hydrothermal vent setting in a geochemically active environment rich in H₂, CO₂ and iron.

< /blockquote >The results depict methanogenic clostridia as a basal clade in the 355 phylogenies examined, and suggest that LUCA inhabited an anaerobic hydrothermal vent setting in a geochemically active environment rich in H₂, CO₂ and iron.

研究结果显示在所研究的355个系统发育中，产甲烷的梭菌是一个基础支系，并表明LUCA栖息在厌氧热液喷口处且地理化学活性环境中富含H₂, CO₂ 和铁。

研究结果显示在所研究的355个系统发育中，产甲烷的梭菌是一个基础支系，并表明LUCA栖息在厌氧热液喷口处且地理化学活性环境中富含H₂, CO₂ 和铁。

Possible precursors for the evolution of protein synthesis include a mechanism to synthesize short peptide cofactors or form a mechanism for the duplication of RNA. It is likely that the ancestral ribosome was composed entirely of RNA, although some roles have since been taken over by proteins. Major remaining questions on this topic include identifying the selective force for the evolution of the ribosome and determining how the [[genetic code]] arose.<ref name="Noller2012">{{cite journal |last=Noller |first=Harry F. |authorlink=Harry F. Noller |date=April 2012 |title=Evolution of protein synthesis from an RNA world. |journal=Cold Spring Harbor Perspectives in Biology |volume=4 |issue=4 |page=a003681 |doi=10.1101/cshperspect.a003681 |pmc=3312679 |pmid=20610545}}</ref>

Possible precursors for the evolution of protein synthesis include a mechanism to synthesize short peptide cofactors or form a mechanism for the duplication of RNA. It is likely that the ancestral ribosome was composed entirely of RNA, although some roles have since been taken over by proteins. Major remaining questions on this topic include identifying the selective force for the evolution of the ribosome and determining how the [[genetic code]] arose.<ref name="Noller2012">{{cite journal |last=Noller |first=Harry F. |authorlink=Harry F. Noller |date=April 2012 |title=Evolution of protein synthesis from an RNA world. |journal=Cold Spring Harbor Perspectives in Biology |volume=4 |issue=4 |page=a003681 |doi=10.1101/cshperspect.a003681 |pmc=3312679 |pmid=20610545}}</ref>

[[Eugene Koonin]] said, <blockquote>Despite considerable experimental and theoretical effort, no compelling scenarios currently exist for the origin of replication and translation, the key processes that together comprise the core of biological systems and the apparent pre-requisite of biological evolution. The RNA World concept might offer the best chance for the resolution of this conundrum but so far cannot adequately account for the emergence of an efficient RNA replicase or the translation system. The MWO ["many worlds in one"] version of the cosmological model of [[eternal inflation]] could suggest a way out of this conundrum because, in an infinite [[multiverse]] with a finite number of distinct macroscopic histories (each repeated an infinite number of times), emergence of even highly complex systems by chance is not just possible but inevitable.<ref name="pmc1892545">{{cite journal |last=Koonin |first=Eugene V. |date=31 May 2007 |title=The cosmological model of eternal inflation and the transition from chance to biological evolution in the history of life |journal=Biology Direct |volume=2 |page=15 |doi=10.1186/1745-6150-2-15 |pmc=1892545 |pmid=17540027}}</ref></blockquote>

[[Eugene Koonin]] said, < blockquote >Despite considerable experimental and theoretical effort, no compelling scenarios currently exist for the origin of replication and translation, the key processes that together comprise the core of biological systems and the apparent pre-requisite of biological evolution. The RNA World concept might offer the best chance for the resolution of this conundrum but so far cannot adequately account for the emergence of an efficient RNA replicase or the translation system. The MWO ["many worlds in one"] version of the cosmological model of [[eternal inflation]] could suggest a way out of this conundrum because, in an infinite [[multiverse]] with a finite number of distinct macroscopic histories (each repeated an infinite number of times), emergence of even highly complex systems by chance is not just possible but inevitable.<ref name="pmc1892545">{{cite journal |last=Koonin |first=Eugene V. |date=31 May 2007 |title=The cosmological model of eternal inflation and the transition from chance to biological evolution in the history of life |journal=Biology Direct |volume=2 |page=15 |doi=10.1186/1745-6150-2-15 |pmc=1892545 |pmid=17540027}}</ref>< /blockquote >

Possible precursors for the evolution of protein synthesis include a mechanism to synthesize short peptide cofactors or form a mechanism for the duplication of RNA. It is likely that the ancestral ribosome was composed entirely of RNA, although some roles have since been taken over by proteins. Major remaining questions on this topic include identifying the selective force for the evolution of the ribosome and determining how the genetic code arose.

Possible precursors for the evolution of protein synthesis include a mechanism to synthesize short peptide cofactors or form a mechanism for the duplication of RNA. It is likely that the ancestral ribosome was composed entirely of RNA, although some roles have since been taken over by proteins. Major remaining questions on this topic include identifying the selective force for the evolution of the ribosome and determining how the genetic code arose.

  | issue = 2

  | issue = 2

Eugene Koonin said, <blockquote>Despite considerable experimental and theoretical effort, no compelling scenarios currently exist for the origin of replication and translation, the key processes that together comprise the core of biological systems and the apparent pre-requisite of biological evolution. The RNA World concept might offer the best chance for the resolution of this conundrum but so far cannot adequately account for the emergence of an efficient RNA replicase or the translation system. The MWO ["many worlds in one"] version of the cosmological model of eternal inflation could suggest a way out of this conundrum because, in an infinite multiverse with a finite number of distinct macroscopic histories (each repeated an infinite number of times), emergence of even highly complex systems by chance is not just possible but inevitable.</blockquote>

Eugene Koonin said, < blockquote >Despite considerable experimental and theoretical effort, no compelling scenarios currently exist for the origin of replication and translation, the key processes that together comprise the core of biological systems and the apparent pre-requisite of biological evolution. The RNA World concept might offer the best chance for the resolution of this conundrum but so far cannot adequately account for the emergence of an efficient RNA replicase or the translation system. The MWO ["many worlds in one"] version of the cosmological model of eternal inflation could suggest a way out of this conundrum because, in an infinite multiverse with a finite number of distinct macroscopic histories (each repeated an infinite number of times), emergence of even highly complex systems by chance is not just possible but inevitable.< /blockquote >

尤金-库宁Eugene Koonin 说，

尤金-库宁Eugene Koonin 说，

<blockquote>

< blockquote >

尽管在实验和理论上做了大量的努力，但对于复制和翻译的起源，目前还没有令人信服的设想，而复制和翻译是构成生物系统核心的关键过程，也是生物进化的明显先决条件。RNA世界概念可能为这一难题的解决提供了最好的机会，但迄今为止还不能充分说明高效RNA复制酶或翻译系统的出现。MWO["多世界合一"]版本的永恒膨胀的宇宙学模型可以提出解决这一难题的方法，因为在一个无限的多元宇宙中，有有限数量的不同的宏观历史（每个历史重复无限次），即使是高度复杂的系统也是偶然出现的，这不仅是可能的，而且是不可避免的

尽管在实验和理论上做了大量的努力，但对于复制和翻译的起源，目前还没有令人信服的设想，而复制和翻译是构成生物系统核心的关键过程，也是生物进化的明显先决条件。RNA世界概念可能为这一难题的解决提供了最好的机会，但迄今为止还不能充分说明高效RNA复制酶或翻译系统的出现。MWO["多世界合一"]版本的永恒膨胀的宇宙学模型可以提出解决这一难题的方法，因为在一个无限的多元宇宙中，有有限数量的不同的宏观历史（每个历史重复无限次），即使是高度复杂的系统也是偶然出现的，这不仅是可能的，而且是不可避免的

</blockquote >

</blockquote >

In the 17th century, people began to question such assumptions. In 1646, [[Sir Thomas Browne|Thomas Browne]] published his ''[[Pseudodoxia Epidemica]]'' (subtitled ''Enquiries into Very many Received Tenets, and commonly Presumed Truths''), which was an attack on false beliefs and "vulgar errors." His contemporary, [[Alexander Ross (writer)|Alexander Ross]], erroneously refuted him, stating:

In the 17th century, people began to question such assumptions. In 1646, [[Sir Thomas Browne|Thomas Browne]] published his ''[[Pseudodoxia Epidemica]]'' (subtitled ''Enquiries into Very many Received Tenets, and commonly Presumed Truths''), which was an attack on false beliefs and "vulgar errors." His contemporary, [[Alexander Ross (writer)|Alexander Ross]], erroneously refuted him, stating:

<blockquote> To question this [spontaneous generation], is to question Reason, Sense, and Experience: If he doubts of this, let him go to ''[[Egypt|Ægypt]]'', and there he will find the fields swarming with mice begot of the mud of ''[[Nile|Nylus]]'', to the great calamity of the Inhabitants.<ref>{{cite journal |last=Balme |first=D.M. |authorlink=David Mowbray Balme |year=1962 |title=Development of Biology in Aristotle and Theophrastus: Theory of Spontaneous Generation |journal=[[Phronesis (journal)|Phronesis]] |volume=7 |issue=1–2 |pages=91–104 |doi=10.1163/156852862X00052}}</ref><ref>{{harvnb|Ross|1652}}</ref></blockquote>

< blockquote > To question this [spontaneous generation], is to question Reason, Sense, and Experience: If he doubts of this, let him go to ''[[Egypt|Ægypt]]'', and there he will find the fields swarming with mice begot of the mud of ''[[Nile|Nylus]]'', to the great calamity of the Inhabitants.<ref>{{cite journal |last=Balme |first=D.M. |authorlink=David Mowbray Balme |year=1962 |title=Development of Biology in Aristotle and Theophrastus: Theory of Spontaneous Generation |journal=[[Phronesis (journal)|Phronesis]] |volume=7 |issue=1–2 |pages=91–104 |doi=10.1163/156852862X00052}}</ref><ref>{{harvnb|Ross|1652}}</ref>< /blockquote >

在17世纪，人们开始质疑这些假设。1646年，托马斯·布朗出版了他的《伪传染病》(副标题为《对许多公认的原则和公认的真理的询问》)，该书攻击了错误的信仰和“庸俗的错误”。与他同时代的亚历山大·罗斯错误地驳斥了他，称:

在17世纪，人们开始质疑这些假设。1646年，托马斯·布朗出版了他的《伪传染病》(副标题为《对许多公认的原则和公认的真理的询问》)，该书攻击了错误的信仰和“庸俗的错误”。与他同时代的亚历山大·罗斯错误地驳斥了他，称:

<blockquote>  

< blockquote >  

质疑这个自然发生，就是质疑理性、感觉和经验。如果他怀疑这一点，让他去埃及， 在那里，他将会发现田野里到处都是由尼罗斯的泥土生出的老鼠， 给当地居民带来了巨大的灾难。

质疑这个自然发生，就是质疑理性、感觉和经验。如果他怀疑这一点，让他去埃及， 在那里，他将会发现田野里到处都是由尼罗斯的泥土生出的老鼠， 给当地居民带来了巨大的灾难。

</blockquote>  

< /blockquote >  

[[File:Anton van Leeuwenhoek.png|thumb|upright|Antonie van Leeuwenhoek]]

[[File:Anton van Leeuwenhoek.png|thumb|upright|Antonie van Leeuwenhoek]]

查尔斯·达尔文（1879年）

查尔斯·达尔文（1879年）

By the middle of the 19th century, biogenesis had accumulated so much evidence in support that the alternative theory of spontaneous generation had been effectively disproven. [[Louis Pasteur|Pasteur]] remarked, about a finding of his in 1864 which he considered definitive, <blockquote>Never will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment.<ref>{{harvnb|Oparin|1953|p=196}}</ref><ref name="Tyndall Fragments2">{{harvnb|Tyndall|1905|loc=IV, XII (1876), XIII (1878)}}</ref> </blockquote>gave a mechanism by which life diversified from a few simple organisms to a variety of to complex forms. Today, scientists agree that all current life descends from earlier life, which has become progressively more complex and diverse through [[Charles Darwin]]'s mechanism of [[evolution]] by [[natural selection]].

By the middle of the 19th century, biogenesis had accumulated so much evidence in support that the alternative theory of spontaneous generation had been effectively disproven. [[Louis Pasteur|Pasteur]] remarked, about a finding of his in 1864 which he considered definitive, < blockquote >Never will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment.<ref>{{harvnb|Oparin|1953|p=196}}</ref><ref name="Tyndall Fragments2">{{harvnb|Tyndall|1905|loc=IV, XII (1876), XIII (1878)}}</ref> < /blockquote >gave a mechanism by which life diversified from a few simple organisms to a variety of to complex forms. Today, scientists agree that all current life descends from earlier life, which has become progressively more complex and diverse through [[Charles Darwin]]'s mechanism of [[evolution]] by [[natural selection]].

Darwin wrote to Hooker in 1863 stating that, <blockquote>It is mere rubbish, thinking at present of the origin of life; one might as well think of the origin of matter.</blockquote> In ''[[On the Origin of Species]]'', he had referred to life having been "created", by which he "really meant 'appeared' by some wholly unknown process", but had soon regretted using the Old Testament term "creation".{{Citation needed|date=July 2020}}

Darwin wrote to Hooker in 1863 stating that, < blockquote >It is mere rubbish, thinking at present of the origin of life; one might as well think of the origin of matter.< /blockquote > In ''[[On the Origin of Species]]'', he had referred to life having been "created", by which he "really meant 'appeared' by some wholly unknown process", but had soon regretted using the Old Testament term "creation".{{Citation needed|date=July 2020}}

到19世纪中叶，生物发生学已经积累了大量的证据，以至于自然发生的替代理论已经被有效地否定。Pasteur说，他在1864年的一项发现被他认为是决定性的：

到19世纪中叶，生物发生学已经积累了大量的证据，以至于自然发生的替代理论已经被有效地否定。Pasteur说，他在1864年的一项发现被他认为是决定性的：

<blockquote>

< blockquote >

生物起源的学说永远不会从这个简单的实验所带来的致命打击中恢复过来。

生物起源的学说永远不会从这个简单的实验所带来的致命打击中恢复过来。

<blockquote>

< blockquote >

实验给出了一个机制，通过这个机制，生命从几个简单的生物体多样化到各种复杂的形式。今天，科学家们一致认为，目前所有的生命都是早期生命的后裔，而早期生命通过Charles Darwin的自然选择进化机制，逐渐变得更加复杂和多样化。Darwin在1863年给Hooker写信指出：

实验给出了一个机制，通过这个机制，生命从几个简单的生物体多样化到各种复杂的形式。今天，科学家们一致认为，目前所有的生命都是早期生命的后裔，而早期生命通过Charles Darwin的自然选择进化机制，逐渐变得更加复杂和多样化。Darwin在1863年给Hooker写信指出：

<blockquote>

< blockquote >

目前思考生命的起源只是垃圾，还不如思考物质的起源。

目前思考生命的起源只是垃圾，还不如思考物质的起源。

<blockquote>

< blockquote >

在《物种起源》中，他曾提到生命是 "被创造的"，他说生命是“被创造出来的”，“实际上是指通过某种完全未知的过程‘出现’”，但很快就后悔使用旧约中的“创造”一词但很快就后悔使用《旧约》中的 "创造 "一词。

在《物种起源》中，他曾提到生命是 "被创造的"，他说生命是“被创造出来的”，“实际上是指通过某种完全未知的过程‘出现’”，但很快就后悔使用旧约中的“创造”一词但很快就后悔使用《旧约》中的 "创造 "一词。

{{further|Miller–Urey experiment}}

{{further|Miller–Urey experiment}}

There is no single generally accepted model for the origin of life. Scientists have proposed several plausible hypotheses which share some common elements. While differing in details, these hypotheses are based on the framework laid out by [[Alexander Oparin]] (in 1924) and [[J. B. S. Haldane|John Haldane]] (in 1925), that the first molecules constituting the earliest cells <blockquote>. . . were synthesized under natural conditions by a slow process of molecular evolution, and these molecules then organized into the first molecular system with properties with biological order".<ref name="bah2">{{cite journal|last=Bahadur|first=Krishna|year=1973|title=Photochemical Formation of Self–sustaining Coacervates|url=http://www.dli.gov.in/rawdataupload/upload/insa/INSA_1/20005b73_455.pdf|url-status=dead|journal=Proceedings of the Indian National Science Academy|volume=39B|issue=4|pages=455–467|doi=10.1016/S0044-4057(75)80076-1|pmid=1242552|archiveurl=https://web.archive.org/web/20131019172800/http://www.dli.gov.in/rawdataupload/upload/insa/INSA_1/20005b73_455.pdf|archivedate=19 October 2013}}

There is no single generally accepted model for the origin of life. Scientists have proposed several plausible hypotheses which share some common elements. While differing in details, these hypotheses are based on the framework laid out by [[Alexander Oparin]] (in 1924) and [[J. B. S. Haldane|John Haldane]] (in 1925), that the first molecules constituting the earliest cells < blockquote >. . . were synthesized under natural conditions by a slow process of molecular evolution, and these molecules then organized into the first molecular system with properties with biological order".<ref name="bah2">{{cite journal|last=Bahadur|first=Krishna|year=1973|title=Photochemical Formation of Self–sustaining Coacervates|url=http://www.dli.gov.in/rawdataupload/upload/insa/INSA_1/20005b73_455.pdf|url-status=dead|journal=Proceedings of the Indian National Science Academy|volume=39B|issue=4|pages=455–467|doi=10.1016/S0044-4057(75)80076-1|pmid=1242552|archiveurl=https://web.archive.org/web/20131019172800/http://www.dli.gov.in/rawdataupload/upload/insa/INSA_1/20005b73_455.pdf|archivedate=19 October 2013}}

对于生命的起源，没有一个普遍接受的模式。科学家们提出了几种可信的假说，这些假说有一些共同的内容。这些假说虽然在细节上有所不同，但都是基于亚历山大-奥帕林Alexander Oparin(1924年)和约翰-霍尔丹John Haldane(1925年)提出的框架，即构成最早的细胞的第一批分子。

对于生命的起源，没有一个普遍接受的模式。科学家们提出了几种可信的假说，这些假说有一些共同的内容。这些假说虽然在细节上有所不同，但都是基于亚历山大-奥帕林Alexander Oparin(1924年)和约翰-霍尔丹John Haldane(1925年)提出的框架，即构成最早的细胞的第一批分子。

<blockquote>

< blockquote >

...是在自然条件下通过缓慢的分子进化过程合成的，然后这些分子组成第一个具有生物秩序特性的分子系统"。

...是在自然条件下通过缓慢的分子进化过程合成的，然后这些分子组成第一个具有生物秩序特性的分子系统"。

<blockquote>

< blockquote >

* {{cite journal|last=Bahadur|first=Krishna|year=1975|title=Photochemical Formation of Self-Sustaining Coacervates|journal=[[Microbiological Research|Zentralblatt für Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene]]|volume=130|issue=3|pages=211–218|doi=10.1016/S0044-4057(75)80076-1|oclc=641018092|pmid=1242552}}</ref> </blockquote>Oparin and Haldane suggested that the atmosphere of the early Earth may have been chemically reducing in nature, composed primarily of methane (CH₄), ammonia (NH₃), water (H₂O), hydrogen sulfide (H₂S), carbon dioxide (CO₂) or carbon monoxide (CO), and [[phosphate]] (PO₄³⁻), with molecular oxygen (O₂) and [[ozone]] (O₃) either rare or absent. According to later models, the atmosphere in the late Hadean period consisted largely of nitrogen (N₂) and carbon dioxide, with smaller amounts of carbon monoxide, hydrogen (H₂), and sulfur compounds;<ref>{{harvnb|Kasting|1993|p=922}}</ref> while it did lack molecular oxygen and ozone,<ref>{{harvnb|Kasting|1993|p=920}}</ref> it was not as chemically reducing as Oparin and Haldane supposed.

* {{cite journal|last=Bahadur|first=Krishna|year=1975|title=Photochemical Formation of Self-Sustaining Coacervates|journal=[[Microbiological Research|Zentralblatt für Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene]]|volume=130|issue=3|pages=211–218|doi=10.1016/S0044-4057(75)80076-1|oclc=641018092|pmid=1242552}}</ref> < /blockquote >Oparin and Haldane suggested that the atmosphere of the early Earth may have been chemically reducing in nature, composed primarily of methane (CH₄), ammonia (NH₃), water (H₂O), hydrogen sulfide (H₂S), carbon dioxide (CO₂) or carbon monoxide (CO), and [[phosphate]] (PO₄³⁻), with molecular oxygen (O₂) and [[ozone]] (O₃) either rare or absent. According to later models, the atmosphere in the late Hadean period consisted largely of nitrogen (N₂) and carbon dioxide, with smaller amounts of carbon monoxide, hydrogen (H₂), and sulfur compounds;<ref>{{harvnb|Kasting|1993|p=922}}</ref> while it did lack molecular oxygen and ozone,<ref>{{harvnb|Kasting|1993|p=920}}</ref> it was not as chemically reducing as Oparin and Haldane supposed.

Oparin和Haldane提出，早期地球的大气可能具有化学还原性，主要由甲烷(CH₄)、氨(NH₃)、水(H₂O)、硫化氢(H₂S、二氧化碳(CO₂)或一氧化碳(CO)和磷酸盐(PO₄³⁻)组成，氧气(O₂)和臭氧(O₃)很少或没有。根据后来的模型，冥古代晚期的大气主要由氮气(N₂)和二氧化碳组成，还有少量的一氧化碳、氢气(H₂)和硫磺化合物;虽然它确实缺乏分子氧和臭氧，但它并不像Oparin和Haldane所认为的那样具有化学还原性。

Oparin和Haldane提出，早期地球的大气可能具有化学还原性，主要由甲烷(CH₄)、氨(NH₃)、水(H₂O)、硫化氢(H₂S、二氧化碳(CO₂)或一氧化碳(CO)和磷酸盐(PO₄³⁻)组成，氧气(O₂)和臭氧(O₃)很少或没有。根据后来的模型，冥古代晚期的大气主要由氮气(N₂)和二氧化碳组成，还有少量的一氧化碳、氢气(H₂)和硫磺化合物;虽然它确实缺乏分子氧和臭氧，但它并不像Oparin和Haldane所认为的那样具有化学还原性。

== Primordial origin of biological molecules: Chemistry ==

== Primordial origin of biological molecules: Chemistry ==

生物分子的原始起源： 化学

生物分子的原始起源： 化学  

The chemical processes on the pre-biotic early Earth are called [[chemical evolution (disambiguation)|''chemical evolution'']].  

The chemical processes on the pre-biotic early Earth are called [[chemical evolution (disambiguation)|''chemical evolution'']].  

====Amino acids====

====Amino acids====

氨基酸

氨基酸

NASA announced in 2009 that scientists had identified another fundamental chemical building block of life in a comet for the first time, glycine, an amino acid, which was detected in material ejected from comet [[81P/Wild|Wild 2]] in 2004 and grabbed by NASA's [[Stardust (spacecraft)|''Stardust'']] probe. Glycine has been detected in meteorites before. Carl Pilcher, who leads the [[NASA Astrobiology Institute]] commented that <blockquote>The discovery of glycine in a comet supports the idea that the fundamental building blocks of life are prevalent in space, and strengthens the argument that life in the universe may be common rather than rare.<ref>{{cite news |author=<!--Staff writer(s); no by-line.--> |date=18 August 2009 |title='Life chemical' detected in comet |url=http://news.bbc.co.uk/2/hi/science/nature/8208307.stm |work=BBC News |location=London |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20150525071228/http://news.bbc.co.uk/2/hi/science/nature/8208307.stm |archivedate=25 May 2015}}</ref></blockquote> Comets are encrusted with outer layers of dark material, thought to be a [[tar]]-like substance composed of complex organic material formed from simple carbon compounds after reactions initiated mostly by ionizing radiation. It is possible that a rain of material from comets could have brought significant quantities of such complex organic molecules to Earth.<ref>{{cite journal |last1=Thompson |first1=William Reid |last2=Murray |first2=B. G. |last3=Khare |first3=Bishun Narain |authorlink3=Bishun Khare |last4=Sagan |first4=Carl |date=30 December 1987 |title=Coloration and darkening of methane clathrate and other ices by charged particle irradiation: Applications to the outer solar system |journal=[[Journal of Geophysical Research]] |volume=92 |issue=A13 |pages=14933–14947 |bibcode=1987JGR....9214933T |doi=10.1029/JA092iA13p14933 |pmid=11542127}}</ref><ref>{{cite web |url=https://www.llnl.gov/news/life-earth-shockingly-comes-out-world |title=Life on Earth shockingly comes from out of this world |last=Stark |first=Anne M. |date=5 June 2013 |publisher=[[Lawrence Livermore National Laboratory]] |location=Livermore, CA |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20150916135630/https://www.llnl.gov/news/life-earth-shockingly-comes-out-world |archivedate=16 September 2015}}</ref><ref>{{cite journal |last1=Goldman |first1=Nir |last2=Tamblyn |first2=Isaac |date=20 June 2013 |title=Prebiotic Chemistry within a Simple Impacting Icy Mixture |journal=[[Journal of Physical Chemistry A]] |volume=117 |issue=24 |pages=5124–5131 |doi=10.1021/jp402976n |pmid=23639050|bibcode=2013JPCA..117.5124G |url=http://nparc.nrc-cnrc.gc.ca/eng/view/fulltext/?id=e89d2ac7-4cf8-40e0-bcc9-3c53f68ed70a }}</ref> Amino acids which were formed extraterrestrially may also have arrived on Earth via comets.<ref name="Follmann2009" /> It is estimated that during the Late Heavy Bombardment, meteorites may have delivered up to five million [[ton]]s of organic prebiotic elements to Earth per year.<ref name="Follmann2009" />

NASA announced in 2009 that scientists had identified another fundamental chemical building block of life in a comet for the first time, glycine, an amino acid, which was detected in material ejected from comet [[81P/Wild|Wild 2]] in 2004 and grabbed by NASA's [[Stardust (spacecraft)|''Stardust'']] probe. Glycine has been detected in meteorites before. Carl Pilcher, who leads the [[NASA Astrobiology Institute]] commented that < blockquote >The discovery of glycine in a comet supports the idea that the fundamental building blocks of life are prevalent in space, and strengthens the argument that life in the universe may be common rather than rare.<ref>{{cite news |author=<!--Staff writer(s); no by-line.--> |date=18 August 2009 |title='Life chemical' detected in comet |url=http://news.bbc.co.uk/2/hi/science/nature/8208307.stm |work=BBC News |location=London |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20150525071228/http://news.bbc.co.uk/2/hi/science/nature/8208307.stm |archivedate=25 May 2015}}</ref>< /blockquote > Comets are encrusted with outer layers of dark material, thought to be a [[tar]]-like substance composed of complex organic material formed from simple carbon compounds after reactions initiated mostly by ionizing radiation. It is possible that a rain of material from comets could have brought significant quantities of such complex organic molecules to Earth.<ref>{{cite journal |last1=Thompson |first1=William Reid |last2=Murray |first2=B. G. |last3=Khare |first3=Bishun Narain |authorlink3=Bishun Khare |last4=Sagan |first4=Carl |date=30 December 1987 |title=Coloration and darkening of methane clathrate and other ices by charged particle irradiation: Applications to the outer solar system |journal=[[Journal of Geophysical Research]] |volume=92 |issue=A13 |pages=14933–14947 |bibcode=1987JGR....9214933T |doi=10.1029/JA092iA13p14933 |pmid=11542127}}</ref><ref>{{cite web |url=https://www.llnl.gov/news/life-earth-shockingly-comes-out-world |title=Life on Earth shockingly comes from out of this world |last=Stark |first=Anne M. |date=5 June 2013 |publisher=[[Lawrence Livermore National Laboratory]] |location=Livermore, CA |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20150916135630/https://www.llnl.gov/news/life-earth-shockingly-comes-out-world |archivedate=16 September 2015}}</ref><ref>{{cite journal |last1=Goldman |first1=Nir |last2=Tamblyn |first2=Isaac |date=20 June 2013 |title=Prebiotic Chemistry within a Simple Impacting Icy Mixture |journal=[[Journal of Physical Chemistry A]] |volume=117 |issue=24 |pages=5124–5131 |doi=10.1021/jp402976n |pmid=23639050|bibcode=2013JPCA..117.5124G |url=http://nparc.nrc-cnrc.gc.ca/eng/view/fulltext/?id=e89d2ac7-4cf8-40e0-bcc9-3c53f68ed70a }}</ref> Amino acids which were formed extraterrestrially may also have arrived on Earth via comets.<ref name="Follmann2009" /> It is estimated that during the Late Heavy Bombardment, meteorites may have delivered up to five million [[ton]]s of organic prebiotic elements to Earth per year.<ref name="Follmann2009" />

美国宇航局在2009年宣布，科学家们首次在彗星中发现了生命的另一个基本化学构件--甘氨酸，这是一种氨基酸，在2004年从彗星野2号喷出的物质中检测到，并被美国宇航局的 "星尘 "探测器抓取。甘氨酸此前也曾在陨石中被检测到。领导美国宇航局天体生物学研究所的卡尔-皮尔彻Carl Pilcher说。

美国宇航局在2009年宣布，科学家们首次在彗星中发现了生命的另一个基本化学构件--甘氨酸，这是一种氨基酸，在2004年从彗星野2号喷出的物质中检测到，并被美国宇航局的 "星尘 "探测器抓取。甘氨酸此前也曾在陨石中被检测到。领导美国宇航局天体生物学研究所的卡尔-皮尔彻Carl Pilcher说。

==== PAH world hypothesis ====

==== PAH world hypothesis ====

多环芳烃世界假说

多环芳烃世界假说  

{{Main|PAH world hypothesis}}

{{Main|PAH world hypothesis}}

=== Chemical synthesis in the laboratory===

=== Chemical synthesis in the laboratory===

实验室中的化学合成

实验室中的化学合成  

As early as the 1860s, experiments have demonstrated that biologically relevant molecules can be produced from interaction of simple carbon sources with abundant inorganic catalysts.

As early as the 1860s, experiments have demonstrated that biologically relevant molecules can be produced from interaction of simple carbon sources with abundant inorganic catalysts.

====Synthesis based on hydrogen cyanide====

====Synthesis based on hydrogen cyanide====

基于氰化氢的合成

基于氰化氢的合成  

A research project completed in 2015 by [[John Sutherland (chemist)|John Sutherland]] and others found that a network of reactions beginning with hydrogen cyanide and hydrogen sulfide, in streams of water irradiated by UV light, could produce the chemical components of proteins and lipids, as well as those of RNA,<ref>{{cite news |last=Service |first=Robert F. |date=16 March 2015 |title=Researchers may have solved origin-of-life conundrum |url=http://news.sciencemag.org/biology/2015/03/researchers-may-have-solved-origin-life-conundrum |work=Science |type=News |location=Washington, D.C. |publisher=American Association for the Advancement of Science |accessdate=2015-07-26 |url-status=live |archiveurl=https://web.archive.org/web/20150812103559/http://news.sciencemag.org/biology/2015/03/researchers-may-have-solved-origin-life-conundrum |archivedate=12 August 2015}}</ref><ref name="patel">{{cite journal |last1=Patel |first1=Bhavesh H.|last2=Percivalle |first2=Claudia |last3=Ritson |first3=Dougal J. |last4=Duffy |first4=Colm D. |last5=Sutherland |first5=John D. |authorlink5=John Sutherland (chemist) |date=April 2015 |title=Common origins of RNA, protein and lipid precursors in a cyanosulfidic protometabolism |journal=[[Nature Chemistry]] |volume=7 |issue=4 |pages=301–307 |bibcode=2015NatCh...7..301P |doi=10.1038/nchem.2202 |pmid=25803468 |ref=harv |pmc=4568310}}</ref> while not producing a wide range of other compounds.<ref>{{harvnb|Patel|Percivalle|Ritson|Duffy|2015|p=302}}</ref> The researchers used the term "cyanosulfidic" to describe this network of reactions.<ref name="patel" />

A research project completed in 2015 by [[John Sutherland (chemist)|John Sutherland]] and others found that a network of reactions beginning with hydrogen cyanide and hydrogen sulfide, in streams of water irradiated by UV light, could produce the chemical components of proteins and lipids, as well as those of RNA,<ref>{{cite news |last=Service |first=Robert F. |date=16 March 2015 |title=Researchers may have solved origin-of-life conundrum |url=http://news.sciencemag.org/biology/2015/03/researchers-may-have-solved-origin-life-conundrum |work=Science |type=News |location=Washington, D.C. |publisher=American Association for the Advancement of Science |accessdate=2015-07-26 |url-status=live |archiveurl=https://web.archive.org/web/20150812103559/http://news.sciencemag.org/biology/2015/03/researchers-may-have-solved-origin-life-conundrum |archivedate=12 August 2015}}</ref><ref name="patel">{{cite journal |last1=Patel |first1=Bhavesh H.|last2=Percivalle |first2=Claudia |last3=Ritson |first3=Dougal J. |last4=Duffy |first4=Colm D. |last5=Sutherland |first5=John D. |authorlink5=John Sutherland (chemist) |date=April 2015 |title=Common origins of RNA, protein and lipid precursors in a cyanosulfidic protometabolism |journal=[[Nature Chemistry]] |volume=7 |issue=4 |pages=301–307 |bibcode=2015NatCh...7..301P |doi=10.1038/nchem.2202 |pmid=25803468 |ref=harv |pmc=4568310}}</ref> while not producing a wide range of other compounds.<ref>{{harvnb|Patel|Percivalle|Ritson|Duffy|2015|p=302}}</ref> The researchers used the term "cyanosulfidic" to describe this network of reactions.<ref name="patel" />

====Issues during laboratory synthesis====

====Issues during laboratory synthesis====

实验室合成过程中的问题

实验室合成过程中的问题  

The spontaneous formation of complex polymers from abiotically generated monomers under the conditions posited by the "soup" theory is not at all a straightforward process. Besides the necessary basic organic monomers, compounds that would have prohibited the formation of polymers were also formed in high concentration during the Miller–Urey and [[Joan Oró]] experiments.<ref>{{cite journal |last1=Oró |first1=Joan |last2=Kimball |first2=Aubrey P. |date=February 1962 |title=Synthesis of purines under possible primitive earth conditions: II. Purine intermediates from hydrogen cyanide |journal=[[Archives of Biochemistry and Biophysics]] |volume=96 |issue=2 |pages=293–313 |doi=10.1016/0003-9861(62)90412-5 |pmid=14482339}}</ref> The Miller–Urey experiment, for example, produces many substances that would react with the amino acids or terminate their coupling into peptide chains.<ref>{{cite book |editor-last=Ahuja |editor-first=Mukesh |year=2006 |chapter=Origin of Life |chapterurl=https://books.google.com/books?id=VJF12TlT58kC&pg=PA11 |title=Life Science |volume=1 |location=Delhi |publisher=Isha Books |page=11 |isbn=978-81-8205-386-1 |oclc=297208106 |ref=harv}}{{Unreliable source?|reason=What material is Ahuja editing? Further, see use of Ahuja material in the Iron-sulfur world section in this WP article, among others. See also: Wikipedia talk:Noticeboard for India-related topics/Archive 42#Problem with ISHA books as references|date=June 2015}}</ref>

The spontaneous formation of complex polymers from abiotically generated monomers under the conditions posited by the "soup" theory is not at all a straightforward process. Besides the necessary basic organic monomers, compounds that would have prohibited the formation of polymers were also formed in high concentration during the Miller–Urey and [[Joan Oró]] experiments.<ref>{{cite journal |last1=Oró |first1=Joan |last2=Kimball |first2=Aubrey P. |date=February 1962 |title=Synthesis of purines under possible primitive earth conditions: II. Purine intermediates from hydrogen cyanide |journal=[[Archives of Biochemistry and Biophysics]] |volume=96 |issue=2 |pages=293–313 |doi=10.1016/0003-9861(62)90412-5 |pmid=14482339}}</ref> The Miller–Urey experiment, for example, produces many substances that would react with the amino acids or terminate their coupling into peptide chains.<ref>{{cite book |editor-last=Ahuja |editor-first=Mukesh |year=2006 |chapter=Origin of Life |chapterurl=https://books.google.com/books?id=VJF12TlT58kC&pg=PA11 |title=Life Science |volume=1 |location=Delhi |publisher=Isha Books |page=11 |isbn=978-81-8205-386-1 |oclc=297208106 |ref=harv}}{{Unreliable source?|reason=What material is Ahuja editing? Further, see use of Ahuja material in the Iron-sulfur world section in this WP article, among others. See also: Wikipedia talk:Noticeboard for India-related topics/Archive 42#Problem with ISHA books as references|date=June 2015}}</ref>

=== Autocatalysis ===

=== Autocatalysis ===

自催化

自催化  

{{Main|Autocatalysis}}

{{Main|Autocatalysis}}

====Membraneless polyester droplets====

====Membraneless polyester droplets====

无膜聚酯液滴

无膜聚酯液滴

Researchers Tony Jia and Kuhan Chandru<ref>{{cite journal |last1=Jia |first1=Tony Z. |last2=Chandru |first2=Kuhan |last3=Hongo |first3=Yayoi |last4=Afrin |first4=Rehana |last5=Usui |first5=Tomohiro |last6=Myojo |first6=Kunihiro |last7=Cleaves |first7=H. James |title=Membraneless polyester microdroplets as primordial compartments at the origins of life |journal=Proceedings of the National Academy of Sciences |volume=116 |issue=32 |date=22 July 2019 |pages=15830–15835 |doi=10.1073/pnas.1902336116|pmid=31332006 |pmc=6690027 }}</ref> have proposed that membraneless polyesters droplets could have been significant in the Origins of Life.<ref>{{Cite journal|last1=Chandru|first1=Kuhan|last2=Mamajanov|first2=Irena|last3=Cleaves|first3=H. James|last4=Jia|first4=Tony Z.|date=January 2020|title=Polyesters as a Model System for Building Primitive Biologies from Non-Biological Prebiotic Chemistry|journal=Life|language=en|volume=10|issue=1|pages=6|doi=10.3390/life10010006|pmc=7175156|pmid=31963928}}</ref> Given the "messy" nature of prebiotic chemistry,<ref>{{cite web |last1=Marc |first1=Kaufman |title=NASA Astrobiology |url=https://astrobiology.nasa.gov/news/messy-chemistry-a-new-way-to-approach-the-origins-of-life/|date = 18 July 2019 |website=astrobiology.nasa.gov |language=en-EN}}</ref><ref>{{cite journal |last1=Guttenberg |first1=Nicholas |last2=Virgo |first2=Nathaniel |last3=Chandru |first3=Kuhan |last4=Scharf |first4=Caleb |last5=Mamajanov |first5=Irena |title=Bulk measurements of messy chemistries are needed for a theory of the origins of life |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |date=13 November 2017 |volume=375 |issue=2109 |pages=20160347 |doi=10.1098/rsta.2016.0347|pmid=29133446 |pmc=5686404 |bibcode=2017RSPTA.37560347G }}</ref> the spontaneous generation of these combinatorial droplets may have played a role in early cellularization before the innovation of lipid vesicles. Protein function within and RNA function in the presence of certain polyester droplets was shown to be preserved within the droplets. Additionally, the droplets have scaffolding ability, by allowing lipids to assemble around them that may have prevented leakage of genetic materials.

Researchers Tony Jia and Kuhan Chandru<ref>{{cite journal |last1=Jia |first1=Tony Z. |last2=Chandru |first2=Kuhan |last3=Hongo |first3=Yayoi |last4=Afrin |first4=Rehana |last5=Usui |first5=Tomohiro |last6=Myojo |first6=Kunihiro |last7=Cleaves |first7=H. James |title=Membraneless polyester microdroplets as primordial compartments at the origins of life |journal=Proceedings of the National Academy of Sciences |volume=116 |issue=32 |date=22 July 2019 |pages=15830–15835 |doi=10.1073/pnas.1902336116|pmid=31332006 |pmc=6690027 }}</ref> have proposed that membraneless polyesters droplets could have been significant in the Origins of Life.<ref>{{Cite journal|last1=Chandru|first1=Kuhan|last2=Mamajanov|first2=Irena|last3=Cleaves|first3=H. James|last4=Jia|first4=Tony Z.|date=January 2020|title=Polyesters as a Model System for Building Primitive Biologies from Non-Biological Prebiotic Chemistry|journal=Life|language=en|volume=10|issue=1|pages=6|doi=10.3390/life10010006|pmc=7175156|pmid=31963928}}</ref> Given the "messy" nature of prebiotic chemistry,<ref>{{cite web |last1=Marc |first1=Kaufman |title=NASA Astrobiology |url=https://astrobiology.nasa.gov/news/messy-chemistry-a-new-way-to-approach-the-origins-of-life/|date = 18 July 2019 |website=astrobiology.nasa.gov |language=en-EN}}</ref><ref>{{cite journal |last1=Guttenberg |first1=Nicholas |last2=Virgo |first2=Nathaniel |last3=Chandru |first3=Kuhan |last4=Scharf |first4=Caleb |last5=Mamajanov |first5=Irena |title=Bulk measurements of messy chemistries are needed for a theory of the origins of life |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |date=13 November 2017 |volume=375 |issue=2109 |pages=20160347 |doi=10.1098/rsta.2016.0347|pmid=29133446 |pmc=5686404 |bibcode=2017RSPTA.37560347G }}</ref> the spontaneous generation of these combinatorial droplets may have played a role in early cellularization before the innovation of lipid vesicles. Protein function within and RNA function in the presence of certain polyester droplets was shown to be preserved within the droplets. Additionally, the droplets have scaffolding ability, by allowing lipids to assemble around them that may have prevented leakage of genetic materials.

=== Lipid vesicles formation in fresh water ===

=== Lipid vesicles formation in fresh water ===

淡水中脂质泡的形成

淡水中脂质泡的形成  

[[Bruce Damer]] and [[David Deamer]] have come to the conclusion that [[cell membrane]]s cannot be formed in salty [[seawater]], and must therefore have originated in freshwater. Before the continents formed, the only dry land on Earth would be volcanic islands, where rainwater would form ponds where lipids could form the first stages towards cell membranes. These predecessors of true cells are assumed to have behaved more like a [[superorganism]] rather than individual structures, where the porous membranes would house molecules which would leak out and enter other protocells. Only when true cells had evolved would they gradually adapt to saltier environments and enter the ocean.<ref>{{cite journal |last1=Damer |first1=Bruce |last2=Deamer |first2=David |date=13 March 2015 |title=Coupled Phases and Combinatorial Selection in Fluctuating Hydrothermal Pools: A Scenario to Guide Experimental Approaches to the Origin of Cellular Life |journal=Life |volume=5 |issue=1 |pages=872–887 |doi=10.3390/life5010872 |pmc=4390883 |pmid=25780958}}</ref>

[[Bruce Damer]] and [[David Deamer]] have come to the conclusion that [[cell membrane]]s cannot be formed in salty [[seawater]], and must therefore have originated in freshwater. Before the continents formed, the only dry land on Earth would be volcanic islands, where rainwater would form ponds where lipids could form the first stages towards cell membranes. These predecessors of true cells are assumed to have behaved more like a [[superorganism]] rather than individual structures, where the porous membranes would house molecules which would leak out and enter other protocells. Only when true cells had evolved would they gradually adapt to saltier environments and enter the ocean.<ref>{{cite journal |last1=Damer |first1=Bruce |last2=Deamer |first2=David |date=13 March 2015 |title=Coupled Phases and Combinatorial Selection in Fluctuating Hydrothermal Pools: A Scenario to Guide Experimental Approaches to the Origin of Cellular Life |journal=Life |volume=5 |issue=1 |pages=872–887 |doi=10.3390/life5010872 |pmc=4390883 |pmid=25780958}}</ref>

金属硫化物沉淀物

金属硫化物沉淀物

William Martin and [[Michael Russell (scientist)|Michael Russell]] have suggested <blockquote>. . . . that life evolved in structured iron monosulphide precipitates in a seepage site hydrothermal mound at a redox, pH, and temperature gradient between sulphide-rich hydrothermal fluid and iron(II)-containing waters of the Hadean ocean floor. The naturally arising, three-dimensional compartmentation observed within fossilized seepage-site metal sulphide precipitates indicates that these inorganic compartments were the precursors of cell walls and membranes found in free-living prokaryotes. The known capability of FeS and NiS to catalyze the synthesis of the acetyl-methylsulphide from carbon monoxide and methylsulphide, constituents of hydrothermal fluid, indicates that pre-biotic syntheses occurred at the inner surfaces of these metal-sulphide-walled compartments,..."<ref name="Martin2003">{{cite journal |last1=Martin |first1=William |authorlink1=William F. Martin |last2=Russell |first2=Michael J. |date=29 January 2003 |title=On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells |journal=Philosophical Transactions of the Royal Society B |volume=358 |issue=1429 |pages=59–83; discussion 83–85 |doi=10.1098/rstb.2002.1183|pmid=12594918 |pmc=1693102}}</ref> </blockquote>

William Martin and [[Michael Russell (scientist)|Michael Russell]] have suggested < blockquote >. . . . that life evolved in structured iron monosulphide precipitates in a seepage site hydrothermal mound at a redox, pH, and temperature gradient between sulphide-rich hydrothermal fluid and iron(II)-containing waters of the Hadean ocean floor. The naturally arising, three-dimensional compartmentation observed within fossilized seepage-site metal sulphide precipitates indicates that these inorganic compartments were the precursors of cell walls and membranes found in free-living prokaryotes. The known capability of FeS and NiS to catalyze the synthesis of the acetyl-methylsulphide from carbon monoxide and methylsulphide, constituents of hydrothermal fluid, indicates that pre-biotic syntheses occurred at the inner surfaces of these metal-sulphide-walled compartments,..."<ref name="Martin2003">{{cite journal |last1=Martin |first1=William |authorlink1=William F. Martin |last2=Russell |first2=Michael J. |date=29 January 2003 |title=On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells |journal=Philosophical Transactions of the Royal Society B |volume=358 |issue=1429 |pages=59–83; discussion 83–85 |doi=10.1098/rstb.2002.1183|pmid=12594918 |pmc=1693102}}</ref> < /blockquote >

William Martin和Michael Russell说

William Martin和Michael Russell说

===Darwin's little pond===

===Darwin's little pond===

Darwin的小池塘

Darwin的小池塘

An early concept, that life originated from non-living matter in slow stages, appeared in [[Herbert Spencer]]'s 1864–1867 book ''Principles of Biology''. In 1879 [[William Turner Thiselton-Dyer]] referred to this in a paper "On spontaneous generation and evolution". On 1 February 1871 [[Charles Darwin]] wrote about these publications to [[Joseph Dalton Hooker|Joseph Hooker]], and set out his own speculation,<ref name="Darwin DCP-LETT-7471">{{cite web | title=Letter no. 7471, Charles Darwin to Joseph Dalton Hooker, 1 February (1871) | website=Darwin Correspondence Project | date= | url=https://www.darwinproject.ac.uk/letter/DCP-LETT-7471.xml | access-date=7 July 2020}}</ref><ref>{{cite web|url=https://www.nsf.gov/news/special_reports/darwin/textonly/polar_essay1.jsp|title=Origin and Evolution of Life on a Frozen Earth|last=Priscu|first=John C.|authorlink=John Charles Priscu|publisher=[[National Science Foundation]]|location=Arlington County, VA|archiveurl=https://web.archive.org/web/20131218070241/http://www.nsf.gov/news/special_reports/darwin/textonly/polar_essay1.jsp|archivedate=18 December 2013|url-status=live|accessdate=2014-03-01}}</ref> suggesting that the original spark of life may have begun in a <blockquote>warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, {{sic|hide=y|&c.}}, present, that a {{sic|hide=y|[[protein]]e}} compound was chemically formed ready to undergo still more complex changes.</blockquote> He went on to explain that <blockquote>at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed.</blockquote>

An early concept, that life originated from non-living matter in slow stages, appeared in [[Herbert Spencer]]'s 1864–1867 book ''Principles of Biology''. In 1879 [[William Turner Thiselton-Dyer]] referred to this in a paper "On spontaneous generation and evolution". On 1 February 1871 [[Charles Darwin]] wrote about these publications to [[Joseph Dalton Hooker|Joseph Hooker]], and set out his own speculation,<ref name="Darwin DCP-LETT-7471">{{cite web | title=Letter no. 7471, Charles Darwin to Joseph Dalton Hooker, 1 February (1871) | website=Darwin Correspondence Project | date= | url=https://www.darwinproject.ac.uk/letter/DCP-LETT-7471.xml | access-date=7 July 2020}}</ref><ref>{{cite web|url=https://www.nsf.gov/news/special_reports/darwin/textonly/polar_essay1.jsp|title=Origin and Evolution of Life on a Frozen Earth|last=Priscu|first=John C.|authorlink=John Charles Priscu|publisher=[[National Science Foundation]]|location=Arlington County, VA|archiveurl=https://web.archive.org/web/20131218070241/http://www.nsf.gov/news/special_reports/darwin/textonly/polar_essay1.jsp|archivedate=18 December 2013|url-status=live|accessdate=2014-03-01}}</ref> suggesting that the original spark of life may have begun in a < blockquote >warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, {{sic|hide=y|&c.}}, present, that a {{sic|hide=y|[[protein]]e}} compound was chemically formed ready to undergo still more complex changes.< /blockquote > He went on to explain that < blockquote >at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed.< /blockquote >

一个早期的概念，即生命起源于非生命物质的缓慢阶段，出现在Herbert Spencer 1864-1867年的《生物学原理》一书中。1879年William Turner Thiselton-Dyer在 "论自然发生和进化 "一文中提到了这一点。1871年2月1日，Charles Darwin将这些出版物写信给Joseph Hooker，并提出了自己的推测，认为生命的最初火花可能是始于

一个早期的概念，即生命起源于非生命物质的缓慢阶段，出现在Herbert Spencer 1864-1867年的《生物学原理》一书中。1879年William Turner Thiselton-Dyer在 "论自然发生和进化 "一文中提到了这一点。1871年2月1日，Charles Darwin将这些出版物写信给Joseph Hooker，并提出了自己的推测，认为生命的最初火花可能是始于

他继续解释说，

他继续解释说，

  <blockquote>

  < blockquote >

在今天，这种物质会被立即吞噬或吸收，而在生物形成之前是不会有这种情况的。

在今天，这种物质会被立即吞噬或吸收，而在生物形成之前是不会有这种情况的。

  <blockquote>

  < blockquote >

{{harvnb|Darwin|1887|p=[http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F1452.3&pageseq=30 18]}}:

{{harvnb|Darwin|1887|p=[http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F1452.3&pageseq=30 18]}}:

深海热液喷口或黑烟

深海热液喷口或黑烟

The deep sea vent, or alkaline [[hydrothermal vent]], theory posits that life may have begun at submarine hydrothermal vents,<ref name=":1">{{Cite journal|author1=Colín-García, M.|author2=A. Heredia|author3=G. Cordero|author4=A. Camprubí|author5=A. Negrón-Mendoza|author6=F. Ortega-Gutiérrez|author7=H. Berald|author8=S. Ramos-Bernal|year=2016|title=Hydrothermal vents and prebiotic chemistry: a review|url=http://boletinsgm.igeolcu.unam.mx/bsgm/index.php/component/content/article/309-sitio/articulos/cuarta-epoca/6803/1620-6803-13-colin|journal=Boletín de la Sociedad Geológica Mexicana|volume=68|issue=3|pages=599–620|url-status=live|archiveurl=https://web.archive.org/web/20170818175803/http://boletinsgm.igeolcu.unam.mx/bsgm/index.php/component/content/article/309-sitio/articulos/cuarta-epoca/6803/1620-6803-13-colin|archivedate=18 August 2017|doi=10.18268/BSGM2016v68n3a13|doi-access=free}}</ref><ref name="hydrothermal vents NASA 2014">{{cite web|url=https://astrobiology.nasa.gov/articles/2014/6/24/hydrothermal-vents-could-explain-chemical-precursors-to-life/ |title=Hydrothermal Vents Could Explain Chemical Precursors to Life |last=Schirber |first=Michael |date=24 June 2014 |website=NASA Astrobiology: Life in the Universe |publisher=NASA |accessdate=2015-06-19 |url-status=dead |archiveurl=https://web.archive.org/web/20141129051724/http://astrobiology.nasa.gov/articles/2014/6/24/hydrothermal-vents-could-explain-chemical-precursors-to-life/ |archivedate=29 November 2014}}</ref>  Martin and Russell have suggested <blockquote>that life evolved in structured iron monosulphide precipitates in a seepage site hydrothermal mound at a redox, pH, and temperature gradient between sulphide-rich hydrothermal fluid and iron(II)-containing waters of the Hadean ocean floor. The naturally arising, three-dimensional compartmentation observed within fossilized seepage-site metal sulphide precipitates indicates that these inorganic compartments were the precursors of cell walls and membranes found in free-living prokaryotes. The known capability of FeS and NiS to catalyze the synthesis of the acetyl-methylsulphide from carbon monoxide and methylsulphide, constituents of hydrothermal fluid, indicates that pre-biotic syntheses occurred at the inner surfaces of these metal-sulphide-walled compartments,...<ref name="Martin2003" /></blockquote> These form where hydrogen-rich fluids emerge from below the sea floor, as a result of [[Serpentinite|serpentinization]] of ultra-[[mafic]] [[olivine]] with seawater and a pH interface with carbon dioxide-rich ocean water. The vents form a sustained chemical energy source derived from redox reactions, in which electron donors (molecular hydrogen) react with electron acceptors (carbon dioxide); see [[Iron–sulfur world theory]]. These are highly [[exothermic reaction]]s.<ref name=":1" />{{efn|The reactions are:<br />

The deep sea vent, or alkaline [[hydrothermal vent]], theory posits that life may have begun at submarine hydrothermal vents,<ref name=":1">{{Cite journal|author1=Colín-García, M.|author2=A. Heredia|author3=G. Cordero|author4=A. Camprubí|author5=A. Negrón-Mendoza|author6=F. Ortega-Gutiérrez|author7=H. Berald|author8=S. Ramos-Bernal|year=2016|title=Hydrothermal vents and prebiotic chemistry: a review|url=http://boletinsgm.igeolcu.unam.mx/bsgm/index.php/component/content/article/309-sitio/articulos/cuarta-epoca/6803/1620-6803-13-colin|journal=Boletín de la Sociedad Geológica Mexicana|volume=68|issue=3|pages=599–620|url-status=live|archiveurl=https://web.archive.org/web/20170818175803/http://boletinsgm.igeolcu.unam.mx/bsgm/index.php/component/content/article/309-sitio/articulos/cuarta-epoca/6803/1620-6803-13-colin|archivedate=18 August 2017|doi=10.18268/BSGM2016v68n3a13|doi-access=free}}</ref><ref name="hydrothermal vents NASA 2014">{{cite web|url=https://astrobiology.nasa.gov/articles/2014/6/24/hydrothermal-vents-could-explain-chemical-precursors-to-life/ |title=Hydrothermal Vents Could Explain Chemical Precursors to Life |last=Schirber |first=Michael |date=24 June 2014 |website=NASA Astrobiology: Life in the Universe |publisher=NASA |accessdate=2015-06-19 |url-status=dead |archiveurl=https://web.archive.org/web/20141129051724/http://astrobiology.nasa.gov/articles/2014/6/24/hydrothermal-vents-could-explain-chemical-precursors-to-life/ |archivedate=29 November 2014}}</ref>  Martin and Russell have suggested < blockquote >that life evolved in structured iron monosulphide precipitates in a seepage site hydrothermal mound at a redox, pH, and temperature gradient between sulphide-rich hydrothermal fluid and iron(II)-containing waters of the Hadean ocean floor. The naturally arising, three-dimensional compartmentation observed within fossilized seepage-site metal sulphide precipitates indicates that these inorganic compartments were the precursors of cell walls and membranes found in free-living prokaryotes. The known capability of FeS and NiS to catalyze the synthesis of the acetyl-methylsulphide from carbon monoxide and methylsulphide, constituents of hydrothermal fluid, indicates that pre-biotic syntheses occurred at the inner surfaces of these metal-sulphide-walled compartments,...<ref name="Martin2003" />< /blockquote > These form where hydrogen-rich fluids emerge from below the sea floor, as a result of [[Serpentinite|serpentinization]] of ultra-[[mafic]] [[olivine]] with seawater and a pH interface with carbon dioxide-rich ocean water. The vents form a sustained chemical energy source derived from redox reactions, in which electron donors (molecular hydrogen) react with electron acceptors (carbon dioxide); see [[Iron–sulfur world theory]]. These are highly [[exothermic reaction]]s.<ref name=":1" />{{efn|The reactions are:<br />

深海喷口或碱性热液喷口理论认为生命可能始于海底热液喷口，Martin和Russell认为

深海喷口或碱性热液喷口理论认为生命可能始于海底热液喷口，Martin和Russell认为

<blockquote>

< blockquote >

生命是在一个渗漏点热液丘中的结构化单硫化铁沉淀物中演化出来的，其氧化还原、pH值和温度梯度介于富含硫化物的热液和哈丹洋底的含铁(II)水之间。在化石渗出地金属硫化物沉淀物中观察到的自然生成的三维分层表明，这些无机分层是自由生活的原核生物中发现的细胞壁和膜的前体。已知FeS和NiS能够催化一氧化碳和甲基硫化物（热液的成分）合成乙酰-甲基硫化物，这表明生物前的合成发生在这些金属硫化物壁隔室的内表面，

生命是在一个渗漏点热液丘中的结构化单硫化铁沉淀物中演化出来的，其氧化还原、pH值和温度梯度介于富含硫化物的热液和哈丹洋底的含铁(II)水之间。在化石渗出地金属硫化物沉淀物中观察到的自然生成的三维分层表明，这些无机分层是自由生活的原核生物中发现的细胞壁和膜的前体。已知FeS和NiS能够催化一氧化碳和甲基硫化物（热液的成分）合成乙酰-甲基硫化物，这表明生物前的合成发生在这些金属硫化物壁隔室的内表面，

<blockquote>

< blockquote >

这些喷口形成于富氢流体从海底下冒出的地方，是超基性橄榄石与海水发生蛇纹石化以及与富含二氧化碳的海水发生pH值界面的结果。这些喷口形成了一个来自氧化还原反应的持续化学能源，其中电子供体(分子氢)与电子受体(二氧化碳)发生反应；见铁-硫世界理论。这些都是高度放热的反应。

这些喷口形成于富氢流体从海底下冒出的地方，是超基性橄榄石与海水发生蛇纹石化以及与富含二氧化碳的海水发生pH值界面的结果。这些喷口形成了一个来自氧化还原反应的持续化学能源，其中电子供体(分子氢)与电子受体(二氧化碳)发生反应；见铁-硫世界理论。这些都是高度放热的反应。

=== Gold's deep-hot biosphere ===

=== Gold's deep-hot biosphere ===

黄金的深热生物圈

黄金的深热生物圈  

In the 1970s, [[Thomas Gold]] proposed the theory that life first developed not on the surface of the Earth, but several kilometers below the surface. It is claimed that the discovery of microbial life below the surface of another body in our Solar System would lend significant credence to this theory. Gold also asserted that a trickle of food from a deep, unreachable, source is needed for survival because life arising in a puddle of organic material is likely to consume all of its food and become extinct. Gold's theory is that the flow of such food is due to out-gassing of primordial methane from the Earth's mantle; more conventional explanations of the food supply of deep microbes (away from sedimentary carbon compounds) is that the organisms [[Microbial metabolism#Hydrogen oxidation|subsist on hydrogen]] released by an interaction between water and (reduced) iron compounds in rocks.

In the 1970s, [[Thomas Gold]] proposed the theory that life first developed not on the surface of the Earth, but several kilometers below the surface. It is claimed that the discovery of microbial life below the surface of another body in our Solar System would lend significant credence to this theory. Gold also asserted that a trickle of food from a deep, unreachable, source is needed for survival because life arising in a puddle of organic material is likely to consume all of its food and become extinct. Gold's theory is that the flow of such food is due to out-gassing of primordial methane from the Earth's mantle; more conventional explanations of the food supply of deep microbes (away from sedimentary carbon compounds) is that the organisms [[Microbial metabolism#Hydrogen oxidation|subsist on hydrogen]] released by an interaction between water and (reduced) iron compounds in rocks.

=== Radioactive beach hypothesis ===

=== Radioactive beach hypothesis ===

放射性海滩假说

放射性海滩假说  

Zachary Adam claims that tidal processes that occurred during a time when the Moon was much closer may have concentrated grains of [[uranium]] and other radioactive elements at the high-water mark on primordial beaches, where they may have been responsible for generating life's building blocks.<ref>{{cite journal |last=Dartnell |first=Lewis |date=12 January 2008 |title=Did life begin on a radioactive beach? |url=https://www.newscientist.com/article/mg19726384.000-did-life-begin-on-a-radioactive-beach.html |journal=New Scientist |issue=2638 |page=8 |accessdate=2015-06-26 |url-status=live |archiveurl=https://web.archive.org/web/20150627101858/http://www.newscientist.com/article/mg19726384.000-did-life-begin-on-a-radioactive-beach.html |archivedate=27 June 2015}}</ref> According to computer models,<ref>{{cite journal |last=Adam |first=Zachary |year=2007 |title=Actinides and Life's Origins |journal=Astrobiology |volume=7 |issue=6 |pages=852–872 |bibcode=2007AsBio...7..852A |doi=10.1089/ast.2006.0066|pmid=18163867}}</ref> a deposit of such radioactive materials could show the same [[Natural nuclear fission reactor|self-sustaining nuclear reaction]] as that found in the [[Oklo]] uranium ore seam in [[Gabon]]. Such radioactive beach sand might have provided sufficient energy to generate organic molecules, such as amino acids and sugars from [[acetonitrile]] in water. Radioactive [[monazite]] material also has released soluble phosphate into the regions between sand-grains, making it biologically "accessible." Thus amino acids, sugars, and soluble phosphates might have been produced simultaneously, according to Adam. Radioactive [[actinide]]s, left behind in some concentration by the reaction, might have formed part of [[Organometallic chemistry|organometallic complexes]]. These complexes could have been important early catalysts to living processes.

Zachary Adam claims that tidal processes that occurred during a time when the Moon was much closer may have concentrated grains of [[uranium]] and other radioactive elements at the high-water mark on primordial beaches, where they may have been responsible for generating life's building blocks.<ref>{{cite journal |last=Dartnell |first=Lewis |date=12 January 2008 |title=Did life begin on a radioactive beach? |url=https://www.newscientist.com/article/mg19726384.000-did-life-begin-on-a-radioactive-beach.html |journal=New Scientist |issue=2638 |page=8 |accessdate=2015-06-26 |url-status=live |archiveurl=https://web.archive.org/web/20150627101858/http://www.newscientist.com/article/mg19726384.000-did-life-begin-on-a-radioactive-beach.html |archivedate=27 June 2015}}</ref> According to computer models,<ref>{{cite journal |last=Adam |first=Zachary |year=2007 |title=Actinides and Life's Origins |journal=Astrobiology |volume=7 |issue=6 |pages=852–872 |bibcode=2007AsBio...7..852A |doi=10.1089/ast.2006.0066|pmid=18163867}}</ref> a deposit of such radioactive materials could show the same [[Natural nuclear fission reactor|self-sustaining nuclear reaction]] as that found in the [[Oklo]] uranium ore seam in [[Gabon]]. Such radioactive beach sand might have provided sufficient energy to generate organic molecules, such as amino acids and sugars from [[acetonitrile]] in water. Radioactive [[monazite]] material also has released soluble phosphate into the regions between sand-grains, making it biologically "accessible." Thus amino acids, sugars, and soluble phosphates might have been produced simultaneously, according to Adam. Radioactive [[actinide]]s, left behind in some concentration by the reaction, might have formed part of [[Organometallic chemistry|organometallic complexes]]. These complexes could have been important early catalysts to living processes.

在地球的早期历史中，具有不同起源过程的不同生命形式可能同时出现。其他形式可能已经灭绝(通过其不同的生物化学--如假设的生物化学类型--留下了独特的化石)。有人提出：

在地球的早期历史中，具有不同起源过程的不同生命形式可能同时出现。其他形式可能已经灭绝(通过其不同的生物化学--如假设的生物化学类型--留下了独特的化石)。有人提出：

<blockquote>The first organisms were self-replicating iron-rich clays which fixed carbon dioxide into oxalic and other [[dicarboxylic acid]]s. This system of replicating clays and their metabolic phenotype then evolved into the sulfide rich region of the hotspring acquiring the ability to fix nitrogen. Finally phosphate was incorporated into the evolving system which allowed the synthesis of nucleotides and phospholipids. If biosynthesis recapitulates biopoiesis, then the synthesis of amino acids preceded the synthesis of the purine and pyrimidine bases. Furthermore, the polymerization of the amino acid thioesters into polypeptides preceded the directed polymerization of amino acid esters by polynucleotides.<ref>{{cite journal |last=Hartman |first=Hyman |date=1998 |title=Photosynthesis and the Origin of Life |journal=Origins of Life and Evolution of Biospheres |volume=28 |issue=4–6 |pages=515–521 |bibcode=1998OLEB...28..515H |doi=10.1023/A:1006548904157 |pmid=11536891|s2cid=2464 }}</ref></blockquote>

< blockquote >The first organisms were self-replicating iron-rich clays which fixed carbon dioxide into oxalic and other [[dicarboxylic acid]]s. This system of replicating clays and their metabolic phenotype then evolved into the sulfide rich region of the hotspring acquiring the ability to fix nitrogen. Finally phosphate was incorporated into the evolving system which allowed the synthesis of nucleotides and phospholipids. If biosynthesis recapitulates biopoiesis, then the synthesis of amino acids preceded the synthesis of the purine and pyrimidine bases. Furthermore, the polymerization of the amino acid thioesters into polypeptides preceded the directed polymerization of amino acid esters by polynucleotides.<ref>{{cite journal |last=Hartman |first=Hyman |date=1998 |title=Photosynthesis and the Origin of Life |journal=Origins of Life and Evolution of Biospheres |volume=28 |issue=4–6 |pages=515–521 |bibcode=1998OLEB...28..515H |doi=10.1023/A:1006548904157 |pmid=11536891|s2cid=2464 }}</ref>< /blockquote >

<blockquote>

< blockquote >

最早的生物是自我复制的富铁粘土，它将二氧化碳固定成草酸和其他二羧酸。这种复制粘土系统及其新陈代谢表型随后进化到富含硫化物的热泉区获得了固氮的能力。最后磷酸盐被纳入进化的系统，使核苷酸和磷脂的合成成为可能。如果说生物合成重述了生物生成，那么氨基酸的合成就先于嘌呤和嘧啶碱基的合成。此外，氨基酸硫酯聚合成多肽，先于多核苷酸定向聚合氨基酸酯。

最早的生物是自我复制的富铁粘土，它将二氧化碳固定成草酸和其他二羧酸。这种复制粘土系统及其新陈代谢表型随后进化到富含硫化物的热泉区获得了固氮的能力。最后磷酸盐被纳入进化的系统，使核苷酸和磷脂的合成成为可能。如果说生物合成重述了生物生成，那么氨基酸的合成就先于嘌呤和嘧啶碱基的合成。此外，氨基酸硫酯聚合成多肽，先于多核苷酸定向聚合氨基酸酯。

Several models reject the self-replication of a "naked-gene", postulating instead the emergence of a primitive metabolism providing a safe environment for the later emergence of RNA replication. The centrality of the [[Citric acid cycle|Krebs cycle]] (citric acid cycle) to energy production in aerobic organisms, and in drawing in carbon dioxide and hydrogen ions in biosynthesis of complex organic chemicals, suggests that it was one of the first parts of the metabolism to evolve.<ref name="Lane 2009">{{harvnb|Lane|2009}}</ref> Concordantly, [[Geochemistry|geochemist]] Russell has proposed that "the purpose of life is to hydrogenate carbon dioxide" (as part of a "metabolism-first," rather than a "genetics-first," scenario). <ref name="Musser">{{cite web |url=http://blogs.scientificamerican.com/observations/how-life-arose-on-earth-and-how-a-singularity-might-bring-it-down/ |title=How Life Arose on Earth, and How a Singularity Might Bring It Down |last=Musser |first=George |authorlink=George Musser |date=23 September 2011 |work=Observations |type=Blog  |accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150617211804/http://blogs.scientificamerican.com/observations/how-life-arose-on-earth-and-how-a-singularity-might-bring-it-down/ |archivedate=17 June 2015}}</ref><ref name="Carroll">{{cite web |url=http://blogs.discovermagazine.com/cosmicvariance/2010/03/10/free-energy-and-the-meaning-of-life/ |title=Free Energy and the Meaning of Life |last=Carroll |first=Sean |authorlink=Sean M. Carroll |date=10 March 2010 |work=Cosmic Variance |type=Blog |publisher=Discover|accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150714074327/http://blogs.discovermagazine.com/cosmicvariance/2010/03/10/free-energy-and-the-meaning-of-life/ |archivedate=14 July 2015}}</ref> [[Physicist]] [[Jeremy England]] has proposed that life was inevitable from general thermodynamic considerations: <blockquote>... when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life.<ref>{{cite journal |last=Wolchover |first=Natalie |date=22 January 2014 |title=A New Physics Theory of Life |url=https://www.quantamagazine.org/20140122-a-new-physics-theory-of-life/ |journal=Quanta Magazine |accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150613052830/https://www.quantamagazine.org/20140122-a-new-physics-theory-of-life/ |archivedate=13 June 2015}}</ref><ref>{{cite journal |last=England |first=Jeremy L. |authorlink=Jeremy England |date=28 September 2013 |title=Statistical physics of self-replication |url=http://www.englandlab.com/uploads/7/8/0/3/7803054/2013jcpsrep.pdf |journal=[[Journal of Chemical Physics]] |volume=139 |issue=12 |page=121923 |arxiv=1209.1179 |bibcode=2013JChPh.139l1923E |doi=10.1063/1.4818538 |pmid=24089735  |accessdate=2015-06-18 |url-status=live |archiveurl=https://web.archive.org/web/20150604131515/http://www.englandlab.com/uploads/7/8/0/3/7803054/2013jcpsrep.pdf |archivedate=4 June 2015|hdl=1721.1/90392 |s2cid=478964 }}</ref></blockquote>

Several models reject the self-replication of a "naked-gene", postulating instead the emergence of a primitive metabolism providing a safe environment for the later emergence of RNA replication. The centrality of the [[Citric acid cycle|Krebs cycle]] (citric acid cycle) to energy production in aerobic organisms, and in drawing in carbon dioxide and hydrogen ions in biosynthesis of complex organic chemicals, suggests that it was one of the first parts of the metabolism to evolve.<ref name="Lane 2009">{{harvnb|Lane|2009}}</ref> Concordantly, [[Geochemistry|geochemist]] Russell has proposed that "the purpose of life is to hydrogenate carbon dioxide" (as part of a "metabolism-first," rather than a "genetics-first," scenario). <ref name="Musser">{{cite web |url=http://blogs.scientificamerican.com/observations/how-life-arose-on-earth-and-how-a-singularity-might-bring-it-down/ |title=How Life Arose on Earth, and How a Singularity Might Bring It Down |last=Musser |first=George |authorlink=George Musser |date=23 September 2011 |work=Observations |type=Blog  |accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150617211804/http://blogs.scientificamerican.com/observations/how-life-arose-on-earth-and-how-a-singularity-might-bring-it-down/ |archivedate=17 June 2015}}</ref><ref name="Carroll">{{cite web |url=http://blogs.discovermagazine.com/cosmicvariance/2010/03/10/free-energy-and-the-meaning-of-life/ |title=Free Energy and the Meaning of Life |last=Carroll |first=Sean |authorlink=Sean M. Carroll |date=10 March 2010 |work=Cosmic Variance |type=Blog |publisher=Discover|accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150714074327/http://blogs.discovermagazine.com/cosmicvariance/2010/03/10/free-energy-and-the-meaning-of-life/ |archivedate=14 July 2015}}</ref> [[Physicist]] [[Jeremy England]] has proposed that life was inevitable from general thermodynamic considerations: < blockquote >... when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life.<ref>{{cite journal |last=Wolchover |first=Natalie |date=22 January 2014 |title=A New Physics Theory of Life |url=https://www.quantamagazine.org/20140122-a-new-physics-theory-of-life/ |journal=Quanta Magazine |accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150613052830/https://www.quantamagazine.org/20140122-a-new-physics-theory-of-life/ |archivedate=13 June 2015}}</ref><ref>{{cite journal |last=England |first=Jeremy L. |authorlink=Jeremy England |date=28 September 2013 |title=Statistical physics of self-replication |url=http://www.englandlab.com/uploads/7/8/0/3/7803054/2013jcpsrep.pdf |journal=[[Journal of Chemical Physics]] |volume=139 |issue=12 |page=121923 |arxiv=1209.1179 |bibcode=2013JChPh.139l1923E |doi=10.1063/1.4818538 |pmid=24089735  |accessdate=2015-06-18 |url-status=live |archiveurl=https://web.archive.org/web/20150604131515/http://www.englandlab.com/uploads/7/8/0/3/7803054/2013jcpsrep.pdf |archivedate=4 June 2015|hdl=1721.1/90392 |s2cid=478964 }}</ref>< /blockquote >

有几个模型否定了 "裸基因 "的自我复制，而是假设出现了一种原始的新陈代谢，为后来出现的RNA复制提供了安全的环境。Krebs循环(柠檬酸循环)在好氧生物体内产生能量，以及在复杂有机化学物的生物合成中吸取二氧化碳和氢离子的中心地位，表明它是新陈代谢中最早进化的部分之一。 与此相一致的是，地球化学家Russell 罗素提出“生命的目的是使二氧化碳氢化”(这是“新陈代谢优先”而不是“基因优先”方案的一部分)。物理学家杰里米-英格兰Jeremy England提出，从一般的热力学考虑，生命是不可避免的：

有几个模型否定了 "裸基因 "的自我复制，而是假设出现了一种原始的新陈代谢，为后来出现的RNA复制提供了安全的环境。Krebs循环(柠檬酸循环)在好氧生物体内产生能量，以及在复杂有机化学物的生物合成中吸取二氧化碳和氢离子的中心地位，表明它是新陈代谢中最早进化的部分之一。 与此相一致的是，地球化学家Russell 罗素提出“生命的目的是使二氧化碳氢化”(这是“新陈代谢优先”而不是“基因优先”方案的一部分)。物理学家杰里米-英格兰Jeremy England提出，从一般的热力学考虑，生命是不可避免的：

Orgel summarized his analysis by stating, <blockquote>There is at present no reason to expect that multistep cycles such as the reductive citric acid cycle will self-organize on the surface of FeS/FeS₂ or some other mineral."<ref>{{cite journal |last=Orgel |first=Leslie E. |date=7 November 2000 |title=Self-organizing biochemical cycles |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=97 |issue=23 |pages=12503–12507 |bibcode=2000PNAS...9712503O |doi=10.1073/pnas.220406697|pmc=18793 |pmid=11058157}}</ref></blockquote> It is possible that another type of metabolic pathway was used at the beginning of life. For example, instead of the reductive citric acid cycle, the "open" [[acetyl-CoA]] pathway (another one of the five recognized ways of carbon dioxide fixation in nature today) would be compatible with the idea of self-organization on a metal sulfide surface. The key enzyme of this pathway, [[carbon monoxide dehydrogenase]]/[[CO-methylating acetyl-CoA synthase|acetyl-CoA synthase]], harbors mixed nickel-iron-sulfur clusters in its reaction centers and catalyzes the formation of acetyl-CoA (similar to acetyl-thiol) in a single step. There are increasing concerns, however, that prebiotic [[Thioacetic acid|thiolated]] and [[thioester]] compounds are thermodynamically and kinetically unfavorable to accumulate in presumed prebiotic conditions (i.e. hydrothermal vents).<ref>{{cite journal|last1=Chandru|first1=Kuhan|last2=Gilbert|first2=Alexis|last3=Butch|first3=Christopher|last4=Aono|first4=Masashi|last5=Cleaves|first5=Henderson James II|title=The Abiotic Chemistry of Thiolated Acetate Derivatives and the Origin of Life|journal=Scientific Reports|date=21 July 2016|volume=6|issue=29883|pages=29883|doi=10.1038/srep29883|pmid=27443234|pmc=4956751|bibcode=2016NatSR...629883C}}</ref> It has also been proposed that [[cysteine]] and [[homocysteine]] may have reacted with [[nitrile]]s resulting from the [[Strecker amino acid synthesis|Stecker reaction]], readily forming catalytic thiol-reach poplypeptides.<ref>{{Cite journal|last1=Vallee|first1=Yannick|last2=Shalayel|first2=Ibrahim|last3=Ly|first3=Kieu-Dung|last4=Rao|first4=K. V. Raghavendra|last5=Paëpe|first5=Gael De|last6=Märker|first6=Katharina|last7=Milet|first7=Anne|date=2017-11-08|title=At the very beginning of life on Earth: the thiol-rich peptide (TRP) world hypothesis|url=http://www.ijdb.ehu.es/web/paper/170028yv/at-the-very-beginning-of-life-on-earth-the-thiol-rich-peptide-trp-world-hypothesis|journal=International Journal of Developmental Biology|volume=61|issue=8–9|pages=471–478|doi=10.1387/ijdb.170028yv|pmid=29139533|doi-access=free}}</ref>

Orgel summarized his analysis by stating, < blockquote >There is at present no reason to expect that multistep cycles such as the reductive citric acid cycle will self-organize on the surface of FeS/FeS₂ or some other mineral."<ref>{{cite journal |last=Orgel |first=Leslie E. |date=7 November 2000 |title=Self-organizing biochemical cycles |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=97 |issue=23 |pages=12503–12507 |bibcode=2000PNAS...9712503O |doi=10.1073/pnas.220406697|pmc=18793 |pmid=11058157}}</ref>< /blockquote > It is possible that another type of metabolic pathway was used at the beginning of life. For example, instead of the reductive citric acid cycle, the "open" [[acetyl-CoA]] pathway (another one of the five recognized ways of carbon dioxide fixation in nature today) would be compatible with the idea of self-organization on a metal sulfide surface. The key enzyme of this pathway, [[carbon monoxide dehydrogenase]]/[[CO-methylating acetyl-CoA synthase|acetyl-CoA synthase]], harbors mixed nickel-iron-sulfur clusters in its reaction centers and catalyzes the formation of acetyl-CoA (similar to acetyl-thiol) in a single step. There are increasing concerns, however, that prebiotic [[Thioacetic acid|thiolated]] and [[thioester]] compounds are thermodynamically and kinetically unfavorable to accumulate in presumed prebiotic conditions (i.e. hydrothermal vents).<ref>{{cite journal|last1=Chandru|first1=Kuhan|last2=Gilbert|first2=Alexis|last3=Butch|first3=Christopher|last4=Aono|first4=Masashi|last5=Cleaves|first5=Henderson James II|title=The Abiotic Chemistry of Thiolated Acetate Derivatives and the Origin of Life|journal=Scientific Reports|date=21 July 2016|volume=6|issue=29883|pages=29883|doi=10.1038/srep29883|pmid=27443234|pmc=4956751|bibcode=2016NatSR...629883C}}</ref> It has also been proposed that [[cysteine]] and [[homocysteine]] may have reacted with [[nitrile]]s resulting from the [[Strecker amino acid synthesis|Stecker reaction]], readily forming catalytic thiol-reach poplypeptides.<ref>{{Cite journal|last1=Vallee|first1=Yannick|last2=Shalayel|first2=Ibrahim|last3=Ly|first3=Kieu-Dung|last4=Rao|first4=K. V. Raghavendra|last5=Paëpe|first5=Gael De|last6=Märker|first6=Katharina|last7=Milet|first7=Anne|date=2017-11-08|title=At the very beginning of life on Earth: the thiol-rich peptide (TRP) world hypothesis|url=http://www.ijdb.ehu.es/web/paper/170028yv/at-the-very-beginning-of-life-on-earth-the-thiol-rich-peptide-trp-world-hypothesis|journal=International Journal of Developmental Biology|volume=61|issue=8–9|pages=471–478|doi=10.1387/ijdb.170028yv|pmid=29139533|doi-access=free}}</ref>

Orgel总结他的分析说，

Orgel总结他的分析说，

=== Fluctuating salinity: dilute and dry-down ===

=== Fluctuating salinity: dilute and dry-down ===

变化的盐度：稀释和干涸。

变化的盐度：稀释和干涸。  

Theories of abiogenesis seldom address the caveat raised by Harold Blum:<ref>Blum, H.F. (1957). On the origin of self-replicating systems. In Rhythmic and Synthetic Processes in Growth, ed. Rudnick, D., pp. 155–170. Princeton University Press, Princeton, NJ.</ref> if the key informational elements of life – proto-nucleic acid chains – spontaneously form duplex structures, then there is no way to dissociate them. <blockquote>Somewhere in this cycle work must be done, which means that free energy must be expended. If the parts assemble themselves on a template spontaneously, work has to be done to take the replica off; or, if the replica comes off the template of its own accord, work must be done to put the parts on in the first place.</blockquote>

Theories of abiogenesis seldom address the caveat raised by Harold Blum:<ref>Blum, H.F. (1957). On the origin of self-replicating systems. In Rhythmic and Synthetic Processes in Growth, ed. Rudnick, D., pp. 155–170. Princeton University Press, Princeton, NJ.</ref> if the key informational elements of life – proto-nucleic acid chains – spontaneously form duplex structures, then there is no way to dissociate them. < blockquote >Somewhere in this cycle work must be done, which means that free energy must be expended. If the parts assemble themselves on a template spontaneously, work has to be done to take the replica off; or, if the replica comes off the template of its own accord, work must be done to put the parts on in the first place.< /blockquote >

非生物起源理论很少涉及哈罗德-布卢姆Harold Blum提出的警告：如果生命的关键信息元素--原核酸链--自发形成双联结构，那么就没有办法将它们解离。

非生物起源理论很少涉及哈罗德-布卢姆Harold Blum提出的警告：如果生命的关键信息元素--原核酸链--自发形成双联结构，那么就没有办法将它们解离。

前RNA世界:核糖问题和及其旁路

前RNA世界:核糖问题和及其旁路

It is possible that a different type of nucleic acid, such as peptide nucleic acid, threose nucleic acid or glycol nucleic acid, was the first to emerge as a self-reproducing molecule, only later replaced by RNA. Larralde et al., say that <blockquote>the generally accepted prebiotic synthesis of ribose, the formose reaction, yields numerous sugars without any selectivity.</blockquote> and they conclude that their <blockquote>results suggest that the backbone of the first genetic material could not have contained ribose or other sugars because of their instability.</blockquote> The ester linkage of ribose and phosphoric acid in RNA is known to be prone to hydrolysis.

It is possible that a different type of nucleic acid, such as peptide nucleic acid, threose nucleic acid or glycol nucleic acid, was the first to emerge as a self-reproducing molecule, only later replaced by RNA. Larralde et al., say that < blockquote >the generally accepted prebiotic synthesis of ribose, the formose reaction, yields numerous sugars without any selectivity.< /blockquote > and they conclude that their < blockquote >results suggest that the backbone of the first genetic material could not have contained ribose or other sugars because of their instability.< /blockquote > The ester linkage of ribose and phosphoric acid in RNA is known to be prone to hydrolysis.

有可能是一种不同类型的核酸，如肽核酸、苏糖核酸或 乙二醇核酸，最先以自我繁殖分子的形式出现，只是后来被 RNA 所取代。Larralde 等人说，

有可能是一种不同类型的核酸，如肽核酸、苏糖核酸或 乙二醇核酸，最先以自我繁殖分子的形式出现，只是后来被 RNA 所取代。Larralde 等人说，

<blockquote>

< blockquote >

普遍接受的原生合成核糖，即甲酸糖反应，产生了许多没有任何选择性的糖类。

普遍接受的原生合成核糖，即甲酸糖反应，产生了许多没有任何选择性的糖类。

他们得出结论，他们的

他们得出结论，他们的

<blockquote>

< blockquote >

结果表明，第一个遗传物质的主干不可能含有核糖或其他糖类，因为它们不稳定。

结果表明，第一个遗传物质的主干不可能含有核糖或其他糖类，因为它们不稳定。

===Viral origin===

===Viral origin===

病毒的起源

病毒的起源  

Recent evidence for a "virus first" hypothesis, which may support theories of the RNA world, has been suggested. One of the difficulties for the study of the origins of viruses is their high rate of mutation; this is particularly the case in RNA retroviruses like HIV. A 2015 study compared protein fold structures across different branches of the tree of life, where researchers can reconstruct the evolutionary histories of the folds and of the organisms whose genomes code for those folds. They argue that protein folds are better markers of ancient events as their three-dimensional structures can be maintained even as the sequences that code for those begin to change. Thus, the viral protein repertoire retain traces of ancient evolutionary history that can be recovered using advanced bioinformatics approaches. Those researchers think that "the prolonged pressure of genome and particle size reduction eventually reduced virocells into modern viruses (identified by the complete loss of cellular makeup), meanwhile other coexisting cellular lineages diversified into modern cells." The data suggest that viruses originated from ancient cells that co-existed with the ancestors of modern cells. These ancient cells likely contained segmented RNA genomes.

Recent evidence for a "virus first" hypothesis, which may support theories of the RNA world, has been suggested. One of the difficulties for the study of the origins of viruses is their high rate of mutation; this is particularly the case in RNA retroviruses like HIV. A 2015 study compared protein fold structures across different branches of the tree of life, where researchers can reconstruct the evolutionary histories of the folds and of the organisms whose genomes code for those folds. They argue that protein folds are better markers of ancient events as their three-dimensional structures can be maintained even as the sequences that code for those begin to change. Thus, the viral protein repertoire retain traces of ancient evolutionary history that can be recovered using advanced bioinformatics approaches. Those researchers think that "the prolonged pressure of genome and particle size reduction eventually reduced virocells into modern viruses (identified by the complete loss of cellular makeup), meanwhile other coexisting cellular lineages diversified into modern cells." The data suggest that viruses originated from ancient cells that co-existed with the ancestors of modern cells. These ancient cells likely contained segmented RNA genomes.

另请参阅

另请参阅

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* {{annotated link|Anthropic principle}} Anthropic principle – Philosophical premise that all scientific observations presuppose a universe compatible with the emergence of sentient organisms that make those observations

* {{annotated link|Anthropic principle}}   Anthropic principle – Philosophical premise that all scientific observations presuppose a universe compatible with the emergence of sentient organisms that make those observations

人类学原理--哲学前提，即所有的科学观察都预设了一个宇宙，与使这些观察得以实现的有意识生物的出现相适应。

人类学原理--哲学前提，即所有的科学观察都预设了一个宇宙，与使这些观察得以实现的有意识生物的出现相适应。

* {{annotated link|Artificial cell}} 人工细胞

* {{annotated link|Artificial cell}} 人工细胞