How did we evolve?

[MidnightFox]

Did humans evolve from mammals?

 

or reptiles?

 

or any other animal?

Is every animal related?

[Klaynos]

It's been many years since I've done any biology, but IIRC.

 

The great apes and humans share a common ancestor (our nearest relatives).

 

And yes all animals come from the same beginnings probably. We'll never find that common ancestor though.

[MidnightFox]

How did life began though?

 

I saw in a book ( i dont think its right though) that lightning struck water and made chemical reactions thus making the first life on earth.

[Klaynos]

How the first life formed is a matter I am not well versed on, I know there is alot of interest in the area though.

[Logix]

Why did we evolve?

[Klaynos]

Why did we evolve?

 

Natural selection.

[Cap'n Refsmmat]

http://en.wikipedia.org/wiki/Evolution

[psynapse]

This experiment was done with nonliving chemicals and created some of the building blocks of life, amino acids.http://en.wikipedia.org/wiki/Miller_experiment

[aguy2]

Logix asked, "Why did we evolve?"

 

Natural selection.

 

"Natural selection" might due for "How did we evolve?", but it would not seem to suffice as an answer to the question "Why did we evolve".

aguy2

[Cap'n Refsmmat]

Environmental forces that caused natural selection.

[DaveC426913]

Why did we evolve?

There is no "why".

[carol]

IMO we evolve because of the need to evovle. Darwinists would say because of natural selection, and that is a pretty neat way to answer how and why did we evolve. But the question why is hard to answer since we can't prove it. Every animal is somewhat related to another. And we are closely related to mammals since we are also mammals. About the experiment of Miller and Urey, there is a logical argument against that. I think you should read it yourself because it is very convincing and will keep us informed of what's new in biology.

[Cap'n Refsmmat]

Can you refer us to this argument so we can read it?

[Mokele]

The Urey-Miller experiment was in a strongly reducing environment, IIRC, with lots of amonia and suchlike, but new evidence suggests that ancient Earth's environment was more neutral or oxidizing.

 

Of course, IIRC, people have repeated the experiment with numerous types of atmosphere and gotten the same or better results. IIRC, we've even gotten RNAs.

 

Mokele

[carol]

http://www.darwinismrefuted.com/molecular_biology_09.html

 

Actually, I read it in a book. I think this one also tells the same.

[swansont]

The Urey-Miller experiment is not a demonstration of an actual pathway for abiogenesis (which is different than evolution), since, as Mokele points out, the conditions were likely different.

 

However, it is useful for refuting the painfully flawed contention that abiogenesis is impossible for probabilistic reasons. Since the amino acids do, in fact, form, despite a purported miniscule probability, it shows the probability calculations to be wrong.

[Mokele]

Carol, that site is a hoax, utterly worthless creationist bullshit.

 

A much better link, this one with real science: http://www.talkorigins.org/faqs/abioprob/

[jackson33]

Did humans evolve from mammals?

 

or reptiles?

 

or any other animal?

Is every animal related?

 

about 2 billion years ago, micro organisms are known to have lived. true evolution would suggest that life evolved to the current level from that point. plant life or inorganic could have come from some chemical or electric action and probably preceded organic. i like to think major forms of life or complex, formed many times from this beginning and not some direct line. each from there went on to be the various types of organic life. that is the evovlement of life happened many times but all with the same elements.

 

reptiles do have the longest history, but mammals were present most of their dominance and did survive through periods reptiles were nearly wiped out. man is mammal and if there is a direct link to mammals w/o reptiles would make sense. if not then ocean life to land and so on, would mean a link to reptiles back to sea life and so on...

 

yes, everything organic and inorganic is somehow related to the others by genetics. if mans genetics is 100% (not to confuse with DNA) many forms of the Ape family are 98 to 99+ equals to mans structure, other mammals in the 90's and so on down to the lowest forms of organic life in the 50 to 70%. trees, plants and the rest are below this but have a good deal of the same genetic structure- 30-40 % or so. so in a way we are related to some degree by genetic to all life on earth. keep in mind however, there are just so many things that can result in life forms and these would be found in all life if ever found from any other planet. so even if something were found on another planet, it could show a genetic structure, similar to a like form on earth. this thing would not necessarily look like anything on earth now or ever in the past. that gets complicated with atmospheric, gravity and other conditions.

[weknowthewor]

All humans develop as per human development stages as we know.

[Dr. Dalek]

plant life or inorganic could have come from some chemical or electric action and probably preceded organic. . . . yes, everything organic and inorganic is somehow related to the others by genetics. . . . . lowest forms of organic life in the 50 to 70%. trees, plants and the rest are below this but have a good deal of the same genetic structure- 30-40 % or so. so in a way we are related to some degree by genetic to all life on earth.

Inorganic? What are you talking about?

[carol]

Carol, that site is a hoax, utterly worthless creationist bullshit.

 

A much better link, this one with real science: http://www.talkorigins.org/faqs/abioprob/

 

Actually, I had second thoughts about that link but I said what the heck, I might as well hear what you might think about it.

[lucaspa]

How did life began though?

 

I saw in a book ( i dont think its right though) that lightning struck water and made chemical reactions thus making the first life on earth.

 

You misunderstood the book. The book was referring to the Miller-Urey experiments that used a simulated thunderstorm to show how amino acids and sugars could form from simpler molecules.

 

One way to get life from non-living chemicals is here:

http://www.theharbinger.org/articles/rel_sci/fox.html

[lucaspa]

"Natural selection" might due for "How did we evolve?", but it would not seem to suffice as an answer to the question "Why did we evolve". aguy2

 

It's also a "why". Evolution is "descent with modification". And a "why" of the modification is natural selection. Another "why" is that there is more than one environment, so natural selection is the "why" is there diversity of species: to find designs to exploit the various environments. A third "why" is Mendelian genetics that ensures that characteristics are inherited.

 

Basically, evolution is an inevitable consequence of living organisms. Unless there is only one way to earn a living, there is going to be evolution.

[Ophiolite]

However, it is useful for refuting the painfully flawed contention that abiogenesis is impossible for probabilistic reasons. Since the amino acids do, in fact, form, despite a purported miniscule probability, it shows the probability calculations to be wrong.

No it doesn't. No one ever contended that producing amino acids would be especially difficult. The probabalistic issue is over stringing them together by the hundreds - and in the right order - to make useful proteins.

We have also found amino acids, by the bucker load, in meterorites and they have been detected in interstellar space.

 

Interestingly enough a group, possibly at Ames, fired amino acid laden ice at a wall with velocity equivalent to that likely during cometary impact. The object was to determine if the amino acids would remain intact and so provide organic materials on the early Earth. Not only did they remain intact, but they linked up to produce polypetides, a precursor of proteins proper.

 

Mokele is quite right: the Miller-Urey experiment assumed a strongly reducing atmosphere. We no longer think this was likely.

[lucaspa]

Interestingly enough a group, possibly at Ames, fired amino acid laden ice at a wall with velocity equivalent to that likely during cometary impact. The object was to determine if the amino acids would remain intact and so provide organic materials on the early Earth. Not only did they remain intact, but they linked up to produce polypetides, a precursor of proteins proper.

 

Actually, polypeptides ARE proteins. Different name, same thing.

 

And the experiment is just one way to get amino acids to string together to make proteins. It happens at hydrothermal vents. It can also happen in a tidal pool as it evaporates under the sun.

 

Rohlfing, DL. Thermal polyamino acids: synthesis at less than 100°C. Science 193: 68-70, 1976.

Syren RM, Sanjur A, Fox SW Proteinoid microspheres more stable in hot than in cold water. Biosystems 1985;17(4):275-80 (protocells at hydrothermal vents)

Yanagawa, H. and K. Kobayashi. 1992. An experimental approach to chemical evolution in submarine hydrothermal. systems. Origins of Life and Evolution of the Biosphere 22: 147-159.

Marshall, W. H. 1994. Hydrothermal synthesis of amino acids. Goechimica et Cosmochimica Acta 58: 2099-2106.

McAlhaney WW, Rohlfing DL. Formation of proteinoid microspheres under simulated prebiotic atmospheres and individual gases. Biosystems 1976 Jul;8(2):45-50

Fouche-CE Jr; Rohlfing-DL Thermal polymerization of amino acids under various atmospheres or at low pressures. Biosystems. 1976 Jul; 8(2): 57-65

SW Fox, Thermal polymerization of amino-acids and production of formed microparticles on lava. Nature, 201: 336-337, Jan. 25, 1964.

Hennon, G, Plaquet, R, Biserte, G. The synthesis of amino acid polymers by thermal condensation at 105° without a catalyst. Biochimie 57: 1395-1396, 1975.

Heinz, B, Reid, W. The formation of chromophores through amino acid thermolysis and their possible role as prebiotic photoreceptors. BioSystems 14: 33-40, 1981.

 

Mokele is quite right: the Miller-Urey experiment assumed a strongly reducing atmosphere. We no longer think this was likely.

 

But it doesn't matter. The experiment has been repeated with several types of non-reducing atmosphere and the results are essentially the same:

 

1. Kawamoto K, Akaboshi H. Study on the chemical evolution of low molecular weight compounds in a highly oxidized atmosphere using electical discharges.**Origins of Life and Evolution of the*Biosphere 12: 133-141, 1982.