Biology, asked by EthanH1037, 1 year ago

Since the origin of life on the earth, there were five episodes of mass extinction of species.
(i) How is the ‘Sixth Extinction’, presently in progress, different from the previous episodes ?
(ii) Who is mainly responsible for the ‘Sixth Extinction’?
(iii) List any four points that can help to overcome this disaster.

Answers

Answered by mdsakirdonpd1cpx
0
Stromatolites from Bolivia, from the Proterozoic (2.3 bilion years ago). Vertical polished section.



Stromatolites growing in Yalgorup National Park in Australia

Further information: Abiogenesis, Astrobiology, Earliest known life forms, and Panspermia

The origin of life on Earth is a scientific problem which is not yet solved. There are plenty of ideas, but few clear facts.[1]

It is generally agreed that all life today evolvedby common descent from a single primitive lifeform.[2] It is not known how this early form came about, but scientists think it was a natural process which took place perhaps 3,900 million years ago. This is in accord with the philosophy of naturalism: only natural causes are admitted.

It is not known whether metabolism or genetics came first. The main hypothesiswhich supports genetics first is the RNA world hypothesis, and the one which supports metabolism first is the protein world hypothesis.

Another big problem is how cells develop. All existing forms of life are built out of cells.[3]

Melvin Calvin, recipient of the Nobel Prize in Chemistry, wrote a book on the subject,[4] and so did Alexander Oparin.[5] What links most of the early work on the origin of life is the idea that before life began there must have been a process of chemical change.[6] Another question which has been discussed by J.D. Bernal and others is the origin of the cell membrane. By concentrating the chemicals in one place, the cell membrane performs a vital function.[7]

Many religions teach that life did not evolve spontaneously, but was deliberately created by a god. Such theories are a part of creationism, which has "old earth" and "young earth" versions. Because of lack of evidence for such views, almost all scientists do not accept them.

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