Origin of Life

A current hypothesis on the origin of sprightliness:
I. Early Earth - the primitive Earth of 4 one thousand thousand eld ago did not contain life.
The early earth, a mass of hot, glowing atoms, began to solidify 4 BYA.
As the lightest atoms cooled, total heat fuck up (H2), methane gas (CH4), ammonia (NH3), carbon dioxide (CO2) and nitrogen gas (N2) were formed. Water vapor (H20) condensed to fill the oceans...
There was no thaw oxygen - yet.
In addition, severe lightning storms, volcanic eruptions, and UV cock added to the excitement....
No evidence of life on Earth at this point!
How old is the Earth and how do we know?
20 Billion Years...Check this out!
II. Life definitely existed ~3.5 - 3.8 million years ago.
Darwin, as well as other scientists were until recently unable(p) to find evidence for life in the pre-Cambrian (older than ~700 MYA).
About 35 years ago (1960s), the reason became apparent - before the Cambrian, in that respect were only microscopic organisms (first prokaryotes and then eukaryotes), spanning over 3 billion years - micro fossils!




The fossil record supports the idea that the first organisms were bacteria
Oldest fossil evidence: stromatolites (rocks containing layered sediments that are the remains of bacterial cells, and their thick coats), found in western Australia and southern Africa - amidst 3.5 - 3.8 BYA.
to a greater extent on Stromatolites
III. So what do scientists propose happened in between???? How might the first cells have originated?
Hypothesis: chemical developing or the chemosynthetic theory: life developed from non-living materials eventually, by the transition of natural selection, over hundreds of millions of years, became able to self-replicate and metabolize. This hypothesis presumes that at least 4 steps happened to bring about this chemical evolution
1. The abiotic (nonliving) deduction and accumulation of small organic monomers like amino acids or nucleotides
2. The Joining of monomers into polymers
3. The self-assembly of molecules into...If you want to get a full essay, coiffure it on our website: Orderessay



If you want to get a full essay, wisit our page: write my essay .