Question

What are some specific examples of cellular mechanisms that support the theory of evolution and common descent?

Answer 1

In 1859 Charls Darwin first formulated natural selection the theory of evolution. Evolution is a change in the heritable characteristic of biological population at successive generation. Change in the character of population depend on many factor including environment but mostly at genetic level. Genetic changes like mutation, genetic drift plays main role in the evolution. Changes doesn't occur instantly, it takes generation to occur at genetic level. And in most of the evolution cellular mechanism had played key role.

Natural selection doesn't operate on direct population but on the variation among individual. Base unit of life is cell and all the mechanism that support evolution are of cellular basic mainly. The life on earth started around 3.8 billion years ago with a single unit of cell. And RNA instead of DNA would have been believed to be initial genetic material which was capable of self replication and this period of evolution is known as RNA world. Successive interaction between RNA and amino acid then evolved in DNA as genetic material and replaced RNA.

Scientist believe that first cell was originated by RNA which self replicated within a phospholipids membrane. In present day also it is evident that plasma membrane of both prokaryote and eukaryotic cell is composed of phospholipids. This molecule is soluble in water at one side and in-soluble at another one this mechanism of phospholipids makes barrier between two aqueous medium separating interior and exterior medium of cell. Enclosure of phospholipids membrane might have provided environment to RNA to self replicate by maintaining them as a unit. In gradual succession RNA directed protein synthesis may have evolved.

After evoluting as a cell it went in many mutation at genetic level. Mutation is alteration of nucleotide sequence at genome level. Mean changing of the sequence of base, it is of three type - base substitution, deletion and addition.

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