Question

What evidence supports the theory of endosymbiosis?

Answer 1

Hint: Endosymbiosis is a mutually beneficial relationship between the host organism and an organism internally associated with the host. The term “endo” means ``within and ‘symbiosis” refers to mutual benefit.

Complete answer:
Where endosymbionts are found? It lives within a cavity of the organism, or within a cell. The location can be vacuoles or in cells that maintain the endosymbiont directly.
The theory which supports this endosymbiosis is:
Although there is no direct evidence, the one which is the most plausible theory is that of an early prokaryotic cell. It is believed that the ancestor to mitochondria entered another prokaryotic cell by means of food or as a parasite.
This way, after over a time it became endosymbiotic, where mitochondria supplied energy to the host and the host provided shelter. And this way, a distinct organelle or eukaryotic cell emerged.
The Another evidence:
If two organisms shared a sequence of exact DNA, then it is most likely that sequence was derived from the same ancestor. If two organisms have to complete, the enzyme that evolves doesn’t have to be similar or be from the same DNA to fill the same role.
That means, ribosomes of mitochondria and chloroplasts, also resemble the smaller ribosomes of bacteria and not the large eukaryotic ribosomes. This is consistent with endosymbiotic theory.

Note:
The basis of endosymbiotic theory has provided a unique niche to many within the cells of another organism. Remember that evidence was DNA originated inside of organelles and separated completely from eukaryotic DNA.