Question

what does the endosymbiotic theory explain? Give 3 pieces of evidence that supports the endosymbiotic theory

Answer 1

In this context, it is important to first analyze the word endosymbiosis. “Endo” means within something, “symbiosis” means a long to short relationship between two organisms. So, the entire word means that one cell is within the other one and they have a long relationship.

This hypothesis propose 3 facts:

•The mitochondria is the result of then endocytosis (engulfment) of the aerobic bacteria by the eukaryotic cell. In other words, the one cell ate a bacterial cell and them that bacterial cell become a mitochondria.

•The chloroplasts are the result of the same process but instead, the bacteria has a photosynthetic pigment.

•In both case, the cell that engulf the bacterial cell was anaerobic, so it got a benefit from the aerobic bacteria and the photosynthetic bacteria.

Evidences:

1)Scientists have found fossils from 3.8 billion years ago of anaerobic cells. They hypothesize that in that period of time, all of the bacteria were anaerobic.

2)Other fossils from 2.5 billion years ago prove that the aerobic cells emerged.

3)Another interesting evidence is that both mitochondria and chloroplasts have their own DNA. In fact, they are able to divide independently within the cell