Question

Following are the two statements regarding origin of the life.
(a) The earliest organisms that appeared on the earth were non-green and presumably anaerobes.
(b) The first autotrophic organisms were the chemoautotrophs that never released oxygen.
Of the above statements which one of the following options is correct?

• A. (a) is correct but (b) is false.
• B. (b) is correct but (a) is false.
• C. Both (a) and (b) are correct.
• D. Both (a) and (b) are false.

Answer 1

Answer: (C)

The earliest organisms that appeared on the earth were non-green and presumably anaerobes.

The first beings were probably much like coacervates. As a group, these bacteria are called heterotrophic anaerobes. Because there was virtually no oxygen in the atmosphere at this time, these bacteria were necessarily anaerobic, meaning they did not breathe oxygen. Heterotrophs, meaning "other feeders", are simply organisms that cannot make their own food. So, "heterotrophic anaerobes" means they were creatures which ate some naturally occurring food and did not breathe oxygen.

The first autotrophic organisms were the chemoautotrophs that never released oxygen. Chemotrophs are organisms that obtain energy by the oxidation of electron donors in their environments.