Evolution Ques 137
The first organisms were prokaryotic cells
[1992]
(a) Chemoautotrophs
(b) Chemoheterotrophs
(c) Autotrophs are organisms that produce their own food through processes like photosynthesis or chemosynthesis.
(d) Eukaryotes
Show Answer
Answer : b
Hints & Solution
(b) Chemoheterotrophs were the first organisms. They were prokaryotic, like bacteria, anaerobes, as molecular oxygen was absent. They obtained energy by fermentation of some of the organic molecules present in the broth. Thus they absorbed organic molecules from outside for body building and energy.
- Chemoautotrophs - Organisms that are capable to synthesize organic molecules from inorganic molecules. E.g., Nitrifying bacteria, sulphur reducing bacteria etc. Autotrophs are organisms that perform photosynthesis.
BETA
