IMAT 2011 Q55 [Natural Selection]

Which of the following organisms are subject to natural selection?

  1. Prokaryotes that reproduce asexually
  2. single-celled eukaryotes that reproduce sexually
  3. organisms living in a changing environment
  4. organisms living in a stable environment

A. 1 and 2 only

B. 2 and 3 only

C. 3 and 4 only

D. 1, 2 and 3 only

E. 1, 2, 3 and 4

The following question is an excellent example of a question from the “evolution” section of the IMAT. We should expect at least one question on evolution.

A list of organisms is shown, and we should test each one and ask ourselves if they are subject to natural selection.

First of all, what is natural selection?

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype.

We should test each one of the organisms and see if they have a different kind of phenotype randomly showing up over generation the somehow let others of the same species, a better chance of survival.

Prokaryotes that reproduce asexually do prokaryotes have different phenotypes over the generation? Of course! Mutation over generations can lead to different kinds of abilities, receptors, and functionalities, that can give a significant advantage over others of the same species. Subject to natural selection.

Single-Celled eukaryotes that reproduce sexually – single-celled eukaryotes that reproduce sexually can go under allele recombination and mutations which can let others in the same species an advantage or disadvantage in a different situation, which means they are also subject to natural selection.

Organisms living in a changing environment – organisms that are living in a changing environment can evolve different kinds of phenotypes to survive in each new environment, which means they must be subject to natural selection.

Organisms living in a stable environment – although these organisms are living in a stable environment, it does not mean they are not evolving, hunting, dying of diseases, etc. Then of course, they are also subject to natural selection.

All of the answers are correct. Therefore the answer must be E