Question

Check all statements below that are true.

All organisms must compete for survival.

When organisms struggle to survive, they usually mutate to increase chances of reproduction.

Some organisms have phenotypes that make them better competitors than others in their environment.

Animals undergo natural selection, but plants and other organisms generally do not.

Natural selection continues to occur even today.

Phenotypes found in the most successful members of a species become the most prevalent after several generations.

A decrease in food availability will increase the variation in a population.

Answer 1

True: 1, 3, 5, 6.

Brief explanations:
- 1 (True in the usual sense) — organisms typically face limited resources (food, space, mates) and so compete in some way for survival and reproduction.
- 2 (False) — mutations arise randomly, not typically as a directed response to a struggle; selection acts on existing variation.
- 3 (True) — phenotypic differences can make some individuals better competitors in a given environment.
- 4 (False) — natural selection acts on all organisms (animals, plants, microbes, etc.), not just animals.
- 5 (True) — natural selection is an ongoing process and continues today.
- 6 (True, with the usual caveats) — heritable traits that confer higher reproductive success tend to increase in frequency over generations.
- 7 (False) — decreased food usually intensifies selection or causes bottlenecks and often reduces, not increases, genetic variation.