Theories in Evolution

Question 1

Bateman’s principle

Answer 1

Bateman’s principle, in evolutionary biology, is that in most species, variability in reproductive success (or reproductive variance) is greater in males than in females.

Question 2

Red queen hypothesis

Answer 2

Organisms must constantly adapt, evolve, and proliferate not merely to gain reproductive advantage, but also simply to survive while pitted against ever-evolving opposing organisms in an ever-changing environment.

The hypothesis intends to explain two different phenomena: the constant extinction rates as observed in the paleontological record caused by co-evolution between competing species,[1] and the advantage of sexual reproduction (as opposed to asexual reproduction) at the level of individuals.[2]

Question 3

Neutral theory of molecular evolution

Answer 3

At the molecular level most evolutionary changes and most of the variation within and between species is not caused by natural selection but by genetic drift of mutant alleles that are neutral. A neutral mutation is one that does not affect an organism’s ability to survive and reproduce. The neutral theory allows for the possibility that most mutations are deleterious, but holds that because these are rapidly removed by natural selection, they do not make significant contributions to variation within and between species at the molecular level. Mutations that are not deleterious are assumed to be mostly neutral rather than beneficial.