Natural Selection Lecture Review

These flashcards cover key concepts related to natural selection and adaptations based on lecture notes.

What is the primary mechanism known to result in adaptations according to the lecture?

Natural selection is the only known mechanism that results in adaptations.

What are the four postulates of natural selection?

1) Phenotypes vary in populations, 2) the phenotype is heritable, 3) more individuals are born than survive and reproduce, 4) survival and reproduction differ among phenotypes (differential fitness).

How is adaptation defined in the context of natural selection?

Adaptation is a characteristic (trait) that enhances survival and reproduction of organisms.

What does the term 'phenotypic plasticity' refer to?

Phenotypic plasticity refers to the ability of an organism to change its phenotype in response to changes in the environment.

What is the difference between natural selection and evolution?

Natural selection is not synonymous with evolution; evolution refers to changes in allele frequency through time.

What does 'fitness' refer to in the context of natural selection?

Fitness refers to reproductive success, specifically the probability of survival to reproductive age and mean number of offspring.

What is the importance of the common ancestor in natural selection discussions?

Natural selection explains why populations might diverge from common ancestors.

How can adaptations be measured according to the lecture?

Adaptations can be measured through their effects on survival and reproductive success.

What is an example of context-dependent adaptation provided in the lecture?

Cacti have adaptations such as modified leaves into spines for reducing water loss in dry environments.

What is the significance of the Galapagos finches in understanding natural selection?

The Galapagos finches illustrate adaptive evolution and the principle that species adapt their traits based on environmental factors.

What is 'exaptation'?

Exaptation is when a previous adaptation is co-opted to serve a new function.

What does it mean that natural selection is 'goal-less'?

Natural selection does not have a predetermined goal; it does not think ahead, and adaptations are not made with specific future purposes.

What does the phrase 'natural selection is the antithesis of chance' imply?

It implies that natural selection is a non-random process that influences survival based on fitness traits.

What is a 'preadaptation'?

Preadaptation refers to a feature that fortuitously serves a new function.

Why is the concept of ‘survival of the fittest’ considered circular reasoning in evolution?

Because it defines fitness as survival, which does not provide a causal mechanism for why certain traits confer survival advantages.

What aspect of evolution does not consider moral values or ethics?

Natural selection only refers to differences among organisms with respect to reproduction, without implying any moral worth.