Biology Flashcards - Evolution

Fitness is the ability of an organism to mate and produce fertile offspring.

The model of puntuated equilibrium holds that evolution is characterized by long periods of stasis punctuated by rapid evolutionary changes.

Homologous structures are similar in structure and origin but not function (e.g., whale flippers/ human arms).

Analogous structures are similar in function but not in origin (e.g., insect wings/bird wings).

A vestigial structure is a remnant structure that has lost its ancestral function (e.g., tail bone in man).

1. p² = frequency of homozygous dominants.

2. 2pq = frequency of heterozygotes.

3. q² = frequency of homzygous recessives.

True.

The following are necessary conditions for the Hardy-Weinberg equation to hold true.

• 1. There are no mutations that affect the gene pool.
• 2. The population must be very large.
• 3. Genes in a population are equally successful at reproducing.
• 4. Mating occurs randomly.
• 5. There is no net migration of individuals into or out of the population.

Genetic drift refers to changes in the gene pool due to chance.

Gene flow refers to the changing of the gene pool due to the migration of individuals.

True.

Disruptive selection favors the phenotypical extremes, leading to the expression of two or more phenotypic forms.

Directional selection favors the expression of one phenotypical extreme.

Two populations are considered to be different species when they can no longer interbreed and produce viable offspring.

Adaptive radiation is the emergence of a number of distinct lineages from a single ancestral species. The different lineages usually result when a group begins to exploit a different niche.

Convergent evolution refers to the independent development of similar characteristic by non-related groups.

Parallel evolution refers to the process whereby related groups independently develop similar characteristics due to analogous environmental pressures.

Divergent evolution refers to the process whereby related groups independently develop dissimilar characteristics.