Biology Flashcards - Evolution
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Define fitness according to Darwin.
Fitness is the ability of an organism to mate and produce fertile offspring.
Describe the model of punctuated equilibrium.
The model of puntuated equilibrium holds that evolution is characterized by long periods of stasis punctuated by rapid evolutionary changes.
What are homologous structures?
Homologous structures are similar in structure and origin but not function (e.g., whale flippers/ human arms).
What are analogous structures?
Analogous structures are similar in function but not in origin (e.g., insect wings/bird wings).
What are vestigial structures?
A vestigial structure is a remnant structure that has lost its ancestral function (e.g., tail bone in man).
Given the Hardy-Weinberg equation : p2 + 2pq + q2 = 1
1. What does p2 represent?
2. What does 2pq represent?
3. What does q2 represent?
1. p2 = frequency of homozygous dominants.
2. 2pq = frequency of heterozygotes.
3. q2 = frequency of homzygous recessives.
(T/F) p+ q = 1
What are the 5 necessary conditions for the Hardy-Weinberg equation to hold 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.
How does genetic drift differ from gene flow?
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.
(T/F) Stabilizing selection maintains a well adapted uniform character in a population.
How does disruptive selection affect the phenotype of a population.
Disruptive selection favors the phenotypical extremes, leading to the expression of two or more phenotypic forms.
How does directional selection affect the phenotype of a population?
Directional selection favors the expression of one phenotypical extreme.
When are two populations descending from the same ancestral stock considered to be different species?
Two populations are considered to be different species when they can no longer interbreed and produce viable offspring.
What is adaptive radiation?
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.
Describe convergent evolution.
Convergent evolution refers to the independent development of similar characteristic by non-related groups.
Describe parallel evolution.
Parallel evolution refers to the process whereby related groups independently develop similar characteristics due to analogous environmental pressures.
Describe divergent evolution.
Divergent evolution refers to the process whereby related groups independently develop dissimilar characteristics.
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