Evolution

Question 1

Speciess

Answer 1

A group of organisms within which gene flow occurs resulting in fertile offspring (under natural conditions)

Question 2

Genetic Drift

Answer 2

unpredictable changes in allele frequencies in a population owing to chance events.
(Has its greatest effect in small populations)

Question 3

Bottleneck effect

Answer 3

After disaster, genetic drift occurs in small surviving population unrepresentative of the original population.

Question 4

Founder effect

Answer 4

Genetic drift in a new colony

Question 5

Natural selection

Answer 5

• Phenotype variation exits in population
• In changing environment, organisms with favored phenotype will have GENETIC FITNESS (surviving and reproducing) over others phenotype
• Hence more offspring will inherit the favored characteristics (alleles)
• Their frequency within population will increase through generations

Question 6

Heterozygote Advantage

Answer 6

two selective forces are in operation (best of both worlds)

Question 7

Directional Selection

Answer 7

• One extreme of trait distribution experiences selection against it
• The population’s trait distribution shifts towards other extreme

Question 8

Stabilizing Selection

Answer 8

Selective pressures select against the two extremes of a trait

Question 9

Disruptive Selection

Answer 9

Selection pressures act against individuals in the middle of the trait distribution

Question 10

Artificial Selection

Answer 10

The action of humans in determining which individuals of a population will produce fertile offspring fot the next generation

Question 11

Allopratric Speciation (4 steps)

Answer 11

1. Population living in same habitat
2. Geographically isolated by barrier, gene flow ceases between groups, with both different habitats now
3. Two populations encounter different selective pressures, each adapt to own habitat
4. Barrier reduces and populations meet again now unable to breed fertile offspring.

Question 12

Lamarekism Theory

Answer 12

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