Micro and Macro Evolution (week 2)

Question 1

Assortative Mating

Answer 1

individuals select mates with their phenotype and reject opposites (increases the number of homozygotes)

Question 2

Disassortative Mating

Answer 2

Dissimilar phenotypes mate preferentially (increases the number of heterozygotes)

Question 3

Inbreeding

Answer 3

Mating of 2 genetically related individuals, choose a mate from same genetic lineage

Question 4

Genetic Drift

Answer 4

the random change in the frequency of a gene variant in a population

Question 5

Bottleneck Effect

Answer 5

an event that drastically reduces the size of a population (ex. African Cheetah and Northern Elephant Seals - low genetic variability due to inbreeding)

Question 6

Founder Effect

Answer 6

a genetic phenomenon that occurs when a small group of individuals separates from a larger population (in the Amish population 1/14 born with Ellis-van Creveld syndrome, in general population its only 1/1000)

Question 7

Natural Selection Requires

Answer 7

Variation
Inheritance
Differential Adaptiveness: some differences affect survivability
Differential Reproduction: some differences affect likelihood of successful reproduction

Question 8

Directional Selection

Answer 8

individuals at one extreme of a phenotypic range have greater reproductive success in a particular environment (ex. body size of horses favored a largest end)

Question 9

Stabilizing Selection

Answer 9

Intermediate phenotype is favored (ex. baby weight at small end and large end are less likely to survive)

Question 10

Disruptive Selection

Answer 10

two more extreme phenotypes favored over intermediates (think camel hump graph)
ex. Cepaea snails vary due to wide geographical range

Question 11

Balancing Selection

Answer 11

Balancing polymorphism: two or more alleles kept in balance and therefore maintained in a population over generation

Question 12

Intrasexual

Answer 12

males directly compete for mating opportunities or territories

Question 13

Intersexual

Answer 13

females choose with males possessing a particular phenotype

Question 14

Macroevolution

Answer 14

Evolutionary changes that create new species and groups of species; accumulation of microevolutionary changes over long periods of time

Question 15

What is a species?

Answer 15

a reproductive community of populations (reproductively isolated others) that occupies a specific niche in nature, interbreeding with common gene pool to produce variable, fertile offspring

Question 16

Prezygotic Mechanisms

Answer 16

discourage attempts to mate (habitat isolation, behavioral isolation ect…)

Question 17

Postzygotic Mechanisms

Answer 17

prevent hybrid offspring from developing or interbreeding (ex. hybrid inviability, hybrid sterility etc)

Question 18

Allopatric Speciation

Answer 18

two geographically isolated populations of one species, become different species over time, can be due to differing selection pressures in differing environments (etc. north rim/south rim

Question 19

Adaptive Radiation

Answer 19

when members of a species invade several new geographically separate environments, populations adapt, many new species evolve from single ancestral species (ex. Darwins finches led to 13 finch species

Question 20

Sympatric Speciation

Answer 20

one population develops into two or more reproductively isolated groups

Question 21

Punctuated Equilibrium

Answer 21

Speciation occurs rapidly, transitional links not found, subpopulation becomes new species (ex. sharks, crocodiles

Question 21

Phyletic Gradualism

Answer 21

speciation occurs gradually, transition links found, transform into a new species (ex. butteflies)