Biogeography Unit 2, Evolution

Front 1

Adaptation

Back 1

heritable aspect of form, function or behavior that improves odds for surviving and producing in a given environment; an OUTCOME of microevolution, enhancement of a species

Front 2

Genetic Equilibrium

Back 2

not evolving as 1) no mutations have occurred, 2) population is very large, 3) fully isolated from all other populations, 4) product of allele being studied has no effect on survival or production, 5) mating is random--> rare

Front 3

Hardy-Weinberg Rule

Back 3

p^2(AA) + 2pqAa + q^2aa = 1
P and q are frequencies of alleles A and a

Front 4

Directional Selection

Back 4

Allele frequencies that give rise to a range of variation in phenotype tend to shift in a consistent direction due to directional change in environment (ie pesticide resistance)

Front 5

Stabilizing Selection

Back 5

intermediate forms of a trait in a population are favored and alleles for the extremes aren't; counter mutation, gene flow, and genetic drift

Front 6

Disruptive Selection

Back 6

where extreme forms are preferred over intermediate ones

Front 7

Gloger's Rule

Back 7

Coloration of related forms is often correlated with humidity of surrounding environment:
The more humid = more vegetation = more shade = animals need darker fur to stay hidden from predators/prey

Front 8

Crypsis/Camouflage

Back 8

how well you can hide. Duh

Front 9

Allen's Rule

Back 9

Among vertebrate animals; among closely related forms, those living in hotter environments tend to have longer appendages (cooling); cooler environment animals have shorter limbs (conservation of heat)

Front 10

Bergmann's Rule

Back 10

Colder weather, the larger the animals (more massive, to conserve body heat and to store food)

Front 11

Lamarck

Back 11

Had the initial idea that changes in the environments forced species to improve on itself to survive; elaborated on by Darwin

Front 12

Sexual Selection

Back 12

is linked to natural selection, since the traits that provide for inheritance are what fe/males look for in partners

Front 13

Balancing Selection

Back 13

referring to all forms of selection that maintain two or more alleles for a trait at frequencies above 1% for the population; balanced polymorphism

Front 14

Genetic Drift

Back 14

random change in allele frequencies over time, brought about by chance alone; increases likelihood that an allele will become more or less prevalent when the population is small

Front 15

Sampling Error

Back 15

rule of probability; you won’t get the expected outcome if there are not enough trials

Front 16

Fixation

Back 16

only one kind of allele remains at a particular locus in a population-- homozygous; happens very fast in smaller populations- in the absence of other forces

Front 17

Bottleneck

Back 17

drastic reduction in population size brought about by severe pressure or a calamity; this alters genetic frequency at random, losing many alleles

Front 18

Founder Effect

Back 18

a few individuals leave population and establish a new genetic outcome somewhere else;

Front 19

Inbreeding

Back 19

nonrandom mating among close relatives, sharing similar alleles, leads to the homozygous condition; possibilities of lowering fitness