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Biology II AP
Evolution (chapters 12-15)
49
Biology
11th Grade
01/28/2008

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Term
Microevolution
Definition
how populations of organisms change from generation to generation and how species originate
Term
Macroevolution
Definition
patters of changes in groups of related species over broad periods of geologic time
Term
Lamarck's idea of use and disuse
Definition
body parts of organisms can develop with increased usage, while unsued parts weaken
Term
Natural Selection
Definition
some individuals possess alleles that generate traits that enable them to cope more successfully with their environment than other individuals. Those who produce more offspring are "fittest"
Term
Stabilizing selection
Definition
eliminates individuals with extreme or unusual traits, most common trait is most adapted
Term
Directional selection
Definition
favors traits that are at one extreme of a range of traits-traits at opposite extreme are selected against; favored traits become more and more extreme through generations
Term
Disruptive selection (diversifying selection)
Definition
environment favors extreme or unusual traits, selecting against common traits
Term
Sexual selection
Definition

differential mating of males in a population-women increase quality of offspring by choosing superior males; males maximize quantity of offspring produced

 

often leads to sexual dimorphism: differences in appearance of males and females 

Term
Sexual selection: male competition
Definition
contests of strength that award mating opportunities to strongest males
Term
Sexual selection: female choice
Definition
leads to traits or behaviors in males that are attractive to females
Term
Artificial selection
Definition
form of directional selection carried out by humans when they sow seeds or breed animals that possess desirable traits (dogs)
Term
Mutations
Definition
provides raw material for new variation-invents new alleles that have never existed in the gene pool
Term
Rearrangements or genetic recombination originate from what three events in the sexual reproductive process?
Definition
  1. crossing over between nonsister chromatids
  2. independent assortment (random combination of mom and dad chromosomes
  3. random joining of gamete during fertilization
Term
diploidy
Definition
the presence of two copies of each chromosome in a cell (can be stored for future generations in heterozygous condition)
Term
Outbreeding
Definition
mating with unrelated partners-mixes alleles and creates new combinations
Term
Balanced polymorphism
Definition
the maintenance of different phenotypes in a popoulation (polymorphism is the coexistance of two or more phenotypes)...can be maintained by heterozygote advantage, hybrid vigor (heterosis), and frequency-dependent selection (minority advantage)
Term
balanced polymorphism: heterozygote advantage
Definition
heterozygous condition bears greater selective advantage than either homozygous condition; (sickle cell anemia)
Term
balanced polymorphism: hybrid vigor (heterosis)
Definition
superior quality of offspring from crosses between two different inbred strains of plants
Term
balanced polymorphism: frequency-dependent selection (minority advantage)
Definition
least common phenotypes have a selective advantage-common phenotypes are selected against, least common phenotypes become common and selective advantage is lost- alternate b/w low and high frequencies
Term
Gene flow
Definition
introduction or removal of alleles from the population when individuals leave or enter the population
Term
genetic drift
Definition
random increase or decrease of alleles; no reason but by chance
Term
genetic drift: founder effect
Definition
allele frequencies in a group of migrating individuals are by chance, not the same as their population of origin
Term
genetic drift: bottleneck
Definition
population undergoes dramatic decrease in size; small population becomes severely vulnerable to genetic drift
Term
Nonrandom mating
Definition
individuals choose mates based on particular traits
Term
nonrandom mating: inbreeding
Definition
individuals mate with relatives
Term
nonrandom mating: sexual selection
Definition
females choose males based on attractive appearence, behavior, or ability to defeat other males in contest
Term
Hardy-Weinberg genetic equilibrium can only occur when:
Definition
  1. All traits are selectively neutral (no natural selection)
  2. Mutations don't occur
  3. Population is isolated from other pop. (no gene flow)
  4. large population (no genetic drift)
  5. mating is random
Term
allopatric speciation
Definition
popoultion divided by a geographic barrier
Term
sympatric speciation
Definition
formation of new species w/o presence of geographical barrier
Term
sympatric speciation: polyploidy
Definition
possession of more than the normal two sets of chromosomes found in diploid cells
Term
sympatric speciation: balanced polymorphism
Definition
 ex. only insects w/ same color can associate and mate because the others die from not being camouflaged
Term
sympatric speciation: hybridization
Definition
two distinctly different forms of species mate and produce progeny along geographic boundary called hybrid zone
Term
Adaptive radiation
Definition
relatively rapid evolution of many species from a single ancestor-ancestral cpecies introduced to are of diverse conditions available for colonization
Term
Prezygotic isolation: habitat isolation
Definition
species don't encounter one another
Term
Prezygotic isolation: temporal isolation
Definition
species mate or flower during different seasons or at different times of the day
Term
Prezygotic isolation: behavioral isolation
Definition
species doesn't recognize other species as a mating partner because it doesn't perform correct courtship rituals
Term
Prezygotic isolation: mechanical isolation
Definition
male and female genitalia are incompatible
Term
Prezygotic isolation: gametic isolation
Definition
male gametes don't survive in environment of female gamete or female gametes don't recognize male gametes
Term
postzygotic isolation: hybrid inviability
Definition
zygote fails to develop properly and aborts before reaching reproductive maturity
Term
postzygotic isolation: hybrid sterility
Definition
hybrids become functional adults, but are reproductively sterile (mule)
Term
postzygotic isolation: hybrid breakdown
Definition
hybrids produce offspring that have reduced viability or fertility
Term
divergent evolution
Definition
two or more species that originate from common ancestor or become increasingly different over time
Term
convergent evolution
Definition
two unrelated species sharing analogous traits because of similar biomes
Term
parallel evolution
Definition
two related species or two related lineages that have made similar evolutionary changes after divergence from a common ancestor
Term
coevolution
Definition
one species in response to new adaptations that appear in another species (happens b/w predator and prey)
Term
Phyletic gradualism
Definition
evolution occurs by the gradual accumulation of small changes
Term
punctuated equilibrium
Definition
evolutionary history consists of geologically long periods of stasis with little or no evolution, interupted or "punctuated" by geologically short periods of rapid evolution
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