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48 Cards in this Set

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Directional selection
ONE of the extremes of phenotype s are selected against
Disruptive selection
both of the extremes of phenotypes are selected for
Stabilizing selection
both extremes of phenotypes are selected against
Example of directional selection
industrial revolution, moths and lichen
Example of disruptive selection
Singer fish and sneaker fish; good singer, small testes/ bad singer big balls
Example of stabilizing selection
Birth weights - better to stay in middle
Balanced polymorphism
Different phenotypes exist at relatively stable frequencies over long term
Sexual selection
Traits that benefit reproduction will stay around even if detrimental
Examples of sexual selection
Deer antlers
2 mechanisms of sexual selection
male competition/female choice
Differential parental investment
female reproductive success limited by resources; male reproductive
2 implications of the Darwinian paradigm
females are choosy and males are less discriminating
What are the evolutionary mechanisms (3)
1. Genetic drift
2. Gene flow/migration
3. Mutation
Genetic drift occurs by what?
bottleneck effect
Founder effect
group picks up and fragments off
Gene flow includes migration of what?
individual alleles
Mutation is the only way to get new ?
genetic material
3 types of mutation
1. silent
2. missense
3. frameshift
Define silent mutation
no effect due to mutation
Why does silent mutation show no effect?
1. Alot of DNA is non-coded
2. redundancy built into system
Define missense mutation
point mutations: change in letter at one point to mess everything up
Define frameshift mutation
mutation that causes entire frame to shift. caused by sun, smoking, naturally
Evolution can only act on ____
existing structures
Define phylogenetics
study of evolutionary relationships
Define monophyletics
all individuals in your group includes all points and comes from common ancestors
Define paraphyletics
when a group is left out
What does "ontogeny recapitulates phylogeny" mean?
We share traits with ancestors that define our chordates
4 characteristics of a chordate
1. notochord
2. dorsal hollow nerve cord
3. pharyngeal pouches
4. post-anal tail
pnedomorphosis
retention of larval characteristics in adult form
What type of rock are most fossils found in?
sedimentary
Endosymbiosis
one bacteria engulfs many others and keeps them as slaves
ex. mitochondria
Name four tools for reconstructing phylogenies
1. morphology
2. development
3. fossils
4. molecular data
What law states the simple steps are more likely than many, complex ones
Parsimony
What is an ancestral character and what is another name for it?
Unites all species in cladogram
- Symplesiomorphy
what is the node?
point of divergence
Define synapomorphy
derived characteristics
Define homologous characteristics and example
characteristics due to common ancestry
example: hair
Define analogous characteristics and example
similar characters that arose independently
example: the wings of a bat are analogous to wings of a duck
Define polyphyletics
group that includes multiple evolutionary lineages
Define species
A group of related organisms or populations in which genes are actually, or potentially, exchanged through interbreeding
What are 3 problems with the definition of species?
1. often based on morphology
2. what to do with asexuals
3. can't get a fossil to have sex
Define allopatric speciation
seperated by physical barriers and evolve separately - if joined again can't reproduce
Define sympatric speciation
occurs due to reproductive barriers not physical
Define pre-zygotic barriers
habitat isolation - move to new area and develop new niches
Post-zygotic barriers
occurs by new alleles arising (mutation) - two species can't reproduce with each other
Allopolyploidy
Chromosomal duplication between two species
Darwin believed in slow, gradual speciation
gradualism
Gould believed in what?
Punctuated equilibrium - short periods of rapid change and long periods of stasis