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26 Cards in this Set
- Front
- Back
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Four observations and two inferences that led Darwin to propose natural selection |
1. A population varies in its traits2. Traits are heritable3. Populations produce more offspring than the environment can support4. Due to lack of resources, many offspring die 1. Individuals with better traits make more offspring2. The unequal ability of organisms to survive will make favorable traits accumulate |
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What is an acquired character and its significance with respect to evolution. |
Modification is structure or function acquired by an organism during its life, caused by environmental factors. - If heritable, can make children more fit |
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Genetic drift |
A change to a population's gene pool by chance (Founder's, bottleneck) |
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Founder effect vs Bottleneck effect |
Founder: small group is seperated by normal means Bottleneck: group is killed off, small group remains |
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5 Conditions for Hardy-Weinberg |
1. No mutation 2. Large population size 3. Random mating 4. No natural selection 5. No gene flow |
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Three types of selection |
Directional, Disruptive, Stabilizing |
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Balancing selection |
Multiple alleles are maintained in a gene pool (seashell colors) |
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Frequency dependant selection |
Fitness of a genotype increases or decreases as frequency increases |
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Allopatric speciation |
Species become physically isolated, interrupts gene flow |
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Sympatric speciation |
Inhabit the same area, but speciate |
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Polyploidy |
Cell has more than 2 paired sets of chromosomes (plants) |
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Prezygotic barriers |
1. Habitat isolation 2. Temporal 3. Behavioral 4. Mechanical 5. Gametic |
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Postzygotic barriers |
1. Reduced hybrid fertility 2. Reduced hybrid viability 3. Hybrid breakdown |
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3 Hybrid Zone outcomes |
1. Reinforcement 2. Fusion 3. Stability |
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Evo-devo |
Compares the developmental processes of different organisms the infer their ancestral relationships |
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Heterochrony |
Evolutionary change in the rate or timing of developmental events |
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Paedomorphosis |
Rate of reproductive development accelerates compared with somatic development (sexually mature but looks like baby, Axolotl) |
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Hox genes |
Position things. Limbs can be made with duplication |
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Exaptation |
Trait has been repurposed for something other than what it was made for (feathers were waterproof, showy, now they can fly) |
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Phylogeny vs Systematics |
Phylogeny: evolutionary history of a species or group of related species Systematics: classifies organisms to determine their evolutionary relationships |
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Rooted tree |
Branch to represent the last common ancestor of all taxa in the tree |
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Basal taxon |
Diverges early in the history of a group and originates near the common ancestor of the group |
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Clade |
Group of species that includes common ancestor and all its descendants |
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Shared ancestral character |
Characteristic that originated in an ancestor of the taxon |
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Shared derived character |
An evolutionary novelty unique to a particular clade |
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Homoplasy |
Shared by a set of species but not present in their common ancestor (evolution of the eye) |
