Term
| Darwin- Theory, Finches, Research (where) |
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Definition
- HMS Beagle
- Galapagos Islands
- Theory of Uniformity – things change in slow, gradual, uniform, and repetitive ways |
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Term
| Populations- characteristics |
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Definition
- group of individuals of the same species living together
- have similar morphological, physiological, and behavioral traits |
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Definition
| - many different possibilities for characteristics |
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Term
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Definition
- all the genes of an entire population
- genes can be shared by all members of population |
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Term
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Definition
- genes that code for different versions of the same trait
- *Genetic mutation
- Crossing over a meiosis
- Independent assortment at meiosis
- Fertilization
- *Change in chromosome number or structure |
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Definition
| - the number of different alleles in a population |
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Definition
| - allele frequencies remain the same at a given locus from one generation to the next (population not evolving) |
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Definition
| - The small scale changes in allele frequency brought about by mutation, natural selection, gene flow, and genetic drift |
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Definition
| - the probability of a gene mutating during or between DNA replication (different for every gene) |
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Term
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Definition
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Term
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Definition
- environmental influences lead to natural selection
- Darwin’s observations
- Fitness – an increase in adaptation to the environment
- Driven by:
o Resources
o Habitat
o Predators |
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Term
| Directional selection-example |
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Definition
- a range of alleles that give rise to a range of variation in phenotype tend to shift in a consistent direction
- Example: Peppered moth blending into the trees; changes with pollution |
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Term
| Negative effects of natural selection |
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Definition
- pesticide resistance
- antibiotic resistance |
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Term
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Definition
- Intermediate forms of a trait in a population are favored and extreme alleles are lost
- Average is better
- Example: gull flies |
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Term
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Definition
| - extreme traits are favored over intermediate ones |
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Term
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Definition
- traits are selected for because they off an advantage in reproduction simply because they are attractive to the opposite sex
- females act as selective agents |
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Definition
| - tend to be brightly colored and have unique features |
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Term
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Definition
- two or more alleles coding for a given trait that are in the population
- sickle cell anemia
- malaria acts as a selective force in some African populations
- heterozygous individuals are more likely to survive malaria |
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Term
| Gene flow: emigration and immigration |
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Definition
- emigration: move out of an area
- immigration: moving into an area
- Example: tree species |
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Term
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Definition
| - a random change in allele frequency brought about by chance alone |
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Definition
- only one allele at a specific site; no genetic diversity
- bad |
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Term
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Definition
| - severe reduction in population size due to severe selection pressure or a calamity |
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Definition
| - reduction of allele frequency after a few individuals start a new population |
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Definition
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Term
| Biological species concept |
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Definition
| - a species is a one or more populations of individuals that are interbreeding under natural conditions, producing fertile offspring, and are isolated from other such populations |
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Term
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Definition
| - gradual accumulation of differences in gene pools of populations after isolation |
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Term
| Mechanisms of reproductive isolation |
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Definition
| - any heritable feature of body form, functioning or behavior that prevents interbreeding between species |
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Definition
- courtship, secret handshake
- birds mostly |
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Term
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Definition
| - Breeding takes place at different times (Cicadas) |
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Term
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Definition
- physical adaptations that limit reproduction
- flower petals and wasps |
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Term
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Definition
| - two species that can cross-breed do not occupy the same area |
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Term
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Definition
- if cross-breeding occurs the gamete will die or yield hybrids
- Example: horse + donkeys = mules |
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Term
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Definition
- Physical barriers separate populations, and prevent gene flow between the two populations, and favors divergences that end in speciation
- Example: blue-headed wrasse and the Cortez rainbow wrasse
- Archipelagos- an island chain some distance away from the mainland (Hawaii)
- Hawaiian honey creepers
- Founder species spreads out and develops adaptations to new environments |
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Term
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Definition
- New species developing within the range of another species
- Cichlids in Lake Tanganyika, Lake Barombi Mbo |
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Term
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Definition
- Neighboring populations become distinct species while maintaining contact along a common border
- Hybrid zone
- Baltimore Oriole and Bullock’s Oriole |
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Term
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Definition
- genetic lineage splits and isolates populations
- big and sudden changes |
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Term
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Definition
- allele frequency change in morphology in line of descendants
- small and gradual changes |
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Term
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Definition
- slight angle branches
- horizontal branches |
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Term
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Definition
- Gradual model of speciation: species emerged from many small morphological changes over a long period of time
- Punctuation model of speciation: most changes of morphology are compressed into a brief period |
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Term
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Definition
- A burst of divergences from a single lineage that give rise to many new species
- Gives rise to a new species
- *Each species adapts to a new habitat or novel resource
- Example: rise of the mammals after the dinosaurs |
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Term
| Extinction- human causes, major cause, survivors |
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Definition
- Extinctions allow for adaptive radiation (resources, niches are unfilled)
- Extinction rates higher than ever today (human impacts: habitat loss)
- human causes
o urban sprawl
o over-harvesting
o * habitat loss
o global warming
o chemical impacts
- survivors
o some is luck
o widely distributed species tend to survive |
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