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52 Cards in this Set
- Front
- Back
Evolution |
Genetic change over time. |
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Natural selection |
Is the mechanism to achieve evolution. |
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Microevolution |
Happening in a small population; change in gene pool |
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Macroevolution |
Large scale process; usually the change leads to a new species. |
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Adaptations |
Are evolved traits that help an organism become best suited to the conditions presented by its environment |
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Mutation |
Alterations to the Dna(substitution, deletions, duplications) that change the expressions of the gene. Cause allele frequencies to change within populations if mutation is passed on. |
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Genetic drift |
Changes in population allele frequencies due to random assortment of genes in the gametes; each generation of mating can Alter the allele frequencies. |
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Bottleneck effect |
Disaster like a disease, or fire, or complete loss of a resource that kups off significant number of the population causes a drastic change in the allele frequencies. |
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Founder effect |
Few individual s leave a population and form a new population of their own, with only a small fraction of the original gene pool |
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Gene flow |
Movement of alleles among populations, either by individuals immigrating in our emigrating out, or alleles migrating as gametes when individuals of different populations breed. |
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Microevolution, macroevolution |
Two main mechanisms driving evolution. |
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Individual variation, inheritance, overproduction, differential fitness |
In order for natural selection to drive evolution of population, the following criteria must be met. Processes of Evolution- Natural Selection. |
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Individual variation |
Organisms within the population are different from one another. |
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Inheritance |
Many of the differences are passed to future generations |
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Overproduction |
More offspring are produced than will survive. |
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Differential fitness |
Individuals that are best adapted to their environment will produce the most offspring, therefore their alleles will be most represented in the population. |
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Stabilizing, directional, disruptive. |
Types of natural selection |
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Stabilizing selection |
Extreme phenotypes selected against, average types selected for; an advantage when confitiond remain relatively constant. |
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Directional selection |
Extreme phenotype becomes the favored one due to a change in environmental conditions; extreme phenotype now has an advantage over more average ones; usually a shift in climate or biome type drives selection-going grassland to forest, a dry climate turns wet, etc. |
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Disruptive selection |
2 or more extreme phenotypes favored over intermediates; usually when population occupies different habitats. |
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Hardy-weinberg equilibrium |
When population is in a stable state of genetic equilibrium; allele frequencies become static after one generation of tandom mating; population size must be large. |
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Speciation |
Splitting of one species into two or more new ones |
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Reproductive isolation |
Genetic differences between species prevent viable offspring from being produced. |
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Divergence |
Accumulation of genetic differences after isolation from original population; when new population expreriences different selective pressures based on new environment, mutations, and drift; can result in new species. |
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Allopatric speciation |
Population becomes separated by a geographic barrier; prevents further gene flow between groups. |
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Synpatric speciation |
No barrier, but group becomes isolated from orginal; best illustrated by plants; multiplication of chromosome number prevents successfull reproduc to on with original (polyploidy) |
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Adaptive radiation |
Adaptations to a change in environment resulting in a new species; two hypothesis about thid process |
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Phylectic gradualism |
Change to organism is slow, steady process |
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Punctured equilibrium |
Long periods of stability followed by rapid periods of major changes resulting in speciation |
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Extinction |
Permanent loss of a species; over geologic time, species come and go at a fairly steady rate without human interference |
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Mass extinction events |
Widespread disappearances of multiple species due to a catastrophic event like a meteor strike, volcano eruption, earthquake, disease epidemic, etc. |
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Fitness |
How successful an individual is at reproducing and passing on its genes vs. Another individual of the same species. |
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Fossils |
Evidence of evolution. Remains or traces of living organisms, such as bones, teeth, hair, shells, footprints, eggs, seeds, buried sedimentary riocks. |
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Archaeopteryx |
Is a famous fossil of what is considered the first bird; shows characteristics of both dinosaurs and birds, teeth claws and a tail and feathers and wings and a I'm beak like nose |
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Biogeography |
Evidence of evolution. How organisms are distributed over the earth. |
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Homologous structures |
Anatomical structures that are similar due to shared common ancestry. Example. The vertebrae forelimb bones. They evolved from the same species so they have vertebrae, phallenges etc. |
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Analogous structures |
Anatomical features that serve the same function but evolves completely separate from each other without common ancestry. Similarities are due to shared functionality. Torpedo shaped fish for swimming. |
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Vestigial structures |
Reduced or useless structures that remain in modern organisms which had a purpose and were nore developed in ancestral forms. |
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Artificial selection |
Controlling who breeds so that the frequency of certain traits increase. |
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Systematics |
Classification and organization of organisms using traits to establish relationships between taxonomic groups. |
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Taxonomy |
Naming and classifying organisms using a naming system that follows specific rules. |
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Taxonomic groups |
Are hierarchial categories that organisms can be placed in according to their relationship with other members of the group |
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Phylogenetics |
A branch of systematics that studies evolutionary relationships of organisms and places then on a "family tree" called a cladogram |
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Hominins |
True humans (belonging to genus homo) and speciez closely related. Tendency towards bipedalism. |
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Homo habilis |
"Handyman", as they are believed to be first of the group to show tool use. |
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Homo ergaster |
Evolved from habilis in africa and emigrated to asia; taller with a larger beain than habilis, but brow ridges and prognathism remain. |
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Homo erectus |
"Upright man"; evolved from the ergaster in asia. Direct ancester to modern humans, controlled fire, probably first hunter/gatherers. |
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Homo floriensis |
"Hobbit man" |
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Homo neandertalensis |
Archaic humans that evolved between 200,000 -28,000 years ago. Brains were actually larger than modern humans. |
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Homo sapiens |
Modern humans, earliest skeletal remains of what are considered our species were the cro magnons. |
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Multi-regional model |
Is based on homo erectus migrating to different regions and evolving into homo sapiens through similar conditions in each region. |
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African emergence model |
Is based on modern humans developing in africa then separating to different regions. |