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67 Cards in this Set
- Front
- Back
Conditions for H/W Equillibrium
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Very large population size, no migration, no net mutations, random mating, no natural selection
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Australopithecines
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First bipedal ancestral organisms, small cranial capacities (450 cc), large teeth & faces, no evidence of stone tools, Lucy & Lactore
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Theory of Natural Selection
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Organisms whose collection of traists make them the most successful will likely pass their traits on to their offspring
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Reduced Hybrid Fertility
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sterile hybrids (i.e., horse + donkey = sterile mule)
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Hominids
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Common ancestor (5-7 mya)
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Hardy-Weinburg Theorem
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The frequency of alleles and genotypes in a popluation's gene pool will remain the same if only acted upon by sexual recombination and random fertilization
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Anthropoids
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monkeys, apes, humans
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Prosimians
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most primitive primates: lemurs, tassiers
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Polygenic
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multiple alleles affect a trait
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Homo Habilis
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2.5 mya, cranial capacity = 700cc, evidence of stone tools
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Allopatric Speciation
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Takes place in geographically isolated populations
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Sexual Recombination
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rsponsible for the bulk of genetic variation
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Applications of the H/W Equation
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1.) If H/W Equillibrium exists, a population is not evolving
2.) Usefal in data prevalence to harmful alleles |
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Gradualism model
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Species diverge at a slow, gradual pace over long spans of time
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Stabilizing Selection
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The extremes are selected against
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Multiregional hypothesis
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Homo sapiens evolved from H. erectus in seperate geographic parts of the world
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Neanderthals
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lived from about 600,000 - 30,000 ya, evolved from H. erectus in Europe, heavily built, much different from us; same brain size as H. sapiens sapiens
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Genetic drift
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change in allele frequencies due to random chance (bottleneck effect: sever reduction in size causes limited pool; founder effect: freq. in a colony is diff. than of a parent's)
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Directional Selection
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One of the extremes is selected for good
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Descent with Modification
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All organisms share a common ancestor; similar species whare a more recent ancestor; we belong to a tree of life, with some branches blooming and others dying
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Out of Africa Hypothesis
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H. sapiens first evolved in Africa, and then dispersed through Europe and Asia, replacing existing H. erectus populations
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Biological species concept
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a population whose members have the potential to produce fertile offspring is a species
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Microevolution
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any change in the allele frequencies using a population
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Mutations
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heritable changes in DNA that will affect allele frequencies
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Punctuated Equillibrium Model
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Species diverge in spurts of rapid change; Evolution taking place rapidly
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Gene flow
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the flow of alleles in and out of a population as a result of migration
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Homo erectus
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1.8 mya, cranial capacity = 1000cc, sophisticated stone tools, use of fire and hunting, first hominid to leave Africa
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Sexual Selection
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secondary sexual characteristics are enhanced because they increase the chane of mating
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Diversifying Selection
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both extremes are favored over the intermediate
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Adaptive radiation
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Evolution of many species from a single common ancestor
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Galapagos Finches
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The diversity in beak shape played an important role in Darwiin's discovery
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3 Summations of Darwin's Ideas
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Natural Selection is this differential success in reproduction, and its product is adaptation; Natural Selection occurs b/o the enfironment and the variability in the population; Variations in a population arise by chance, but natural selection is determined by reproductive success
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Non-random mating
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Certain genotypes will be selected over another
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Primates
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hands and feet adapted for grasping; binocular vision
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Macroevolution
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Evolution w/ new taxonomic groups (i.e. reptiles ---> birds)
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Gametic isolation
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Failure of gametes to fuse during fertilization (prezygotic)
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Gene Pool
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Pool of genees for a opulation; sum of all alleles of a population
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Uniformitariansim
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Lyell: Geologic processes have been changing phases and has existed in the past
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Temporal Isoluation
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Breeding at different times of the day (prezygotic)
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Diploidy
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harmful recessive traits can be masked in a diploid organism
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Evolutionary fitness
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Darwinian Fitness: measures the contribution an individual makes to the next generation's genepool; Relative fitness: red v. white (80 v. 20 per cent, etc)
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Limitations to the biological species concept
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Existence of fertile hybrids, doesn't account for organisms taht reproduce asexualy, can't distinguish extinct species based on fossil evidence
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Habitat Isolation
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Living in different areas (prezygotic)
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Contributions from Malthus
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"Essay on Principles of Population" : Organisms produce more offspring than can survive (population regulation)
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Evidence for evolution
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Biogeography, fossil record, comparative anatomy, comparative embryology, molecular biology, field studies
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Polymorphism
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multiple forms for a particular trait
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Distinct variations
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two alleles (B or b)
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Artificial Selection
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Choosing traits in plants or animals to perpetuate (i.e. Dog Breeds)
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Reduced Hybrid Viability
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failure to develop into a healthy adult
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Behavioral isolation
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Courtship rituals
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Cline
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gradual change in phenotype over a geographical range
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Mutation
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Only if it occurs in gametes; rare and random events that may result in a new allele; few mutations that are beneficial will be selected for
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Geographic variation
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environment will influence which traits are selected for and against
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Natural Variation
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alleles that are not selected for or against will persist and will add to the variation
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Comparative Anatomy
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homologous structures (similar structures with different functions)
vestigal structures (those no longer used or needed) |
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Heterozygous Advantage
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If the heterozygous genotype has an advantage, both the R and r alleles will be preserved (i.e., sickle cell anemia)
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Sympatric Speciation
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Takes place in geographically overlapping populations
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Mechanical Isolation
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anatomical incapability
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Modern Synthesis
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unifying theme in biology; it includes genetics, anatomy, etc.
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Fossil Record
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Largely incomplete record of fossils
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Frequency dependant selection
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the genotype that is most prevalent becomes selected against
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Biogeography
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the study of geographical distribution of organisms
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Adaptive Evolution
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results from a combination of chance events that produce new genetic variation (sexual recombination and mutation) and natural selection that propogates some variations over the others
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Population genetics
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The study of the genetics for the particular population in individuals
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Theory of Acquired Characteristics
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Lamarck proposed a law of use and disuse by which acquired characteristics explained evolution (disproved by Mendel)
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Field Studies
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watching natural selection take place
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Molecular Biology
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Similarities in nucleotides, genetic code, and proteins
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