Term
| The Origin of Species (2 things) |
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Definition
-species evolved from ancestral species
-natural selection: mecanism for evolution |
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Term
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Definition
PLATO: evolution is counterproductive since the world is made of ideal organisms perfectly adapted to the environment
ARISTOTLE: species are fixed (scale of nature) each organism is placed on a particular rung of ladder of complexity
NATURAL THEOLOGY: Old Testament account of creation where the creator designed each species for a particular purpose
LINNAEUS (1700s): taconomy/ binomial nomenclature: god creates and Linneus arranges. Evolution was irrelevant to his classification system but Darwin uses it as focus for argument (Darwin tries to explain how linneus's similarities between species really happened) |
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Term
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Definition
-show succession of organisms on Earth over time
1. rivers bring sediment to the ocean, and sedimentary rocks containing fossile form on the ocean floor
2. over time, additional strata are added, containing fossils from each time period
3. as sea leve changes and the seafloor is pushed upward, sedimentary rocks are exposed. Erosion by rivers reveals strata, older strata contain older fossils |
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Term
| Darwin's influences: Cuvier / Wallace (date, what he did) |
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Definition
1769-1832, developed fossils/paleontology and opposed evolution: believed in "catastrophism" where periodic catastrophes cause mass extinctions which are repopulated by immigrating species and the few that survive
/ Proposed theory of natural selection around the same time as Darwin, but his work was not as extensive. Darwin published his book so fast becuase of this man |
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Term
| Darwin's influences: Hutton / Lyell |
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Definition
1795, Principle of Gradualism, where there is a profound change in landforms that cumulates slowly but continuously
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1830, Theory of Uniformitarianism where geological processes are uniform and rates and effects balance out over time, sow and subtle.
*DARWIN: if it happened with the earth, why can't it happen with animals? |
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Term
| Darwin's influences: Lamark |
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Definition
1809, one of the earliest models that attempted to explain evolution where organisms evolve to greater complexity and perfection so they are better adapted to their environment
Idea of Use and Disuse: parts used to survive in environment grow bigger and stronger, parts not used deteroriate.
Inheritance of Acquired Characteristics: gene variations that are acquired in your lifetime) |
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Term
| Darwin's background and study |
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Definition
Born in england in 1809, quid med school, joined the clergy, sailed around the world in the HMS Beagle and observed and collected specimens from different habitats.
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Studied finch beaks, and each species was adapted for food on their particular island, fr example deep beaks for cracking large seeds and small ones for small seeds, and during droughts there are fewer seeds so there was an increase of deep-beaked birds. Why would god create such biodiversity? |
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Term
| Descent with Modification (3 things) |
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Definition
-less scary than evolution so it was more believable at the time
-the change in proportions o variations in populations over many generations explains both life's unity and diversity
-all diverse organisms descended from unknown prototype of remote past and were ordered into "groups subordinate to groups" |
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Term
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Definition
| differential success in reproduction results in adaptation of organism to environment over long period of time (each species has favorable taits that survive) |
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Term
| Natural Selection and Adaptation: Observations |
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Definition
| -all species have huge reoroduction potential because if they can't reproduce it's automatic low fitness, and so they need variation for evolution so the good traits can survive (aka 5 colors of Asian lady beetles) |
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Term
| Natural Selection and Adaptation: inferences (3) |
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Definition
-if more individuals are produced than environment can suport, then there is a struggle for existence so a fraction of offspring survive each generation (so Malthus in 1798 saying that species are ONLY here to reproduce must be wrong)
-survival is NOT random: individuals whose inherited characteristics fit them best with the environment will leave more offspring than less fit individuals
-^ leads to gradual change in a population where favorable characteristics accumulate over time |
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Term
| Why we don't have wheels / elephants don't have perfect trunks |
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Definition
-we have a certain gene pool that natural selection/evolution can pick and choose from (can only edit existing variations)
-evolution is limited by historical constraints
-adaptations are often compromises (standing upright = more injuries)
-not all evolution is adaptive |
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Term
| Artificial selection (what is it, ex) |
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Definition
breeding of domesticated plants and animals for desired traits that causes huge changes in populations over time
ex. dog-shows with perfect breed, breeds of cattle in ancient Africa, divergent types of veggies from selecting different parts of wild mustard plant |
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Term
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Definition
| HIV which is constantly and fastly evolving, which makes it hard to find a cure for HIV (or insects?) |
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Term
| 5 things to validate evolution |
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Definition
| biogeography, fossil record, comparitive anatomy, comparitive embryology, molecular biology |
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Term
| biogeography (convergent evolution) |
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Definition
geographical distribution of species (different geographic regions cause different species)
Convergant evolution: organisms that appear similar and related due to similar environments but have evolved independently from separate ancestors, so they are not genetically related |
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Term
| fossil record (transitional fossil) |
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Definition
fossil ages agree with evolution and can show evolutionary missing links
ex. fossilized leg bones of ancient whales link aquatic mammals to terrestrial predecessors
transitional fossil: links past and present becuase it shows two taxanomic groups |
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Term
| comparitive anatomy (homologous structures vs. vestigal organs) |
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Definition
confirms that evolution is a remodeling process
homologous structures: anatomical signs of descent with modification - the basic similarity of forelimbs is a consequence of descent of all mammals from a comon ancester
ex. human, cat, whale, and bat all have very similar fingers and hand bones
vestigal organs: rudimentary homologous structures with marginal or no functions
ex. snakes with pelvis and leg bones |
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Term
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Definition
closely related organisms go through similar stages in embryonic development
ex. all vertebrate embryos with gills, postnatal tails, and pouches, or how frog, cow, human, and cat all have exact same early embry, so they came from a common ancestor |
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Term
| molecular biology (2 things and example) |
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Definition
-more alike the genes and proteins of 2 species, the closer their evolutionary relationship.
-all life forms have a common genetic code
ex. amino acids differ in hemoglobin peptide is different from human (146 peptides)--> monkey (3 diff) --> mouse (27) --> chicken(45) --> frog(67) --> lamprey(125) |
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Term
| population genetics (4 things) |
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Definition
-studies genetic variation within populations
-empasized quantitative characteristics
-reconsildes Mendelism and Darwinism
-provides a genetic basis for variation and natural selection
-individual organisms are selectied, but POPULATIONS evolve, NOT individuals |
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Term
| population / species / gene pool |
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Definition
| localized group of individuals of same species / individuals with potential to interbreed and produce fertile ooffspring / total aggregate of genes in a population that consist of all alleles in all individuals (varies from area to area and evolution is the change of the gene pool over time) |
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Term
| hardy weinberg theorem (3 things) |
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Definition
-describes gene pool of nonevolving population (large, no migrations, no net mutations, random mating, no natural selection)
-frequences of alleles and genotypes in a population's gene pool will remain constant over generations unles sacted upon by agents other than mendelian segreagation and recombination |
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Term
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Definition
p^2 + 2pq + q^2=1, where p is frequency of dominant allele and q is frequency of recessive
ex. 1 in 50 babies born with PEUP (recessive) so 1/50=q^2, square root that to find q and 1-q to find p |
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Term
| microevolution (def. and 4 causes) |
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Definition
| change in populations frequencies of alleles (genetic drift, natural selection, gene flow, mutation) |
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Term
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Definition
SMALL POP SIZE
-changes in gene frequences due to chance events when populations are finite in size
-smaller the sample, the more chance of deviation from idealized result
-BOTTLENECK EFFECT: population # drastically reduced by disaster, so alleles may be over, under, or not represented among surviors, which is why endangered species need to be protected
FOUNDER EFFECT: new population started by a few individuals taht don't represent gene pool of larger population, ex human pops that start from colonists where the genes go from whole population of engliand to only the genes of the few colonists |
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Term
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Definition
MIGRATION
genetic exchange due to migration ofg fertile individuals or gametes between population that increase the frequency of particular alleles in next generation and reduces differences between species |
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Term
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Definition
NATURAL SELECTION
-change in organisms DNA tat when transmitted into gametes can immediately change the gene pool of a population
-any single mutation alone doesn't have much effect on a large pop in a single generation
-original source of genetic variation, so it serves as raw material for natural selection |
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Term
| genetic variation / polymorphism |
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Definition
variation that includes inheritable and nonheretible traits,
ex. butterflies have genetically identical coleration at loci but emerge at different seasons which causes different phenotype (cumulation of GENOTYPE and ENVIRONMENTAL INFLUENCES)
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2 or more discrete characteristics present that are in contrasting forms called "morphs"
ex. humans polymorphic for a variety of characters both physical and biochemical, but height doesn't work because it is quantitative and varies in continuum |
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Term
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Definition
| differences in gene pools between populations or subgroups (produced when environment is patchy or if dispersal of individuals is limited) of populations that may result from natural selection due to differences in local environmental factors or genetic drift |
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Term
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Definition
-geographic variation in the form of graded change in a trait along a geographic axis ex. as altitide gets higher the plant gets smaller
-represents ones where individuals from neighboring, genetically different populations interpreed
-may reflect the influence of natural selection on gradation (direct environmental effects on phenotype) |
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Term
| preserving variation (preventing natural selection from reducing it!) |
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Definition
DIPLOIDY: prevents elimination of recessive alleles via selection but doesn't impact phenotype in heterozygote (it is the heterozygote protection that mantains the alleles not suitable under present conditions, like most recessive, but beneficial when environment changes)
BALANCED POLYMORPHISM: maintains genetic diversity (stable frequencies of 2 or more phenotypes) in a population via natural selection by HETEROZYGOTA ADVANTAGE |
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Term
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Definition
-individuals heterozygoes at a particular locus have greater survivorship and reproductive success than homozygotes, which promotes balanced polymorphism
ex. heterozygous advantage maintains genetic diversity of a chain of hemoglobin where homozygous individuals have sickle-cell disease and heterozygous individuals are resistant to malaria! |
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Term
| modes of selection: DIRECTIONAL |
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Definition
SHIFTED RIGHT OR LEFT - shifts frequency curve for a phenotypic character in one direction by favoring what had been rare individuals, and is common during periods of environmental change or when members of a population migrate to a new habitat with a different environment
ex. beak size in Galapagos population of medium ground finch where beak depth increased every dry year |
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Term
| modes of selection: DIVERSIFYING |
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Definition
FORMS 2 MOUNDS ON EITHER SIDE - environmental conditions favor individuals at both extremes of phenotypic range over intermediate phenotypes
ex. larger-billed black-bellied seedcrackers are efficient in feeding on hard seeds, and smaller bills are efficient with soft seeds, and since there is no medium-billed efficienty it is selected against and the extremes are favored |
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Term
| modes of selection: STABALIZING |
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Definition
SMALLER/HIGHER LUMP IN MIDDLE - favors intermediate variants and acts against extreme phenotypes, so variation is reduced and predominant phenotypes are maintained
ex. human birth weight |
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Term
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Definition
-males and females of a species differ in secondary sexual characteristics not directly associated with reproduction (sexual dimorphism), like coloration, size, or feature differences
-male vertebrates are usually the larger and showier sex |
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Term
| intrasexual selection VS. intersexual selection |
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Definition
direct competition of one sex (usually males dighting temself) for mate sof the opposite sex, where dominance may be determined by direct physical battle or ritualized displays
ex. peacocks, deer w/ antlers
VS.
individuas of one sex (usually female) choosing their mates of opposite sex, so some traits that attract females are not adaptive and may be disafvantageous(female choices perpetuate certain alleles) |
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Term
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Definition
ANAGENESIS (phyletic evolution): accumulation of heritable changes in a population to change the species over time
CLADOGENESIS (branching evolution): budding of new species from parent species when there is a mating with some mutation |
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Term
| macroevolution vs. speciation vs. biological species concept |
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Definition
| origin of new taxonimc groups vs. origin of new species vs. can't reproduce with another species or offspring are infertile |
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Term
| Barriers to separate species |
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Definition
PREZYGOTIC: habitat, behavioral, tempral, mechanical, gametic (BEFORE embryo is formed)
POSTYGOTIC: reduced hybrid viability, reduced hybrid vertility, hybrid breakdown (AFTER embyro is formed) |
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Term
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Definition
HABITAT ISOLATION: populations live in different habitats and do not meet
BEHAVIORAL ISOLATION: little or no sexual attraction between males and females
TEMPORAL ISOLATION: mating or flowering occurs in different seasons or times of day
------mating-------
MECHANICAL ISOLATION: structural differences in genetilia or flowers prevent copulation or pollen transfer
GAMETIC ISOLATION: female and male gametes fail to attract eachother or are inviable (can't live on it's own)
------fertilization------- |
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Term
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Definition
------fertilization-------
REDUCED HYBRID VIABILITY: hybrid zygotes fail to develop or fail to reach sexual maturity (no cell signaling pathways, etc)
REDUCED HYBRID FERTILITY: hybrids fail to produde functional gametes = sterile
HYBRID BREAKDOWN: offspring of hybrids have reduced viability or fertility (pretty much none = sterile) |
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Term
| modes of speciation: allopatric vs. sympatric |
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Definition
| new population forms geographically apart from parent pop vs. new species within geographically overlapping opulations becuase there is some barrier that allows different niches within the same location |
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Term
| adaptive radiation over millions of years(3 things) |
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Definition
-evolution of many diversely adapted species from a common ancestor
-adaptive = changing based on factors, radiation = radiating into separate species
-island chains are key sites becuase they are far enough for populations to evolve in osilation but close enough for dispersion to occur |
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Term
| barriers in sympatric populations |
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Definition
polyploid speciation in plants: creating new species by changing the number of chromosomes
POLYPLOIDY: extra set of chromosomes
AUTOPOLYPLOID: self-polination with nondisjunction to form polyploid
ALLOPOLYPLOID: two separate species with nondisjunction to form new polyploid
Botanist Hugo De Vries: polynate to get polyploid plants
animals: reproductively isolated from parents within geographical range if they depend on different resources or females mated preferentially with males having specific genes |
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Term
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Definition
GRADUALISM: big changes occur by accumulation of many small ones so species diverge slowly and gradually
PINCTUATED DQUILIBRIUM: species diverge in spurts of relatively rapid change and are modified when first budded off parent then change a little ( mutations, disasters, etc) |
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Term
| Evolution of Morphology vs. Intelligent Design |
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Definition
| Descent with modification accounts for major morphological transofmarions (ex. a rang eof eye comlpexity among mollusks) vs. can't change structure like the mollusk so there must be a reason that the perfect eye was created in the first place! You can't gradually change it because if you remove one small part, itll all fall apart! |
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Term
| fossil record (and drawbacks), + sedementation |
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Definition
-ordered array in which fossils apppear within layers of sedimentary rocks that mark the passing of geological time
SEDEMENTATION: layers of minerals depositied in intervals (strata) in which organisms settle and are preserved
drawbacks: dossil discovery is based on a series of chance events, fossil record is incpmlete, facors certain long-lived, shelled species lik scorpions or trilobites |
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Term
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Definition
shells, bones, or teeth that are petrified and preseved between layers of sandstone or shale (these petrifications are replicas of organisms, aniaml burrows, footpritns, or impressions)
ex. leaf impression, rane, petrified trees, dino tracks, dinosaurs, mammoth tusks, trilobites |
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Term
| geological time scale (each era separated by some mass extinction!) |
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Definition
4 eras representing distinct ages in the history of life on Earth:
1. Precambrian: 4600mil, origin of earth
2. Paleozoic - 543 mil, origin of animal phyla, pangea
3. mesozoic - 245 mil, dinosaurs gymno/angiosperms, pange splits up
4. Cenozoic - 65, mammals, birds, insects, primates, humans, split up pangea --> curent day (IMPORTANT!) |
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Term
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Definition
RELATIVE DATING: compare relative ages of fossils based on younger sediments superimposed ton older ones
ABSOLUTE DATING: age given in years
-RADIOMETRIC: measuring radioactive isotopes in fossils
HALF-LIFE: number of years it takes for half of the original sample to decay
ex. carbon-14 = 5730 years
Uranium 238 = 4.5 billion years |
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Term
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Definition
| factors correlate with spatial distribution of life and extinctions: drifting continents aka plate tectonics, climates and ocean currents changing, or emergence of volcanic islands |
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Term
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Definition
WHY: habitat destroyed, unfavorable environment, impact of other species
INFLUENCE: mass extinctinctions are followed by extensive diversification of taxonomic groups
2 MAIN EXTINCTIONS:
-permian mass etinction: 250 million years ago
-cretaceous mass extinction - 65 million years ago (ice age shiit) |
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Term
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Definition
study of biological diversity in an evolutionary context
PHYLOGENETICS SYSTEMATICS: classification based on evolutionary history
TAXONOMY: naming and classifying organisms
LINNAEUS: systeme naturale - first to classify organisms in 18th century
BINOMIAL: 2 part latin name (genus species) ex. panthera pardus for leopard, panthera leo for lion, panthera tigris for tiger |
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Term
| "Trauma for planet Earth and its Cretaceous life" |
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Definition
they think it wsa a huge meteor that hit near the yucitan peninsula near mexico (Chicxulub crater)
EVIDENCE: there is a layer of uridium that you can't get from anywher but space, and it is unifform from that many years ago |
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Term
| Hieracrchial classification |
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Definition
| grouping species into broader taxonomic categories (KINGDON, PHYLUM, CLASS, ORDER, FAMILY, GENIUS, SPECIES) where "taxon" is a level, with each more comprehensive than the previos, and phylogenetic trees that are diagrams illustrating evolutionary relationships among organisms |
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Term
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Definition
| CLADISTIC ANALYSIS: studying evolutionary relationships by looking at fossil records, anatomical comparisons, and genetics where a CLADOGRAM is a tree based on a series of two way brnaches where each point represents the divergence of two species |
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Term
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Definition
likeness due to shared ancestry
ex. forelimbs of mammals
vs.
likeness due to similar environments and natural selection NOT from common ancestor aka convergent evolution
ex. wings of bats and birds |
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Term
| construcing cladograms / moleculer clocks |
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Definition
| distinguish between homology and analogy by identifying shared derived characteristics and shared primitive characteristics, and comparing nucleotide sequences |
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Term
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Definition
| method for placing the origin of taxonomic groups in time based on observation that at least some regions of genomes evolve at constant rates |
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Term
| cladistics (taxonomy- class, order, family, etc) vs. linneus (binomial nomenclature) |
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Definition
| genotypes and evolution vs. only phenotype like eggs? fur? walk/swim? 4 legs? |
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