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51 Cards in this Set
- Front
- Back
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fossil record |
uranium used for dating; transitional forms link birds to dinosaurs and whales to land-dwelling ancestors |
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biogeography |
geographic distribution of species ex. Australia has marsupials because it was isolated |
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comparative anatomy |
We see homology in anatomical structures. |
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vestigial structures |
remnants of structures that served important functions in the organism's ancestors (ex. arrector pili muscle) |
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comparative embryology |
early embryonic stage of different species is identical (ex. gill pouches, yolk sac, and post-anal tail) |
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molecular biology |
we sequences genomes of different species and see how similar they are; some animals that look similar actually have very different DNA |
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overproduction |
populations tend to produce more offspring than the environment can support; struggle for existence is inevitable |
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individual variation |
individuals in a population vary |
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natural selection |
shown by overproduction and individual variation |
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natural selection and viruses |
we have resistant MRSA and HIV |
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modern synthesis |
the combination of genetics with evolutionary biology |
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population genetics |
studies populations, not individuals; allows the study of modern synthesis |
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population |
group of individuals of the same species living in the same place at the same time |
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Hardy-Weinberg formulas |
p + q = 1: frequency of alleles p^2 + 2pq + q^2 = 1: genotype frequencies p is heterozygous dominant, q is heterozygous recessive |
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microevolution |
a change from generation to generation of a population's allele frequencies
-changes in Hardy-Weinberg "equilibrium" |
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mechanisms of microevolution |
genetic drift -bottleneck effect -founder effect gene flow mutation |
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genetic drift |
a change in the gene pool of a small population due to chance -bottleneck effect: disasters (earthquakes, floods) kill large numbers of individuals, leaving a small surviving population, which may not have the same gene pool -founder effect: establishment of a new population whose gene pool differs from the parent population (like the pilgrims on the Mayflower) |
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gene flow |
when fertile individuals move in or out of a population and mate in a new population |
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mutation |
changes in an organism's DNA |
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three outcomes of natural selection |
directional selection: it becomes better for the organism to become one type of thing (bell curve shifts to one side) disruptive selection: it is better to be at either extreme, but not the average stabilizing selection: it is best to be the average |
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Why is sickle-cell so prevalent in Africans and African-Americans? |
In areas where there is malaria, only people who have normal blood cells are affected -if you have sickle-cell, you won't get malaria when you're bitten -heterozygotes (Rr) usually don't get sickle-cell OR malaria (heterozygous advantage) |
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macroevolution |
major changes in the history of life |
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speciation |
formation of new species |
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biological species concept |
a species is a population or group of populations whose members have the potential to interbreed with one another in nature to produce fertile offspring |
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pre-zygotic barriers |
-temporal isolation (mate at different times of year) -habitat isolation (you live in different places) -behavioral isolation (no sexual attraction between populations) -mechanical isolation (parts don't fit together) -gametic isolation (gametes fail to unite) |
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reproductive barriers |
prevent species from mating |
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post-zygotic barriers |
-hybrid inviability (embryo dies or organism dies early in life; doesn't reach sexual maturity) -hybrid sterility (organism that is born can not give birth to any others) -hybrid breakdown (live birth, but offspring is very feeble) |
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allopatric speciation |
geographic barrier forms; isolates some species but not others; most common in small, isolated populations -doesn't ALWAYS lead to formation of a new species |
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sympatric speciation |
no geographic isolation; more common in plants than other animals -random genetic change produces a reproductive barrier -how we have so many polyploid plants today |
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punctuated equilibrium |
species most often diverge in spurts of relatively sudden change (ex. onset of polyploidy)
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exaptation |
structure that evolves in one way and can later adapt for other functions |
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evo-devo |
evolutionary and development novelty; very few genetic changes; slight changes in genes that program the rate, timing, and spatial pattern of development can have profound effects |
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paedomorphosis |
retention of juvenile features in an adult (ex. axolotl or human skull vs. chimp skull) |
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geologic time scale |
precambrian, paleozoic, mesazoic, cenazoic |
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What happens to organisms during the dramatic shifts in land movements? |
-major geographic isolation (allopatric speciation) -led to extinctions when organisms found themselves in environments in which they couldn't adapt |
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Did a meteor kill the dinosaurs? |
-How did the iridium get into the clay layer from 65 million years ago? -Chicxulub crater was found near Mexico's Yucatan Peninsula, which could have blocked sunlight and disturbed the climate for months |
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systematics |
study of the diversity and relationship of organisms past and present |
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taxonomy |
identification, naming, and classification of species |
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binomial naming system |
Carolus Linnaeus developed binomial naming system which is made up of genus and species name |
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Classifications |
domain>kingdom>phylum>class>order>family>genus>species |
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phylogeny |
evolutionary history of species -how an organism is named should reflect its place in evolution -create phylogenietic trees |
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convergent evolution |
different organisms have similar traits simply due to environment, not because they have a common ancestor |
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cladistics |
the scientific search for clades; looks at genome sequence |
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clades |
ancestral species and all of its descendants = a branch in the tree of life |
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kingdoms (5) |
prokaryotes (bacteria), protists, plants, animals, fungi |
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domains (3) |
domain bacteria, domain archaea, domain eukarya |
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Why is a small, isolated population more likely to undergo speciation than a large one? |
The population already lacks a lot of genetic variation, so a small event will have a more dramatic effect on the gene pool. (Also likely to become extinct) |
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spontaneous generation |
life can emerge from inanimate material -Louis Pasteur disproved in 1862 -added to cell theory |
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biogenesis |
all life comes from pre-existing life -founded by Pasteur |
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Current theory on development of organisms (4 stages) |
1. Abiotic synthesis of small organic molecules, such as amino acid and nucleotide monomers 2. joining of small molecules into polymers including proteins and nucleic acids 3. origin of self-replicating molecules that eventually made inheritance possible 4. packaging of all these molecules into pre-cells, droplets with membranes that maintained an internal chemistry different from the environment |
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Stage 1: Abiotic synthesis of organic monomers |
In 1953, Harold Urey and Stanley Miller -created a system of glass beakers and tubes in which they recreated early earth atmosphere, with "sea" -after a week, amino acids formed in the "sea" |
