biooo-Evolution Chapterrr
Terms
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- homologous structures and example
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different organisms that have parts that are similar in structure and embryological development but have different forms and functions
ex. human hand, whale pectoral fin, and a bats wing - analogous structures
- similar external forms and functions but different internal structures
- biogenisis
- the theory that living organisms arise from other living organisms
- heterotroph hypothesis
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proposes that groups of organic molecules were formed from the chemical elements in the Earth's primitive ocean-the organic molecules combined, using energy from heat, lightning, solar radiation, and radioactive materials in the rocks
1st organisms- heterotrophs-do not make their own food-like anaerobic bacteria-used free organic molecules in the sea for food-genetic changes made photosynthetic forms of life (autotrophs) which released oxygen and made aerobic forms of life - who developed/supported the heterotrpoh hypothesis?
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AI Oparin-experimental data showed that life could have begun in or near the ocean
Stanley Miller-made amino acids in the laboratory to support the hypothesis - differences between earth then and now: part of heterotroph hypothesis
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ATMOSPHERE
today- 78% nitrogen, 21& oxygen, small% Carbon dioxide
then- hydrogen, water vapor, ammonia, and methane (similar to jupiter and saturn)
ENERGY
today- ultravoilet radiation absorbed by the ozone, visible light reaches the ground, x-rays, lightning, radioactive elements
then- same except also the new formed earth itself
TEMPERATURES
-much higher then-oceans at boiling point - what did the ocean being "thin, hot spup" have to do with the heterotroph hypothesis
- under these conditions there were enough energy and inorganic materials to break chemical bonds and reform more complex organic compounds: 1) nucleotides 2) amino acids 3) sugars
- what was stanleyt miller's experiment
- he duplicated the primitive earth environment
- what was AI Oparin's hypothesis?
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that protein likw aubstances called coa cervates formed aggrefates (clusters of large molecules) which were surrounded by a shell of H20 molecules-h20 molecules formed a simple membrane which allowed them to 1) develop biochemical system
2) absorb material from the environment
3) grow in size -splitting - Lamarck's theory of evolution
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1) the principle of use and disuse- the more an animal uses a part of its body, the stronger and more developed it becomes (true)
2) the inheritance of acquired characteristics-the characteristics of use and disuse could be passed on to its offspring (false) - august weisman
- disproved lamarcks theory of acquired characteristics by removing the tails of mice for 22 generations and all the offspring produced had tails of normal length
- Darwins theory of evolution
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natural selection-nature selects all the survivors-without it, everything falls apart
-6 points of darwins theory - THeory of Evolution Part 1- o
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overproduction- more offspring are produced than are needed-
-species population is relatively constant
-only a small # of offspring survive to reproduce - Point 2- c
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competition-
-food, water, shelter, and living space are needed
-compete against all individuals (same and diff. species)
-only a small # of offsrping survive to reproduce - Point 3- v
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variation-
-no individuals are exactly alike
-individual differences may or may not increase organisms chance of survival - Point 4-a
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adaptations-b/c of variations
any kind of inherited trait that improves an organisms chance of survival and reproduction in a given environment - Point 5-ns
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natural selection-
the environment selects plants and animals with optimal traits to be parents - Point 6- s
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speciation-over time (many generations)
-favorable adaptations increase in a species
-unfavorable ones will disappear in a species
the accumulated (positive) changes will ultimately result in a new species - gradualism
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possible rate of evolution
-the evolution of a new species occurs slowly and continuously over thousands/millions of years through the accumulation of small variations - puntuated equilibrium
- long periods of no change (equilibrium), then suddenly, in a short time frame, 100 or 1000 years, a new species is formed
- population
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a group of the same species living together in a given region and are able to interbreed
INDIVIDUALS DO NOT EVOLVE, POPULATIONS DO - gene pool
- the total of all of the alleles present in a population
- what are some sources of variation
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1) mutations
2) genetic recombination
3) migration-movement of an individual in or out of a given population
4) genetic drift-small populations-a change in the gene pool brought about by chance-decrease the variation of a gene pool - genetic equilibrium
- the condition in which allele frequencies (how often an allele occurs) do not change from one generation to the next
- Hardy-Weinberg Law
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sexual reproduction does not alone affect genetic equilibrium
-random mating will ensure that the allele frequency remains unchanged - what are the 4 conditions of the hardy weinberg law?
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FOUND IN NATURE:
1) the population must be large
2) Individuals must not migrate in or out of the population
ALMOST NEVER FOUND IN NATURE:
-Mutations must not occur
-reproduction must be completely random
*all individuals, not matter their genetic make-up, must have the same chance to produce offspring - how does the hardy-weinberg law allow is to discover if evolution os occuring in a population?
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1) failure is a sign that evolution is happening
2) the amount of variation from the prediction is a measure of the speed of evolutionary change - structural adaptation
- involves the organism's body
- physiological adaptations
- involves the metabolism of the organism
- camoflauge
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-an adaptation
-the blending of the organism with its environment
ex. warning coloration and mimicry - warning coloration
- is an indication of whether or not an organism is dangerous
- mimicry
- ability to mimmick a different creature
- directional selection
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extreme phenotype becomes a favorable adaptation
-results from environmental changes or species migration
ex. long neck giraffes - stabilizing selections
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average phenotype is favored over an extreme phenotype
*MOST COMMON TYPE OF SELECTION*
ex. mice in cold climates- small mice cannot borrow low enough and get eaten by a predator-large mice-wrong size and surface area/volume - disruptive selection
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-rare
-both ends of the extreme phenotype are favorable adaptations over the average - convergent evolution
- natural selection causes unrelated species to resemble each other
- coevolution
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two or more species change in response to each other through competition or cooperative adaptations
-reduces competition between species and benefits all species involved - english peppered moths
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found in england
-come in light and dark colors (dark WAS rare)
before 1850, light ones had a greater chance for survival b/c their coloration matched the lichen that covered the trees
-industrial revolution causes pollution, which darkened the trees, killed the lichen, and the dark phase individuals became dominant - range
- a particular region of the earth where a particular species is found
- isolation
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-type of speciation
-anything that prevents 2 groups within a species from interbreeding - geographic isolation
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population is divided by a natural barrier
ex. mountain, river, destert, etc. - reproductive isolation
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two isolated groups lose the ability to interbreed
-differences in courtship (behavior that initiates mating)
-differences in mating time
-differences in sex organ structure - adaptive radiation
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-a species changges into a number of different species, each living in a new environment
--organisms evolved from a common ancestor - polyploidy
- type of isolation