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biooo-Evolution Chapterrr


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homologous structures and example
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
the theory that living organisms arise from other living organisms
heterotroph hypothesis
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?
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
today- 78% nitrogen, 21& oxygen, small% Carbon dioxide
then- hydrogen, water vapor, ammonia, and methane (similar to jupiter and saturn)
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
-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?
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
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
natural selection-nature selects all the survivors-without it, everything falls apart
-6 points of darwins theory
THeory of Evolution Part 1- o
overproduction- more offspring are produced than are needed-
-species population is relatively constant
-only a small # of offspring survive to reproduce
Point 2- c
-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
-no individuals are exactly alike
-individual differences may or may not increase organisms chance of survival
Point 4-a
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
natural selection-
the environment selects plants and animals with optimal traits to be parents
Point 6- s
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
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
a group of the same species living together in a given region and are able to interbreed
gene pool
the total of all of the alleles present in a population
what are some sources of variation
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
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?
1) the population must be large
2) Individuals must not migrate in or out of the population
-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?
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
-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
ability to mimmick a different creature
directional selection
extreme phenotype becomes a favorable adaptation
-results from environmental changes or species migration
ex. long neck giraffes
stabilizing selections
average phenotype is favored over an extreme phenotype
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
-both ends of the extreme phenotype are favorable adaptations over the average
convergent evolution
natural selection causes unrelated species to resemble each other
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
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
a particular region of the earth where a particular species is found
-type of speciation
-anything that prevents 2 groups within a species from interbreeding
geographic isolation
population is divided by a natural barrier
ex. mountain, river, destert, etc.
reproductive isolation
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
-a species changges into a number of different species, each living in a new environment
--organisms evolved from a common ancestor
type of isolation

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