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90 Cards in this Set
- Front
- Back
How old is the earth?
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Around 4.6billion years old
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What was the primitive atmosphere made of?
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Carbon dioxide, nitrogen, ammonia, and methane
-no ozone layer -lots of UV light hitting the ground -lots of lightening |
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What is the current atmosphere made of?
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78% nitrogen
21% Oxygen .03% carbon dioxide |
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Who was the Oparin hypothesis propopsed by?
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Alexander Oparin (1920s)
-independently described by Haldane around the same time |
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What is the Oparin Hypothesis?
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-Life evolved from nonliving substances by interacting with the natural environment
-lighting and UV radiation provided the energy for the chemical reactions that produced the major organic macromolecules |
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What is the heterotroph hypothesis?
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Heterotrophs (anaerobic prokaryotic cells that used organic compounds for food)--> Photosynthetic bacteria (gave off oxygen) --> eukaryotic cells (possibly came from cells which engulfed other cells which became organelles...)
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What did Miller and Urey do in 1950?
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Test Oparins ideas about the origin of life
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How did they test Oparins ideas?
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Laboratory experiments verified that these ideas were in fact possibly and probably under the conditions believed to exist on the primitive earth
-they mixed gases that were in primitive atmosphere with a spark from an electrode -found amino acids and other organic compoundsw necessary for life as result |
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What was a popular hypothesis of where cells came from?
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Monomers --> polymers --> membranes --> Cells
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why were monomers important in milley and ureys experiment
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They were found in the "organic soup"
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What were Miller and Ureys 2 hypothesis' with polymers?
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-small puddles evaporated and concentrated amino acid pools were left
-monomers were in clay crystals and joined with other monomers |
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What were miller and ureys hypothesis about membranes?
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-formed around vcery primitive "pre-cells" called protocells, which contained only random nutrients
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What were miller and ureys hypothesis about cells?
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THey were likely developed from proto-cells
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What was the pinching in hypothesis?
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Organelles were formed by folding in and pinching off of portions of the cell membrane
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What is the Endpsymbiont hypothesis?
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Organelles such as the mitochondria and chloroplase were formed by larger prokaryotic cells engulfing smaller cells
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what are the 2 hypothesis' of how we arised as we know today?
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spontaneous generation
-biogenesis |
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spontaneous generation
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The idea that life could come from nonliving matter- proposed by aristotle
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biogenesis
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the principle that life only comes from life
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How did Redi try to disprove spontaneous generation
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did an experiment with meat jars
open jars --> maggots sealed jars --> no maggots jars covered w/ cloth--> no maggots (Strong evidenec that things only arise from living things) |
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How did Needham try to prove spontaneous generation?
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-broiled broth, then sealed loosely with cork stoppers--> bacteria appeared
(concluded bacteria came from broth by spontaneous generation) |
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How did Spallazani try to disprove spontaneous generation?
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repeater Needhams experiement with more tightly sealed flasks-->no bacteria
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How did Pasteur disprove spontaneous generation?
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Experimented with broiled broth and curved neck flasks:
-boiled broth in regular flasks-->bacteria -boiled broth in curved neck flasks--> no bacteria |
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definition of evolution
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A gradual change over time
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types of evolution
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geologic evolution
organic evolution |
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Geologic evolution
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the slow change of the eaarth itself since its formation about 4.6 billion years ago
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organic evolution
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the change of a species since its appearance on earth
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definition of a fossil
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any trace or remains of an organism that has been preserved
-the fossil record provides the greatest evidence for evolution -by comparing the remains of ancient organisms to current organisms we can determine whether or not organic evolution has occured |
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Homologous structures
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are similar in structure and development, but have different functions
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analogous structures
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are similar in appearance and function, but have different structures
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vestigial structures
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are remnant structures with no current usage (over 100 in humans)
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what are the 2 hypothesis' of how we arised as we know today?
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spontaneous generation
-biogenesis |
|
spontaneous generation
|
The idea that life could come from nonliving matter- proposed by aristotle
|
|
biogenesis
|
the principle that life only comes from life
|
|
How did Redi try to disprove spontaneous generation
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did an experiment with meat jars
open jars --> maggots sealed jars --> no maggots jars covered w/ cloth--> no maggots (Strong evidenec that things only arise from living things) |
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How did Needham try to prove spontaneous generation?
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-broiled broth, then sealed loosely with cork stoppers--> bacteria appeared
(concluded bacteria came from broth by spontaneous generation) |
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How did Spallazani try to disprove spontaneous generation?
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repeater Needhams experiement with more tightly sealed flasks-->no bacteria
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How did Pasteur disprove spontaneous generation?
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Experimented with broiled broth and curved neck flasks:
-boiled broth in regular flasks-->bacteria -boiled broth in curved neck flasks--> no bacteria |
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definition of evolution
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A gradual change over time
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types of evolution
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geologic evolution
organic evolution |
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Geologic evolution
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the slow change of the eaarth itself since its formation about 4.6 billion years ago
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organic evolution
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the change of a species since its appearance on earth
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definition of a fossil
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any trace or remains of an organism that has been preserved
-the fossil record provides the greatest evidence for evolution -by comparing the remains of ancient organisms to current organisms we can determine whether or not organic evolution has occured |
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Homologous structures
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are similar in structure and development, but have different functions
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analogous structures
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are similar in appearance and function, but have different structures
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vestigial structures
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are remnant structures with no current usage (over 100 in humans)
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embryology
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-similar development is a clue towards evolution
-similarities are greatest in early stages -later in development organisms resemble adults of their own species |
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biochemical similarities
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-close phylogenetic relationships based on morphology and anatomy indicate in DNA and protein structure
-related organisms have similar hormones and enzymes-->allows humans to recieve pig insulin for treatment for diabetes -testing for similarity can be done by injecting foreign blood and examining the antibodies produced |
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Lamarck's theory
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(coninced that species evolve from other species)
-the more an organism uses a structure, the stronger and more significant it becomes -structures not used and developed become smaller and weaker |
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Theory of acquired characteristics
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-characteristics developed through use and disuse could be passed on to offspring
-ie. giraffes constantly stretch their necks making it grow (true) it can be passed on to offspring (false) |
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How did Weismann disprove the 2nd part of the theory of acquired characteristics
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he cut off the tails of mice for 22 generations and saw that no short tailed mice evolved
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Who was Darwin?
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A naturalist who traveled around the world observing organisms and differences between them
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What were Darwin's finches?
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several species of finches there (island off of Ecuador) are generally alike, but wioth slight variations
-adapted to fit different nickes -returned to England in 1836 convinced of evolution but unable to prove it |
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What were Darwins 6 components of his theory of evolution by means of natural selection?
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-overproduction
-competition -variation -adaptions -natural selection -speciation |
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Overproduction
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-most spsecies produce more offspring than necessary to maintain the population
-remain constant only because not all members live to reproductive age |
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Competition
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-offspring of a population compete for resources
-only a fraction survive to reproduce again |
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Variation
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-individuals in a population are not identical
-certain differences may prove benefecial |
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Adaptions (of a species NOT of an individual)
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-an inherited trait which increases chances fro survival
-individuals with favorable adaptions survive to pass those on to the next generation |
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NATURAL SELECTION (main idea of Darwin's theory)
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-environment selects individuals with the favorable adaptions to be the parents for the next generation
-new generation tends to inherit favorable adaptions |
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Speciation (a side not of Darwin's theory)
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-ocer time favorable adaptions accumulate while unfavorable ones disappear
-eventually accumulated changes are so great that the result is a new species |
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definition of species
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A group of organisms that mate and produce fertile offspring under natural conditions
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Two types of rates of evolution
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gradualism
punctuated equilibrium |
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gradualism
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Darwin's idea that evolution occurs slowly and continuously over many years
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Punctuated Equilibrium
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-species remains the same for long periods of time
-sudenly over a short period of time (100-1000s of years) chances occur and new species arise |
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Does evolutino happen to populatiosn or individuals
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POPULATIONS
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Definition of population
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a group of organisms of the ame species living in the same area at the same time and interbreeding
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Definition of population genetics
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changes in the genetic makeup of a population
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definition of gene pool
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total of all the genes in a population
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definition of gene frequency
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the frequency of a gene within a population
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definition of genetic equilibrium
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gene frequencies do not change from generation to generation
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What are DeVries' Genetic sources of variation
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-mutations
-genetic recombination -migration -nenetic drife (-change in gene pool of small popultions brought on by change -if only a few individuals carry a gene and they do not reproduce successfully there will be a change in the gene frequency) |
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Hardy-Weinberg Law
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-sexual reproduction alone does not affect genetic equilibrium
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what 4 conditiosn must occur in order to have genetic equilibrium (according to h-w law)
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-population must be large
-migration must not occur (neither immigration or emigration) -mutatiosn must not occur -mating must be completely random |
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Why is the law still useful even if the 3rd and 4th conditions are almost never met
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-It provides a means for determining whether evolution is occuring in a population
-The fact that frequencies change indicates that evolution is occuring -the extent of variation from the law indicates the rate of evolution |
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What does natural selection disrupt?
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Natural selection disrupts gene frequencies
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What is directional selection?
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One extreme phenotype becomes the favorable adaption
-usualy occurs with environmental change or migration |
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What is stabilizing selection?
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The average phenotype becomes favorable while extremes are highly unfavorable
-operates in many populations and often maintains genetic equilibrium |
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What is Disruptive Selection?
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Both extreme phenotypes become favorable while the average is unfavorable
-often results in two subpopulations which eventually become two seperate species |
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How does a new species emerge?
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-Each species inhabits a region of the earth, which its range.
-Members of the same species may shoe minor differences throughout their range -if evolution favors the variations, two separate species may result |
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What are some types of variation?
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-Isolation
-Polyploidy -Adaptive radiation |
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Isolation
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-The gene pool becomes isolated in 2 groups and the groups no longer interbreed
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Polyploidy
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-Abnormal mitosis or meiodid reults in a reproductively isolated group, which is a new species
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Adaptive radiation
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population spreads into different regions, each adapting to tis new environment and becoming separate species (Darwin's Finches)
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How can we identify promates?
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-eyes face forward allowing to see in 3-D
-complex brains -an opposable thumb -flexible shoulders and rotating forelimbs |
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