Changes in allele frequencies over time. "Descent with modification."
What 3 things can evolution be due to?
1) Natural Selection (adaptive, non-random) inc. sex/kin selection 2) Genetic Drift (non-adaptive,random) 3) Artificial Selection/ Experimental Evolution
2 importances of studying evolution
1) Fundamental Importance 2) Applied importance (antibiotic-resistance) (crop/animal breeding)
order 3 scientists in history of evolutionary biology
1) Lamarck - proposed transmutation of species through time and adaption from simple to complex ones 2) Darwin/Wallace - descent with modification from a common ancestor 3) Modern Synthesis (1932-53) evo is gradual results from small changes acted upon by natural selection
3 general sources of evidence for evolution
1) Change through time 2) From fossil record 3) Common ancestry
Sources of evidence for changes through time suggesting evolution
Direction observation (soapberry bug beak length) and Vestigial Organs (wings in flightless birds)
evidence from common ancestry suggesting evolution
ring species, homology of traits (morphological = bones & molecular = genetic code), relationships among species
Name the 4 ingredients for evolution by natural selection
1) Individuals in a population to have variation of a trait 2) Variation must be , at least in part, heritable 3) Some individuals are more successful at surviving and reproducing than others 4) The differential survival and reproduction of individuals is nonrandom, relating instead to the variation in the trait
The extent to which an individual contributes genes to the next generation
Define ' Adaptation '
a trait that increases fitness relative to other members of the population
Briefly descirbe the test of natural selection in Snap Dragon Flowers
1) set up a mix of yellow 3:1 white 2) plants varied in pollen donated, therefore white flowers increased bee visits increased seeds 3) so, white plants had greater reproductive success (fitness) 4) F2: more white, had evolved
answer the 4 ingedients in repsonse to the medium ground finch 1200 on Dapne Major
1) variation? YES - large sample size 2) heritable? YES 3) vary in sex/survival? YES - 67% survived 76/77 drought 4) non random? YES - less/harder seeds in drought so beak size increased
7 key things to remember (first 4)
1) acts on individuals but consequences occur in populations 2) acts on phenotypes but changes in phenotype must be heritable 3) NOT FORWARD LOOKING only present 4)Acts on existing traits but new traits can evolve by mutation etc
7 key things to remember (last 3)
5) Leads to adaption but not perfection e.g mosquito fish habitat context 6) is non random but NOT PROGRESSIVE e.g snakes now less complex 7) acts on individuals not for good of species
define 'sexual selection'
differential reproductive success due to variation in mating success
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