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6 Cards in this Set

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in roder for beak size t and shpae to evolve there must be enough INHERITABLE VARIATION in order to provide raw material
-second, differnces in beak size and shape must prodcue differneces in FITNESS that cause natural selction to orccur
variation with the grants
they identified and measured as many birds possible on the island
-they recorded leg, wing length, color, bird mass, etc. many appeared in polygenic traits, from this they concluded that there is great variation of inheritable traits among the galapgaos finches
natural selection with the grants
so the next step is that in the rainy season there is plenty of food but they realized that when it got dry drought there was less food and differneces in beak size were a matter of life or death. birds with bigger beaks were more likeyl to sruvive average beak size increased dramtically
rapid evoolution with the grants LAST STEP!
they provided evidence of evolution by documenting natural selction: the next gernation of finches had larger beaks than did the gernation before selection had occurred
they found that natural selction take place frewuently and at times rapidly
Competitive Exclusion Principle
no two species can:
occupy the same niche-lifestyle
in the same place
at the same time
for any length of tiem
--you can have two differnet finches in the same forest as long sa tehy dont have the same niche
competition can lead to natural selection if tehy have alleles to find food theyll be fine
genetic drift: random change in allele frequencies that occurs in small popualtions
natural selction:process by which individuals that are better suited to their environment survive and reproduce most successfully also called survival of the fittest