BILD 3 Notes

BILD 3 Notes - BILD 3 Notes Darwins Finches o 13 species of...

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BILD 3 Notes Darwin’s Finches o 13 species of finches on Galapagos island The finches look rather similar (similar songs and looks) But the size of the beak and size of the head is very different Finches arose from an ancestral finch that arrived on the island some millions years ago (travelled) Darwin didn’t know about DNA o But the DNA sequences for each finch didn’t resemble (some did, some didn’t) o If you built a tree, some finches are close with similar DNA, but some are on the opposite sides of the tree since the DNA is not similar Insect eating finches Cactus eating finches Fruit eating finches Ground-dwelling finches o Each have different behaviors Galapagos Island has a very simple environment, that unusual animals are easily seen and easily noticed with different evolution behaviors Cormorants (birds) are very different depending on their environment. Some are flightless birds (don’t need to fly) and some have large wings. Water and Land iguanas o Iguanas on the island; some have evolved to swim in the ocean to eat algae. Tower island is a volcanic base o Prickly pear cactuses are there and is very different from the rest of the cactuses around the world (like in the Galapagos) o The cactuses on the tower island are not prickly and are soft Insects pollinators didn’t get on the island (like bees) so they don’t pollinate on the cactus – so instead, birds can land on it since it’s so soft. Darwin then discovered the mechanism that underlies the process of evolution (after looking at cactuses) o He wrote a lot of letters and try to build graphs and processes to figure out evolution Thomas Robert Malthus who wrote “Unpopulation” that talked about how human population is growing dramatically and the resources to are growing arithmetically (bad) o Human population, without resources, have to fight for resources Darwin after reading the book, figured that there was natural selection o With less resources, animals and organisms and humans need to compete for resources. o It results to evolution change Said that: 1. Species are mutable- can alter overtime and can have a rise of a new specie (how some organisms can survive in certain environments) 2. Natural Selection can give rise to new adaptations and new species- The principle of Malthus applies to natural populations. Because the reproduction of resources might lag, not all individuals can survive and reproduce. The struggle of existence, leading to an increase in the probability that the best- adapted individuals will survive.
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3. Natural and artificial selection are very similar but not identical- talked about artificial selection used by plant and animal breeders to produce rapid changes over short periods o time in a wide variety of domesticated breeds. (pigeon breeding…or dog breeding)
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This note was uploaded on 04/09/2010 for the course BILD 3 taught by Professor Wills during the Spring '07 term at UCSD.

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BILD 3 Notes - BILD 3 Notes Darwins Finches o 13 species of...

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