how does evolution happen ch 7.2 7th
DESCRIPTION
Information obtained from: Holt Science and Technology: Life Science. Austin: Holt Rinehart & Winston, 2007. Print.TRANSCRIPT
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Chapter 7 Section 2
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List 4 sources of Charles Darwin’s ideas about evolution.
Describe the 4 parts of Darwin’s theory of evolution by natural selection.
Relate genetics to evolution.
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He was interested in the study of plants and animals
1831 - He signed on as a naturalist for a 5 year voyage around the world on the British ship the HMS Beagle
He made observations the helped form his theory of evolution
http://biblauragraphy.files.wordpress.com/2009/02/darwin.jpg
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1000’s of plant and animal samples were taken
Observations were recorded Most notable stop: The Galápagos
Islands (965km west of Ecuador in South America)
http://farm1.static.flickr.com/21/97887748_cba82d3784.jpg
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http://upload.wikimedia.org/wikipedia/commons/4/42/Voyage_of_the_Beagle.jpg
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The Galápagos Island plants and animals were very similar to those in Ecuador
Ex: Finches of Galápagos were similar, but different; each island also showed differences in the finches
Their beaks were adapted to the way the bird gets their food
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http://biology.unm.edu/ccouncil/Biology_203/Images/PopGen/darwin_finches.jpg
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Darwin hypothesized that the island finches were descended from South American finches
Over many generations the finches evolved adaptations for the various island environments
http://www.blackwellpublishing.com/ridley/images/finch_magnirostris.jpg
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Vocabulary: Trait: a characteristic that can be passed
from parent to offspring through genes
Selective Breeding: the human practice of breeding animals or plants that have certain desired traits
Ex: pets (dogs) are bred for desired traits
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Thomas Malthus: An Essay on the Principle of Population
Malthus thought that the human population could increase more quickly than the food supply
Darwin: populations of all species are limited by starvation, disease, competition, and predation
Only a limited number of individuals survive to reproduce; offspring of the survivors inherit traits that help them survive in their environment
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Most geologists in Darwin’s time did not think the Earth was old enough to allow for these slow changes
Charles Lyell: Principles of Geology
The Earth has formed by natural processes over a long period of time; the Earth was pretty old!
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1858 – Alfred Russel Wallace arrived at the same ideas as Darwin
1859 – Darwin published Origin of Species by Means of Natural Selection
Natural selection: the process by which organisms that are better adapted to their environment survive and reproduce more successfully that less adapted organisms do
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1. Overproduction
2. Inherited variation
3. Struggle to survive
4. Successful reproduction
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http://evolution.berkeley.edu/evolibrary/images/interviews/naturalselection1.gif
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Darwin lacked some evidence for parts of his theory
He did not know HOW organisms inherited traits
Differences in genes
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What did Darwin learn from Lyell’s data about the age of the Earth?
Give an example of selective breeding.