Chapter 7 Section 2

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.

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

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

http://upload.wikimedia.org/wikipedia/commons/4/42/Voyage_of_the_Beagle.jpg

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

http://biology.unm.edu/ccouncil/Biology_203/Images/PopGen/darwin_finches.jpg

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

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

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

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!

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

1. Overproduction

2. Inherited variation

3. Struggle to survive

4. Successful reproduction

http://evolution.berkeley.edu/evolibrary/images/interviews/naturalselection1.gif

Darwin lacked some evidence for parts of his theory

He did not know HOW organisms inherited traits

Differences in genes

What did Darwin learn from Lyell’s data about the age of the Earth?

Give an example of selective breeding.