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Darwin and Lamarck
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Slide 1

Lamarck and Darwin

Lamarck and Darwin

Varying Views of Evolution

Slide 2

French naturalist Jean-Baptiste de Lamarck (1744-1829)

French naturalist Jean-Baptiste de Lamarck (1744-1829)

“The theory of

Acquired Traits”

Slide 3

Lamarckism #1

Lamarckism #1

Giraffe seeks food, and stretches its neck to acquire the leaves

Slide 4

Lamarckism #2

Lamarckism #2

Continual stretching results in longer neck. Longer neck is passed on to offspring.

Slide 5

British naturalist Charles Darwin (1809 –1882)

British naturalist Charles Darwin (1809 –1882)

“The theory of

Natural Selection”

Slide 6

Influences on Darwin

Influences on Darwin

1. British tradition of selective breeding of livestock and domestic pets

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Influences on Darwin

Influences on Darwin

2. Observations made while serving on HMS Beagle during a journey to the Galapagos Islands (1831 – 1836).

Slide 8

Galapagos Islands

Galapagos Islands

900 km to Ecuador

Slide 9

Darwin’s Finches

Darwin’s Finches

Darwin observed differences in the beaks of finches on the islands. He assumed the finches all descended from common ancestors that migrated from the mainland.

Slide 10

Darwin’s Finches

Slide 11

Natural Selection: Variation within Offspring

Natural Selection: Variation within Offspring

Slide 12

Natural Selection

Natural Selection

Selective Advantage:

The variation provides an advantage to one of the offspring. The others will not pass on their genes.

Slide 13

Questions that Darwin Couldn’t Answer

Questions that Darwin Couldn’t Answer

What was the source of variation within a species? (genes, alleles)

How did new traits arise? (mutations)

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