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Unit 5. Central Ideas of Evolution: ◦ Life has a history ◦ It has changed over time ◦ And different species share common ancestors.

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Presentation on theme: "Unit 5. Central Ideas of Evolution: ◦ Life has a history ◦ It has changed over time ◦ And different species share common ancestors."— Presentation transcript:

1 Unit 5

2 Central Ideas of Evolution: ◦ Life has a history ◦ It has changed over time ◦ And different species share common ancestors.

3 Science tries to explain the past in terms of events/processes we can observe, measure and replicate today.

4 The variety of living things is called biological diversity.

5  He contributed most to the understanding of evolution  Born in England  Naturalist on the crew of H.M.S. Beagle (1831)  During travels, made numerous observations and collected evidence to propose how life changes over time.

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7  Collected plant and animal specimens at every stop.  Well educated and curious  Strong interest in natural history  Noted more diversity than his native country  Collected 68 different beetle species in one Brazilian forest.

8  Darwin also found and collected fossils He questioned:  Why had so many species disappeared?  How were they related to living species?

9 Actual Remains - Real tissue or portion of once living thing Casts - Imprint in rock - Color of imprint same as surrounding Mineral Replacement - Organic changed to mineral rock

10 1000 km west of South America Influenced Darwin the most Although islands close, they had very different climates. Most fascinated by land tortoises and marine iguanas

11 Pinta Island Intermediate shell Pinta Isabela Island Dome-shaped shell Hood Island Saddle-backed shell Hood Floreana Santa Fe Santa Cruz James Marchena Fernandin a Isabela Tower

12 Although Darwin observed plants and animals varied noticeably among different islands, could it be possible they had evolved from an original South American species?

13  Darwin also knew that individuals differ from all the other members of its species  Sometimes differences easy to observe  Sometimes differences are subtle  Variation necessary for evolution by natural selection

14 Do Lima Beans Show Variation? Procedure: 1. Count out 10 lima beans and measure the length of each in millimeters. Record your results in a data table. 2. Combine your data with the data of two other classmates. Place all the data on one graph. Plot the length on the x-axis and the number of beans of each length on the y-axis. Analyze your data and Make predictions.


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