EVOLUTION Unit 5 Introduction to Evolution Central Ideas

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EVOLUTION Unit 5

EVOLUTION Unit 5

Introduction to Evolution Central Ideas of Evolution: ◦ Life has a history ◦ It

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

Scientific Explanation Science tries to explain the past in terms of events/processes we can

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

15. 1 The Puzzle of Life’s Diversity The variety of living things is called

15. 1 The Puzzle of Life’s Diversity The variety of living things is called biological diversity.

� He Charles Darwin 1809 -1882 contributed most to the understanding of evolution �

� He Charles Darwin 1809 -1882 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.

Voyage of the Beagle (5 years)

Voyage of the Beagle (5 years)

Darwin’s Observations � Collected plant and animal specimens at every stop. � Well educated

Darwin’s Observations � 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.

Living Organisms and Fossils � Darwin also found and collected fossils He questioned: �

Living Organisms and Fossils � Darwin also found and collected fossils He questioned: � Why had so many species disappeared? � How were they related to living species?

Fossils preserved remains of once living organisms Actual Remains - Real tissue or portion

Fossils preserved remains of once living organisms 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

Galàpagos Islands 1000 km west of South America Influenced Darwin the most Although islands

Galàpagos Islands 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

Shell Shape/Neck Length Varied by Habitat Pinta Island Intermediate shell Fernandin a Isabela Tower

Shell Shape/Neck Length Varied by Habitat Pinta Island Intermediate shell Fernandin a Isabela Tower Marchena James Santa Cruz Santa Fe Floreana Isabela Island Dome-shaped shell Hood Island Saddle-backed shell

Could Isolation and Habitat Produce New Species? Although Darwin observed plants and animals varied

Could Isolation and Habitat Produce New Species? Although Darwin observed plants and animals varied noticeably among different islands, could it be possible they had evolved from an original South American species?

Variation within a Species � Darwin also knew that individuals differ from all the

Variation within a Species � 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

Variation Activity Do Lima Beans Show Variation? Procedure: 1. Count out 10 lima beans

Variation Activity 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.