Ch. 15 Darwin’s Theory of Evolution

A. Voyage of the Beagle December of December of Beagle set out from England Beagle set out from England five-year cruise around the world with Darwin on board five-year cruise around the world with Darwin on board

B. Darwin’s Observations 1. Living diversity 1. Living diversity Brazilian rain forest Brazilian rain forest Galapagos Islands Galapagos Islands Madagascar Madagascar

2. Fossils 2. Fossils Preserved remains of ancient organisms Preserved remains of ancient organisms

After being on the boat for 5 years…he went home to England

C. Ideas That Shaped Darwin’s Thinking… 1. An Ancient, Changing Earth 1. An Ancient, Changing Earth Earth might be many millions of years old Earth might be many millions of years old Hutton and Lyell Hutton and Lyell If the earth is changing, If the earth is changing, the life on earth might be the life on earth might be changing, too changing, too

2. Lamark’s Hypotheses 2. Lamark’s Hypotheses Aquired characteristics are inherited Aquired characteristics are inherited Wrong! Wrong! Why do we care? Why do we care? Paved way for scientists to start thinking about what might cause living things to adapt to their environment Paved way for scientists to start thinking about what might cause living things to adapt to their environment C. Ideas That Shaped Darwin’s Thinking…

3. Population Growth 3. Population Growth Thomas malthus Thomas malthus babies were being born faster that people were dying babies were being born faster that people were dying Same is true for other living things? Same is true for other living things? What determines which living things live and which die? What determines which living things live and which die? C. Ideas That Shaped Darwin’s Thinking…

D. Darwin’s Solution Read Read What happened next?? What happened next?? What motivated Darwin to do this?? What motivated Darwin to do this?? He wrote a book and in 1859 published a book called On the Origin of Species He wrote a book and in 1859 published a book called On the Origin of Species An essay he received that contained the same ideas he had… An essay he received that contained the same ideas he had…

D. Darwin’s Solution-Evolution by Natural Selection

1. There’s a struggle for existence

2. Survival of the fittest Fitness is the ability to survive and reproduce Adaptation is a trait that increases chances of survival

3. Decent with modification  -species today look a little different than their ancestors

Read Handout with questions Handout with questions Due today OR tomorrow at beginning of period Due today OR tomorrow at beginning of period

E. Evidence of Evolution 1. Fossil record 1. Fossil record

2. Geographic distribution of living species 2. Geographic distribution of living species South America South America Australia Australia Madagascar Madagascar

200 mya? 200 mya? Broke up about 130 mya Broke up about 130 mya

3. Homologous Structures-develop from similar structures 3. Homologous Structures-develop from similar structures 4. Vestigial organs-functionless in some, useful in others

5. Embryological similarities 5. Embryological similarities Similar patterns of development Similar patterns of development