DARWIN AND EVOLUTION

armadillo

hawk

Giant tortoise

finch

mockingbird

cormorant

sloth

Read pps. 140-150

Think about Darwin´s observations and how he began to form ideas of evolution.

READING COMPREHENSION QUESTIONS (COPY IN YOUR NOTEBOOK)

1. What was Darwin´s job on the HMS Beagle? (p.140)

2. Define species (p.141)

3. What observation did Darwin make about animals from South America and those on the Galapagos? (p.142)

4. What reason did Darwin use to explain the differences he saw between the organisms from South America and those on the Galapagos? (p.142)

5. Define adaptation (p.143)

6. Define evolution (p.143)

7. Define natural selection (p.144)8. Explain the difference between overproduction,

competition, variation and selection (pps. 144-145)

The process of Selective Breeding gave Darwin ideas about Evolution

DARWIN´S KEY IDEA

vs

Which is more likely to survive?

AB

NATURAL SELECTION Natural Selection = Process where

individuals with traits beneficial for their environment are more likely to survive

Natural selection causes evolution

EVOLUTION = change in inherited characteristics of a population (not individuals) from one generation to the next

What happens to the number of green

beetles?

Why are there only orange beetles?

Example of Natural

Selection:

4 STEPS TO THE THEORY OF EVOLUTION BY NATURAL SELECTION1. Overproduction = populations

produce more offspring than can possibly survive

4 STEPS TO THE THEORY OF EVOLUTION BY NATURAL SELECTION2. Variation = Every population has

variation. Much of this is due to inherited traits.

4 STEPS TO THE THEORY OF EVOLUTION BY NATURAL SELECTION3. Selection = In specific environments

certain traits are more advantageous and they make the individual more likely to survive (therefore passing on the trait more frequently).

4 STEPS TO THE THEORY OF EVOLUTION BY NATURAL SELECTION4. Adaptation = Over time, traits that

improve survival and reproduction become more common.

Theory of Natural Selection Animation