Warm up Questions?1. What are some things that a person your

age would not have in 1795?2. Rich people liked to entertain themselves by

making collections. What kinds of things do you think they collected?

3. What do you think they learned from these collections?

Darwin vs. LamarckIn the late 18th-century, scientists were beginning to understand that living things change over time.

Jean Baptiste Lamarck also recognized that animals somehow adapted to the environment.In explaining how adaptations worked Lamarck made these assumptions:a. Changing environment creates a need for certain

features to be developed in order to survive.b. Organisms desire to change because they have an

inborn urge to better themselves and become more fit to the environment. Example: ancestors of birds acquired an urge to fly.

c. Through use/non-use, features needed for survival are developed in each individual. Example: by trying to use their forelimbs for flying bird ancestors could eventually transform those limbs into wings. Called the law of Use and disuse.

d. Acquired characteristics are somehow passed onto offspring who continue to develop the characteristic. Called the law of inheritance of acquired characteristics.

e. Eventually enough differences have developed that there is a new species.

We now know that Lamarck’s assumptions were WRONG.

Darwin recognized that Lamarck’s theories were wrong.Darwin proposed the Theory of Natural Selection instead:1. More offspring are produced than will survive to

reproduce themselves.

2. Inheritable features vary from individual to individual

3. Environment changes in some way.eg. Climate, food supply, habitat

4. Members of the same species must compete for resources. Eg. Food, habitat, survival from being eaten

5. Those with more adaptive traits tend to survive longer and produce most offspring (survival of the fittest)

6. Traits involved are inheritable7. Once traits have changed enough that two individuals

can no longer reproduce and new species is formed.Remember,1. Only groups (populations or species) of organisms

evolve, not individuals2. Adaptations occur over a long period of time.

Natural selection works much the same way as artificial selection: On a farm cows that give more milk are intentionally selected to be parents to the next generation. Corn plants with bigger ears are also

selected to produce the seeds for the next generation. In this way farm plants and animals gradually produce more food.