1. How do you think giraffes acquired a long neck over time?
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, acquired, traits, use, disuse.
Do Now:
How do you think giraffes acquired a long neck over time?

2. Jean-Baptiste Lamarck
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, acquired, traits, use, disuse.
Jean-Baptiste Lamarck

3. How Species Acquired New Traits?
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, acquired, traits, use, disuse.
How Species Acquired New Traits?
Original short-necked ancestor
Keeps stretching neck to reach leaves higher up on tree
Long-necked descendant after many generation

4. How Species Acquired New Traits?
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, acquired, traits, use, disuse.
How Species Acquired New Traits?

5. How Species Acquired New Traits?
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, acquired, traits, use, disuse.
How Species Acquired New Traits?

6. How Species Acquired New Traits?
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, acquired, traits.
How Species Acquired New Traits?
Lamarck believed that this occurred through use and disuse.
If an animal often used a certain trait or characteristic, that trait would become larger or more pronounced. If the trait went unused, it would no longer develop fully and would become reduced
Organisms change over time by inheritance of acquired characteristics

7. How Species Acquired New Traits?
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, acquired, traits.
How Species Acquired New Traits?

8. How Species Acquired New Traits?
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, acquired, traits.
How Species Acquired New Traits?
Because the front claw
has been used repeatedly,
it becomes larger 1 2
The male crab uses its small front claw to attract mates and ward off predators 3
The acquired
characteristics, a larger claw,
is then passed on to the crab’s offspring

9. How Species Acquired New Traits?
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, acquired, traits.
How Species Acquired New Traits?
2. How did Lamarck explain species acquire new traits?
3. Do you agree or disagree with Lamarck’s explanation of how evolution works? Explain.
Species acquire new traits through use and disuse. (False)
If an animal often used a certain trait, that trait would become larger. (True)
Then, the offspring will inherit the new trait.(False)
Disagree. Body traits are determined by DNA. The use or disuse of any trait do not change the DNA.

10. How Did Giraffes Acquire Long Necks?

12. Jean-Baptiste Lamarck
Objective: Understand How Organisms Change Over Time.
Key words: Lamarck, Darwin, acquired, traits, natural selection
Jean-Baptiste Lamarck
Charles Darwin
Similarities
How organisms change over time?
The idea of evolution: Species change over time
Organisms struggle to survive in their environments
The accumulation of small changes could accomplish big results
All organisms are related
Organisms inherit acquired characteristics
Species evolve by natural selection: survival of organisms better adapted to the environment