1. Lamarck V. Darwin Theories of Evolution
Review
Lamarck V. Darwin
Theories of Evolution

2. Differences Lamarck Darwin
Use and disuse
Organisms have a desire of something and can change traits
Inheritance of Acquired Traits
Tendency towards complexity and perfection
Initially not much variation within a population
Evolution = thousands of years
Natural Selection
Mutation  Variation in a population  environment selects “good” genes
Can pass on traits if mutation is in DNA of sex cells
Evolution requires millions of years

3. Use and Disuse Theory: if an organism wants something badly enough (desire), it can acquire a new trait by use or disuse. Inheritability of Acquired Traits = if an organism acquires (gets) a trait it did not have before, it can then pass the trait on to its offspring

4. Similarities Lamarck and Darwin
Trying to answer the same question:
How do populations change over time?
Agree that organisms change over time
Environment drives evolution of traits
Common descent

5. Example Lamarck Darwin
Giraffes
Long Bird Legs
Sharp Vision of Hawks

6. Example Lamarck Darwin
Giraffes
Wanted to reach food high in trees  used neck to reach leaves  long neck  pass to offspring
Some giraffes already had slightly longer necks (from mutation)  created variation in population  environment favored longer necks  long necks survived and passed on trait
Long Bird Legs
Sharp Vision of Hawks

7. Example Lamarck Darwin
Giraffes
Wanted to reach food high in trees  used neck to reach leaves  long neck  pass to offspring
Some giraffes already had slightly longer necks (from mutation)  created variation in population  environment favored longer necks  long necks survived and passed on trait
Long Bird Legs
Needed to stretch legs to get food in deeper water  passed on trait to offspring
There was variation in leg length of birds due to mutation  environment favored longer legged birds  shorter legged birds died or moved
Sharp Vision of Hawks

8. Example Lamarck Darwin
Giraffes
Wanted to reach food high in trees  used neck to reach leaves  long neck  pass to offspring
Some giraffes already had slightly longer necks (from mutation)  created variation in population  environment favored longer necks  long necks survived and passed on trait
Long Bird Legs
Needed to stretch legs to get food in deeper water  passed on trait to offspring
There was variation in leg length of birds due to mutation  environment favored longer legged birds  shorter legged birds died or moved
Sharp Vision of Hawks
Strained eyes to see prey further away  passed to offspring
Some hawks had better vision  able to get more prey and out compete other birds  poor-visioned birds died

9. Questions Why was Lamarck incorrect?
Changing the phenotype does not change the genotype.
Variation already exists in populations from mutation
How can you pass on a trait caused from mutation?
Only if the mutation is in the DNA of the sex cells (sperm or eggs)

11. HUMAN EVOLUTION

13. Taxonomic Classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae (Hominids)
Genus: Homo (humans), Pan (chimps),
Gorilla (gorillas)

14. Primates

15. Primates
animals with five flexible fingers with an opposable thumb (include monkeys, apes, and humans)
Have binocular and color vision
Evolved about 35 million years ago
Human DNA and chimp DNA is 98.4% similar!!!

16. Cladogram of Human Evolution

17. Man’s Closest Living Relatives
THE GREAT APES
Chimpanzee
Bonobo
Gorilla
Orangutan
Man’s Closest Living Relatives

18. Evolutionary Origins of Humans

19. HOMINIDS humans and their closest fossil relatives

20. Skulls are evidence for human evolution

22. A bonobo with bipedal locomotion.

23. “Lucy” The oldest hominid (3 myo)
Discovered by Johanson in in Ethiopia
About 3.5 ft tall / 62 lbs
Walked upright
Evidence that hominids walked upright before they evolved larger brains

24. The First Humans

25. The genus Homo evolved in Africa about 2 million years ago

26. Darwin’s Explanation
How would Darwin explain the evolution of humans from a monkey ancestor?
Mutations produced variability in monkey populations  the environment selected those organisms that were best adapted (high fitness)  over millions of years and much change in the environment, humans evolved because they were the best adapted to the environment.