1. Theory of evolution
Chapter 15

2. Evolution Development of new organisms from pre-existing ones
Heritable change in the characteristics within a population from one generation to the next
Charles Darwin published “On the Origin of the Species” in 1859
descent with modification (DwM)

3. Descent with modification (DwM)
Every species must have descended by reproduction from preexisting species
Species must be able to change over time

4. Natural selection Mechanism for DwM
Four main parts of Darwin’s reasoning
Overproduction: more offspring produced than can survive
Genetic variation: individual within a population have different traits
Struggle to survive: individuals compete
Some variations improve chance for survival and reproduction
Adaptation: trait that makes an individual successful in its environment

5. Natural selection
4. Differential reproduction: organisms with best adaptations are most likely to survive and reproduce
Through inheritance, adaptations become more frequent in a population
This leads to change in a population
Fitness: measure of an individual’s heredity contribution to the next generation
More than survival
Must reproduce offspring that will reproduce in turn
Notebook assignment: See page 300

6. Contributors to Darwin
Before Darwin’s time, most scientist thought the earth and it’s organisms were permanent and unchanging
Earth was thought to only be thousands of years old
How old is it actually?
About 4.5 Billion years old
Geologists started to identify the actual age of the earth by looking at the rock strata: rock layers
Oldest layers on bottom

7. Contributors French anatomist Georges Cuvier
Reconstructed fossils
Some organisms in the past differed greatly form any living species
“sudden changes” result of catastrophism >> caused extinction
English geologist Charles Lyell
Uniformitarianism
the theory that changes in the earth's crust during geological history have resulted from the action of continuous and uniform processes
French biologist Jean Baptiste Lamarck
INHERITANCE OF ACQUIRED CHARACTERISTICS
is the idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring

8. Inheritance of Acquired Characteristics

10. Fossil record Fossil: remains or traces of past life
Fossils show that different organisms have appeared at different times and places on Earth
Superposition: oldest rocks on the bottom

11. How old is it? Relative vs absolute age
Which is older: A fossil at A or F?
If a radioactive isotope has a half-life of 50 years, how much is left after 250 years if the original amount was 5,000 mg?
Half-lifes
Mass remaining
5000 mg
1 (50 years)
2500 mg
2 (100 years
1250 mg
3 (150 years)
625 mg
4 (200 years)
312.5 mg
5 (250 years) mg

12. Transitional species
Intermediate species between ancestral species and later descendants
Page 304

13. Biogeography Studies why living things are found where they are
Unrelated organisms with similar features

14. Comparative anatomy
Homologous structures: found in related species that share a common ancestor
May have different functions but similar structure
Analogous structures: related functions, but different structure

17. Vestigial structures Structures with no current function
May have been functional in ancestral species

18. Evolution in action Evolution is continuous and ongoing
Scientists can study evolutionary patterns today
Case study: anole lizards
Page 308

19. Convergent evolution
Process by which different species evolve similar traits

20. Divergence and radiation
Divergent evolution: process in which descendants of a single ancestor diversify into species that each fit into different parts of their environment

21. Adaptive radiation
Many species evolve from a single ancestral species

23. Artificial selection
Selective breeding of organisms for specific traits
DONE BY HUMANS!!!
This is in contrast to natural selection in which the environment places pressure on certain traits

26. Coevolution
When two or more species have evolved adaptations to each other’s influence
Why are flowers different colors?
Why do they have different scents?
Why are flowers shaped differently?
Why do we keep having to develop new antibiotics?
Methicillin Resistant Staphylococcus aureus
MRSA