1. 7th Chapter 7-3 Cornell Notes
“Evolution of Species”

2. 7th Chapter 7-3 Cornell Notes
Key Questions
1. How do new species form?
2. What causes the extinction of species?

3. Chapter 7-3 Cornell Notes: Terms
habitat
extinct

4. Chapter 7-3 Cornell Notes
Paragraph 1
different environments + genetic variation + natural selection = variety of organisms;
natural selection created organisms adapted to their habitats;
habitat: specific environment gives what organisms need to live/grow/reproduce.

5. Chapter 7-3 Cornell Notes
Paragraph 2
traits vary between organisms in a species;
causes: DNA mutation, genes shifting during meiosis;
total gene pool: sum of genetic variations in a species;
the more variation in a species = the better chance of surviving environmental change.

6. Chapter 7-3 Cornell Notes
Paragraph 3
new species can form through geographic isolation (i.e. Kaibab squirrel);
new species then cannot mate with the old species successfully.

7. Chapter 7-3 Cornell Notes
Paragraph 4
evolutionary relationships:
DNA evidence (nitrogen base sequences)
protein structure
fossils
early development (embryos gill slits)
body structure (homologous bones) ;

8. Chapter 7-3 Cornell Notes
Paragraph 5
extinct: no members of the species still alive;
cause: change in environment;
needs adaptation to survive changes ( to survive and reproduce);
climate change may destroy habitats but adaptations can help survival.