1. How can reproductive isolation lead to speciation?
SPONGE
How can reproductive isolation lead to speciation?

2. KEY CONCEPT Evolution occurs in patterns.

3. Main Ideas
Evolution through natural selection is not random
Species can shape each other over time
Species can become extinct
Speciation often occurs in patterns

4. Evolution through natural selection is not random.
Natural selection can have direction.
The effects of natural selection add up over time.

5. Both used to propel through water.
Convergent evolution describes evolution toward similar traits in unrelated species.
Shark: fish, tail is vertical
Both used to propel through water.
Dolphin:
mammal, tail is
horizontal

6. Divergent evolution describes evolution toward different traits in closely related species.
Ex: The Kit fox and Red fox evolved from a common ancestor while adapting to different environments.
Kit fox: Desert regions Red fox: temperate regions

7. Species can shape each other over time.
Two or more species can evolve together through coevolution.
evolutionary paths become connected
species evolve in response to changes in each other
Beneficial: Bumble bees and the flowers they pollinate have coevolved to depend on each other for survival.

8. Coevolution can occur in beneficial relationships.
Stinging ants and the Bull-thorn acacia plant have coevolved together.
The ant eats the nectar inside the thorns and sting any other organisms that try to eat the leaves.
The ant gets food and the plant gets protections (mutualism)

9. Coevolution can occur in competitive relationships, sometimes called evolutionary.

10. Set up Cornell Notes on pg. 27 Topic: 11.6 Patterns in Evolution
Essential Question:
What are some of the causes of background and mass extinctions?
What is the major difference between a background and mass extinction?
11.6 Patterns in Evolution
2.1 Atoms, Ions, and Molecules
What are some of the causes of background and mass extinctions?
What is the major difference between a background and mass extinction?

11. Species can become extinct.
Extinction is the elimination of a species from Earth.
Often occurs when a species as a whole is unable to adapt to change in its environment

12. Background extinctions occur continuously at a very low rate.
occur at same rate as speciation
usually affects a few species in a small area
caused changes in environment
Ex: The Iberian lynx is the most endangered feline. May only be 200 left.

13. Mass extinctions are rare but much more intense.
destroy many species at global level
thought to be caused by catastrophic events
at least five mass extinctions in last 600 million years

14. Dinosaurs 1 5 3 4 2

15. A pattern of Episodic speciation exists in the fossil record
episodes of speciation occur suddenly in geologic time followed by long periods of little evolutionary change
Usually occur after a mass extinction
Happens because new species inhabit environments that have been cleared of life