1. Bellringer
What is speciation?

2. Speciation

3. Learning Targets
Explain how populations can become isolated, leading to speciation.
Compare and contrast the different types and rates of evolution and extinction

4. 
Speciation
The origin of new species is called speciation. Speciation occurs when an ancestral species branches into separate species.

5. 
Species
Reminder of a species: Groups of organisms that can successfully reproduce, having viable offspring.

6. Speciation is a result of …
Speciation is a result of …
Isolation

7. How does one group become separated and isolated?

8. Reproductive Isolation
Speciation requires reproductive isolation
(If they cannot mate, they’re considered different species)
Western Meadowlark
Eastern Meadowlark

9. Reasons For Reproductive Isolation May Be…
Reasons For Reproductive Isolation May Be…
Geographical
separated by habitat
Ex: land & water, mountain & valley, tree & grass separating species from each other.

10. Reasons For Reproductive Isolation May Be…
Reasons For Reproductive Isolation May Be…
Temporal
Separated by time
Ex: nocturnal v. diurnal, different mating seasons.

11. Reasons For Reproductive Isolation May Be…
Reasons For Reproductive Isolation May Be…
Behavioral
Ex: mating song or dance is different.

12. Reasons For Reproductive Isolation May Be…
Reasons For Reproductive Isolation May Be…
Mechanical
physically do not fit, cannot mechanically mate

13. Discuss with your Partner
What defines a species?
Come up with 2 examples of reproductive isolation.
Be ready to share!

14. 
Adaptive Radiation
Occurs when one common ancestral species evolves into many diverse species adapted to different environments.
Usually occurs as a result of the founder effect where organisms migrate from their ancestral population to colonize a new area (island chain) and develop adaptations to the diverse environments on the different islands.

15. 
Macroevolution
How then do we get from the mechanism of speciation to evolution on a grand scale; i.e., macroevolution?
Two models:
Gradualism model
change is gradual with the accumulation of unique morphological adaptation.
Punctuated Equilibrium model
rapid change occurs, with a new species “erupting” from the ancestral lineage and then staying the same thereafter.

17. Evolution is not random, it occurs in response to specific environmental conditions:
Convergent evolution = evolution toward similar characteristics in unrelated species
Example  wings in birds and insects
Divergent evolution = when closely related species evolve in different directions
Example  mammals
Co-evolution = when two or more species evolve in response to changes in each other
Example  flowering plants and their pollinators (insects/birds)

18. Species can become extinct…
Permanent loss of a species
(Usually followed by adaptive radiation of other species)

19. Extinction
Background extinctions = occur continuously but at a very low rate
Part of the natural cycle of life on Earth, cause local, small-scale changes to ecosystems
Mass extinctions = global events that destroy many species
Examples  asteroid impact, ice age

20. Speciation Worksheet
Please complete speciation worksheet. Once done make sure your name is on it and turn it in to the tray.
If you finish early, you may work on your vocabulary that is due on Tuesday.