Name: ____________________________
Objective: SWBAT understand how speciation occurs.
Questions/Main Ideas:
What is species?
Species= a group of organisms that breed with one another and produce
fertile offspring (all individuals come from same gene pool).
Speciation= the process that leads to the formation of new species.
What is speciation?
What are the three
methods of
How does speciation
What are patterns of
Reproductive isolation= keeping populations separated, so they are unable
to breed, eventually creating separate gene pools.
1. Behavioral Isolation= when two populations have different courtship
rituals or other types of behaviors.
- Ex) Frogs are attracted to only certain calls or birds have specific
mating dances
2. Geographic Isolation= when two populations are separated by
geographic barriers such as rivers, mountains or bodies of water.
- Ex) Abert and Kaibab
squirrels of the Grand
3. Temporal Isolation= when
two populations reproduce
at different times.
- Ex) Frogs having different
mating times throughout
the spring and summer
- Founders Effect= when the
pioneer species starts the first generation
Ex) First birds that fly to the Galapagos from South America
- Geographic isolation leads to changes in the gene pool because
different birds are better adapted for different islands.
- They will not be able to interbreed with one another – even if they
fly to other islands. At this point in time the birds are different
- Competition for food and inhabiting different niches will further
Patterns of Evolution
1. Mass extinction= sudden death of organisms within a species,
which opens up a lot of niches for other organisms to move into.
Ex) Dinosaurs
2. Adaptive radiation= when a single species evolves into several
different species over time.
Ex) Darwin’s finches
3. Convergent Evolution= when unrelated organisms resemble one
another because of the environment that they live in.
Ex) Dolphins and sharks
4. Coevolution= when two species evolve in response to changes in
each other over time (so they evolve together).
Ex) Bees and flowers
5. Gradualism= organisms are always changing at a slow and constant
6. Punctuated Equilibrium= long periods of stabilization followed by
short periods of rapid evolution (proposed by scientist Stephen