HAPPY WEDNESDAY Explain in 32 words what is happening in this PEDIGREE comparing long-necked giraffes vs short-necked giraffes.

Essential Question: How do evolutionary mechanisms other than

natural selection affect adaptation and diversity?

Standard 7F: Analyze and evaluate effects of other evolutionary mechanisms.

It is widely accepted that the first living things on Earth were prokaryotic cells (bacteria). How did prokaryotic cells turn into eukaryotic ones?

The answer is The Endosymbiotic Theory.

K. The Endosymbiotic Theory is the theory that eukaryotic cells formed from a symbiosis (two

organisms live together) among several different prokaryotic organisms.

• Sometimes organisms that are closely connected to one another by ecological interactions evolve together.

• An evolutionary change in one organism may also be followed by a corresponding change in another organism.

• The process by which two species evolve in response to changes in each other over time is called coevolutioncoevolution.

Co-evolution

Coevolution can occur with species that help or compete with each other

• Mimicry occurs when one organism evolves to look like the other in order to benefit itself. The mimic benefits from the situation while the organism it mimics in unaffected.

Example:Example: Orchid flowers that mimic female wasps

Mimicry is another example of coevolution

Convergent Evolution

• Convergent evolution describes evolution toward similar traits in unrelated species.

• When two species are similar in a particular characteristic, it’s only convergent evolution if their ancestors were not similar

Convergent Evolution

Divergent Evolution

• Divergent evolution describes evolution toward different traits in closely related species.

• Divergent evolution can lead to speciation.

kit fox

ancestor

red fox

Scenarios

Mix-Freeze-Group

• I am going to survive! Because I have the best genes for my environment.

• I am HUGELY affected by genetic drift.• I am VERY picky. I will only choose you, because your traits

are most attractive to me.• I am a mistake in the DNA sequence

Natural Selection

SmallPopulation

GeneticMutation

Non-RandomMating

1. Amish people are required by their religion to only marry and have children with other Amish people.

2. The DNA sequence in a bird is changed from ATT CCG TTG to TTA CCG TTG which changes the beak shape from long and thin to short and fat.

3. Peppered moths are eaten by birds. The moth color varies from light to dark. Light colored moths can blend in with a nearby species of tree. In the 1800s factories released large amounts of soot, which changed the tree color, so the birds were able to more easily find the lighter moths instead of the darker moths.

4. Northern elephant seals were hunted almost to extinction by people in the 1890s. The remaining population has reduced genetic variation.

5. A lioness joins a new pride and has cubs with the male lion.

6. A small group of birds flies from the mainland to an island and starts a new colony. (The birds never return to the mainland.)

WHICH PATTERN IS IT? coevolution convergent evolution divergent evolution

divergent evolution

The Galápagos finches evolved through natural selection from a common ancestor into a wide variety of different looking species with different kinds of beaks

http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T014608A.gif

WHICH PATTERN IS IT? coevolution convergent evolution divergent evolution

coevolution

Hummingbirds have a beak just the right length to reach the nectar in a cardinal flower and as they feed their foreheads bump into the pollen structure. Cardinal flowers are red which hummingbirds can see, but bees can’t, and their pollen structure is at just the right height forthe hummingbird to pick up pollen as it feeds.

WHICH PATTERN IS IT? coevolution convergent evolution divergent evolution

Convergent evolution

Whales, sharks, and penguins all have streamlined bodies and fins/flipper for moving in water even though they belong in different animal groups (mammals, fish, and birds)

WHICH PATTERN IS IT? coevolution convergent evolution divergent evolution

divergent evolution

Beaver in North America and capybara in South America are closely related species living in very differentenvironments that have evolved to look differentover time.

Beaver

NORTH AMERICA

Muskrat

CapybaraSOUTH AMERICA

Coypu

Beaver

Muskrat

Beaver andMuskrat

Coypu

BIOLOGY by Miller and Levine Pearson Publishing

WHICH PATTERN IS IT? coevolution convergent evolution divergent evolution

divergent evolution

The tortoises on the Galapagos islands share a

common ancestor, but over time they have become adapted for obtaining food in different habitats on different islands by having different neck lengths