Read the information below and follow the directions as given.
Imagine that you are traveling in
Madagascar when you find the flower to the left. You see that it has a large spur containing nectar in the tip. You remember learning in science class that some moths feed on nectar.
Draw a picture of what you think a moth would look like that feeds on this plant.
Now answer this question:
How do you think natural selection could help the flower and the moth evolve together?

• Watch the video “Cladograms” by Bozeman
Science.
• http://www.youtube.com/watch?v=ouZ9zEkxGWg
• Complete the homework page you picked up on the way in.
• Bring your homework to class tomorrow!

CO: I will evaluate and analyze mechanisms and patterns of evolution.
LO: I will take notes about evolution, and discuss scenarios with my group.

KEY CONCEPT
Evolution occurs in patterns.

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

The 3 patterns we’re going to discuss today are…
1. Coevolution
2. Convergent Evolution
3. Divergent Evolution
– We’ll also look at how these might be seen in the fossil record

•
•
•
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 coevolution.

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

Mimicry is another example of coevolution
• 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 is unaffected.
Example: Orchid flowers that mimic female wasps

• 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

• Divergent evolution describes evolution toward different traits in closely related species.
• Divergent evolution can lead to speciation. kit fox ancestor red fox

Changes in the frequency of a gene in a gene pool leads to
Microevolution: small changes over a period of time leads to
Macroevolution: total of many changes that transform organisms over a long period of time.
leads to
Speciation: creation of 2 different species from 1 original species

• Stasis - The organisms in the fossil record look the
same from when they appear to when they disappear;
• Sudden appearance - When a species does not arise by gradually changing steadily from its ancestors; it appears all at once and fully formed.
• Sequential nature - Based on the layers of rock, we
sequence organisms in the fossil record.
• What might cause stasis or sudden appearance?

http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T014608A.gif
WHICH PATTERN IS IT?
coevolution convergent 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 divergent evolution

WHICH PATTERN IS IT?
coevolution convergent evolution divergent evolution
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 for the hummingbird to pick up pollen as it feeds.
coevolution

WHICH PATTERN IS IT?
coevolution convergent evolution divergent 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) convergent evolution

WHICH PATTERN IS IT?
coevolution convergent evolution divergent evolution
Beaver
NORTH
AMERICA
Muskrat
Capybara
SOUTH AMERICA
Coypu
Beaver
Muskrat
Beaver and
Muskrat
Coypu
Beaver in North America and capybara in South America are closely related species living in very different environments that have evolved to look different over time.
BIOLOGY by Miller and Levine Pearson Publishing divergent evolution

WHICH PATTERN IS IT?
coevolution convergent 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 divergent evolution