Evolution  Spider monkeys use their claws to climb trees and reach food. There is not enough food for everyone. A spider monkey population has some monkeys with large claws, and other monkeys with smaller claws.  What is the environmental pressure exerted on this population?  What will happen to the frequency of the gene that produces large claws? EXPLAIN how you know. Write in complete sentences! Don’t talk during the Catalyst!

Objectives By the end of today all SWBAT…  Define species  Describe how evolution leads to new species

Agenda  Catalyst Review  Microevolution  Two Practice Problems  Speciation/Macroevolution  Mouse and mango ooh la la  Exit Question

Microevolution  Key Point #1: Natural selection causes microevolution  Microevolution = change WITHIN a species  Examples There are white and brown bears at the North Pole. The white bears live longer and have more kids. Eventually, all bears are white. Some eagles have claws, others don’t. The eagles with claws live longer and have more kids. Eventually, all eagles have claws.

Practice 1  In a population of beetles, some are green and some are brown. They live in the dirt and are hunted by birds flying overhead.  What will happen to the green beetles? Why?  What will happen to brown beetles? Why?  Over the course of 1000 years, what will happen?

Practice 2  Peppered moths are white with black spots. They live on light-colored trees. Occasionally, mutants were born that were all black. One day, humans build a nearby factory that covered all the trees with black dirt and soot!  What will happen to the gene for spotted moths? Why?  What will happen to gene for black moths? Why?  Over the course of 1000 years, what will happen?

What is a species exactly?  Species = a group of organisms that can produce fertile offspring with each other. They cannot breed, therefore, they are not the same species

Make a Hypothesis  Remember, microevolution is small, heritable changes in a population of organisms.  But what do you think would happen if many traits changed… Over and over again, for millions of years…

Mouse and Mango!

Evolution  Key Point #2: If a population is reproductively isolated, it may develop into a new species.  Speciation = formation of new species. Also called macroevolution

Original species New species shares 98% of DNA with original species New species #2 shares 96% of DNA with original species Original species New species

Speciation  Key Point #3: Speciation requires reproductive isolation  Reproductive isolation = something that prevents two organisms from making children

Independent Practice  Evolution Worksheet  Complete sentences  When you are done, work on your Skittles lab

Key Point Wrap-Up  Key Point #1: Natural selection causes microevolution  Microevolution  Key Point #2: If a population is reproductively isolated, it may develop into a new species.  Speciation  Key Point #3: Speciation requires reproductive isolation.  Reproductive isolation

Exit Question  A horse and a donkey cannot mate to produce fertile offspring. Are they in the same species?  Describe what reproductive isolation is.  Describe how reproductive isolation could cause speciation (macroevolution) using at least TWO complete sentences.