Look for: At different scales of penguin groups (betwee…

4.B Develop an explanation that predicts what the variation in a chosen body structure or behavior of Galápagos penguins and king penguins looks like at different scales (between species versus between individuals within a population).

Students should include the following ideas in their predictions:

• At different scales of penguin groups (between species versus between individuals within a population of a species), the variation we are accounting for is different.
• Within a population of the same species of penguin we can also look at variation within a trait (a body structure or behavior that species has)--this variation makes individuals within a population different from one another.
• We look at variations of body structures or behaviors that are shared among all individuals in a species of penguin, and we look for differences in these variations of body structures or behaviors between different species of penguins.

If students are struggling with differentiating the between-species and within-population variations, use the height example as a comparison and walk them through the sequence of thinking for comparing height, then ask the students to do the same for the structure they chose. Two good options to steer students toward are weight and incubation time.

The reason this distinction is important to establish now is that eventually we need to figure out that some individuals will have variations that make them more successful (at getting resources, escaping predators, attracting mates, and so forth) under certain conditions compared to other individuals in the same population with different variations.