Natural Selection (Variation and Distribution)

Natural Selection

Exploring Variation and Distribution

Multiple Choice

A population can be described by a group of organisms that live in the same area and

• share the same features and traits.

• share the same features but may have different traits.

• have different features and traits.

• have different features but the same traits.

Multiple Choice

Which of these would describe a trait of the horses?

• Hooves

• Tails

• Hair Color

• Nostrils

Describing a Trait in a Population

Variation and Distribution

Variation - the number of different traits (variations) that exist for a feature

Distribution - the number of organisms that have each trait (variation) for a specific feature

Multiple Choice

True or False: The variation of a trait describes how many different traits there are for a given feature.

• True

• False

Simulation Exploration

1. Open the simulation by clicking the link above
2. Press "ctrl" and "-" two times so the whole simulation fits on your screen
3. On the top left, click the hamburger icon and selection "Explore Variations"
4. Take about 5 minutes to look around and play with settings

Simulation Exploration Missions

1. Set up the Thornpalm population where all the Thornpalms have medium thorns
2. Set up a Thornpalm population where the Thornpalms have many different thorn sizes
3. Set up a Thornpalm population that has a lot of short Thornpalms, a few medium Thornpalms, and no tall Thornpalms
4. Set up an Ostrilope population that has blue, green, and yellow Ostrilopes
5. Set up an Ostrilope population where one feature has high variation and another has no variation.
6. Set up a Carnithon population where most of the Carnithons have high levels of fur, but some have medium levels of fur.
7. Choose one of the Carnithon features. Set up a Carnithon population with the highest level of variation possible.

Histograms

​These histograms show the different variations and distributions for the spot size trait in Guppies from Brazil and Venezuela. We can tell from the histograms that the guppies in Venezuela have more variation and on average have larger spot sizes.

Multiple Choice

Scientists measured the heights of giraffes in Niger and Somalia. Which population has the higher number of tall giraffes?

• The population of Niger has more tall giraffes

• The population of Somalia has more tall giraffes

• They both have an equal number of tall giraffes

• The bar graphs don't show which population has taller giraffes

Multiple Choice

Which histogram shows a population that's all one color?

• A

• B

• C

• D

Multiple Choice

Which histogram shows a population with a lot of variation?

• A

• B

• C

• D

Multiple Choice

Which histogram shows a population with mostly yellow Ostrilopes with some variation?

• A

• B

• C

• D

Multiple Choice

Which two histograms have the same amount of variation?

• A and B

• A and D

• B and C

• B and D