Question

student exploration:natural selection
directions: follow the instructions to go through the simulation. respond to the questions and prompts in the orange boxes.
vocabulary: biological evolution, camouflage, industrial revolution, lichen, morph, natural selection, peppered moth
prior knowledge questions (do these before using the gizmo.)
the peppered moth (biston betularia) is a common moth found in europe, asia, and north america. it is commonly found in two forms, or morphs: a dark morph and a light, speckled morph. birds are a frequent predator of the peppered moth.

1. which morph do you think would be easier to see on a dark tree trunk?
2. which morph do you think would be easier to see on a light tree trunk?

the natural selection gizmo allows you to play the role of a bird feeding on peppered moths. the initial population of 40 moths is scattered over 20 tree trunks. click on moths to capture them. click the next tree button (or the spacebar on your keyboard) to advance to the next tree.

1. check that light trees is selected. click play (), and hunt moths for one year.

a. how many dark moths did you capture?
b. how many light moths did you capture?
c. camouflage is coloring or patterns that help an organism to blend in with the background. which type of moth is better camouflaged on light bark?

1. if a forest contained mostly light-colored trees, which type of moth would you expect to be most common?

how many moths can you find?

Explanation:

1. For the prior knowledge questions, light moths contrast with dark tree trunks, making them easier to spot, while dark moths contrast with light tree trunks.
2. For the simulation on light trees:

A-B. The exact capture numbers come from running the simulation, but dark moths are easier to catch on light bark.
C. Light moths match light tree bark, so they are better camouflaged.

1. Natural selection means better-camouflaged moths survive more, so light moths will be most common in a forest with mostly light trees.

Answer:

Prior Knowledge Questions:

1. The light, speckled morph
2. The dark morph

Simulation Questions:

1. A. (Example answer from typical simulation: 8)

B. (Example answer from typical simulation: 2)
C. The light, speckled morph

1. The light, speckled morph