Name: ______Date: ______Period: ______Amoah

Natural Selection Directional Charts:

Directional, Stabilizing, & Disruptive Selection

Directions: Read the scenarios below and determine if the story represents Directional, Stabilizing, or Disruptive Selection. Make sure you can draw & explain the graph, each scenario is describing.

  1. There are 3 populations of turtles. One population has a large shell, one population has a medium shell, and one population has small shells. To survive, turtles must have a large shell, to protect them from the turtle-eating predator. Over the next 100 years, the large shell turtles keep having babies, while the small and medium turtles slowly die. What type of Natural Selection is taking place? DRAW THE GRAPH & INCLUDE THE NECESSARY ARROWS.
  2. In the JuJu forest, there are plenty of tall and short trees. The tall-neck giraffe has plenty of food, and produces many tall giraffe babies. The short-neck giraffe has plenty of food, and produces many short giraffe babies. The average-neck giraffe has a serious problem, because he cannot eat from the tall trees, nor can he eat from the short trees. What type of Natural Selection is taking place? DRAW THE GRAPH & INCLUDE THE NECESSARY ARROWS.
  3. In a human population, people that are extremely skinny (anorexic) are having health problems. People that are extremely over-weight (obese) are also having health problems. People that are in the middle (average weight) seem to have the least amount of health problems. What type of Natural Selection is taking place? DRAW THE GRAPH & INCLUDE THE NECESSARY ARROWS.
  4. The brown-camouflaged butterfly and the green-camouflaged butterfly are surviving very well in the Gwinnett forest. The pale-camouflaged butterfly is not having the same type of luck. The brown-camouflaged butterfly can blend into the brown trees. The green-camouflaged butterfly can blend into the green leaves. Over the years, the brown and green butterflies have many, many babies. The pale-camouflaged butterflies die off. What type of Natural Selection is taking place? DRAW THE GRAPH & INCLUDE THE NECESSARY ARROWS.
  5. Koala bears are beautiful animals that live in the hot sun of Australia. The koala bears with thick fur have problems surviving (they are too hot from the sun). The koala bears with light fur are having a lot of babies. The koala bears with medium fur are also having problems, because they are too hot. The medium fur koala bears are not having many babies. What type of Natural Selection is taking place? DRAW THE GRAPH & INCLUDE THE NECESSARY ARROWS.