Goldfish Natural Selection

5th Grade/Unit 3: Evolution and Traits of Organisms

Goal:

  1. In this lab, you will simulate how predators hunt a variety of prey.
  2. The students will learn how predators prey on the weaker organisms.
  3. L.HE.05.11 Explain that the traits of an individual are influenced by both the environment and the genetics of the individual.
  4. L.EV.05.12 Describe the physical characteristics (traits) of organisms that help them survive in their environment.

Background:

  1. Prior Knowledge:

The students should be aware that organisms adapt to better survive in their ecosystem.

  1. Reference Sources: Adapted from
  2. Common Student Misconceptions:
  3. Timeframe of Activity: 30 minutes to 1 hour

Vocabulary:

Materials:

Student worksheets

Two varieties of Goldfish crackers

Procedure:

  1. Obtain a mixed population of goldfish from your teacher. (Orange goldfish are pizza flavored. Yellow goldfish are cheddar flavored.)
  1. Place your fish on a paper towel and record the numbers of orange fish and yellow fish on the chart below. This is generation 1.
  1. You are a predator that preys upon these fish. Remember, that the orange fish are slow and easily caught. The yellow fish are fast and not easily caught. Eat 3 orange fish. If you do not have three orange fish, then eat the remainder in yellow fish.
  1. Each surviving orange fish produces one new orange fish, and each yellow fish produces one new yellow fish. Obtain the new generation of fish from the extras given to you. Record these numbers as the start of generation two.
  1. Repeat steps 3 and 4 for two more generations.
  1. Create a bar graph for the totals of each type of fish in each generation.

Results and Conclusions:

The worksheet that is included on the bottom of this activity will help the teacher to gauge the students understanding of adaptation. The organisms that are unable to adapt will be less successful in surviving that ecosystem.

Name:______Date:______

Natural Selection in Goldfish

Problem

A predator feeds on a fish population made up of orange fish, which are slow and easily caught, and yellow fish, which are fast and not easily caught. What effect does natural selection have on these two fish populations?

Hypothesis

______

Materials

  • Yellow (cheddar flavored) “Goldfish” from Pepperidge Farm
  • Orange (pizza flavored) “Goldfish” from Pepperidge Farm

Procedure

  1. Obtain a mixed population of goldfish from your teacher. (Orange goldfish are pizza flavored. Yellow goldfish are cheddar flavored.)
  1. Place your fish on a paper towel and record the numbers of orange fish and yellow fish on the chart below. This is generation 1.
  1. You are a predator that preys upon these fish. Remember, that the orange fish are slow and easily caught. The yellow fish are fast and not easily caught. Eat 3 orange fish. If you do not have three orange fish, then eat the remainder in yellow fish.
  1. Each surviving orange fish produces one new orange fish, and each yellow fish produces one new yellow fish. Obtain the new generation of fish from the extras given to you. Record these numbers as the start of generation two.
  1. Repeat steps 3 and 4 for two more generations.
  1. Create a bar graph for the totals of each type of fish in each generation.

Data Table

Generation / Orange Fish / Yellow Fish / Total Fish
1
2
3
4
Orange / Yellow / Orange / Yellow / Orange / Yellow / Organ / Yellow
Gen. 1 / Gen. 12 / Gen. 3 / Gen. 4

Bar Graph of Generation vs. Number of Fish

Analysis Questions

  1. Use your knowledge of natural selection to explain what happened to each population of fish over the four generations?
  1. What do you think will happen to each type of fish over 10 to 20 generations? Why?
  1. Was your hypothesis correct? If not, rewrite it here.