Natural Selection
Natural Selection
Objectives
In this lesson, students conduct a laboratory simulation to demonstrate the relationship between gene frequencies and natural selection. Then, students learn the principles of natural selection and relate them to the lab activity. Students will:
- analyze data and draw conclusions about how natural selection can affect which alleles are passed from one generation to the next in a population.
- explain how different characteristics in individuals of a population may affect survivability or reproductive success.
- explain how the number of offspring that survive to reproduce successfully is limited by environmental factors.
- distinguish between a scientific theory and a hypothesis.
Essential Questions
Vocabulary
- Population: Group of individuals of the same species that live in the same area.
- Evolution: The process that results in heritable changes in a population spread over many generations.
- Natural Selection: The process by which individuals in a population inherit genes that allow them to survive and be reproductively successful.
- Fitness: Ability of an organism to survive and reproduce in its environment.
- Adaptation: Inherited characteristic that increases an organism’s chances for survival.
- Allele: One of several different forms of a gene.
- Theory: The summary of a hypothesis or group of hypotheses that have been supported by repeated testing.
- Hypothesis: Possible explanation for observations or possible answer to a scientific question; educated guess.
- Law: Generalizes a group of observations for which no exceptions have been found (e.g., law of gravity).
Duration
90 minutes/2 class periods
Prerequisite Skills
Materials
- What Evolution Is Not/What Evolution Is (S-B-9-1_What Evolution Is Not.docx)
- Rabbit Natural Selection Laboratory Activity–Student Version (S-B-9-1_Rabbit Natural Selection Laboratory Activity-Student Version.doc), one copy of this packet per lab group
- Rabbit Natural Selection Laboratory Activity–Answer Key (S-B-9-1_Rabbit Natural Selection Laboratory KEY.doc)
- colored cereal, 50 pieces each of two colors per lab group (M & M’s also work well for this activity)
- three Petri dishes or other containers per lab group
- one small paper bag per lab group
- three labels per lab group
- computers with spreadsheet software, or one sheet of graph paper per lab group
- Principles of Natural Selection–Teacher Version (S-B-9-1_Principles of Natural Selection-Teacher Version.doc)
Related Unit and Lesson Plans
Related Materials & Resources
The possible inclusion of commercial websites below is not an implied endorsement of their products, which are not free, and are not required for this lesson plan.
- What Evolution Is Not/Evolution: What It Is
www.indiana.edu/~ensiweb/lessons/ev.not.html
- Theory of Natural Selection
www.biology-online.org/2/10_natural_selection.htm
- Comparison of Evolution Mechanisms: Summary (an activity comparing Darwin and Lamarck’s ideas)
www.indiana.edu/~ensiweb/lessons/ev.mech.pdf
- Darwin’s Finches
http://people.rit.edu/rhrsbi/GalapagosPages/DarwinFinch.html
- The Chips are Down: A Natural Selection Simulation
www.indiana.edu/~ensiweb/lessons/ns.chips.html
- The Natural Selection of Bean Hunters (lab activity)
www.indiana.edu/~ensiweb/lessons/ns.beans.html
- The Hardy-Weinberg Equation
www.phschool.com/science/biology_place/labbench/lab8/hardwein.html