Natural Selection

This unit introduces students to the concepts of natural selection and adaptation. The unit begins with a Science Scene in which a group of friends discuss whether or not the death of pigeons that aren’t smart/fast enough to get out of the way of an oncoming car helps pigeons as a species through the process of evolution. Students also learn about the process of natural selection by considering the story of the peppered moth. Adaptation is introduced, and students consider a science-fiction scenario where humans could evolve to adapt to unfamiliar, extraterrestrial environments. Students also consider a fictional case in which a barrier across a river has an unintended impact on salmon reproduction, allowing only smaller salmon to spawn. Students design a solution to the problem and write a persuasive letter that advocates for their design. They’ll use what they’ve learned about natural selection in their letter.

Activities

Scene: Those Poor Pigeons!

Erica, Shawnte, and Will think about breeding, evolution, selection, survival, and reproduction after witnessing some pigeon roadkill.

Duration: Approximately 50 minutes

Reading: The Amazing Story of the Peppered Moth

Students learn about a classic, true story of the peppered moth, a scientific discovery of the effects of variation and selection.

Duration: Approximately 50 minutes

Project: Fish Fence Crisis

Students jump into the deep end of a story of a "Fish Fence Crisis."

Duration: Approximately 55 minutes

Conversation: Suited for Survival—Animal Adaptations

Students learn why some animals are particularly well suited for survival in their particular environment, then reflect on how and why different adaptations have worked well for certain species.

Duration: Approximately 40 minutes

Writing: Science-Fiction Science—Planets X and Y

Students imagine the distant futures of Planets X and Y, after the descendant of Earthling explorers have adapted through variation and selection.

Duration: Approximately 40 minutes

Teacher Tune-ups

• What are the common misconceptions related to evolution?

• Why is the story of the peppered moth so famous and important?

Student View of Visuals and Activities

Some teachers prefer to have students view the slides and other visual assets in this unit directly instead of projecting them in class. Below is a web page to share with students with links to some of same items that are within in the teacher lesson plans, but without the explanatory text for the teacher.

 

• Student Links to Unit L4 Slides and Other Visuals

Original SciGen Unit

This unit has been adapted from "7.6 Thinking About Natural Selection" in the Word Generation program led by Catherine Snow (Harvard University) through a SERP collaboration with the Boston Public Schools and other districts in Massachusetts and Maryland.

PDFs of that earlier unit's teacher and student editions are available at the Science Generation Download Center.

survival

noun – the state of continuing to live due to being well adapted

Why might darker moths have a greater survival rate during a period of heavy pollution?

random

adjective – without a particular order or method

Janay reached into the raffle ticket box, drew out a ticket at random, and won. Was that fair? Explain.

reproduction

noun – the production of offspring

How might wolves’ reproduction rates be affected by an increase in the bison population?

selection

noun – a process where certain organisms live more successfully

Explain how selection might cause iguanas that live on rocks at the seashore to have longer claws.

evolution

noun – the process by which living things slowly change from earlier forms

Think of an animal with an unusual trait. How might evolution explain the development of this trait?

species

noun – a group of living things capable of breeding and exchanging genes

Do you think there are more insect species or mammal species? How could you find out?

adaptation

noun – a change where a species becomes better fit for a certain environment

Due to adaptation, sea otters have very dense fur to keep warm in cold ocean water. Can you think of an animal adaptation related to color?

fitness

noun – compatibility for a certain environment

What qualities demonstrate the fitness of fish for living under water?

breed

verb – to mate for reproduction

Do you think people are justified in breeding dogs even though many strays end up in shelters? Why or why not?