Life-Cycle
Sleuth Students Develop Hypotheses About Migration |
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Time Materials |
Overview: Why do animals migrate? As students study an animal's life cycle and behaviors closely, they gather clues about what animals need to stay alive and/or reproduce. This helps them develop hypotheses about the reasons for migrations.
Teacher's
Background
Migration takes a huge amount of energy, so why do animals do it? Most move
to places where they can better survive during that season. Many migrate to
find food or more liveable conditions (e.g., daylight, shelter, safety from
predators, less overcrowding) for themselves or their young. When cold weather
halts the supply of insects, birds that rely on them head to warmer climates
where food is plentiful. Monarchs spread north in the spring to take advantage
of vast areas with emerging milkweed for their young and nectar for themselves.
These are
all behavioral responses that evolved over time. But don't reveal this
to your students! Have your young detectives use the Checklist
for Student Research. As migration updates arrive throughout the
season, they'll look for clues and gather information about their selected
animal's basic biology and habitat. (Each checklist question relates
to survival of the individual its young.) At the end of the season
they'll re-examine their initial theories about why animals migrate.
Laying the Groundwork:
Before Migration
Help students grasp the idea that behavioral adaptations are responses that
help animals survive in particular environments.
- Begin
with a classroom discussion about animals' physical adaptations.
Spark students' thinking by asking questions such as, Why do
you think hummingbirds have long tongues? (To reach in and draw
nectars from flowers.) Why are polar bears furry? (To survive
in a cold environment.) Why do humans have thumbs?
- Next, discuss how an animal's behavior can also be adapted to its environment. Unlike physical adaptations, such as fur and fat, behavioral adaptations are actions animals take in order to survive. Ask, Can you think of any examples of animal behaviors that help them or their offspring survive? Students might suggest foraging for food, building nests, hibernation, and so on. If they don't mention migration, ask, How might migration help animals survive?
- Explore
why only some animals migrate. Ask, Which animals stay in our
area year round? What might be some advantages of living in the north
year round? Of migrating south? Of remaining in the tropics? Of migrating
north in the spring? Document students' responses and revisit
these at the end of the season.
- As a class, make a list of all the Journey North migrations. After discussing why different animals might migrate (e.g., hummingbirds, whales, cranes), shift the focus to the animals your students have selected to track this spring. Challenge students to form their own theories to explain why these animals migrate. Have each student write a paragraph to explain his or her hypothesis and make a prediction about when his selected animals will migrate.
- Give students the Checklist for Student Research to guide their research throughout the season. If you have younger students, select just a few questions from each category. Students can write each question on an index card as use them to write notes as they discover answers.
- As the migration updates arrive, students should search for clues to their questions. They may need to find additional resources for climatic data about a specific region or information on the biology of the animals being tracked. Journey North Updates will suggest many online resources.
- Encourage
students to constantly evaluate the relative importance of their
research findings. You may want to suggest this clue to help them: Scientists
suspect that the timing of an animal's migration
is closely related to the reason it migrates. Remember,
this mystery is theirs to unfold.
See sample student work from Mr. Murray's 7th grade class in Ontario.
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By Janice G. |
By Jon. M |
Have students review their theories and predictions about the causes and timing of migration. Discuss these questions as a class, in groups, or in essay form:
- Did your hypothesis about the reasons for migration change? What new information caused you to change your hypothesis? How would you now explain why your animal migrates?
- How did your prediction compare to the actual timing of migration?
- What did you learn about the food upon which your animal depends? Does your animal fit neatly in one spot on a simple food chain, or is its food chain more complicated?
- How might your animal's food needs affect where it spends the winter? Where it spends the breeding season? How might its food needs affect the timing of its migration? The route it takes?
- What did you learn about your animal's breeding requirements? What effects might these requirements have on its migration?
Assessment
- Mr. Murray's evaluation rubric
- Students' theories about the reasons for migration should include that idea that animals migrate to find food or other living conditions that help them and their young survive. Older students should understand that this behavioral adaptation evolved over many generations as animals that expressed this behavior were better able to survive and produce offspring.
National Science Education Standards
Science
as Inquiry
Use data to conduct a reasonable explanation. (K-4)
Think critically and logically to make relationships between evidence and explanations.
(5-8)
Life
Science
Organisms have basic needs. They can survive only in environments in which
their needs can be met. (K-4)
The behavior of individual organisms is influenced by internal cues (such as hunger) and by external cues (such as a change in the environment). (K-4)
An organism's behavior patterns are related to the nature of that organism's environment. (K-4)
An organism's behavior evolves through adaptation to its environment. (5-8)
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