In this unit on selection and adaptations, students discover how different environments caused land iguanas and marine iguanas to appear so different from one another. They then solve a mystery on how traits become more prominent in populations over time and complete a hands-on team challenge to gather evidence to support this idea. The unit culminates with an engineering challenge in which students design and build a product inspired by an animal or plant adaptation that humans can use.
Solve: Iguana Comparison + Peppered Moth Mystery
Make: Compete in a bird beak challenge!
Make Extension: Research and Display an Adaptation over Time
Engineer: Build a Product from an Animal or Plant Adaptation
- Next Generation Science Standards
- Use argument based on empirical evidence and scientific reasoning to support an explanation for how characteristic animal behaviors and specialized plant structures affect the probability of successful reproduction of animals and plants respectively. [Clarification Statement: Examples of behaviors that affect the probability of animal reproduction could include nest building to protect young from cold, herding of animals to protect young from predators, and vocalization of animals and colorful plumage to attract mates for breeding. Examples of animal behaviors that affect the probability of plant reproduction could include transferring pollen or seeds, and creating conditions for seed germination and growth. Examples of plant structures could include bright flowers attracting butterflies that transfer pollen, flower nectar and odors that attract insects that transfer pollen, and hard shells on nuts that squirrels bury.]
- Construct an explanation based on evidence that describes how genetic variations of traits in a population increase some individuals’ probability of surviving and reproducing in a specific environment. [Clarification Statement: Emphasis is on using simple probability statements and proportional reasoning to construct explanations.]
- Use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time. [Clarification Statement: Emphasis is on using mathematical models, probability statements, and proportional reasoning to support explanations of trends in changes to populations over time.] [Assessment Boundary: Assessment does not include Hardy Weinberg calculations.]
- Inquiry Scale
- Each lesson in the unit has an Inquiry Scale that provides directions on how to implement the lesson at the level that works best for you and your students.
- “Level 1” is the most teacher-driven, and recommended for students in 4th-5th grades. “Level 4” is the most student-driven, and recommended for students in 7th-8th grades.
- For differentiation within the same grade or class, use different inquiry levels for different groups of students who may require additional support or an extra challenge.
- Common Misconceptions
- In order for a trait to become more common in a population, it not only has to help an individual survive, it must also help them survive long enough to reproduce and pass on that trait.
- Learners often hear the word “adapt” used in conversation to mean a short-term change willfully done by an individual in a lifetime. Emphasize to students that the term "adapt" has a very different meaning in biology. Evolutionarily-speaking, adaptations happens over many years and generations, depending on reproductive cycle. This is something that is not willfully done by an individual, but occurs at the population level. This should be emphasized frequently throughout the unit.
- Students may be familiar with the term "survival of the fittest." Note that “fittest” does not necessarily mean strongest, but instead most fit to the environment.
- Content Expert
- Bruce Grant
Ph.D, Professor of Biology, Emeritus College of William & Mary
- Bruce Grant
- Leveled Reading
* To give our users the most comprehensive science resource, Mosa Mack is piloting a partnership with RocketLit, a provider of leveled science articles.
- Speciation - How Evolution Happens
How does a new species form? In this rigorous article, we look at famous examples (such as Darwin's Finches!) and explain a few different factors that can lead one population to separate and diverge into independent species that can no longer have offspring.
- Evidence for Evolution: Analogous and Homologous Structures
The fossil record provides a wealth of evidence for evolution, both in organisms who've evolved similar structures in the same environment and organisms who are genetically related that share similar traits. This article give a few examples of each and explains the difference between the two.
- The Story of Corn
Corn has changed A LOT and it's not due to natural selection. In this article, natural selection is defined and students continue to read about the changes that artificial selection and selective breeding have had on corn.
- How do Living Things Change?
How do living things change into all the different organisms around us? In this article, students read an introduction to the idea that genes are responsible for creating proteins. Mutations in genes can change the proteins that are made and this can change the traits of the organism.
- How Do Birds Stay Warm?
Birds have many behavioral adaptations that allow them to stay warm in the coldest regions on Earth. This article reviews a few of the behaviors of birds that help them to survive and also explains how countercurrent blood flow works.
- Speciation - How Evolution Happens