Lesson 44: Variation Within a Species
Individuals of the same species can differ in their traits. The lesson covers inherited information, environmental influences, and how variation relates to selective breeding and responses to change.
Key Ideas
- Members of a species can differ in their bodies and behavior. These differences are called variation.
- A trait is a feature we can describe or measure, such as fur color or leaf size.
- Some traits are influenced by information inherited from parents. Others develop through experiences or conditions during life.
- Inherited information and the environment work together. Even living things with very similar genes can develop differently.
- Inherited differences can help a population survive changing conditions. People also choose inherited traits when breeding plants and animals.
Vocabulary
- Trait: A characteristic that can be described or measured, such as leaf width.
- Variation: Differences between individuals of the same species.
- Inherited Trait: A feature influenced by information passed from parents to their young.
- Acquired Trait: A feature developed during life, such as a scar or a learned skill.
- Gene: A section of DNA that carries information used by living things. Genes can be passed from parents to their young.
- Heredity: The passing of genetic information from parents to their young.
Discussion Questions
- Identical twins start with the same genes. Name three ways two identical twins could still end up different from each other by the time they are twenty.
- A runner wins every race she enters. How much of that is inherited and how much is acquired? What would you need to know to decide?
- Farmers keep seeds from old plant varieties in storage even when nobody grows them anymore. After today's lesson, why do you think they bother?
Supplies
- Twenty leaves from a single tree, a ruler, and paper
- Paper, a pencil, and a family member to compare with
- Two pots, the same soil, several seeds from one packet, water, a ruler