Workbook page

Key Ideas

• No two members of a species are identical. Those differences are called variation.
• A trait is one feature at a time. Traits are what we actually measure and compare.
• Inherited traits come from parents through genes. Acquired traits come from a living thing’s own life and stop with it.
• Genes set what is possible. The surroundings a living thing grows up in decide how much of it happens.
• Variation is what lets a species survive change, and it is what people put to work in selective breeding.

• Trait: A single measurable feature of a living thing, such as leaf width, height, or eye color.
• Variation: The differences in traits found among members of the same species. Variation is normal, not a mistake.
• Inherited trait: A trait a living thing is born with, passed down from its parents.
• Acquired trait: A trait gained during life, from surroundings or effort. Acquired traits are not passed to offspring.
• Gene: A set of instructions inside a living thing’s cells that carries an inherited trait from parent to offspring.
• Heredity: The passing of traits from parents to offspring. Selective breeding is people choosing which parents breed in order to shape a trait.

1. 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.
2. 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?
3. 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?

• 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