Key Idea.
Section 1
A Part's Shape Shows Its Job
An animal's body parts are called traits. Each trait has a special shape and makeup, which is its structure. Every trait also has a job to do that helps the animal survive. This job is its function.
The structure of a trait is a clue to its function. A hummingbird has a long, thin beak. This structure helps it perform the function of sipping nectar from deep inside a flower. A shark has sharp, pointed teeth. This structure helps it tear its food.
Section 2
Scientists Read Clues in Fossils
Fossils are preserved parts of ancient life. They give scientists clues about what an organism looked like by showing its structures, such as the shape of its teeth or bones.
Scientists study these fossil structures to figure out their function. They can infer what a body part did by comparing it to similar parts on animals today. A sharp fossil tooth probably had the same function as a sharp tooth now—tearing meat.
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Section 1
A Part's Shape Shows Its Job
An animal's body parts are called traits. Each trait has a special shape and makeup, which is its structure. Every trait also has a job to do that helps the animal survive. This job is its function.
The structure of a trait is a clue to its function. A hummingbird has a long, thin beak. This structure helps it perform the function of sipping nectar from deep inside a flower. A shark has sharp, pointed teeth. This structure helps it tear its food.
Section 2
Scientists Read Clues in Fossils
Fossils are preserved parts of ancient life. They give scientists clues about what an organism looked like by showing its structures, such as the shape of its teeth or bones.
Scientists study these fossil structures to figure out their function. They can infer what a body part did by comparing it to similar parts on animals today. A sharp fossil tooth probably had the same function as a sharp tooth now—tearing meat.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter