Name the structure
A structure is a part of an organism, such as a bird’s beak, a fish’s gills or a leaf. Its function is the job it performs.
Structures & functions
Explain how the shape and parts of a structure help it do a job.
Class notes
Open PDF →Explain the connection
Do more than name a job: identify a feature and explain how it helps. A duck’s broad, webbed feet push against water, helping it swim.
Variation and adaptation
Individuals in a population vary. Across generations, inherited features that improve reproduction in an environment can become more common through natural selection. Individuals do not change their genes because they need to.
Explore the idea
01Structure
A structure is a part or arrangement, such as a cell membrane or a leaf.
02Function
A function is what that structure does.
03Connection
Features of a structure can help explain how it performs its function.
How do a duck’s webbed feet help it swim?
Reveal the reasoning
The webbing increases the surface area that pushes against the water. This structure helps the duck propel itself forward when it swims.
Try it yourself.
A bird has a long, narrow beak. Suggest a food source and explain your reasoning.
Check your thinking
A long beak could reach nectar inside a flower. The explanation connects the beak’s shape to a possible job; evidence about the bird’s actual diet would strengthen it.
Common question: Does an organism choose an adaptation?
No. Adaptations are inherited characteristics that become common in populations over generations.
Take it further.
Compare a fish fin and a whale flipper. How can different structures perform a similar function?
See a possible explanation
Both help an animal move or steer in water, even though their internal structures and evolutionary histories differ.