Page 172 - Science Course 3 (Book 1)

Mo4-L6a: What is Variation in Adaptation?

Key Concept Over many generations, more and more offspring
inherit the variation.
What is Variation in Adaptation?
Eventually, the variation becomes an adaptation
How are mutations related to variations?

How Adaptations Occur

Natural selection is the process by which organisms
with variations that help them survive in their environ-
ment live longer, compete better, and reproduce more
than those that do not have the variation.

An organism with a beneficial variation lives longer
and has more offspring.
1. Variation in Traits
In this population of beetles, some and yellow and
some are brown. The color does not affect the ability
of the beetles to survive in their environment.

2. Organism Compete
A new predator eats yellow beetles more often
because it sees the yellow beetles more easily that
brown beetle.
3. Traits are inherited
The yellow beetles do not live as long as the brown
beetles, and – since color is inherited – fewer yellow
beetles hatch.

4. Adaption over Time
Nearly all individuals in a population are brown. The
color brown has become an adaption that helps the
beetles avoid predators in that environment.
164