Page 208 - Science Course 3 (Book 1)

Mo5-L3a: What is Natural Selection?

Variation: Adaptations
Individuals in a population
differ from one another. In An adaptation is an inherited trait that increases an
this population, some organism’s chance of surviving and reproducing in a
sunflower are taller than particular environment.
others.
Inheritance: Structural adaptations involve
Traits are inherited from physical characteristics, such as
parents. Tall sunflower color or shape.
produce tall sunflower.
Short sunflowers produce
short sunflowers.

Competition:
Due to limited resources, not
all offspring will survive.
Individuals with a trait that
better suite the environment
are more likely to survive and
reproduce. In this environment,
short sunflowers are more
successful. Adaptations of the Polar Bear
most bears do eat some plant matter, but where
polar bears live, there is almost no plant matter avail-
Natural Selection: able, so they have adopted to a totally carnivorous
Over time, the average height lifestyle.
of the sunflower population is
short if the short sunflowers
continue to reproduce
successfully

Key Concept

What is Natural Selection? Whiter fur is an obvious Big furry feet, like snow-
adaptation to the polar shoes to help walk in
How does natural selection occur?
bear’s life on arctic ice the snow.
pack. It helps them hide
in plain slight. Thick bubbler to help
keep them warm.

Functional adaptations
involve internal systems
that affect an organism’s
physiology or biochemistry.

Behavioral adaptations,
such as migration, involve
the ways an organism
behaves or acts.

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