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Adaptations |
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Sometimes a change, or mutation,
happens in an organism’s
genes. The changed gene can pass from a parent to the offspring.
Mutations may be harmful, helpful, or neutral. Mutations are
often harmful. For example, a mutation may cause an animal
to no longer have the correct genes to make white blood cells
that fight germs. A helpful mutation can be the first step towards
an adaptation. Adaptations make an organism fit an ecosystem
better. Colors that help an animal hide are adaptations. |
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Adaptations are especially important
when an ecosystem
changes. At such times, competition for limited food, water, or
other resources is the strongest. Organisms that have the best
adaptations to compete for the limited resources may survive
best, reproduce more, and pass their genes to their offspring. |
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Structural Adaptations |
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Helpful mutations or some
new combinations of DNA may
cause changes in body parts. Structural
adaptations are
changed body parts that help the organism survive in its
ecosystem. For example, if a hummingbird was born with a
longer beak than other hummingbirds, the bird might be better
at getting food from some flowers in its ecosystem. The longer
beak is a structural adaptation that is helpful when living
around these flowers. During a drought, this bird may survive
when many other birds cannot find enough food. The bird
might pass the genes for this adaptation to its offspring. After
many generations, a large part of the hummingbird population
may have this kind of long beak and survive better than other
hummingbirds. |
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Natural selection involves the
process of a species developing
adaptations. All species of living things may experience natural
selection. Natural selection helps them survive in different
niches and environments. |
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Behavioral Adaptations |
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Were you born knowing how to build
a house? That is
impossible! Hummingbirds though, like other birds, are born
knowing how to make the kind of home they need. They are
also born knowing how to take care of their offspring. These
behaviors are due to genes passed from parent to offspring. |
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This
frog can
better avoid its
enemies because
of structural
adaptations such
as the suction cups
on its toes and its
green skin. |
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Rough play with their
parents and other cubs helps these lion cubs learn to hunt. |
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