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7.1 Adaptation and Variation
Definitions
• Species: a group of organisms that can
interbreed and produce fertile offspring.
• Species diversity: the variety and abundance
of species in a given area
Genetic Diversity
• Genetic diversity: the variety of heritable
characteristics in a population of
interbreeding individuals
• Population: a group of
individuals of the same
species in an area.
Challenges to survival
Why is diversity within a species
important?
What kind of variations exist within a
species?
Adaptation
• A structure, behaviors or physiological process
that helps an organism survive and reproduce
in a particular environment
• Q : What kid of adaptations does a polar bear
have?
Structural Adaptations
• Any physical feature that helps the organism
survive.
– Ex …..
– The stick insect uses
________ as an adaptation
Mimicry
• Mimicry: A structural adaptation in which a
harmless species resembles a harmful species
– Example: viceroy butterfly mimics the harmful
monarch.
Batesian vs. Mullerian mimicry
• Batesian mimicry: unharmful species mimics a
harmful one
• Mullerian mimicry: 2 harmful species mimic
eachother
Behavioral Adaptations
• Something that an organism does, an action,
that helps them survive
• Example:
Physiological Adaptations
• A body function that helps an organism
survive
– venom
– Tolerance to environmental conditions (salt
temperature, chemicals)
– Hibernation
How do adaptations develop?
• Variation exists naturally, due to random
genetic mutations in DNA and development
• Not all variations become adaptations
• Environmental conditions determine whether
a variation in an individual will have a positive
or negative or neutral effect
• Individuals with a helpful variation are more
likely to survive and that variation will
become more frequent in the population.
Adaptations in Action
• https://www.youtube.com/watch?v=wEDxTh
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