Download Adaptation and Natural Selection Notes

Adaptation and Natural Selection Notes
p. 42-43
Evolution
-change in the genes of a population over time
-this can happen because of a mutation or natural selection
-evidence: fossil record, anatomy, DNA
Adaptation
-an increase in traits that help survival
-can be a noun or a verb
-Noun-something that an organism or species has or does
that makes them better suited for survival.
-Example: An adaptation that the Galapagos Island finches
have are beaks that are good at getting to their food source.
-Verb-the act of a species having changed to be better suited
for survival.
-Example: The Galapagos Island finches adapted so their
beaks are better suited to getting their food source.
-Mostly we will be using the noun form.
Behavioral Adaptations
-can be learned or instinctive
-learned comes from an organism’s parents or others around
them (ex. A male songbird learning more songs to better
attract a mate)
-instinctive is something an organism is born with (ex.
migrating, hibernating)
-some things are learned in some species and instinctive in
others
Physical Adaptation
-a trait that helps survival (ex. Camouflage, mimicry, longer
necks, sharper teeth)
-these can occur from a mutation or through natural selection
Natural Selection
-the process where traits become more or less common in a
population based on whether or not they have a survival
advantage
-more offspring are produced that can survive to reproduce
-offspring compete for resources (food, water, shelter, etc.)
and a mate
-offspring must be better able to fight off predators
-variation in genes means some are better adapted to survive
and reproduce
-if an organism does not reproduce, it does not matter if they
survived or not; they must pass on their genes to matter
-Charles Darwin called this “Survival of the Fittest”
Selective Breeding
-humans control breeding to bring out desired traits
-similar to natural selection, but humans choose which
organisms get to reproduce rather than nature
-examples: horses that run faster, a specific breed of dog,
fruits that have very small seeds, vegetables that taste better
or can resist disease, cows that give more milk