Download Name________________ Where does variation come from

Name________________
Where does variation come from? - Guided Notes
_____________ are controlled by genes.
Individuals within a population are not
_____________, there is _______________ or
differences within the populations genes.
________________________: process by
which organisms with traits best suited to the
environment are most likely to survive, reproduce and pass on their genes to next generation.
There is a certain amount of genetic __________________ in any population. This is because
each individual carries a different set of alleles within their DNA for certain traits.
There is an _______________of offspring. Organism usually produce more offspring than can
survive.
Example:
Organisms face a constant struggle to survive; trying to avoid
predators and locating enough food. In the __________________
for these resources, some of these individuals survive long enough
to pass the alleles for those successful traits on to their offspring.
Later generations will have increased numbers of individuals with those alleles/traits.
Natural Selection causes a change in ________________ ________________.
The environment determines which alleles are favored as species _____________ to their
environment and __________________ into new species.
What turtle do you think lives on the
island with lower vegetation?
The _____________________ of individuals may vary from one end of the curve to the other.
Natural selection can affect the ____________________ and hence the shape of the bell
curve.
_______________________ occurs when individuals at one
end of the curve have higher fitness than individuals in the
middle or at the other end.
Stabilizing selection occurs when individuals
near the center of the curve have higher
fitness than individuals at either end.
Draw a graph that represents stabilizing selection.
_____________________ occurs when individuals at the
upper and lower ends of the curve have higher fitness than
individuals near the middle.
Conclusion:
Evolution is any change in the relative frequency of alleles in the gene pool of a population
over time.
Natural selection operates on individuals, but resulting changes in allele frequencies show up
in populations.
Populations, rather than individuals, evolve!!