Week 3 Exam Notes
Adaptation is a characteristic that enhances the survival and/or reproduction of organisms
that bear it, relative to alternative (especially ancestral) character states.
Adaptation is a physical, physiological, behavioural, or other characteristic evolved
through natural selection.
Mutation (the origin of new genetic variation), genetic drift (changes due to chance,
specifically founder effects and population bottlenecks), and gene flow (movement of
genes among populations) are mechanisms of evolution.
Natural selection is non-random differences in survival and/or reproduction among
individual entities on the basis of differences in heritable characteristics.
There are many kinds of barriers that can block gene flow and therefore contribute to the
origin of new species.
Gene flow is the movement of genes from one population to another.
Ecological specializations such as eating different foods can cause a population to split
and cease sharing genes.
Matching terms with the appropriate description:
Alternate (i.e., different and mutually exclusive) forms 1
__3__ of a gene. . Frequency
__4__ The set of genes possessed by an organism. 2
__1__ The proportional representation of a phenotype,
genotype, gamete, or allele in a population. 3 Alleles
The physical expression of the genotype (in .
__2__ combination with the environment). 4
For sexual species, a group of interbreeding .
__5__ individuals and their offspring. 5
All mussels have mantle tissue, and it predates the evolution of lures.
The process of “co-option” is when a feature that serves one function takes on a new function
(often while still serving the original function, as with mantle tissue in mussels).
Over many generations of mussels, the accumulation of beneficial mutations can lead to the
evolution of complex lures that are very effective at attracting particular fish hosts.
Extirpated mussels are species in which individuals still exist, but that they are no longer found
in an area where they were once common. Key Points:
• Not every feature of a given organism is