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Chapter 17 Assessment

Terms in this set (27)

The combined genetic information of all members of a particular population forms a
gene pool.
Mutations that improve an individual's ability to survive and reproduce are
beneficial.
Traits, such as human height, that are controlled by more than one gene are known as
polygenic traits.
The meaning of allele frequency.
The frequency of a certain allele among all alleles of the same gene in a population.
Explain why sexual reproduction is a source of genetic variation.
Sexual reproduction allows for variety and it allows species to evolve and change over time.
Explain what determines the number of phenotypes for a given trait.
Molecular biology techniques based on rRNA sequences.
What is lateral gene transfer?
Physical transfer of a gene from a species in one lineage to a species in another lineage.
Define evolution in genetic terms
A change in the frequency of alleles in a population overtime.
Which kind of mutation has the greater potential to affect the the evolution of a population: a mutation to a body cell or a mutation in an egg cell?
egg cell mutation
Explain how natural selection is related to phenotypes and genotypes.
Over a long period of time, natural selection can lead to evolution. A new species can form when a group individuals remains separated from the rest of its species long enough to evolve different traits.
Explain how natural selection is related to individuals and populations.
The theory of natural selection was postulated by Charles Darwin (and also independently by Alfred Wallace) who described it as 'survival of the fittest
How does genetic recombination affect genetic variation?
It makes offspring different from their parents by combining the alleles for traits given by each parent during sexual reproduction.
The type of selection in which individuals of average size have greater fitness than small or large individuals have is called
disruptive selection.
If coat color in a rabbit population is a polygenic trait, which process might have produced the chart below?
Genetic equilibrium
A random change in a small population's alleles frequency is known as
mutation.
What is fitness in genetic terms?
How well an organism can survive and reproduce in its environment.
How do stabilizing selection and disruptive selection differ?
In stabilizing selection, individuals near the center of the curve have higher fitness than individuals.
What is genetic equilibrium?
When there are no factors causing allele frequencies to change in a population.
Distinguish between the ways in which natural selection affects single-gene traits and the ways in which it affects polygenetic traits.
Causes a desired action by stimulating or inhibiting cell function.
In a certain population of plants, flower size is a polygenetic trait. What kind of selection is likely to occur if environmental conditions favor small flowers?
Organisms with extreme traits.
A road built through a forest splits a population of frogs into two large groups. The allele frequencies of the two groups are identical. Has genetic drift occurred?
No
DDT is an insecticide that was first used in the 1940s to kill mosquitoes and stop the spread of malaria. As time passed, people began to notice that DDT became less effective. Explain, in genetic terms, how the insects became resistant to the pesticide.
The insects grew immune to the pesticide over time.
Temporal isolation occurs when two different populations
reproduce at different times.
When two populations no longer interbreed, what is the result?
reproductive isolation
Explain how the different species of Galapagos finches may have evolved.
Each of the finches evolved to their surroundings to be able to eat and reproduce.
Explain why reproductive isolation usually must occur before a population splits into two distinct species.
Because without reproductive isolation the populations can't split into two distinct species.
A botanist identifies two distinct species of violets growing in a field, as shown in the left of the illustration below. Also in the field are several other types of violets that, although somewhat similar to the two known species, appear to be new species. Develop a hypothesis explaining how the new species may have originated.
Alloploidy, a hybrid formed from species A and C.
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