Ch 13

Genetic Variation

100

Evolution is goal-directed it leads to the perfect organism: True or False?

False

200

Mutation and sexual reproduction produce what?

Genetic variation

300

List 3 random components of sexual reproduction:

- Crossing over (random exchange of DNA, happens in prophase of meiosis)

- Independent orientation (homologous chromosomes separate into gametes independently of other chromosome pairs)

- Random fertilization (By chance one female gamete and one male gamete fertilize)

400

A change in the genetic information of a cell, which can be in DNA or RNA is called a?

Mutation

500

Consists of all copies of every type of allele, at every locus, in all members of the population is?

gene pool

The Evolution of Populations

100

Penicillin, a byproduct of mold on bread, was made into an antibiotic, but over time it stopped working, why?  

Bacteria reproduce rapidly and while penicillin killed most bacteria the few ones that survived had gained resistance. 

200

? is a change in the frequencies of alleles in a population’s gene pool -evolution occurring on its smallest scale

Microevolution

300

If a mutation arises without external pressure is it natural selection?

No

400

Explain why an individual can't evolve:

Evolution involves changes in the genetic makeup of a population over time. An individual’s genetic makeup rarely changes during its lifetime.

500

Mutations are always beneficial: True or False?

False mutations can be positive, negative, or neutral

The Hardy-Weinberg Equation

100

Describe what a population is:

A group of individuals of the same species that live in the same area and interbreed.

200

We can measure evolution as a change in the prevalence of certain heritable traits in a population over a span of generations: Name an example

The increasing proportion of resistant insects in areas sprayed with pesticides is one example. Natural selection favored insects with alleles for pesticide resistance; these insects left more offspring than nonresistant individuals, changing the genetic makeup of the population. 

300

The Hardy-Weinberg Equation can test whether a population is?

Evolving

400

The Hardy-Weinberg equilibrium states that allele and genotype frequencies will remain constant if:

- a population is large

- mating is random

- there is no mutation, gene flow, or natural selection

500

The condition for Hardy-Weinberg equilibrium is that there be no (?) —that all individuals in a population be (unequal or equal?) in the ability to reproduce

-natural selection

-equal

Mechanisms of Microevolution

100

The three main causes of evolutionary change are?

- natural selection

- genetic drift

- gene flow

200

Deviations from the five conditions named for Hardy-Weinberg equilibrium can alter allele frequencies in a population which is called? 

microevolution

300

Although new genes originate by mutation, these random and rare events cause little change in allele frequencies within a population why?

For any given gene, the chance of a mutation occurring in a given gamete is very low. Thus, mutations alone do not have much effect on allele frequencies.

400

Describe genetic drift:

a change in the gene pool of a population due to chance

500

Which is least likely to alter allele and genotype frequencies in a few generations of a large, sexually reproducing population: gene flow, mutation, or natural selection? Explain.

Mutation. Because mutations are rare, their effect on allele and genotype frequencies from one generation to the next is likely to be small.

Genetic Flow

100

Why does genetic drift have more of an impact on small populations?

because smaller populations have less variation and, therefore, a lower ability to respond favorably — that is, adapt — to changing conditions.

200

Give an example of genetic drift (explain if its the bottleneck effect or the founder effect)

Catastrophes such as hurricanes, floods, or fires may kill large numbers of individuals

300

? resulting from a drastic reduction in population size, usually the surviving population is  no longer genetically representative of the original population  

the bottleneck effect

400

Genetic drift is also likely when a few individuals colonize an island or other new habitat, producing what is called the ?

founder effect

500

Cheetahs are almost genetically identical and are very inbred due to genetic drift. About 10,000 years ago a disaster almost wiped them out which plummeted their genetic diversity. Which type of genetic drift is this bottle neck or the founder effect?

bottleneck effect