12 ATAR HB - Gene Pools

Define evolution in genetic terms.

• any change in the frequency of alleles in populations of organisms from generation to generation.

• any change in the frequency of alleles in an individual organism over it's lifespan.

• any change in the frequency of alleles in communities of organisms from generation to generation.

• any change in the frequency of alleles in an ecoystem of organisms from generation to generation.

Tags

NGSS.HS-LS4-4

NGSS.HS-LS4-2

Alternative forms of a gene are called

• Alleles
• Homozygous
• DNA
• Genetics

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

The allele combinations

• genetics
• mitosis
• genotype
• phenotype

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

The physical appearance, physiological functions, and behavioral characteristics (instinctual) of an organism based on traits

• Genotype

• Phenotype

• Meiosis

• Genetics

Why do we say that natural selection never acts directly on genes?

• Because natural selection is in dire need of acting classes.

• Because natural selection “selects” an entire organism—not a single gene or group of genes—to either survive and reproduce or die without reproducing.

• Because specific forms of a gene, called alleles, may vary from individual to individual. Natural selections "selects" form these groups of genes.

• Because members of a population interbreed with one another, they share a common group of genes called a gene pool.

the total genetic information available in a population

• population genetics

• microevolution

• gene pool

• allele frequency

determined by dividing the number of a certain allele by the total number of alleles of all types in the population

• population genetics

• microevolution

• gene pool

• allele frequency

equal to the number of individuals with a particular phenotype divided by the total number of individuals in the population

• phenotype frequency

• hardy-weinberg genetic equilibrium

• gene pool

• allele frequency

Retinitis pigmentosa (RP) is an autosomal recessive trait that results in progressive blindness in humans.

On the island of Tristan da Cunha in the Atlantic Ocean, the frequency of the allele causing RP is four times greater in its population of a few hundred individuals than in the original British population from which it was colonised in the early 1800s. No natural disasters have occurred on the island since it was colonised.

The process that is most likely responsible for this observation related to allele frequency is

• Founder effect

• Genetic bottleneck

• Genetic drift

• Natural selection

Lucilia cuprina, the sheep blowfly, lays its eggs in wounds and the wet fleece of sheep. The larvae hatch and burrow into the sheep's skin, causing distress, reduced wool production and sometimes death. Particular chemicals were used in the past to control the L. cuprina but these became less effective as sheep blowfly developed a resistance to the chemicals.

The cause of the increased resistance to the chemicals was most likely due to

• farmers successively reducing the levels of insecticide applied to sheep.

• the insecticide producing a change in a gene which enhanced the survival of the blowfly.

• a chance mutation in a blowfly gene conferring a survival advantage in the chemical environment

• the insecticide producing a change in phenotype which enhanced reproduction of the blowfly.