gene variation

Question 1

what 3 characteristics must a species have to be considered a species?

Answer 1

1. physically similar population 2. interbreeding population, 3. not interbreeding with other groups

Question 2

what 2 characteristics must a population have in order to be considered a population?

Answer 2

1. same species, 2. continuing to mate and produce offspring

Question 3

what is a gene pool?

Answer 3

its all the genes in a population (including alleles)

Question 4

In what 2 ways are gene pools described?

Answer 4

1. by the # of different alleles in a pool and 2. the frequency an allele shows up (like a % amount…Ex. a little toe allele showing up 60% in humans)

Question 5

Does allele frequency bear any relationship to allele dominance?

Answer 5

Nope. Sometimes a recessive allele will show up more often than a dominant allele.

Question 6

What causes EVOLUTION (as defined in terms of alleles)?

Answer 6

It’s the change in the FREQUENCY of ALLELES over time.

Ex. The little toe allele shows up more often.. might lead to humans having a littler toe.

Question 7

Does natural selection DIRECTLY effect phenotype or genotype? Why?

Answer 7

Phenotype. Although it indirectly effects genotype. Phenotypes (expressed alleles) are a part of the genotype (our actual DNA) but phenotypes better suited to any environment will be most likely to survive and benefit from natural selection.

Question 8

In what 3 ways is genetic variation produced?

Answer 8

1. mutations, 2. genetic recombination during sexual reproduction, 3. lateral gene transfer

Question 9

What is a mutation?

Answer 9

a heritable change in genetic information.

Question 10

What must happen for a mutation to be important to evolution?

Answer 10

mutations must occur in eggs pr sperm in order for it to be passed from generation to generation. If a cell mutates into cancer, that is not going to effect evolution as it is not passed on to future generations.

Question 11

what 2 things contribute to genetic recombination?

Answer 11

1. During meiosis, one member of each chromosome pair is shuffled randomly into each egg or sperm. 2. crossing over during meiosis of DNA from the chromatids

Question 12

What is lateral gene transfer?

Answer 12

passing of genes without sexual reproduction ( such a bacteria to human causing antibacterial resistance)

Question 13

The # of phenotypes produced for a trait depend on what?

Answer 13

depend on how many genes control that trait.

Question 14

if just 1 gene controls a trait, that trait is called a …

Answer 14

single gene trait. Traits controlled by only 1 gene will have very few phenotype possibilities and few genotype possibilities)

Question 15

traits controlled by 2 or more genes are called?

Answer 15

polygenic traits. Usually creating more phenotype possibilities and have 2 or more alleles involved (therefore more genotype possibilities).