21 Microevolution lecture questions

83 slides (got to slide 42, class stopped at 39)

what are the two levels of evolutionary change?

microevolution and macroevolution

microevolution vs macroevolution

microevolution - small-scale genetic changes in populations, responds to shifting environmental circumstances

macroevolution - larger-scale, an evolution that occurs at or above the level of the species.

(micro/macroevolution) can result in speciation or the emergence of new species

macroevolution

a gradual accumulation of microevolutionary changes can result in

macroevolution

antibiotic resistance and the shift in bill size of darwin’s finches are both examples of

microevolution

includes all individuals of a single species that live together in the same place and time

population

how do bacteria become resistant to antibiotics?

when antibiotics are administered, an environment favoring bacteria that are even slightly resistant to the drug is created. the surviving bacteria reproduce, which can lead to antibiotic resistance for the next time the person is sick.

proper use of antibiotics minimizes this effect.

what is phenotypic variation among members of a population?

all differences in appearance or function that are passed from generation to generation

what is quantitative variation?

the variation of traits that can be measured (measurable phenotypes). examples: weight, height, blood pressure

when quantitative data is graphed, what represents the variation among individuals?

the width of the curve is proportional to the variation among individuals

what is a qualitative trait?

a trait that fits into discrete categories. examples: feather color, eye color

qualitative traits exist in 2+ discrete states or ___

polymorphisms

qualitative variation is described by

the percentage of each trait

qualitative traits are frequently controlled by ___, meaning they are simply-inherited traits.

one/few genes

do organisms with the same genotype always exhibit the same phenotypes?

no, organisms with the same genotype can exhibit different phenotypes. also, organisms with different genotypes can exhibit the same phenotype.

block rock pocket mice from NM have the same fur color as rock pocket mice with a MC1r mutation from AZ. they have the (same/different) genotype and the (same/different) phenotype.

different genotypes, same phenotype

when hydrangeas are grown in acidic soil, it produces blue flowers. when grown in neutral or alkaline soil, it produces pink flowers. They have the (same/different) genotype and the (same/different) phenotype.

same genotype, different phenotype

an organism’s phenotype is frequently the product of an interaction between

its genotype and its environment

why is it important to know whether phenotypic variation is caused by genetic differences, environmental factors, or an interaction between the two?

only genetically based variation is subject to evolutionary change

what are the two potential sources of genetic variation?

production of new alleles

rearrangement of existing alleles into new combinations

where do rearrangements of existing alleles result from?

larger scale changes in chromosome structure or number, or from genetic recombination (crossing over, independent assortment, random fertilizations)

why do some variations in protein-coding regions of DNA not affect phenotypes?

because they do not change the amino acid sequences of the proteins for which the genes code

how do biologists detect genetic variations?

gel electrophoresis and DNA sequencing technology

what is the field of genetics that deals with understanding the causes of genetic variation within populations?

population genetics

what does a population’s gene pool include?

the sum of all gene copies (alleles) at all gene loci in all individuals in the population.

define genotype frequencies and allele frequencies

genotype frequencies - the percentages of individuals in a population possessing each genotype

allele frequences - the relative abundances of the different alleles, can be calculated

what is an allele?

a particular version of DNA sequence at a given genomic location

for a gene locus with two alleles, there are ___ genotype frequencies, but only ___ allele frequencies

3 genotype frequencies, 2 allele frequencies

(recall punnett squares)

null models serve as ___ in experiments

theoretical reference points

a mathematical model that describes how genotype frequencies are established in sexually reproducing organisms.

Hardy-Weinberg principle

the hardy-Weinberg principle states that a population’s allele and genotype frequencies…

remain constant unless there is some type of evolutionary force acting upon them

the hardy-weinberg principle states that genetic equilibrium is possible only if

all of the following are met:

1. no mutations are occurring

2. the population is closed to migration

3. the population is infinite in size

4. all genotypes survive and reproduce equally well

5. individuals mate randomly with respect to genotypes

what are the 5 processes that foster microevolutionary change?

(opposite of hardy-weinberg)

1. mutation

2. gene flow

3. genetic drift

4. natural selection

5. nonrandom mating

a spontaneous and heritable change in DNA

mutation

if an organism has two of the same alleles for the same trait, it is

homozygous

in punnett squares, what are p and q?

p is the dominant trait, q is the recessive

for most animals, only mutations in ___ are heritable

the germ line (cell lineage that produces gametes)

what are deleterious mutations?

mutations that alter an individual’s structure, function, or behavior in harmful ways

ehlers-danlos syndrome

mutation in gene coding for collagen, a major component of the ECM. results in a disruption of collagen synthesis, resulting in loose skin, weak joints, or sudden death from the rupture of major blood vessels, the colon, or uterus

ehler’s danlos syndrome is an example of what type of mutation?

deleterious

dermatospraxis ehler-danlos (dEDS)

an inherited connective tissue disorder associated with extremely fragile skin leading to severe bruising and scarring, saggy redundant skin. stretchy skin and characteristic facial structure

what are lethal mutations?

mutations that may kill all carriers (if dominant) or homozygous (if recessive)

Huntington’s disease is an example of what kind of mutation?

lethal (dominant)

sickle cell anemia is an example of which type of mutation?

lethal (recessive)

what are neutral mutations?

mutations that are neither harmful nor helpful

neutral mutations mostly arise because of a change in the ___ position of a codon, the wobble base pair

third

what is an advantageous mutation?

a mutation that is beneficial to the individual

the movement of organisms or their gametes, or genetic variation from one population to another

gene flow

what are some examples of gene flow?

pollen spreading from plants, birds carrying acorns from one oak population to another, mammals moving from one population to another and reproducing

what is the founder effect?

an extreme example of genetic drift. when a small group splits off from the main population to find a new colony