Exam 9: Evolution at Multiple Loci: Quantitative Genetics

Data on survival of juvenile black-bellied seedcrackers as a function of beak size is shown in the accompanying figure.Given the relative survival rates of juvenile birds in terms of both the lower mandible width and length,this is a clear example of ________.

Multiple trait analysis (beak width and beak depth)on the medium ground finch,in response to the drought of 1976-77,has generated the three-dimensional graph,shown in the accompanying figure.If the blue triangles represent fitness levels for the quantified parameters,then the birds showing the greatest fitness should have ________.

Continuously variable traits typically have a(n)________,[two words] otherwise known as a "bell-curve."

The fraction known as the broad-sense heritability (where VG = genetic variation,VP = phenotypic variation,and VE = environmental variation)is expressed by ________.

Variation among individuals that is due to variation in factors other than environmental influences is called ________.

________ selection and ________ selection tend to reduce the amount of variation in a population,whereas ________ selection tends to increase the amount of variation in a population.

In populations where individuals with extreme values of a trait have the highest fitness,the average value of the trait may not change,but the amount of variance in the trait does increase over time.This set of circumstances is known as ________.[two words]

The total variation in a trait is known as the ________.

Some have proposed that where human IQ scores are concerned,heritability can tell us something about the causes of differences between population means such as ethnic groups.Explain why this perspective is erroneous.

Traits that are conditioned by one locus are most appropriately termed ________.

________ refers to the fraction of the total variation in a trait that is due to variation in genes.

Determining the slope of the best-fit line for a data set of midparent versus midoffspring values by utilizing least-squares linear regression generates an estimate of heritability known as the ________.

When Bradshaw and colleagues investigated the quantitative trait loci (QTL)of two species of Mimulus (Mimulus cardinalis and Mimulus lewisii),they used marker loci as a way to map the QTLs.Their results are shown in the accompanying figure.According to these results,________.

Compare and contrast qualitative traits/genetics with quantitative traits/genetics.

In populations where individuals with intermediate values of a trait have the highest fitness,the average value of the trait does not change over time,but the variation tends to be reduced.This set of circumstances is known as ________.[two words]

It becomes possible to predict evolutionary changes in a population after we have measured two attributes affecting the population in question.What two measures allow us to make such predictions?

Variation among individuals that is due to factors other than genetic factors is called ________.

In cases where selection consistently favors a higher (or lower)value of a trait or phenotype,the result over time is a change in the average value of a trait in the population.This mode of selection is known as ________.

The abbreviation QTL stands for ________,[three words] which are those genes that influence nonqualitative traits.

To learn the location of and determine the role that QTLs have on phenotypes,researchers look for associations between a marker locus genotype and phenotype.Examples of research focusing on such methods have been conducted on ________.