A species of hummingbird feeds on nectar of a particular plant whose flowers form a long, skinny cup. Beak length is a heritable trait that varies among individual hummingbirds. The birds' beaks must be long enough to reach the nectar, but longer beaks are also heavier and make flying more costly in terms of energy. a. Which mode of selection is this hummingbird species experiencing? b. How does this mode of selection affect the mean and standard deviation over time?

A species of hummingbird feeds on nectar of a particular plant whose flowers form a long, skinny cup. Beak length is a heritable trait that varies among individual hummingbirds. The birds' beaks must be long enough to reach the nectar, but longer beaks are also heavier and make flying more costly in terms of energy. a. Which mode of selection is this hummingbird species experiencing? b. How does this mode of selection affect the mean and standard deviation over time?

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Is each of the following examples due to directional, disruptive, balancing, or stabilizing selection? A. Polymorphisms in snail color and banding pattern as described. B. Thick fur among mammals exposed to cold climates C. Birth weight in humans D. Sturdy stems and leaves among plants exposed to windy climates
the aggresive behavior in cats is controlled by a completely dominant gene locus A. There are 46 docile cats in subdivision with a population of 158. Question: Determine if how many animals are heterozygous and how many animals have the dominant allele? provide solution
Assuming a population is in Hardy-Weinberg equilibrium, an increase in the frequency of the p(A) allele from 0.6 to 0.9 would result in which of the following outcomes? a. A decrease in the number of homozygous dominant individuals within the population b. A decrease in the number of homozygous recessive individuals within the population c. An increase in the number of homozygous recessive individuals within the population d. An increase in the number of heterozygotes within the population e. No change in genotypic frequency within the population
Consider a gene with two alleles, C and M. The table below describes fitness for different genotypes in two populations. Fitness CC CM MM Population 1 1.0 1.0 0.6 Population 2 0.9 0.9 1.0 Assume that both populations begin with frequencies of 0.5 for each allele, population size is infinite, and there is no migration between populations. Which of the following statements is true based on the information you have on these populations?
In a species of beetle, the size and color of the wings are controlled by two distinct genes. There are two alleles for the size gene: the big allele makes wings large, and the small allele makes them smaller. There are two alleles for the color gene: red and yellow. You are able to estimate the frequency of the four haplotypes from a museum collection from 60 years ago. You also estimate haplotype frequencies in the present day. The data are shown in the table below. Museum (60 ya) Present day big/red 0.69 0.5452 big/yellow 0.00 0.1448 small/red 0.09 0.2348 small/yellow 0.22 0.0752 A) What is linkage disequilibrium (LD) between the size and color loci in the museum collection? What is LD in the present day? B) Assuming one generation per year, what is the recombination fraction between the size and color loci?
Threatened species often have small, isolated populations where mating between relatives occurs. Let's assume one of these threatened species has a disease controlled by a gene that has two alleles A and a. Only individuals with two copies of the "a" allele have the disease and die before reproducing. Question: What are the effects of inbreeding on the frequency of the "a" allele, and the frequency of the disease in the population?
A. What does it mean if an allele is “fixed”? B. Explain one reason why EVEN if an allele is undergoing strong positive selection it may not become fixed in the population.
Calculate selection for the following scenario. In a population of prairie dogs living on a prairie, prairie dogs with genotype AA have 9 offspring per year on average, those with genotype Aa have 5 offspring per year on average, and those with genotype aa have 8 offspring on average. Round selection to the nearest hundredth, report selection as a value ranging from "0.00" to "1.00" • Selection on genotype Aa: • Selection on genotype AA: • Selection on genotype aa: Which genotype has the highest fitness? Fill in the blank with homozygous dominant, heterozygous, or homozygous recessive
You are studying a population of mulberry plants. The average mulberry produces 55 leaves, but an insect herbivore preferentially kills plants with more leaves, and therefore the remaining population has an average of 35 leaves after the insects kill certain plants due to the herbivory. The heritability of leaf number is 0.75. What is the response to the selection imposed by the insect herbivores? a. -10 leaves b. -20 leaves c. -15 leaves d. -5 leaves