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
Give typing answer with explanation and conclusion
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
Below is a diagram showing decreased fitness before and after a hypothetical bottleneck in which all of the inbreeding depression is due to increased homozygosity for deleterious recessive alleles. The open circles show the average fitness of hypothetical 'mutant-free' individuals that have no deleterious alleles. The shaded circles show the average fitness of individuals produced by random mating. The dark circles show the average fitness of individuals with an Fof 0.25 (equivalent to full-sib matings). In the diagram on the right, imagine that 'before' refers to before genetic rescue has been instituted (that is, before managed gene flow into a small and isolated population). The circles are defined the same as above. Draw what the circles (unfilled, grey filling, and dark filling) would look like in the 'after' portion of the diagram, that is, after a single pulse of gene flow from a small number (~5) of translocated individuals, if fixed genetic load decreases in this population.…
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
What is the covariance of the two traits?
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?
After making the Punnett square for the P-generation, you should have come up with the probabilities of the offspring having the combination of traits for the tail and scales. Write the probabilities down in a table. Assign a range of random numbers between 1 and 10 000 to each of the combinations produced in the Punnett square. The range must correspond with the percentage of each combination. Write the assigned ranges down in a table. For example: each of the combinations has a 25% chance of being produced. Thus, combination 1 will have a range of 1 to 2 500, combination 2 will have a range of 2 501 to 5 000, combination 3 will have a range of 5 001 to 7 500, and combination 4 will have a range of 7 501 to 10 000.
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.
Storage of excess carbohydrates in the diet in the form of fat would have helped human populations survive famine. However, this process is also a risk factor for obesity and type 2 diabetes in modern populations. Modern populations vary greatly in the prevalence of type 2 diabetes, but there is no evidence that alleles increasing type 2 diabetes susceptibility have been under positive selection in human populations. Which of the following is the best inference we can draw from these findings. Selected answer will be automatically saved. For keyboard navigation, press up/down arrow keys to select an answer. b C d Past selection for alleles increasing fat storage probably does not explain differences in type 2 diabetes prevalence in modern populations. Storage of excess carbohydrates probably does not contribute to type 2 diabetes. There is no genetic basis for differences between populations in type 2 diabetes. Fat storage has always been a deleterious trait for humans.