Exam 3: Evolutionary Change and Adaptation

Which of the following lead(s) to genetic variation in sexually reproducing organisms?

All of the following lead to increased genetic variation in a population EXCEPT

As humans move into an area, the habitat often becomes fragmented due to clearing of land to build homes and roads, while leaving small areas of natural habitat. For small species that cannot navigate long distances from one habitat fragment to the next, speciation will likely occur due to __________ barriers.

A gardener is constantly struggling with the growth of weeds in his perennial flower beds. At the start of the growing season one year, he sprays an herbicide to reduce the number of weeds. Although the herbicide kills many of the weeds, some develop resistance to the herbicide and continue to grow and spread among his flowering plants. After a few years, the gardener decides to stop all herbicide applications. One of the changes that he notices is that the weeds that have resistance to herbicides grow much more slowly and are easily outcompeted by other weeds when no pesticides are sprayed (i.e., the herbicide-susceptible weeds produce more seeds and quickly overtake some of the areas in the garden where the herbicide-resistant weeds had been growing). In a single individual, how might herbicide resistance occur?

Hip dysplasia is a common ailment in large dog breeds including Rottweilers in the United States. One breeder decides to import several females from Germany where the disease is less common to mate with his male dogs. This introduction of new alleles into his dog population is an example of __________.

The Irish elk was misnamed because it was neither exclusively Irish, nor was it an elk. The Irish elk is a giant extinct deer, the largest deer species ever, which stood up to 7 feet at the shoulder. In sexually mature males, the antlers spanned up to 12 feet and weighed 90 pounds. These large antlers were likely used in displays and ritual combat between males during the mating season. Although females preferred males with large antlers, these structures were also unwieldy and may have lead to decreased survivorship in males. Thus, this trait arose through the process of __________.

The graph below represents the results of an experiment looking at mate preference in female black widowbirds. The researcher used three groups of male birds: one with artificially shortened tails, one with artificially lengthened tails, and the control group with unaltered tail lengths. In the natural population of black widowbirds, there is some variation in tail length. Tail length is an inherited trait; the versions of this trait that result in different lengths are called __________.

Among cats, there is great variation in color and length of coats from long-haired, orange and white Ragdolls and Persians to cats with little to no hair. The different versions of genes that code for hair color and length are examples of __________.

This figure shows the happy face spider found in Hawaii. Despite their variation, these individuals can interbreed. Has adaptive radiation occurred?

Which of the following are required for evolution to occur?

Among eukaryotes, only animals undergo meiosis.

In the Chiricahua Mountains in Arizona, a species of spider is found in both the woodland areas around streams and in the desert shrub areas. In the woodland areas, these spiders are under constant threat of predation from birds. Because of this, they spend little time in the exposed portion of their sheet webs. However, in the desert areas where birds are less of a threat, spiders constantly forage in the exposed portion of their webs. Offspring of matings between spiders from woodland and desert regions behave more like spiders from the desert habitat, even if they are living in the woodland area. The offspring quickly fall prey to birds, often before they have had a chance to reproduce. Over time, two different species arise. What type of reproductive barrier led to this speciation event?

Among cats, there is great variation in color and length of coats from long-haired, orange and white Ragdolls and Persians to cats with little to no hair. These traits associated with fur type are examples of __________ traits.

When breeding cats, what cellular process must take place in both males and females to ensure the correct number of chromosomes in the offspring?

Typically, flower color and shape are associated with what type of selective pressures?

The common garter snake is a predator of the rough-skinned newt. These newts produce a potent neurotoxin that is concentrated in their skin, but garter snakes have evolved resistance to this toxin. This is an example of __________.

A gardener is constantly struggling with the growth of weeds in his perennial flower beds. At the start of the growing season one year, he sprays an herbicide to reduce the number of weeds. Although the herbicide kills many of the weeds, some develop resistance to the herbicide and continue to grow and spread among his flowering plants. After a few years, the gardener decides to stop all herbicide applications. One of the changes that he notices is that the weeds that have resistance to herbicides grow much more slowly and are easily outcompeted by other weeds when no pesticides are sprayed (i.e., the herbicide-susceptible weeds produce more seeds and quickly overtake some of the areas in the garden where the herbicide-resistant weeds had been growing). Within this community, which would be the fittest organisms?

Imagine that in one portion of their range, black widowbird numbers are declining due to the introduction of a non-native snake that eats their eggs and nestlings. Because birds such as the black widowbird eat fruit and insects, they are considered to be __________.

Although there is a strong genetic component to hip dysplasia in dogs, new research suggests that environment also plays a role. Environmental factors that influence the development of hip dysplasia include such things as overweight condition, injury at a young age, or repetitive motion on the forming joint (e.g., jogging with a puppy under the age of one year). Based on this, which of the following is true about this disease?

A male pheasant performs a courtship display for a female pheasant from a different population. The female interprets the behavior as aggressive rather than amorous. This is an example of what type of reproductive isolation?