Exam 24: Evolution by Natural Selection

Who proposed that organisms could be organized into a great chain of being?

Many crustaceans (e.g. ,lobsters,shrimp,and crayfish)use their tails to swim,but crabs have reduced tails that curl under their shells and are not used in swimming.This is an example of _____.

The Irish "elk" described by Georges Cuvier suggests that _____.

Which of the following scientists argued that variation among individuals allows evolution to occur?

Use the following information when answering the corresponding question(s). The following question(s)are based on information from Frank M.Frey,"Opposing Natural Selection from Herbivores and Pathogens May Maintain Floral-Color Variation in Claytonia virginica (Portulacaceae)," Evolution 58(11),2004: 2426-37. -Claytonia virginica is a woodland spring herb with flowers that vary from white to pale pink to bright pink.Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two),and plants experiencing severe herbivory were more likely to die.The bees that pollinate this plant also prefer pink to white flowers,so that Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers.A researcher observes that the percentage of different flower colors remains stable in the study population from year to year.Given no other information,if the researcher removes all slugs from the study population,what do you expect to happen to the distribution of flower colors in the population over time?

A farmer uses triazine herbicide to control pigweed in his field.For the first few years,the triazine works well and almost all the pigweed dies;but after several years,the farmer sees more and more pigweed.Which of these explanations best describes this observation?

Which of the following statements is an example of typological thinking?

An individual with a novel adaptation has evolved that adaptation.

There is a population of beetles that typically have black wings.A scientist studying these beetles knows that their eggs hatch in early spring,the baby insects grow through the late spring and summer,they lay eggs in the early fall,and die in the early winter.Recently some beetles have been born with white wings.Early in life the black and white winged beetles seem to be very similar in number of mating events,eggs laid,and survival rates,but shortly after laying their eggs the white beetles die and there are only black winged beetles during the late fall.Which of the following is a true statement about the beetles?

Fossils of Thrinaxodon,a species that lived during the Triassic period,have been found in both South Africa and Antarctica.Thrinaxodon had a reptile-like skeleton and laid eggs,but small depressions on the front of its skull suggest it had whiskers and,therefore,fur.Thrinaxodon may have been warm-blooded.Thrinaxodon shows _____.

Figure 24.3 -In Figure 24.3,chart X above shows the frequency of the most common neutral mitochondrial DNA allele (an allele for a gene that does not affect and is not linked to coat color)across six pocket-mouse populations.Populations C,D,and E live on dark volcanic rock;populations A,B,and F live on light-colored granite.Compare this figure with chart Y above.What should you conclude after comparing these two figures?

Gill pouches in chick,human,and house-cat embryos are an example of _____.

Which of the following,if discovered,could refute our current understanding of the theory of evolution?

Tourist companies start visiting Island X,where a population of medium ground finches (see question 20)feeds on the tough-fruited Tribulus cistoides.The tourist companies set up reliable feeding stations with a variety of bird seeds (different types and sizes),so that tourists can get a better look at the finches.Which of these events is now most likely to occur to finch beaks on Island X?

Figure 24.1 The following question(s)are based on information in Hopi E.Hoekstra,Kristen E.Drumm,and Michael W.Nachman,"Ecological Genetics of Adaptive Color Polymorphism in Pocket Mice: Geographic Variation in Selected and Neutral Genes," Evolution 58(6),2004: 1329-41. -The figure above shows the distribution of pocket-mouse coat colors in several Arizona populations found either on light-colored granite substrate or on dark volcanic rock (dark substrate).The Melanocortin-1 receptor (Mc1r)alleles,D and d,differ by four amino acids.Mice with DD and Dd genotypes have dark coats,whereas mice with the dd genotype are light colored.What sort of genotype frequencies might you expect to find in the Xmas,Mid,and O'Neill populations?

Why was Darwin and Wallace's theory of evolution by natural selection revolutionary?

Which of these conditions are always true of populations evolving due to natural selection? Condition 1: The population must vary in traits that are heritable. Condition 2: Some heritable traits must increase reproductive success. Condition 3: Individuals pass on all traits they acquire during their lifetime.

Evolutionary theory predicts that species are related,not independent.Four of the following examples provide support for this prediction.Which one of these examples does not support the claim that species are related?

Vestigial traits and neutral changes in DNA sequences are good examples of _____.

Which of the following is the best modern definition of evolution?