Bio exam 6
Soon after the island of Hawaii rose above the sea surface (somewhat less than 1 million years ago) and organisms colonized the island, the evolution of life on this new island should have been most strongly influenced by ________.
founder effects
Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. Pollen grains (which contain sperm nuclei) from one species are unable to germinate and make pollen tubes to bring the sperm nuclei to the female ovules (which contain egg cells) of the other species. These two juniper species are kept separate by ________.
gametic isolation
In hybrid zones where reinforcement is occurring, you should see a decline in ________.
gene flow between distinct gene pools
One defining characteristic of allopatric speciation is____________.
geographic isolation
If limited resources are concentrated males will compete for mating opportunities by.....
fighting for and defending territory
After the drought of 1977, researchers hypothesized that on the Galápagos island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough T. cistoides fruits. A tourist company sets 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 this island?
increased variation in beak size and shape over time
Disruptive selection favors________.
individuals at both extremes of the range of phenotypes
Directional selection favors________.
individuals at only one extreme of the range of phenotypes
Stabilizing selection favors______________.
individuals with intermediate phenotypes
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. The fossils of Thrinaxodon are consistent with the hypothesis that ________.
mammals evolved from a reptilian ancestor
If modern day organisms are DISTANTLY related in an evolutionary sense, then one should predict that __________.
they would share fewer DNA sequence similarities than two more closely related organisms
Which of the following describes intrasexual competition?
two male pheasants fighting for territory
Which of the following men has higher evolutionary fitness?
A man that dies at 30, after fathering 5 healthy children
Which of the following statements explains why animals are less likely than plants to speciate by polyploidy?
Animals self-fertilize less often than plants, so diploid gametes are less likely to fuse.
Evolution in a population of island iguanas can be caused by the following agent(s):
All of these can be agents
A group of boys work out and practice for long hours and as a result they become very good at playing basketball. Which of the following statements is true?
All the boys' efforts wont lead to evolutionary change, because their changes lack a genetic basis.
How are two different species most likely to evolve from one ancestral species?
Allopatrically, after the ancestral species has split into two populations
Which of the types of reproductive barriers listed below corresponds to the following situation: two species of frogs who use different mating calls?
Behavioral Isolation
On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. What is the best way to promote fusion between two related populations of mosquitofish, one of which lives in a predator-rich pond and the other of which lives in a predator-poor pond?
Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators.
Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. If reinforcement is occurring, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?
Calls would be more different in areas of sympatry.
How do the theories of Lamarck and Darwin differ?
Darwin proposed that populations evolove; lamarck proposed that individuals evolve.
Three-spined stickleback fish (Gasterosteus aculeatus) show substantial heritable variation in gill-raker length related to differences in their diets. Longer gill rakers appear to function better for capturing open-water prey, while shorter gill rakers function better for capturing shallow-water prey. Which of the following types of selection is most likely to be found in a large lake (open water in the middle and shallow water around the sides) with a high density of these fish?
Disruptive Selection
In eusocial insects with the haploid-diploid system (like ants or bees), which group(s) are haploid?
Drones (males)
Which of the following statements best summarizes evolution by natural selection as it is viewed today?
Evolution by natural selection is the differential survival and reproduction of the most-fit phenotypes.
During the 1977 drought on the island of Daphne Major, medium ground finches did not reproduce and 84% of the birds died. Did evolution occur at this time?
Evolution occured although there was no reproduction because mortality was not random
In a small population of alpine foxes, you observe increased ear length over a 10-year period. Based on this information you cab conclude that increase in ear length is advantageous in this population.
False
For a biologist studying a small fish population in the lab, which Hardy—Weinberg condition is the most EASY to meet?
No gene flow
Resistance to a wide variety of insecticides, fungicides, antibiotics, antiviral drugs, and herbicides has recently evolved in hundreds of insects, fungi, bacteria, viruses, and plants. Why?
Humans are altering the environments of these organisms, and populations of these organisms are evolving by natural selection.
What must be TRUE of any organ described as vestigial?
It must be homologous to some feature in an ancestor.
Wikelski and Romero (2003) studied large marine iguanas and found that they had higher reproductive success than smaller iguanas did. However, the large iguanas were generally in poor body condition because they could not eat enough; at higher temperatures, their foraging efficiency improved, allowing them to eat more. Thus, Wikelski and Romero hypothesized that iguana size will ________ as global warming gradually increases air and water temperatures in the Galápagos Islands.
Increase
Why doesn't inbreeding depression, by itself, cause evolution?
It does not change the population's allele frequencies.
Vestigial traits and neutral changes in DNA sequences are good examples of ________.
Non-Adaptive Traits
Natural selection acts directly _________.
On the Phenotype
Which of the following mating strategies can result in complex penis and vaginal structures for internal mate selection?
Polyandry
The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when the hybrids mate with other hybrids or with adults of either species, they are rarely successful in producing offspring. What can you infer from this information?
Postzygotic isolation exists between the two frog species.
Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?
Relationships between DNA sequences among the species did not match relationships between skeletal Patterns.
Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?
Relationships between DNA sequences among the species did not match relationships between skeletal patterns.
Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation?
Simple morphologies convey some advantages in most parasites.
The same basic internal organs (kidneys, stomach, heart, lungs) are found in frogs, birds, snakes, and rodents. This is primarily an example of ________.
Structural Homology
Pea aphids (Acyrthosiphon pisum) are the only animals able to synthesize their own carotenoid pigments, due to lateral gene transfer from the genome of a fungus to the genome of a recent ancestor of the pea aphids. The resulting red or green coloration alters the risk the aphids face from specific predators and parasites. Select the correct statement below.
The lateral transfer of genes for carotenoid synthesis from a fungus to an aphid is a form of mutation.
The following question is 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 are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so 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?
The percentage of pink flowers should increase over time.
Two frog populations (same species) living in two neighboring lakes sing slightly different courtship songs. Increased irrigation makes the land between the two lakes wetter, allowing frogs to expand their ranges to the area between the lakes. Females in both populations prefer loud frogs to quieter frogs but do not distinguish between the two slightly different songs. Assuming that courtship song differences have a genetic basis, predict what will likely happen to the songs of the two frog populations.
The songs will become more similar to each other.
Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if TRUE, would be cause for this reclassification?
The two forms interbreed often in nature, and their offspring have good survival and reproduction.
About thirteen different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the thirteen species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza). If the six ground finch species have evolved most recently, then which of these is the most logical prediction?
Their genomes should be more similar to each other than are the genomes of the five tree finch species.
Many songbirds breed in North America in the spring and summer and then migrate to Central and South America in the fall. They spend the winter in these warmer areas, where they feed and prepare for the spring migration north and another breeding season. Two hypothetical species of sparrow, A and B, overwinter together in mixed flocks in Costa Rica. In spring, species A goes to the east coast of North America, and species B goes to the west coast. What can you say about the isolating mechanisms of these two species?
Their winter habitat has no bearing on their degree of reproductive isolation.
If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, what would happen in environments that lack antibiotics?
These bacteria would be outcompeted and replaced by bacteria that have lost these genes.
In eusocial insects, like ants or bees, how related are the worker ants?
They share 75% DNA
You are studying a group of related fossils, and you notice that a particular trait is present in older fossils, but disappears in more recent species. What does this mean
This means that in more recent species, individuals without the trait had higher fitness
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 explains what happened?
Triazine-resistant weeds were more likely to survive and reproduce.
Which of the following is a fitness trade-off (compromise)?
Turtle shells provide protection but are heavy and burdensome when moving.
Over long periods of time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?
Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.
Why did Darwin document and describe vestigial traits?
Vestigial traits indicate that species c\Change over time. This is an important pattern component of the theory of evolution and is inconsistent with the theory of special creation.
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 young insects grow through the late spring and summer, they lay eggs in the early fall, and they 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?
White- and black-winged beetles have equal fitness.
Three populations of crickets look very similar, but the males have courtship songs that sound different. What function would this difference in song likely serve if the populations came in contact?
a behavioral reproductive isolating mechanism
An earthquake decimates a ground-squirrel population, killing 98 percent of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake?
a genetic bottleneck
In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20 percent of the β hemoglobin alleles in the human gene pool. The sickle-cell allele is pleiotropic (that is, it affects more than one phenotypic trait). Specifically, this allele affects oxygen delivery to tissues and affects one's susceptibility to malaria. Heterozygous individuals who have one normal and one sickle-cell allele have a phenotype that has both costs and benefits. The cost: Under conditions of low atmospheric oxygen availability, individuals heterozygous for this allele can experience life-threatening sickle-cell "crises." The benefit: Such individuals are less susceptible to malaria. Thus, pleiotropic genes/alleles reveal that ________.
adaptations are often compromises
"Common ancestry" is supported by data from _______.
all of these support the idea of common ancestry
House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of ________.
allopatric speciation
This type of organism requires considerable parental care
altricial
A hybrid zone is properly defined as ________.
an area where mating occurs between members of two closely related species, producing viable offspring
The biological species concept (BSC) is NOT useful for organisms only known from fossils because_________.
an area where mating occurs between members of two closely related species, producing viable offspring
Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian Islands have different elaborate courtship rituals. These rituals involve fighting other males and making stylized movements that attract females. What type of reproductive isolation does this represent?
behavioral isolation
On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. Which type of reproductive isolation operates to keep the mosquitofish isolated, even when fish from different ponds are reunited in the same body of water?
behavioral isolation
Which of the types of reproductive barriers listed below corresponds to the following situation: two species of meadowlarks with different mating songs.
behavioral isolation
Carnivory in plants has evolved at least 5 times independently, yet there is a great deal of morphological similarity among these groups. This independent evolution of similar traits is called__________.
convergent evolution
Currently, the only predators of Galápagos marine iguanas are Galápagos hawks. Iguana body size is not correlated with risk of hawk predation, although small iguanas can sprint faster than large iguanas. If predators (for example, cats) that preferentially catch and eat slower iguanas are introduced to the island, iguana body size is likely to ________ in the absence of other factors; the iguanas would then be under ________ selection.
decrease; directional selection
On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. The very closely related species Drosophila santomea is found at higher elevations and only on Sao Tomé. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, where hybrids are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago.
descended from an original colony of D. yakuba, of which there are no surviving members; the current island D. yakuba represent a second colonization event from elsewhere
Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is adaptive in these males, you should ________.
determine if hair length is heritable
A researcher wants to know if gene flow is contributing to evolution of drought tolerance of pitcher plants in a specific bog. As a control, she should
determine if the population is in Hardy—Weinberg equilibrium.
Similar gill pouches in embryos of a chick, human, and cat are an example of ________.
developmental homology
In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population?
directional selection
Which of the following is most likely to produce an African butterfly species in the wild whose populations show two strikingly different color patterns?
disruptive selection
A researcher notices that in a certain moth species, some females prefer to feed and lay eggs on domesticated solanaceous plants like potatoes and tomatoes. Other females prefer to feed and lay eggs on wild solanaceous plants like Datura. Both male and female moths primarily use scent to find these plants from afar. Females tend to mate where they feed, and the researcher finds a genetic basis for scent preference in these moths. Based on the above information, what might be occurring in this moth species?
divergence in sympatry
After the drought of 1977, researchers on the island of Daphne Major hypothesized that medium ground finches that had large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. If this hypothesis is correct, what would you expect to observe if a population of these medium ground finches colonizes a nearby island where T. cistoides is the most abundant food for the next 1000 years? Assume that (1) even the survivors of the 1977 drought sometimes had difficulty cracking the tough T. cistoides fruits and would eat other seeds when offered a choice; and (2) food availability is the primary limit on finch fitness on this new island.
evolution of yet larger, deeper beaks over time
Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?
habitat isolation
Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees. What keeps the two populations separate?
habitat isolation
Which of the types of reproductive barriers listed below corresponds to the following situation: two species of moose, one living in Russia and the other living in Canada
habitat isolation
If you say that a ground squirrel has greater evolutionary fitness than another ground squirrel in the same population, you mean that the animal
has more offspring that survive and reproduce themselves.
Genetic variation ________.
must be present in a population before natural selection can act upon the population
A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. The actual forelimbs of these mammals do NOT seem to be optimally arranged because ________.
natural selection is generally limited to modifying structures that were present in previous generations and/or in previous species
For a biologist studying a small fish population in the lab, which Hardy—Weinberg condition is easiest to meet?
no gene flow
In Darwin's thinking, the more closely related two organisms are__________.
the more recently they shared a common ancestor
Which of the following breeding systems typically leads to sexual dimorphism, where the males are larger and/or more ornate than females?
polygyny
On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, but hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago. If the low number of hybrid flies in the hybrid zone, relative to the number of D. santomea flies there, is due to the fact that hybrids are poorly adapted to conditions in the hybrid zone, and if fewer hybrid flies are produced with the passage of time, these conditions will most likely lead to ________.
reinforcement
When nonrandom mating occurs in a population so that individuals prefer to mate with similar individuals, allele frequencies should
remain the same, but homozygotes will be overrepresented in the population.
How does artificial selection differ from natural selection?
the only real difference is that humans, and not the environment is doing the selecting
Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer or more than this have reduced fitness. Which of the following terms best describes this situation?
stabilizing selection
In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In the western United States, pronghorns and cattle often associate with one another in the same open rangeland. Some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood. The host mammal can be considered as the fleas' habitat. If this situation persists, and new species evolve, this would be an example of ________.
sympatric speciation and habitat isolation
Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers but mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it?
sympatric speciation; habitat isolation
A small number of birds arrive on an island from a neighboring larger island. This small population begins to adapt to the new food plants available on the island as selection favors those birds with larger beaks. About twice a year, one or two more birds from the neighboring island arrive. These new arrivals ________.
tend to retard adaptation to the new food plants
A tornado passes over a lake with a large and diverse population of frogs. The tornado sucks up some of the water along with a male and female frog. The two frogs are dropped in a large lake 20 miles away that has no frogs living in it. These two frogs mate and populate the lake, which results in a population that is very different from the source lake. This story, in addition to having a happy ending, is an example of ______________.
the Founder Effect
Biological fitness is best defined as
the ability of an individual to produce offspring that survive and reproduce, relative to other individuals in the population.
Of the following anatomical structures, which is homologous to the bones in the wing of a bat?
the bones in the flipper of a whale
