Ch 22
To apply parsimony for constructing a phylogenetic tree,
choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology
Which value(s) would be required to calculate how long ago the most recent ancestor of ungulates lived? I. The number of base pairs that differ among species in a certain genetic sequence II. The total number of base pairs in the genetic sequence examined III. The age of a fossil ancestor for calibration
1, II, and III
Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. 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
For many years, scientists believed that almost all animal lineages burst into being during the Cambrian era (just after the end of the Precambrian Which of the following best explains why it took so long to realize there was animal-like life in the Precambrian?
Animals from the late Precambrian had soft bodies.
will test it with them. You get in, and there is an immediate You are the lucky student of a professor who develops a time machine. They ask if you glitch: the date readout fails so that when you land, you are not sure what era you are in. As your time machine before you. As you open the door, you realize you cannot breathe. You quickly shut the door, realizing you are in the --- lands, you see an unusual landscape
Archaean eon
How did Aristotle's "Great Chain of Being" differ from Plato's concept of the origin of organisms?
Aristotle proposed that species were fixed types organized into a sequence based on increased size and complexity.
A dairy farmer chooses to mate a male bull only with the female heifers that always make the greatest amount of milk, rather than heifers that produce a small amount of milk. What process is the dairy farmer employing when producing the next generation of calves?
Artificial selection
On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. 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
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
This potential bias in paleobotanical climate estimates is due to which type of bias in the fossil record? (R. J. Burnham, N. C. A. Pitman, K. R. Johnson, and P. Wilf. 2001. Habitat-related error in estimating temperature from leaf margins in a humid tropical forest. American Journal of Botany 88:1096-1102.)
Habitat bias
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
The Earth's organisms are now experiencing the sixth mass extinction, with extinction rates higher than those experienced during the end-Cretaceous extinction 66 million years ago. Which of the following is thought to be responsible for this sixth mass extinction?
Human impacts including habitat loss, pollution, overexploitation, invasive species, and climate change
Which of the following statements about species, as defined by the biological species concept, is (are) correct? I. Biological species are defined by reproductive isolation. II. Biological species are the model used for grouping extinct forms of life. III. All members of a species can potentially interbreed.
I and III
Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related but separate species of tree frogs in South America. What outcomes could possibly occur where the ranges of two species overlap? I. The species will interbreed, eventually fusing over time. II. A stable hybrid zone will form if hybrids are better adapted to the area of overlap than either parent species is. III. Species will continue to diverge and be isolated by behavioral or genetic mechanisms.
I, II, and lII
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
Which piece of evidence supports the hypothesis that cetaceans (whales) evolved from terrestrial mammals as opposed to some aquatic organisms?
Many independent lines of evidence converge on the conclusion that whales gradually evolved from a terrestrial mammalian ancestor about 50 million years ago.
The Cambrian Explosion refers to the rapid evolution of major animal body plans. Does this mean that animals quit evolving after this time?
No-animals continued to evolve during and after the adaptive radiation.
have a wide distribution, 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.
When using a cladistic approach to systematics, which of the following is considered most important for classification?
Shared derived characters
How could the duplication of the Hox gene complex help facilitate animal adaptive radiation?
The new gene copies helped facilitate the evolution of more complex body plans.
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.
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 plants 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. With 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.
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 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.
There is an island in the middle of a large river that houses a large population of ants. Damming of the river causes the island to flood and only the highest points of the island are now above water. The ants cannot swim, so are now in multiple isolated populations. Which of the following best describes this event?
This situation represents isolation by vicariance.
Given that phylogenies are based on shared derived characteristics, which of the following traits is useful in generating a phylogeny of species W, X, Y, and Z?
Trait 2
Considering the phylogenetic trees shown here as strictly hypothetical and applying the principle of parsimony to the trait "ability to fly," which of the two phylogenetic trees shown is better?
Tree 1
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
a vestigial trait
Ichthyosaurs, now extinct, were aquatic reptiles with dorsal fins and tails, similar to those of fish, Their most recent ancestors were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are
adaptations to a common environment and examples of convergent evolution
A hybrid zone is properly defined as
an area where mating occurs between members of two closely related species, producing viable offspring
All of the following events can trigger an adaptive radiation EXCEPT
an unusual event splitting a habitat, such as a severe hurricane
Lamarck developed a hypothesis to explain the inheritance of traits that is often referred to as the "inheritance of acquired characters." This idea suggests that
as an individual develops, its phenotype changes in response to challenges posed by the environment, and it passes on these phenotypic changes to offspring
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
Similar gill pouches in embryos of a chick, human, and cat are an example of
developmental homology
The two populations are
different subspecies, under the morphological species concept
In hybrid zones where reinforcement is occurring, you should see a decline in
gene flow between distinct gene pools
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
Reinforcement is most likely to occur when
hybrids have lower fitness than either parent 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
Most causes of speciation are relatively slow, in that they may take many generations to see changes, with the exception of
polyploidy
Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). If the molecular data best reflect the evolutionary history of these two groups, then the morphological similarities of these two species is most likely due to
possession of homoplasic traits
The origin of a new plant species by hybridizing two existing species, coupled with accidents during cell division, is an example of
sympatric speciation and allopolyploidy
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
