Concept explainers
One possible explanation for the distinctive collection of species found in the Annamite and Andes Mountains lies in the geological history of these regions. During the ice ages that have occurred repeatedly during the past million years or so, the area covered by tropical forests must have shrunk dramatically. Organisms that depended on the forests for survival would have been restricted to any remaining “islands” of forest, isolated from their fellows in other, distant patches of forest. As we have learned, this kind of isolation can set the stage for allopatric
Want to see the full answer?
Check out a sample textbook solutionChapter 17 Solutions
Biology
- A species that has a high rate of long-distance dispersal is more likely to colonize new habitat. But that species may also be less likely to adapt to local conditions, because migration will be stronger than local selection pressures for many loci. In light of those considerations, when do you expect that increasing dispersal might result in the evolution of a larger geographic range, and when might it not?arrow_forwardPlate tectonics were a major factor in shaping life on this planet. Explain how plate tectonics can both increase and decrease species diversityarrow_forwardThere are several other species pairs like these meadowlarks in the Great Plains (orioles, chickadees, yellow-rumped warblers, and flickers). Some are considered separate species and others aren’t, even though they are quite different in physical appearance. What might have geologically isolated these different bird populations, leading to speciation? Group of answer choices A. recent (geologically) continental glaciation B. hurricanes from the Gulf of Mexico C. the Mississippi River D. prairie fires in the springarrow_forward
- The diagram below represents the ranges of 3 species (A, B, and C), which are separated by a mountain range and river. It has been hypothesized that these three species arose via vicariance ecological speciation. Specifically, the entire area was originally occupied by a single species. Its range was split first by the mountain range. Later, the river formed, separating populations on the eastern side of the mountains. If this hypothesis is correct, phylogenetic analysis should reveal that: NIS 4 44444 U LEL B All three species are equally related to each other. Species A and B are each other's closest relatives (sister taxa). Species B and C are each other's closest relatives (sister taxa). Species A and Care each other's closest relatives (sister taxa).arrow_forwardTwo hundred years ago, the fly species Rhagoletis pomonella only laid its eggs on fruit of the hawthorn tree. Today, different "host races" of R. pomonella lay their eggs on hawthorns OR apples. Apples occur within the range of hawthorns, so divergence between apple flies and hawthorn flies could be the first step in sympatric speciation. Choose the evidence that would suggest that R. pomonella is currently undergoing sympatric speciation. Check ALL answers that apply. A. Apple flies and hawthorn flies are able to form fertile hybrids. B. Apple flies and hawthorn flies are physically indistinguishable from each other. C. Apple flies typically mate with apple flies, and hawthorn flies typically mate with hawthorn flies. D. Apple flies and hawthorn flies emerge from their hosts at different times of the year.arrow_forwardFire creates disturbance in the temperate coniferous forest of the Pacific Northwest. Prior to the early 1900s, patchy, moderately intense, and moderately frequent fires created intermediate amounts of disturbance. Following the early 1900s, a policy of fire suppression greatly reduced fires, creating low disturbance. Today, hotter, drier, longer summers are creating extremely large, intense, and frequent fires, which cause severe disturbance. Which of the following most accurately describes how these levels of disturbance affect species diversity? O Low disturbance allows for the greatest species diversity, because all the organisms are allowed to thrive. Severe disturbance allows for the greatest species diversity, because it facilitates colonization by r-selected species. Moderate disturbance allows for the greatest diversity, because it allows both early and late successional species to exist within an ecosystem. Disturbance does not generally affect species richness. Severe…arrow_forward
- A species that has a high rate of long-distance dispersal is more likely to colonize new habitat. But that species may also be less likely to adapt to local conditions, because migration will be stronger than local selection pressures for many loci. in light of those considerations, when do you expect that increasing dispersal might result in the evolution of a larger geographic range, and when might it not? Your answerarrow_forwardThere are hundreds of species of cichlid fish in Lake Victoria in Africa. Some scientists argue that they evolved sympatrically, but recent studies of the lake suggest that it periodically dried out, leaving a series of small ponds. Whyis this observation relevant to evaluating the hypothesis that these species arose by sympatric speciation?arrow_forwardIf the phylogenetic species concept (PSC) were used to define species, rather than the biological species concept (BSC), how might that change the estimates of species diversity (numbers of species) on a worldwide basis? True or False: Estimates of species diversity are likely to change if the PSC is used. In particular, one would expect the number of species to increase. This is because individuals from divergent allopatric populations that can potentially interbreed would belong to the same species under the BSC. These same organisms would be classified as members of different species under the PSC.arrow_forward
- Clade A began diversifying 20 million years ago. There are 33 living species in Clade A and 6 species have gone extinct. Clade B began diversifying 10 million years ago. It has 14 living species and 5 species in Clade B have gone extinct. CALCULATE SPECIATION, EXTINCTION AND NET DIVERSIFICATION RATE (to the nearest 2 decimal places) TO DETERMINE WHETHER NET DIVERSIFICATION DIFFERS BETWEEN THE TWO CLADES. Clade B has higher net diversification because despite having a higher extinction rate, it also has a higher speciation rate compared with Clade A. Clade A has higher net diversification because despite having a lower speciation rate, it also has a lower extinction rate compared with Clade B. Clade A has higher net diversification because it has both a higher speciation rate and a lower extinction rate than Clade B. Clades A and B have the same net diversification; Clade A has a higher speciation rate, but Clade B has a lower extinction rate. Clades A and B have the same net…arrow_forwardMany endemic species are found in areas that are geographically isolated. Suggest a plausible scientific explanation for why this is so.arrow_forwardWhat is the difference between parapatric speciation and sympatric speciation?I understand that it has to do with habitat but I am having trouble conceptualizing the differences. A simplistic analogy or metaphor to help understand the differences would be very appreciated as I am a disabled student. Thank You.arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education