Concept explainers
Distinguish between morphological, phylogenetic, and biological species concepts. What are the advantages and disadvantages of each? What notion is common to each of the species definitions that we considered? Why do species definitions matter in conservation biology?
What are the most common mechanisms of sympatric
Describe the modern theory of evolution and discuss how it is supported by evidence from two of the following three areas.
a. Population genetics
b. Molecular biology
c. Comparative anatomy and embryology
Evolution is one of the major unifying concepts of modern biology. Explain the mechanisms that lead to evolutionary change. Describe how scientists use each of the following as evidence for evolution.
• Bacterial resistance to antibiotics
• Comparative biochemistry
• The fossil records
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- The biological species concept depends on the existence of barriers to reproduction. What are they? Does this species concept apply in all situations? Think of an example from nature where the biological species concept would NOT be that applicable. Which species concept would be better in this example? How does speciation occur? What environmental factors might contribute to speciation? Can an individual speciate? Use terminology for the two kinds of speciation we have learned about. What is “gene flow”? What does it mean if there is NO gene flow? Two groups of individuals are separated by either side of a canyon. One researcher found that they do not cross the canyon at any point. The group on the north side have fluffy tails and thicker coats, and they do not eat moss. The south side individuals eat moss almost exclusively, have a thin coat and tail, but otherwise are generally identical. When in the lab they mated successfully, and the offspring of that mating also mated…arrow_forwardWhich of the following statements about sympatric speciation is correct? It is a process through which two populations can diverge and develop reproductive isolation while in two different geographic area. It is the most common mechanism for populations to form independent species. Postzygotic isolation is the main form of reproductive isolation for the sympatric speciation process. Genetic isolation through large scale chromosomal mutations, such as chromosome inversion or polyploidy, are more likely contributing to sympatric speciation. None of the abovearrow_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
- What are the most common mechanisms of sympatric speciation and in which major group of organisms does this happen most often? Distinguish between sympatric, allopatric and parapatric speciation. What is considered the (far) more common mechanism of species formation? What does "gene flow" between populations mean?arrow_forwardHow does one species diverge from another? (When do we call a group a new species—and how does that process happen?) Using anole lizards or another very specific example(s), compare and contrast microevolutionary processes with speciation. As you discuss speciation, be sure to compare and contrast sympatric speciation with allopatric speciation and say whether the example you’ve chosen is allopatric or sympatric.arrow_forwardIndicate the order in which the following steps would take place to result in Allopatric Speciation [enter 1 for the first step, 2 for the second, etc; write only the number -- no words, no spaces] The two groups develop reproductive isolating mechanisms so that they no longer interbreed. Interbreeding populations connected via gene flow occur across a range. The two separate groups adapt to their new environments. Some sort of physical barrier develops to split the once contiguous population(s) into two separate groups If they come back together, any hybrids formed are less fit.arrow_forward
- Indicate the order in which the following steps would take place to result in Parapatric Speciation [enter 1 for the first step, 2 for the second, etc; write only the number -- no words, no spaces] Something happens so that the environment is different in one part of the range relative to the other, even though the populations are still contiguous. As they adapt to their specific environments, the fitness of any hybrid formed is reduced. The populations adapt to their environment in the part of the range where they live. Interbreeding populations connected via gene flow occur across a range. Reproductive isolating mechanisms are selected for so that less fit hybrids are not formed. Two species now exist.arrow_forwardWhat are the most common mechanisms of symptoms speciation and in which major group of organisms does this happen most often ? Distinguish between sympatric , allopatric and parapatric speciation. What is considered the (far) more common mechanism if species formation ? What does "general flow " between population do ?arrow_forwardDistinguish between morphology,phylogenetic and biological species concepts.what are the advantages and disadvantages of each?what notion is common to each of the species definitions that we considered?why do species definitions matter in conservation biologyarrow_forward
- Hybridization was not originally recognized as a mechanism of speciation by either Darwin or the researchers of the "new synthesis". However, today there are many examples of species that have originated through hybridization. What is the best explanation for why we have so many examples of species originating through hybridization? Hybridization is more likely to occur in regions where scientists have put in more effort studying speciation Hybridization has been carried out frequently by farmers attempting to produce new, better species to grow Hybridization occurs fairly regularly, and when it leads to new species only takes a few generations, which is fast enough for researchers to see fairly easily Hybridization is fairly easy to study in captivityarrow_forwardOf the following species concept, which one emphasizes reproductive isolation as the major cause for speciation? Phylogenetic species concept Morphological species concept Biological species concept Evolutionary species conceptarrow_forwardOver time, enough genetic variations can develop within a population to cause it to undergo speciation. Identify the various mechanisms that will prevent different species from being able to reproduce successfully. Which of these mechanisms is the most influential in keeping species sperate?arrow_forward
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