One way that isolation by resistance can be reinforced in a landscape is that if "hybrids" produced by dispersing individuals between locations undergoing IBE have: Question 12 options: lower fitness than individuals in the resident/migrant receiving population higher fitness than individuals in the resident/migrant receiving population the same fitness as individuals in the resident/migrant receiving populationOne way that isolation by resistance can be reinforced in a landscape is that if "hybrids" produced by dispersing individuals between locations undergoing IBE have: Question 12 options: lower fitness than individuals in the resident/migrant receiving population higher fitness than individuals in the resident/migrant receiving population the same fitness as individuals in the resident/migrant receiving population
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IBR refers to the phenomenon where gene flow between populations is limited due to barriers in the landscape, which can lead to reduced genetic exchange and increased differentiation between populations. Show more…
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Compare the fitness of hybrids in cases where reinforcement occurs versus cases where speciation by hybridization occurs. When reinforcement occurs, hybrids have the same fitness; this creates fusion between the two populations because they can freely interbreed. In contrast, the hybrids in the case of speciation by hybridization have lower fitness, usually because they do not have the proper adaptations for certain ecological conditions. When reinforcement occurs, a hybridization zone develops in a well-defined zone. Hybrids have higher fitness that stabilizes the hybrid zone. The hybrids in the case of speciation by hybridization also have higher fitness, usually because they happen to have adaptations for certain ecological conditions. They may form a new species. When reinforcement occurs, hybrids have higher fitness; this is why increasing hybridization improves the fitness of reproductive individuals. In contrast, the hybrids in the case of speciation by hybridization have lower fitness; therefore, the separation of the two species is accelerated. When reinforcement occurs, hybrids have low fitness; this is why avoiding hybridization improves the fitness of reproductive individuals (their reproductive efforts are not wasted). In contrast, the hybrids in the case of speciation by hybridization have higher fitness, usually because they happen to have adaptations for certain ecological conditions.
Kerissa B.
When the ranges of two different species meet, a stable "hybrid zone" occupied by hybrid individuals may form. How is this possible? a. Hybrid individuals may have intermediate characteristics that are advantageous in a given region. b. Hybrid individuals are always allopolyploid and are thus unable to mate with either of the original species. c. Hybrid individuals may have reduced fitness and thus be strongly selected against. d. One species has a selective advantage, so as hybridization continues, the other species will go extinct.
Two subspecies of salamanders in Southeast Asia, salamander S1 and Salamander S2, are thought to have diverged genetically and morphologically through sympatric speciation. At the southern tip of their respective native ranges, they can co-occur in secondary contact. They can mate successfully and produce viable, fertile offspring; the offspring can therefore also reproduce. However, the hybrid offspring have a coloration that is disproportionately attractive and easily detectable by predators, leading to decreased survival. The relatively low fitness of the S1 x S2 hybrid salamander would be an example of: a. postzygotic behavioral isolation b. gametic incompatibility c. mechanical isolation d. reinforcement e. prezygotic isolation Assuming that mating occurs freely in secondary contact, what is the fitness of the parent salamanders S1 and S2 in the scenario? a. low. Fitness involves reproductive success and survival; if survival is low in the offspring, the parents cannot pass their genes on to future generations. b. zero. c. high. Fitness involves reproductive success and survival, the parents are reproductively successful and able to survive. d. high. Fitness of the parents is not related to the fitness of the progeny. e. none of the above
Shaiju T.
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