Prezygotic isolating mechanisms include all of the following except
a. hybrid sterility.
b. courtship rituals.
c. habitat separation.
d. seasonal reproduction
Introduction:
The reproductive isolation is achieved through the reproductive barriers which are the evolutionary mechanism or behaviors that prevent organism of a different species from breeding and leads to the prevention of exchange of genetic material. There are two types of reproductive barriers: Prezygotic barrier prevents the fertilization between species and postzygotic barrier prevents the maturation of hybrid zygote formed by the mating of two different species. Prezygotic barrier involves habitat, mechanical, gametic, behavioral, and temporal isolation. Postzygotic barriers involve reduced viability of the hybrid formed, reduced fertility of the hybrid and the breakdown of the hybrid that result in the sterile generations.
Answer to Problem 1U
Correct answer:
Hybrid sterility is the postzygotic barrier in which the produced hybrid formed due to the mating of two different species either does not develop properly (are sterile) or the adults do not survive for long. Therefore option a. is the correct answer.
Explanation of Solution
Reason for the correct statement:
The isolating mechanisms that prevent the formation of a zygote are known as the prezygotic isolation mechanism. It includes prevention of the fusion of gametes, ecological, behavioral, temporal, and mechanical isolation. Hybrid sterility is the postzygotic isolating mechanism in which the hybrid formed will be sterile and will not be able to reproduce.
Option a. is given as “hybrid sterility”.
As, “hybrid sterility is not a prezygotic isolating mechanism”, is the right answer.
Hence option a. is correct.
Reasons for the incorrect statements:
Option b. is given as “courtship rituals”.
The difference in courtship rituals is due to behavioral isolation which is a prezygotic isolating mechanism. So, it is a wrong answer.
Option c. is given as “habitat separation”.
Habitat separation is due to ecological isolation of species which is a prezygotic isolating mechanism. So, it is a wrong answer.
Option d. is given as “seasonal reproduction”.
Temporal isolation occurs when the species do not mate with each other due to their different reproduction seasons. It is also a prezygotic isolating mechanism. So, it is a wrong answer.
Hence options b., c., and d. are incorrect.
There are two types of reproductive isolating mechanisms: The prezygotic isolating mechanism which prevents the fertilization between species and the postzygotic isolating mechanism that prevents the maturation of hybrid zygote formed by the mating of two different species. These mechanisms are the barriers to facilitate successful reproduction and prevent the exchange of genetic material between species.
Want to see more full solutions like this?
Chapter 22 Solutions
BIOLOGY CONNECT ACCESS CARD
- If reinforcement is weak and hybrids are not completely infertile, a. genetic divergence between populations may be overcome by gene flow. b. speciation will occur 100% of the time. c. gene flow between populations will be impossible. d. the speciation will be more likely than if hybrids were completely infertile.arrow_forwardWhat is required for sympatric speciation to occur? A. Continuous gene flow between different populations B. Geographic separation of populations C. Two populations that are different begin to reproduce and create hybrids D. Emergence of a reproductive barrierarrow_forwardProblems with the biological species concept include the fact that a. many species reproduce asexually. b. postzygotic isolating mechanisms decrease hybrid viability. c. prezygotic isolating mechanisms are extremely rare. d. All of the choices are correct.arrow_forward
- The first step leading to allopatric speciation is (a) hybrid inviability (b) hybrid breakdown (c) adaptive radiation (d) geographic isolation (e) paedomorphosisarrow_forwardThe reproductive isolating mechanism in which two closely related species live in the same geographic area but reproduce at different times is (a) temporal isolation (b) behavioral isolation (c) mechanical isolation (d) gametic isolation (e) hybrid inviabilityarrow_forwardWhich variable increases the likelihood of allopatric speciation taking place more quickly? a. lower rate of mutation b. longer distance between divided groups c. increased instances of hybrid formation d. equivalent numbers of individuals in each populationarrow_forward
- What is the ecological definition of a species? A) A group of individuals that can breed and produce viable offspring B) A group of interbreeding individuals that share the same environment C) A group of individuals that share a common ancestorarrow_forwardA physical barrier separates a single species, causing two separate populations to form. Over time these two populations adapt to their environments. Eventually, these two populations are no longer able to successfully reproduce with each other. This is known as __________. A. Sympatric speciation B. Allopatric speciation C. Autopatric speciation D. Parapatric speciationarrow_forwardWhich of the following would be a good example of premating reproductive isolation? A. Cross-fertilizations between the gray treefrogs, Hyla versicolor and H. chrysoscelis result in a high degree of mortality prior to hatching of hybrid eggs. B. The mule, a hybrid between horses and donkeys is viable, but sterile. C. Males of H. versicolor produce an advertisement call with a much slower pulse rate than males of H. chrysoscelis and females use pulse rate differences to avoid mating with the wrong species. D. Hybrid offspring are produced from matings between leopard frogs and green frogs, but usually die before the tadpoles metamorphose into froglets.arrow_forward
- Which variable increases the likelihood of allopatric speciation taking place more quickly? a. lower rate of mutation b. longer distance between divided groups c. increased instances of hybrid formation d. equivalent numbers of individuals in each populationarrow_forwardThe first step leading to allopatric speciation is (a) hybrid inviability(b) hybrid breakdown (c) adaptive radiation(d) geographic isolation (e)paedomorphosisarrow_forwardWhat is the biological definition of a species? A) A group of individuals that can breed and produce viable offspring B) A group of interbreeding individuals that share the same environment C) A group of individuals that share a common ancestorarrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College