AP Biology : Understanding Reproductive Barriers
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Example Question #1611 : Ap Biology
In cases of mechanical isolation, what is the barrier to reproduction between two species?
Zygote inviability
Mating behavior
Genital incompatibility
Habitat
Genital incompatibility
Mechanical isolation is a type of pre-zygotic barrier that maintains distinct species through genital incompatibility. In this type of reproductive isolation, the genitals of a male and female of the same species allow for copulation and reproduction, while the genitals of individuals of different species mechanically will not allow for reproduction.
Example Question #23 : Speciation
In which of the following habitats is gametic isolation common?
Tundra
Coral reef
Tropical rain forest
Desert
Coral reef
Gametic isolation is a type of pre-zygotic reproductive isolation in which gametes of different species are unable to hybridize due to genetic incompatibility. In coral reef ecosystems, large numbers of gametes are released by many species of marine reefs, making gametic isolation important in preventing hybridization.
Example Question #21 : Speciation
Which of the following is not true regarding zygote mortality?
After fertilization, the resulting zygote is inviable
Fertilization does not occur
It is an example of post-zygotic reproductive isolation
Fertilization occurs between gametes
Fertilization does not occur
Zygote mortality is an example of post-zygotic reproductive isolation. In this type of reproductive isolation, gametes from two species may fuse, however the zygote is inviable shortly after fertilization due to improper development.
Example Question #114 : Evolution And Genetics
In hybrid sterility, at what stage does reproductive isolation occur?
Post-zygotic
Behavioral
Temporal
Pre-zygotic
Post-zygotic
Hybrid sterility is an example of post-zygotic reproductive isolation. In the case of hybrid sterility, hybridization can occur between two species, however the resulting hybrids are unable to produce; the hybrids are sterile.
Example Question #11 : Understanding Reproductive Barriers
Which of the following is true regarding speciation?
It is an outcome of evolution
Allopatric and sympatric speciation are two major types of speciation
All of these
Barriers to reproduction are critical in speciation
All of these
Speciation is a process in which one species diverges into two. Two major types of speciation are allopatric and sympatric speciation, with each type featuring a unique barrier to reproduction that halts genetic exchange between populations.
Example Question #1622 : Ap Biology
Which of the following is not an example of a reproductive barrier?
Two species of cicada live in the same area. Species A is sexually mature every 7 years. Species B is sexually mature every 2 years.
For a certain species of walrus, males defend large groups of females called harems. Typically, one male's harem will consist of about 20 females, and he will mate with all of them. Some male walruses don't have harems.
Horses and donkeys are different species, but can breed with each other to produce mules. However, mules are sterile (they cannot have offspring of their own).
Two species of birds live in the same area. Species A has dull gray plumage and has developed an elaborate courtship dance. Species B has vibrant orange plumage and has no courtship dance. Females from Species A choose mates based on their dance, and females from Species B choose mates based on their plumage.
For a certain species of walrus, males defend large groups of females called harems. Typically, one male's harem will consist of about 20 females, and he will mate with all of them. Some male walruses don't have harems.
A reproductive barrier is something that prevents two populations from interbreeding, eventually leading to speciation. The cicada populations are an example of temporal isolation--the two species do not interbreed because they do not breed at the same time. The horse and donkey example shows hybrid sterility--the two species can produce offspring, but the offspring cannot have offspring of their own. The bird species are an example of behavioral isolation--the two species have different courtship rituals (dance vs. plumage) which leads to minimal interbreeding.
Example Question #12 : Understanding Reproductive Barriers
Which of the following is an example of a post-zygotic reproductive barrier?
Two species of toads do not interbreed because one species breeds in the summer and the other breeds in the spring.
Two species of sticklebacks do not interbreed because one species lives in fresh water and the other lives in coastal estuaries.
Two species of beetle do not interbreed because the males have different pheromones.
A horse and a donkey breed successfully to produce a mule, which is sterile.
A horse and a donkey breed successfully to produce a mule, which is sterile.
A post-zygotic reproductive barrier occurs after fertilization has occurred. That is, the two individuals have already mated but either the offspring has died or it is sterile. A pre-zygotic barrier occurs before fertilization occurs. Pre-zygotic barriers are those that prevent individuals of different species from mating in the first place.
Example Question #13 : Understanding Reproductive Barriers
There was once a population on planet M311, called the Freg, who lived on a planet not unlike Earth. At the height of the Fregs technology and evolution, a collection of asteroids bombarded the planet and the devastation was so great that the planet was split in two, as was the Freg population. Much of the Freg population died, but many still survived on both pieces of M311.
Thousands of years ago, the environment on M311 was almost entirely dry and the Freg had evolved to suit that environment. Over time, the environment became more water-based and the Freg developed webbed feet and gills. However, as a result of the asteroid catastrophe, the climate returned to a more hot, dry, desert-like climate. As a result, the Freg began to to lose their webbed feet and gills. What is this process called?
Devolution
Amphibiatory genesis
Anti-evolution
Hydrocorporeal restoration
Regressive growth
Devolution
The correct answer to this question is devolution. Devolution refers to when a species reverts to an earlier, more primitive physical form as a result of environmental demands.
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