BIO final Flashcards
In some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called “ligers.” Male ligers are sterile but some female ligers are fertile. In the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. Furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences.
The natural differences in the ranges of wild tigers and lions is an example of ________.
a prezygotic barrier
Under the biological species concept, what criterion is used to assign populations of organisms to the same biological species?
ability to interbreed and produce fertile offspring
The biological species concept cannot be applied to ________.
fossils
Which scenario describes allopatric speciation?
A population of squirrels is separated by the Grand Canyon. The two subpopulations evolve into two distinct species.
Which taxonomic level is most inclusive?
order
Of the following taxonomic levels, species found within the same ________ are the most closely related.
family
Homology is evidence of ________.
common ancestry
Which one of the following is an example of a postzygotic barrier?
the production of sterile hybrids
In _____ a population isolated by a geographic barrier becomes a new species as it accumulates changes by natural selection or genetic drift.
allopatric speciation
In _____ a new species may arise as mating and gene flow are reduced between populations that share the same area.
sympatric speciation
Many plant species have formed by
_____ in which accidents in cell division result in extra sets of chromosomes.
polyploid speciation
Both allopatric speciation and sympatric speciation depend on the establishment of
_____ which prevent(s) gene flow between a new species and its parent species.
reproductive barriers
_____ occur(s) when a species gives rise to many new species after colonizing a region with diverse habitats
Adaptive radiation
A biologist spends her summer break collecting frogs from a remote jungle in Peru. She discovers two distinct color forms that could be variants of a single species or two different species. What would be the most direct test of their species statusunder the biological species concept?
Compare the color patterns of the two groups. If they are distinct enough, the two forms belong to different species.
Observe mating in the natural environment of the two groups. If the two forms do not mate with each other, they are different species.
Compare the habitat use of the two groups. If they use different habitats, they must be different species.
Compare the DNA of the two groups. If their genes are different, they must be different species.
Observe mating in the natural environment of the two groups. If the two forms do not mate with each other, they are different species.
In _____ isolation, it is physically impossible for two species to mate with each other, often because their genitalia do not fit together properly.
behavioral
temporal
mechanical
habitat
mechanical
Eastern and western spotted skunks breed at different times of the year. Therefore, they are prevented from interbreeding by _____ isolation.
behavioral
temporal
mechanical
habitat
temporal
The process of speciation starts with a single species. It often involves the following steps: (1) two populations become physically separated from one another by a barrier to dispersal and stop exchanging genes; (2) the populations experienceindependent evolutionary changes; (3) changes in one or both populations result in development of reproductive isolating mechanisms that prevent interbreeding; further changes in geography may bring the groups back into contact. When do you officiallyhave two separate species?
step 1
step 2
step 3
none of the above
step 3
Darwin thought that significant evolution was much too slow to be witnessed in a human lifetime. Recent experiments by biologists have _____.
- confirmed Darwin’s view
-indicated that evolution takes place extremely quickly; in fact, individuals can evolve to become new species within their life spans
-shown that evolutionary change takes even longer than Darwin imagined
-shown that some populations can evolve quite rapidly, with important changes occurring over several generations in the laboratory
shown that some populations can evolve quite rapidly, with important changes occurring over several generations in the laboratory
Plate tectonics has been responsible for instances of all of the following EXCEPT ________.
allopatric speciation
mass extinction
volcanic explosions
sympatric speciation
sympatric speciation
Characid fishes are found naturally only in South America and Africa. Fossils of these fish are not found on any other continents. What is the most likely explanation of this distribution pattern?
-These fishes arose in either Africa or South America and migrated across the South Atlantic Ocean to the other continent.
-Convergent evolution is responsible for the distribution of characid fishes.
-Characid fishes arose prior to the separation of the African and South American continents.
-Characid fishes arose in the South Atlantic Ocean and migrated to Africa and South America.
Characid fishes arose prior to the separation of the African and South American continents.
Dinosaurs (aside from the lineage that produced birds) were extinct by the end of the ________.
cretaceous
A period of mass extinction is often followed by ________.
explosive diversification
global warming
continental drift
explosive diversification
Which one of the following is an example of a subject in evo-devo?
sympatric speciation
microevolution
paedomorphosis
allopatric speciation
paedomorphosis
Which of the following is a true statement?
-Pangaea started to break up to form geographic isolation for many species about 65 million years ago.
-As dinosaurs became extinct, reptiles remained as their sole descendants.
-Massive extinction of species results in less species diversity but is followed by an explosive diversification of certain remaining species.
-Mammals were the prominent species just before the extinction of dinosaurs.
Massive extinction of species results in less species diversity but is followed by an explosive diversification of certain remaining species.