Biology Chapter 24

Which of the following statements about species, as defined by the biological species concept, is (are) correct? I. Biological species are defined by reproductive isolation. II. Biological species are the model used for grouping extinct forms of life. III. The biological species is the largest unit of population in which successful reproduction is possible. A) I only B) II only C) I and III D) II and III E) I, II, and III

What is generally true of two very closely related species that have diverged from each other quite recently? A) They shared a common ancestor recently in evolutionary time. B) Genes are unable to pass from one speciesʹ gene pool to the otherʹs gene pool. C) They are unable to produce hybrid offspring upon interbreeding. D) Their reproductive isolation from each other is complete.

Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools? A) phylogenetic B) ecological C) biological D) morphological

Which species concept is currently most popular among most biologists? A) phylogenetic B) ecological C) biological D) morphological

There is still some controversy among biologists about whether Neanderthals should be placed within the same species as modern humans, or into a separate species of their own. Most DNA sequence data analyzed so far indicate that there was probably little or no gene flow between Neanderthals and Homo sapiens. Which species concept is most applicable in this example? A) phylogenetic B) ecological C) morphological D) biological

A biologist discovers two populations of wolf spiders whose members appear identical. Members of one population are found in the leaf litter deep within the woods. Members of the other population are found in the grass at the edge of the woods. The biologist decides to designate the members of the two populations as two separate species. Which species concept is this biologist most closely utilizing? A) ecological B) biological C) morphological D) phylogenetic

You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use? A) biological B) phylogenetic C) ecological D) morphological

Males of one species sing only when its predators are absent; males of another species sing only when its predators are present. A) behavioral B) gametic C) habitat D) temporal E) mechanical

One species lives only in tree holes; another species lives only in streams. A) behavioral B) gametic C) habitat D) temporal E) mechanical

Females of one species choose mates based on song quality; females of another species choose mates on the basis of size. A) behavioral B) gametic C) habitat D) temporal E) mechanical

One species mates at the season when daylight is increasing from 13 hours to 13 hours, 15 minutes; another species mates at the season when daylight is increasing from 14 hours to 14 hours, 15 minutes. A) behavioral B) gametic C) habitat D) temporal E) mechanical

Males of one species are too small to perform amplexus (an action that stimulates ovulation) with females of all other species. A) behavioral B) gametic C) habitat D) temporal E) mechanical

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms? A) reduced hybrid fertility B) hybrid breakdown C) mechanical isolation D) habitat isolation E) gametic isolation

Rank the following from most general to most specific: 1. gametic isolation 2. reproductive isolating mechanism 3. pollen-stigma incompatibility 4. prezygotic isolating mechanism A) 2, 3, 1, 4 B) 2, 4, 1, 3 C) 4, 1, 2, 3 D) 4, 2, 1, 3 E) 2, 1, 4, 3

Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate? A) the postzygotic barrier called hybrid inviability B) the postzygotic barrier called hybrid breakdown C) the prezygotic barrier called hybrid sterility D) gametic isolation E) adaptation

Theoretically, the production of sterile mules by interbreeding between female horses and male donkeys should A) result in the extinction of one of the two parental species. B) cause convergent evolution. C) strengthen postzygotic barriers between horses and donkeys. D) weaken the intrinsic reproductive barriers between horses and donkeys. E) eventually result in the formation of a single species from the two parental species.

The biological species concept is inadequate for grouping A) plants. B) parasites. C) asexual organisms. D) animals that migrate. E) sympatric populations.

Which example below will most likely guarantee that two closely related species will persist only as distinct biological species? A) colonization of new habitats B) convergent evolution C) hybridization D) geographic isolation from one another E) reproductive isolation from one another

In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In rangelands of the western United States, pronghorns and cattle often associate with one another. If some of these fleas develop a strong preference, instead, for cattle blood and mate only with fleas that, likewise, prefer cattle blood, then over time which of these should occur, if the host mammal can be considered as the fleasʹ habitat? 1. reproductive isolation 2. sympatric speciation 3. habitat isolation 4. prezygotic barriers A) 1 only B) 2 and 3 C) 1, 2, and 3 D) 2, 3, and 4 E) 1 through 4

A defining characteristic of allopatric speciation is A) the appearance of new species in the midst of old ones. B) asexually reproducing populations. C) geographic isolation. D) artificial selection. E) large populations.

A rapid method of speciation that has been important in the history of flowering plants is A) genetic drift. B) a mutation in the gene controlling the timing of flowering. C) behavioral isolation. D) polyploidy.

The difference between geographic isolation and habitat differentiation is the A) relative locations of two populations as speciation occurs. B) speed (tempo) at which two populations undergo speciation. C) amount of genetic variation that occurs among two gene pools as speciation occurs. D) identity of the phylogenetic kingdom or domain in which these phenomena occur. E) the ploidy of the two populations as speciation occurs.

Among known plant species, which of these have been the two most commonly occurring phenomena leading to the origin of new species? 1. allopatric speciation 2. sympatric speciation 3. sexual selection 4. polyploidy A) 1 and 3 B) 1 and 4 C) 2 and 3 D) 2 and 4

Beetle pollinators of a particular plant are attracted to its flowersʹ bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it? A) allopatric speciation, ecological isolation B) sympatric speciation, habitat differentiation C) allopatric speciation, behavioral isolation D) sympatric speciation, sexual selection E) sympatric speciation, allopolyploidy

The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is A) sexual selection. B) habitat differentiation. C) polyploidy. D) pollution. E) introduction of a new predator.

According to the concept of punctuated equilibrium, the ʺsuddenʺ appearance of a new species in the fossil record means that: A) the species is now extinct. B) speciation occurred instantaneously. C) speciation occurred in one generation. D) speciation occurred rapidly in geologic time. E) the species will consequently have a relatively short existence, compared with other species.

According to the concept of punctuated equilibrium: A) natural selection is unimportant as a mechanism of evolution. B) given enough time, most existing species will branch gradually into new species. C) a new species accumulates most of its unique features as it comes into existence. D) evolution of new species features long periods during which changes are occurring, interspersed with short periods of equilibrium, or stasis. E) transitional fossils, intermediate between newer species and their parent species, should be abundant.

Which of the following would be a position held by an adherent of the punctuated equilibrium theory? A) A new species forms most of its unique features as it comes into existence and then changes little for the duration of its existence. B) One should expect to find many transitional fossils left by organisms in the process of forming new species. C) Given enough time, most existing species will gradually evolve into new species. D) Natural selection is unimportant as a mechanism of evolution.

Speciation A) occurs at such a slow pace that no one has ever observed the emergence of new species. B) occurs only by the accumulation of genetic change over vast expanses of time. C) must begin with the geographic isolation of a small, frontier population. D) proceeds at a uniform tempo across all taxa. E) can involve changes involving a single gene.

Which of the following statements about speciation is correct? A) The goal of natural selection is speciation. B) When reunited, two allopatric populations will not interbreed. C) Natural selection chooses the reproductive barriers for populations. D) Prezygotic reproductive barriers usually evolve before postzygotic barriers. E) Speciation is a basis for understanding macroevolution.

Upon undergoing change, which of these genes is most likely to result in speciation while a geographic barrier separates two populations of a flowering-plant species? A) one that affects the rate of chlorophyll a synthesis B) one that affects the amount of growth hormone synthesized per unit time C) one that affects the compatibility of male pollen and female reproductive parts D) one that affects the average depth to which roots grow down through the soil E) one that affects how flexible the stems are

In order for speciation to occur, what is true? A) The number of chromosomes in the genome must change. B) Changes to centromere location or chromosome size must occur within the genome. C) Large numbers of genes that affect a single phenotypic trait must change. D) Large numbers of genes that affect numerous phenotypic traits must change. E) At least one gene, affecting at least one phenotypic trait, must change.

The largest unit within which gene flow can readily occur is a A) population. B) species. C) genus. D) hybrid. E) phylum.

Bird guides once listed the myrtle warbler and Audubonʹs warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow -rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification? A) The two forms interbreed often in nature, and their offspring have good survival and reproduction. B) The two forms live in similar habitats. C) The two forms have many genes in common. D) The two forms have similar food requirements. E) The two forms are very similar in coloration.

Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian islands have different elaborate courtship rituals that involve fighting other males and stylized movements that attract females. What type of reproductive isolation does this represent? A) habitat isolation B) temporal isolation C) behavioral isolation D) gametic isolation E) postzygotic barriers

Which of the following factors would not contribute to allopatric speciation? A) A population becomes geographically isolated from the parent population. B) The separated population is small, and genetic drift occurs. C) The isolated population is exposed to different selection pressures than the ancestral population. D) Different mutations begin to distinguish the gene pools of the separated populations. E) Gene flow between the two populations is extensive.

According to the punctuated equilibria model: A) natural selection is unimportant as a mechanism of evolution. B) given enough time, most existing species will branch gradually into new species. C) most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species. D) most evolution occurs in sympatric populations. E) speciation is usually due to a single mutation.