Bio Lab 5

The fact that small, nonfunctioning hind legs are found in the skeletons of many snakes suggests that snakes a) evolved from organisms with legs. b) are in the process of evolving legs. c) evolved from eels (snakelike fish). d) are really populations of lizards with severe mutation in limb development.

The fact that small, nonfunctioning hind legs are found in the skeletons of many snakes suggests that snakes a) evolved from organisms with legs. b) are in the process of evolving legs. c) evolved from eels (snakelike fish). d) are really populations of lizards with severe mutation in limb development.

How closely related two DNA molecules, and the organisms from which they came, are is measured through a) DNA sequence similarity. b) homologous traits. c) amino acids. d) vestigial traits.

a) DNA sequence similarity.

Which of the following statements accurately distinguishes tissues from organs? a) Organs consist of multiple tissue types, whereas tissues consist of one or more cell types. b) Each organ performs multiple functions, whereas a designated tissue performs only one function. c) Organs consist of cells, whereas tissues do not. d) Organs are limited to one location in the human body, whereas most tissues move throughout the body.

a) Organs consist of multiple tissue types, whereas tissues consist of one or more cell types.

The two squirrel species shown in the figure below arose from the same ancestor. The Kaibab squirrel lives on the north rim of the Grand Canyon, and the Abert's squirrel lives on the south rim. Which is the most likely explanation for their speciation? a) The population of the ancestral squirrel was split by the formation of the Grand Canyon. Since the habitats were different on each rim, the populations evolved differently and became reproductively isolated. b) The ancestral squirrel was actually a hybrid of two squirrel species. When the populations were separated and could no longer mate, the characteristics of the two species became more obvious. c) The population of ancestral squirrel occupied only one of the rims of the Grand Canyon. As the population grew, some members of the population crossed the Grand Canyon to form a new population. d) When the Grand Canyon formed, competition for food and shelter became fierce. The two species arose through sympatric speciation as some individuals gathered food on the north rim rather than on the south rim.

a) The population of the ancestral squirrel was split by the formation of the Grand Canyon. Since the habitats were different on each rim, the populations evolved differently and became reproductively isolated.

Two populations of lizards live in the same area. Which of the following evidence would convince you that they are two distinct species? a) The two populations are not capable of interbreeding and producing fertile offspring. b) Individuals in one population display a different color pattern than individuals in the second population. c) The two populations are capable of interbreeding and producing fertile hybrid offspring. d) Individuals in one population are noticeably larger than individuals in the second population.

a) The two populations are not capable of interbreeding and producing fertile offspring.

Whales have tiny thighbones embedded in the skin next to their pelvis. This is an example of a) a vestigial structure. b) genetic drift. c) fossilization. d) an analogous structure.

a) a vestigial structure.

During gene flow, a) alleles exchange between populations. b) chance events alter the gene pool of a population. c) gametes circulate within a population. d) crossing-over creates new combinations of alleles during gamete formation.

a) alleles exchange between populations.

A large population of animals is split in two by a physical barrier. Over time, the genetic makeup of the two resulting populations becomes more and more different until each population becomes a separate species. This is an example of a) allopatric speciation. b) sympatric speciation. c) natural selection. d) genetic drift.

a) allopatric speciation.

The hands of a human and the hands of a chimpanzee are similar in structure because humans a) and chimpanzees share a recent common ancestor. b) artificially selected for chimpanzees with hands during domestication. c) evolved from chimpanzees. d) and chimpanzees evolved from different organisms that lived in similar environments.

a) and chimpanzees share a recent common ancestor.

Disruptive selection operates whenever a) both extremes of the phenotype are more successful. b) there is a balanced gene pool. c) natural selection is disrupted by genetic drift. d) only the smallest individuals survive.

a) both extremes of the phenotype are more successful.

Speciation a) can result from geographic isolation. b) reduces variation. c) occurs in the absence of genetic divergence. d) occurs only in species living on remote islands.

a) can result from geographic isolation.

Two species live in the same area but breed in different parts of their habitat. These species are a) ecologically isolated. b) geographically isolated. c) likely to produce hybrids. d) artificially isolated.

a) ecologically isolated.

b) is the principle cause of evolutionary change.

a) in different parts of a small lake

For which of the following would a mountain range most likely represent a geographic barrier that would block gene flow? a) mice b) birds c) deer d) butterflies

a) mice

For a population to evolve, there must be genetic differences between organisms in that population. These differences arise by a) mutation. b) a change in an organism's behavior. c) common descent. d) natural selection.

a) mutation.

Evolutionary changes occur when __________ acts upon populations containing individuals with genetic differences. a) natural selection b) mutation c) weather d) continental drift

a) natural selection

Sympatric speciation a) occurs when a new species emerges from a population in the absence of a geographical barrier. b) is impossible, because the populations of a species must be isolated from one another for speciation to occur. c) is always a result of polyploidy. d) occurs only in plants.

a) occurs when a new species emerges from a population in the absence of a geographical barrier.

Epithelial, connective, muscle, and nervous are the four broad categories of animal body a) organ systems. b) cells. c) organs. d) tissues.

a) organ systems.

Natural selection acts directly on __________ that increase survival and reproductive success. a) phenotypes b) allele frequencies c) bottlenecks d) genotypes

a) phenotypes

Individuals of the same species generally a) share many common physical and behavioral characteristics. b) experience prezygotic barriers to reproduction. c) do not interbreed extensively. d) vary only slightly in appearance.

a) share many common physical and behavioral characteristics.

When individuals with intermediate values of an inherited phenotypic trait, like head circumference at birth, have an advantage over other individuals in the population, __________ is the apparent pattern of natural selection. a) stabilizing selection b) disruptive selection c) genetic drift d) directional selection

a) stabilizing selection

Evolution is a) strongly supported by scientific evidence. b) not supported by the fossil record. c) not supported by scientific evidence. d) too obscure to study.

a) strongly supported by scientific evidence.

How does geographic isolation lead to speciation? a) Geographic isolation does not lead to speciation. b) Geographic isolation allows mechanisms of evolution to cause genetic divergence. c) The habitats for geographically isolated species are always different, and this leads to morphological differences. d) Populations that are geographically isolated develop reproductive barriers.

b) Geographic isolation allows mechanisms of evolution to cause genetic divergence.

A lizard is attacked by a bird. The lizard escapes and survives without his hind legs. Fortunately for this lizard, the loss of his hind limbs allows him to live within a smaller crevice than other lizards of the same species, so he experiences less competition. Which of the following is true for this lizard? a) A lack of hind limbs should become more common in this population. b) The loss of his legs provided an overall advantage within his environment. c) The loss of his hind legs would be considered an adaptive trait. d) This lizard will be unable to reproduce.

b) The loss of his legs provided an overall advantage within his environment

Which of the following is an example of a postzygotic barrier? a) The breeding seasons are different. b) The zygote fails to develop. c) The courtship behaviors are different. d) The gametes cannot join.

b) The zygote fails to develop.

According to the biological species concept, a species is defined when individuals of the same species a) always have the same physical traits. b) are capable of interbreeding and producing fertile offspring. c) differ widely in their DNA sequences. d) must reproduce asexually.

b) are capable of interbreeding and producing fertile offspring.

The formation of a new species a) can occur only when two populations are geographically isolated. b) can occur any time genetic divergence occurs. c) can occur only when two populations are sympatric. d) is a process that stopped occurring thousands of years ago.

b) can occur any time genetic divergence occurs.

What is biological evolution? a) adaptations to common descent over time b) change in the inherited characteristics of a group of organisms over generations c) the process of direct observation of the fossil record d) the unchanging nature of life on Earth

b) change in the inherited characteristics of a group of organisms over generations

Convergent evolution occurs when natural selection causes distantly related organisms to a) evolve into the same species despite the fact that they are members of separate populations. b) evolve similar structures in response to similar environmental challenges. c) merge into one continuous population because of reversals in continental drift. d) evolve both analogous and homologous characteristics.

b) evolve similar structures in response to similar environmental challenges.

Although populations of North American apple maggot flies are not geographically isolated, they appear to be in the process of diverging into two new species. Which of the following could be causing speciation between two populations in the absence of geographic isolation? a) producing fertile hybrids b) feeding on two different types of food c) increased gene flow between them d) laying their eggs in the same location

b) feeding on two different types of food

Geographic isolation limits the __________ between separated populations of a species. a) directional selection b) gene flow c) genetic differences d) adaptation

b) gene flow

When a brightly colored guppy population is placed in an area containing many predators, the population changes in only a few generations to one containing only guppies with drab, dull colors that blend into their environment. This is an example of how natural selection can a) change the color preferences of female guppies. b) improve the match between guppies and their environment. c) convert a dominant allele into a recessive allele. d) force new color mutations to occur.

b) improve the match between guppies and their environment.

When a brightly colored guppy population is placed in an area containing many predators, the population changes in only a few generations to one containing only guppies with drab, dull colors that blend into their environment. This is an example of how natural selection can a) convert a dominant allele into a recessive allele. b) improve the match between guppies and their environment. c) change the color preferences of female guppies. d) force new color mutations to occur.

b) improve the match between guppies and their environment.

An example of evolution that has been readily observed is a) a chameleon changing colors as it moves from a leaf of one color to a leaf of another color. b) increased resistance of bacteria to an antibiotic that is used to kill them. c) humans teaching dogs to obey certain commands. d) chimpanzees learning sign language.

b) increased resistance of bacteria to an antibiotic that is used to kill them.

Natural selection a) cannot occur without genetic drift. b) is the principle cause of evolutionary change. c) is the principle cause of extinctions. d) occurs only in gametes.

b) is the principle cause of evolutionary change.

Gene flow between two populations a) magnifies the effects of genetic drift. b) makes the genetic composition of the two populations more similar. c) creates genetic differences between the populations. d) eliminates harmful alleles.

b) makes the genetic composition of the two populations more similar.

The result of ____________ over evolutionary time spans is that alleles that allow organisms to survive and reproduce at a higher rate than other individuals become more common in the population. a) gene flow b) natural selection c) homology d) artificial selection

b) natural selection

Peppered moths are generally light in color and blend into the trunks of the trees on which they live. Populations of peppered moths found in areas where soot has blackened the tree trunks are dark in color. This example demonstrates a) vestigial coloration. b) natural selection. c) artificial selection. d) genetic drift.

b) natural selection.

If you drink a large, sugary cola, your blood glucose levels will rise. Cells within your pancreas will respond by producing insulin, a hormone that allows glucose to enter the cells. As more glucose enters your cells, there will be less glucose in your bloodstream. Once the glucose level in your blood has dropped to a healthy concentration, your pancreas will cease to produce extra insulin. This is an example of a __________ loop. a) neutral feedback b) negative feedback c) thermoregulation d) positive feedback

b) negative feedback

Using the biological species concept as a method of defining a species is NOT useful for a) organisms that reproduce sexually. b) organisms known only from fossils. c) species whose ranges overlap. d) species that cannot produce hybrids.

b) organisms known only from fossils.

Which of the following is a type of epithelial tissue? a) neurons b) skin c) tendons d) bone

b) skin

When robins lay a clutch of more than four eggs, their chicks are often malnourished because they have so many to feed. If the robins lay fewer than four eggs, they may not have any viable offspring. As a result, robins typically lay a clutch of four eggs. This is an example of a) convergent evolution. b) stabilizing selection. c) disruptive selection. d) directional selection.

b) stabilizing selection.

Which of the following is one of the three important characteristics of an adaptation? a) An adaptation must be a physical change. b) An adaptation must result in a perfect match between an organism and its environment. c) An adaptation improves an organism's survival in its environment. d) Adaptations are typically simple behavioral changes.

c) An adaptation improves an organism's survival in its environment.

Which of the following must occur for one species to split into two or more species? a) One species must undergo geographic isolation. b) Morphological changes must be obvious within the population. c) DNA sequences of genes must accumulate differences. d) The species must move into a new habitat.

c) DNA sequences of genes must accumulate differences.

Homeostatic pathways are a sequence of steps that reestablish the "normal state" of a living organism's internal environment. What determines the parameters of this "normal state"? a) Actually, most living systems do not regulate temperature or water content, so these features typically fluctuate a great deal. b) Living systems monitor positive feedback mechanisms and shut off negative feedback loops to regulate these processes. c) Organisms have a genetically predetermined set point that must be internally maintained. d) Living systems depend on signals from the environment to regulate these conditions.

c) Organisms have a genetically predetermined set point that must be internally maintained.

Select the correct statement regarding natural selection and sexual selection. a) Sexual selection specifically targets individuals of the opposite sex, whereas natural selection is a random process. b) Sexual selection is a permutation of genetic drift that influences which individuals in a population actually reproduce each generation. c) Sexual selection is a form of natural selection that acts on phenotypes that give individuals advantages in mating opportunities. d) Sexual selection transfers alleles between populations, whereas natural selection acts on individuals within a population.

c) Sexual selection is a form of natural selection that acts on phenotypes that give individuals advantages in mating opportunities.

Why do human embryos develop gill slits? a) This is an unexplained mutation in humans that does not exist in other animals. b) This helps the embryo breathe in the womb. c) The ancestor of humans had gills. d) The gill slits become the lungs.

c) The ancestor of humans had gills.

Some whales have teeth as embryos but do not as adults. What is the most likely explanation of this phenomenon? a) The allele for teeth is unusually common in some whale populations. b) Whale teeth appear as the result of a frequently occurring mutation. c) Whales evolved from organisms that have teeth. d) Whales are in the process of evolving teeth.

c) Whales evolved from organisms that have teeth.

Which of the following would NOT be expected after a population undergoes geographic isolation? a) a decrease in gene flow b) allopatric speciation c) an increase in gene flow d) formation of adaptive traits

c) an increase in gene flow

Convergent evolution produces a) homologous traits. b) lines of common descent. c) analogous traits. d) genetic drift.

c) analogous traits.

What is genetic drift? a) gene mutation within, or between, populations b) shifts in allelic frequencies due to mutation c) chance evolutionary change occurring in small populations d) natural selection acting on large populations

c) chance evolutionary change occurring in small populations

Two different species may have similar features because of a) the founder effect. b) genetic drift. c) descent from a common ancestor. d) a bottleneck.

c) descent from a common ancestor.

Which of the following is NOT a mode of natural selection? a) disruptive selection b) stabilizing selection c) dormant selection d) directional selection

c) dormant selection

Populations of a single species are connected by a) genetic drift. b) continental drift. c) gene flow. d) speciation.

c) gene flow.

Which of the following is a collection of organs? a) bone, tendons, and fat b) reproductive, immune, and integumentary c) heart, lungs, and liver d) neurons, smooth muscle, and skin

c) heart, lungs, and liver

Both humans and whales evolved from a common ancestor. Although our forelimbs are quite different, they are made of the same bones. This is an example of a(n) a) artificial selection. b) vestigial structure. c) homologous structure. d) transition fossil.

c) homologous structure.

Natural selection tends to a) lead to an increase in genetic drift. b) decrease the number of individuals in any given population. c) increase the commonality of characteristics that enhance survival and reproduction. d) decrease the likelihood of adaptation.

c) increase the commonality of characteristics that enhance survival and reproduction.

Two populations of __________ are NOT an example of speciation. a) small rodents that look similar but have genetic differences b) sea urchins in the same territory that are physically unable to mate c) morphologically distinct lizards that lack differences in DNA sequences d) butterflies that live in the same area but breed in different seasons

c) morphologically distinct lizards that lack differences in DNA sequences

Several related bird species live in a desert. One species is much smaller than the other species. This small species nests in holes in cacti. Because the bird is so small, it can easily squeeze between the spines of the cactus and create a well-protected nest. This is an example of a) gene flow. b) genetic drift. c) natural selection. d) mutation.

c) natural selection.

The central driver of evolution is a) genetic drift. b) gene flow. c) natural selection. d) disruptive selection.

c) natural selection.

For homework, an instructor asks students to write a paragraph discussing how the mouth, stomach, and small intestines work together to process food and provide nutrients to the body. Which level of biological organization is the class studying? a) cells b) tissues c) organ systems d) organs

c) organ systems

Negative feedback a) determines what the set point of a process should be. b) prevents positive feedback. c) slows down or shuts off a process when a set point is reached. d) stops a process before it reaches its set point.

c) slows down or shuts off a process when a set point is reached.

Genetic adaptations in two closely related species living within the same territory indicate that a) gene flow is extensive between the two species. b) allopatric speciation has occurred. c) sympatric speciation has occurred. d) geographic isolation is required for evolution.

c) sympatric speciation has occurred.

Gene flow occurs a) as a result of genetic drift. b) as a result of mutations in one population but not in another. c) when an individual migrates between two otherwise isolated populations of a species. d) when individuals within a population interbreed.

c) when an individual migrates between two otherwise isolated populations of a species.

Bacteria reproduce asexually, so scientists classify them based on a) the biological species concept. b) reproductive isolation. c) the idea that they are all strains of the same species. d) DNA sequence similarity and morphology.

d) DNA sequence similarity and morphology.

Which of the following statements is true about adaptation? a) It is an increase in the adaptiveness of many species that have already evolved. b) It occurs when a more adapted species causes the extinction of a less adapted one. c) It is large-scale movement of a single species over a new geographic area. d) It is the process by which natural selection improves the match between an organism and its environment over time.

d) It is the process by which natural selection improves the match between an organism and its environment over time.

Which of the following is true with regard to mutations? a) Mutations occur in response to environmental pressures. b) Several mutations must occur at one time for a new phenotype to appear. c) Mutations are more common in slowly growing organisms. d) Mutations appear without regard to environmental pressures.

d) Mutations appear without regard to environmental pressures.

Evolution can be described as a) sudden shifts in the genetic characteristics of an individual in a population. b) isolation of populations due to geologic forces. c) predesigned change in the genetic characteristics of a population of organisms over time. d) a change in the genetic characteristics of a population of organisms over time.

d) a change in the genetic characteristics of a population of organisms over time.

A population of 8,250 mice occupies the sand dunes in a coastal area. A severe hurricane washes out several miles of sand dunes. As a result, only 50 mice remain. The population has experienced a) horizontal gene transfer. b) gene flow. c) a founder effect. d) a genetic bottleneck.

d) a genetic bottleneck.

Which of the following organisms would best be identified as a species using the biological species concept? a) a bacteria found living in the human gut with thousands of other bacteria b) dinosaurs identified by morphologically similar fossil remains located in a single valley in South America c) a rare plant living in a remote location in Peru that reproduces asexually d) a population of mice living on a mountaintop where the nearest population of mice is 50 miles away

d) a population of mice living on a mountaintop where the nearest population of mice is 50 miles away

During blood clotting, a broken blood vessel triggers a cascade of factors that collectively reduce blood loss. In this example, the clotting factors are functioning as part of a) a negative feedback loop. b) thermoregulation. c) osmoregulation. d) a positive feedback loop.

d) a positive feedback loop.

Evolution by natural selection allows species to a) decrease genetic variation. b) hybridize. c) reduce mutation rate. d) adjust to environmental changes.

d) adjust to environmental changes.

Disruptive selection operates whenever a) only the smallest individuals survive. b) there is a balanced gene pool. c) natural selection is disrupted by genetic drift. d) both extremes of the phenotype are more successful.

d) both extremes of the phenotype are more successful.

Two unrelated species evolving to look more similar due to environmental pressures is called a) gene flow. b) genetic drift. c) divergent evolution. d) convergent evolution.

d) convergent evolution.

Two different species may have similar features because of a) the fossil record. b) artificial selection. c) continental drift. d) descent from a common ancestor.

d) descent from a common ancestor.

Genetic variation is based on a) the formation of new combinations of alleles during asexual reproduction. b) the inheritance of alleles accumulated during the lifetime of an individual. c) the accumulation of mutations in somatic cells (as opposed to gametes). d) differences in genotypes between the individuals in a population.

d) differences in genotypes between the individuals in a population.

The red-breasted nuthatch and the white-breasted nuthatch are similar in appearance and, in many regions of the United States, their ranges overlap. The two organisms do not interbreed. Based on this information, red-breasted and white-breasted nuthatches are a) polyploids. b) different populations of the same species. c) hybrids. d) different species.

d) different species.

Convergent evolution occurs when natural selection causes distantly related organisms to a) evolve both analogous and homologous characteristics. b) evolve into the same species despite the fact that they are members of separate populations. c) merge into one continuous population because of reversals in continental drift. d) evolve similar structures in response to similar environmental challenges.

d) evolve similar structures in response to similar environmental challenges.

Both insects and humans evolved jointed legs to allow locomotion on land. These structures are considered analogous because insects and humans a) cannot breed. b) faced different environmental challenges during evolutionary time. c) stopped evolving at different times in Earth's history. d) evolved from different ancestors.

d) evolved from different ancestors.

Some freshwater snail eggs are accidentally introduced into a new habitat that is geographically isolated from the original population. Which of the following must occur before these snails are described as two separate species? a) sympatric speciation b) adaptation c) gene flow d) genetic divergence

d) genetic divergence

Whale DNA is more similar to hippopotami DNA than to the DNA of any other mammal. This indicates that a) hippos descended from whales. b) whales and hippos may be the same species. c) whales descended from hippos. d) hippos are whales' closest living relatives.

d) hippos are whales' closest living relatives.

New alleles emerge in a species via a) nonrandom mating. b) allele frequency. c) genetic drift. d) mutation.

d) mutation.