Final Exam

The protostomes are divided into two monophyletic groups, the:

Lophotrochozoa and Ecdysozoa.

Which of the following best describes the kind of resource for which individuals may compete?

It can be any resource that is limited in the environment.

Giant clams synchronize their reproduction with the phases of the moon. During these reproductive bouts a single clam can release approximately 500 million eggs to be fertilized in the water column by sperm released from other clams. However, the population sizes of giant clams are very low because many of the fertilized eggs and larvae will be eaten by fish in the local area. Based on this information what can be said of the reproductive strategy of the giant clam?

It is an r-strategist.

Humans have changed the selective landscape of Plasmodium, the infectious agent that causes malaria, by developing drugs that kill this parasite. Plasmodium is resistant to many of these drugs. Which of the following is a likely characteristic of this parasite that contribute to its ability to develop resistance? (Select all that apply.)

It occurs in a region where medical treatments are not regularly monitored. The parasite has a quick generation time, and high mutation rates.

Because energy transfer is not 100% efficient across trophic levels, a maximum of about _____% of energy and biomass available at one trophic level is available at the next.

10

Tropical rainforests have high species richness of trees. Which of the following statements provides the MOST reasonable explanation why animal species richness is also high in tropical rainforests?

Animals have diversified into the vast number of niches provided by tree diversity.

What is the predominant hypothesis to explain why animals only appeared in the fossil record about 3 billion years after life originated?

Animals large enough to be recorded in the fossil record could not evolve until oxygen reached levels sufficient to support aerobic respiration.

Using records taken by Henry David Thoreau in the 1840s, scientists have documented what pattern of change in flowering plants around Boston, Massachusetts?

As temperatures have warmed, flowering occurs earlier in many species.

The fossil remains of animals with body plans recognizable as arthropods, echinoderms, mollusks, and other bilaterians first appeared during the _____ Period, around _____ million years ago.

Cambrian; 541

The U.S. Department of Energy's energy outlook report for 2015 estimates that electricity generation in the United States will increase by nearly 25% by 2040. Both the amount and percentage of electricity generated by burning coal, however, will drop, as more and more electricity is generated by burning natural gas and exploiting renewable energy sources. Which is an expected consequence of this shift?

Carbon dioxide levels in the atmosphere will increase, but at a lower rate than if coal burning continued to be the major source of electricity.

A population that has a high mortality earlier in the life cycle than later in the life cycle would have a ____________ survivorship curve.

Type III

Giant clams synchronize their reproduction with the phases of the moon. During these reproductive bouts a single clam can release approximately 500 million eggs to be fertilized in the water column by sperm released from other clams. However, the population sizes of giant clams are very low because many of the fertilized eggs and larvae will be eaten by fish in the local area. What type of survivorship curve would you expect to see in giant clams?

Type III

Which of the following is not a habitat island?

a freshwater pond in a meadow a black basalt lava flow in the middle of the desert a deep sea hydrothermal vent

Imagine a frog at a pond where multiple species are mating. Female frogs are able to discern males making their species-specific calls. How is she able to do this?

The female frog hears all of the calls at the pond, but only male calls from her species excite a specific group of neurons which results in her going to a male frog of her species.

An age structure diagram that is broad at the base and narrow at the top would indicate

a growing population

When sea otters are present in a kelp forest community, there are more than 12 species in the community. If sea otters are removed, there are 5-7 species that remain in the community. These data suggest that sea otters are:

a keystone species.

When two species compete for similar resources, resource partitioning can alter the niche of the species that compete. The figure below shows an example of this. Resource partitioning results in:

a move from the fundamental niche to the realized niche for both species.

Golden-collared manakin birds perform an elaborate mating dance that includes jumping on perches and repeatedly hitting their wings together to make a popping noise. Data suggest that females select the fastest jumpers and those that make the popping noise more rapidly for mating. The __________ is the mechanistic explanation of this behavior; the ___________ is the adaptive function of this behavior.

ability to jump; mate choice

According to Niko Tinbergen, which of the following defines―and helps researchers understand―an animal's behavior?

adaptive function causation development evolutionary history

Male Australian bowerbirds build and decorate elaborate structures, called bowers, out of grasses and other vegetation. If we want to understand how this behavior promotes a male bowerbird's ability to survive and reproduce, we want to understand its:

adaptive function.

An individual's ecological footprint is equivalent to the:

amount of land required to provide all the resources used by that individual.

Associative learning, also called conditioning, occurs when:

an animal learns that two events are correlated.

Many species are introduced into new areas every day through ballast water and international shipping; however, not all of them become established or invasive. For those species that do become invasive, which of the following characteristics would be the MOST likely in an invasive species?

an r-strategist

An invasive species is:

any non-native species that becomes established in a new ecosystem.

Displays are patterns of behavior that:

are species-specific, are highly stereotyped, and function as signals.

A behavior is shaped by:

both environmental and genetic factors.

Population size can fluctuate with many different factors. Which of the following would not affect population size?

change in primary predators on the population change in resource availability for the population change in birthrate in the population change in death rate in the population

Which of the following correctly matches the name of a biological clock to the timescale at which it operates or the type of activity with which it might be associated?

circadian: feeding, sleeping

Each morning before work a cat owner opens the utensil drawer in the kitchen, grabs the can opener, and then shuts the drawer making a lot of noise. Each morning her new cat would run into the kitchen to be fed. After a few weeks, the cat owner notices that the cat runs into the kitchen whenever she hears the utensil drawer close. This is an example of:

classical conditioning.

Spanish moss is not a moss, but a flowering plant (Tillandsia usneoides) often seen draped from the branches of live oaks, cypress, and other large trees in the southeastern United States. The trees on which it grows provide support but no nutrients or moisture—the plant provides those things for itself, without apparently harming its support tree. This, then, is an example of a:

commensalism

An ecological _____ is the set of all populations of all species found in a given place.

community

In the late 1960s, Robert Paine conducted landmark studies on diversity in the rocky intertidal zone, comparing the species diversity in control plots with diversity in experimental plots from which he removed the top predator, sea stars. After 5 years, 15 species of intertidal invertebrates lived in the control plots, while the experimental plots were dominated by only two species, one mussel and one barnacle. The process MOST likely responsible for the loss of species diversity in the experimental plots was:

competitive exclusion.

What are the potential consequences of increasing crop growth to feed a growing human population?

decreased biological storage of carbon through deforestation greater input of carbon dioxide into the atmosphere through the burning of fossil fuels loss of biodiversity through conversion of forests and grasslands to agricultural fields eutrophication and dead zones resulting from increased use of fertilizer

As a population approaches its carrying capacity, its growth rate:

decreases.

Insects are likely so successful because of which adaptations that allow them to live in a wide range of habitats?

desiccation-resistant eggs wings metamorphosis

In deeper waters, nutrients primarily come from:

detritus from more productive shallower waters.

The figures below represent three hypothetical populations; each circle is an individual. Select the pattern above that describes the following scenario: Individuals are distributed randomly within the environment.

diagram K

The "waggle dance" of honeybees conveys what information about a food source to other foragers in the hive?

direction and distance from the hive

The Coriolis effect governs the:

direction of ocean currents.

Which of the following factors are communicated by bees performing the waggle dance?

distance and direction to the food source

According to MacArthur and Wilson's theory of island biogeography, both the land area (size) of an island and the _____ contribute to species diversity.

distance of the island from neighboring land masses

Animals with bilateral symmetry typically have: (Select all that apply.)

distinct front (head) and back (tail) ends. specialized sensory organs clustered at the front, or head, end

Imprinting is MOST likely to occur:

during a critical point in development.

The role played by a species in its environment is called its:

ecological niche.

A(n) _____ is a community of organisms and the physical environment it occupies.

ecosystem

Examine Figure 49.1 below illustrating human population growth. What pattern of growth are we currently exhibiting?

exponential growth

When a population is small relative to its carrying capacity, its growth will be:

exponential.

Only density-dependent factors impact population growth.

false

Species richness could be the same on islands H and M.

false

One characteristic found only in chordates is the presence of pharyngeal slits. Early in chordate history what was the function of this structure?

feeding

Certain species of digger wasps will dig a central channel straight down underground. After that they will dig a chamber off to the side where they will leave a cricket they have paralyzed to feed developing larvae. After the wasp hunts and captures a cricket, she paralyzes it and brings it back to the burrow. She will leave it a fixed distance from the burrow entrance and go down in her burrow to inspect the chamber one more time before bringing the cricket down. If an observer moves the cricket any distance from where she left it, she will place it at the same fixed distance from the burrow entrance and again go down to inspect the chamber before going back up to retrieve the cricket. This can go on for many iterations. This pattern of behavior is best described as a:

fixed action pattern.

Patterns of behavior that are species-specific and highly repeatable are called displays and are an example of a(n) _____ pattern.

fixed-action

A _____ depicts the flow of carbon through an ecosystem, whereas a _____ depicts the transfer of energy.

food web; trophic pyramid

Giant sequoia trees (Sequoiadendron giganteum) are among the largest and longest-living organisms on Earth. These trees grow in weight by up to 1000 pounds of wood per year. As these trees are growing, they:

generate some CO2 through cellular respiration. incorporate CO2 into their biomass (wood, roots, and needles). are probably a net sink of CO2.

Most amphibians have an aquatic larval form with _____ and a terrestrial adult form with _____.

gills; lungs

Crustaceans:

have a hard external skeleton composed of chitin.

Warm air is _____ dense than cold air, and warm air holds _____ moisture than cold air.

less; more

Lyre birds have their own species-specific songs that they sing. However, they are also known to produce vocalizations that sound very similar to sounds in their environment—a chainsaw, and a camera shutter opening and closing, for example. Their performance making these types of sounds is the result of:

imitation

A severe drought is an example of a density-_____ factor that can influence population size. The availability of nest sites is an example of a density-_____ factor.

independent; dependent

Instinctive behaviors that are carried out regardless of earlier experience are called _____ behaviors and are a product of an individual's genotype.

innate

The majority of all known animal species are:

insects

The "realized niche" of Canada geese depends on which of the following?

interspecific competition between Canada geese and other birds competitive exclusion of Canada geese by other organisms the distribution of Canada geese parasites the climate of a given environment

Tropical leafcutter ants collect leaf cuttings which they transport to special underground chambers. There, they chew the leaves to create nursery beds on which they grow a species of fungus they use for food. When ant queens disperse to establish new colonies, they carry the fungus with them, dispersing it as well (this benefits the fungus). In the ants' nest, the fungus is at risk of being destroyed by another fungal species that is able to grow in the same habitat, using the same limited resources. On their bodies, the ants carry and provide a home for bacteria that produce antibiotics the ants use to kill this second fungus and thereby protect their food supply. In this system, the relationship between the two fungal species is:

interspecific competition.

Male peacocks have tail feathers that make up 60% of their body length. During the mating season they fan their tails and shake these feathers in front of females. Females evaluate the tail-shaking behavior as part of selecting their mate. Which of the behaviors below is most likely to have been the original behavior that, through natural selection, resulted in this mate choice behavior of tail shaking?

involuntary muscle contraction like shivering

Which of the following BEST describes a species' niche?

its habitat and how it uses available resources in that habitat

A behavior that depends on experience has been:

learned

The source of nitrogen in nitrogen fertilizer manufacture is:

nitrogen gas.

Sponges have _____ symmetry.

no

The presence of bacteria that produce essential amino acids in the bodies of aphids is an example of:

obligate mutualism.

We think of termites as insects that "eat" wood. In fact, however, termites rely on a variety of eukaryotic and prokaryotic gut microbes to digest cellulose—without the microbes, the termites will ingest wood, but will starve. This, then, is an example of a(n);

obligate mutualism.

Trial-and-error learning is also called _____ conditioning.

operant

An airborne chemical that is used to communicate with members of the same species is called a:

pheromone.

In a pond, tadpoles eat algae and fish eat the tadpoles. Around the pond, grasshoppers eat grass and, at night, are preyed upon by bats. Other bats eat the fish that eat the tadpoles. In this community, the tadpoles are:

primary consumers.

In general, a species' _____ niche will be smaller than its _____ niche due to interactions with other organisms in the community.

realized; fundamental

In many primate species, individuals in the same group will often "groom" each other to get rid of ectoparasites and matting in their fur. This behavior is an example of:

reciprocal altruism.

What is one "low-tech" method currently available to actively remove CO2 from the air?

reforestation of previously cleared landscapes

Linnaeus sorted animals into groups based on body plans. Today, these groupings are called:

phyla.

A _____ consists of all the individuals of a given species that live and reproduce in a particular place.

population

Habitat fragmentation occurs frequently with current logging practices. The figure below shows a fragmented set of patches in a logged area. At equilibrium, which forest fragment is likely to hold the LARGEST number of species?

population J

Habitat fragmentation occurs frequently with current logging practices. The figure below shows a fragmented set of patches in a logged area. Which of the subpopulations is MOST likely to go extinct?

population K

Prairie dogs are rodents that live in colonies. Black-tailed prairie dog (Cynomys ludovicianus) colonies typically have around 12 adult animals per hectare. What aspect of the population ecology of the black-tailed prairie dog does this statement describe?

population density

You sample the solid waste of three infants from three different families each week for 24 weeks. You find that the population of bacteria in the gut is dominated by one species for the first 12 weeks, and then shifts to another species. This shift in the biological composition of a community over time is called:

succession

Primary productivity is affected by the availability of:

sunlight, water, and nutrients.

Male moths are able to sense pheromones released by females of their species through chemoreceptors on their antennae. When female pheromones are detected the males alter their flight pattern and follow the increasing concentration gradient of the signal until they reach the female to mate. This is an example of:

taxis.

Tropical biomes have evolved over _____ years. Biomes at higher latitudes have experienced an ice age within the past _____ years.

tens of millions of; few million

What characteristic associated with male Anolis lizards caused a change in behavior in female Anolis lizards?

testosterone that causes courting behavior in males

Which ratio provides a good estimate of vegetation type within biomes?

potential evapotranspiration to precipitation

Meerkats are small desert mammals that live in groups of 20-50 individuals. You observe one meerkat standing upright on a stump, looking around, while other meerkats forage for food. You hypothesize that this is an example of kin selection. What additional information would you need to know to evaluate your hypothesis?

the degree of genetic relatedness of this meerkat to all members of the group

An ecosystem includes: Select all that apply.

the interacting organisms in the area. abiotic factors of the area. predators in the area

Primary producers are the basis for all aquatic and terrestrial food webs. How does the amount of primary production affect community structure?

the more energy available from primary producers, the more individuals that could be supported at higher trophic levels in the community

Energy use by individuals varies among countries primarily because of differences in: (Select all that apply.)

the need to heat buildings in countries at high latitude. amount of travel. standard of living.

Which of the following could be used to define the ecological niche of a plant species?

the pH of its soil the insects that eat it the depth to which the soil freezes in the winter

A tundra ecosystem would include which of the following?

the rainfall patterns the tundra experiences all of the mammals inhabiting the tundra the amount/duration of sunlight the tundra receives all of the bryophytes inhabiting the tundra

Which of the following would you expect to observe as you go from the base to the top of a mountain?

the same pattern of climate and biome change one would experience if hiking from low to high latitude

What is the approximate size of the human population today?

7 billion people

The _____, which includes the sharks, skates, and rays, are unique in possessing skeletons made of _____.

Chondrichthyes; cartilage

_____ is an interaction in which individuals require the same resource, and therefore the availability of that resource is lowered.

Competition

Most deserts occur at approximately 30° latitudes. Which of the following statements BEST reflects this finding?

Cool dry air descends at 30° latitude.

The latitudinal diversity gradient refers to what pattern of species diversity?

For many kinds of organisms, species diversity is greatest near the equator and lowest near the poles.

When sea turtle eggs hatch, predators gather and mortality among the hatchlings is extremely high. Once turtles reach adult size, they can live for decades. This is an example of Type _____ survivorship.

III

_____ is a form of learning typically seen in young animals and involves acquiring specific behaviors in response to key experiences during critical times called sensitive periods.

Imprinting

Juveniles of many different species are known to imprint on their parents. Which of the following is one of the necessary conditions in order for imprinting on parents to occur?

Imprinting requires exposure to the parents during a short window of time, called the critical period.

Recent studies indicate that the addition of iron to areas of the ocean could increase productivity. Increased productivity could be beneficial for many reasons. What may be one of the LARGEST negative impacts that could occur with "fertilizing the oceans with iron"?

Increased productivity could result in higher respiration rates and regions of depleted oxygen in the ocean.

Which of the following statements about patterns of energy use among countries is NOT true?

Individuals in larger countries use more energy than individuals in smaller countries.

As air moves from the base up the side of a mountain, it cools. What is one consequence of this movement of air?

Moisture will drop as rain as the air moves up the side of the mountain.

In 1987, 18 black-footed ferrets, the last known individuals of this species, were captured and brought into a captive breeding program in Wyoming. In 1989, the total ferret population, still in captivity, was 120 animals. These 120 animals in 1989 represented:

N, the total population size.

One of the goals of conservation biology is to conserve biodiversity. An important part of conservation strategy is the design of reserves. Reserves are often designed to be as large as possible. How does the theory of island biogeography support biologists' efforts to utilize large reserves in order to conserve as much biodiversity as possible?

Species area curves show that island size (i.e., habitat patch) is correlated to the number of species that can be supported within that area.

_____ is the proportion of individuals of an initial cohort that survives to each successive age or stage of the life cycle.

Survivorship

_____ are close interactions between species that have evolved over long periods of time. When these interactions enhance the reproduction and population growth of both species, they are called _____.

Symbioses; mutualisms

There are many climatological factors that contribute to high levels of rainfall at the equator. Which of the following is NOT a reason for high rainfall at the equator?

Temperatures are relatively constant.

The steelheaf in this system is a:

Tertiary consumer Both secondary and tertiary consumer

A group of scientists in Alaska notices that not only have atmospheric CO2 levels increased at their sampling site but so too have methane levels. What could account for this increase in methane levels?

The release of methane from thawed permafrost.

In the past, species of sponges, cnidarians, and ctenophores were referred to as "lower" or "primitive" animals because of their relatively simple body plans and lack of any sophisticated organ differentiation. Which of the following suggest that the terms "lower" or "primitive" are not useful as descriptors for these organisms?

These groups have been around for millions of years, therefore their evolutionary path has been successful in spite of limited complexity.

Sponges move huge volumes of water through their bodies every day. Although this serves the function of filter feeding for the organism, how might this also provide an "ecosystem" service (something that affects and/or benefits other organisms in their environment)?

They create small currents in their microenvironment that help to circulate and clean water locally for other organisms.

Theoretical predictions suggest that the North Pole should be cooler than it actually is. What helps to warm regions at high latitudes?

Warm air from the equator moves toward the poles before descending.

Some types of dinoflagellates (single-celled eukaryotes) are photosynthetic. They have flagella and can swim through the water. If you grow them in a container that is lit from the right side, the cells will swim to the right side of the container. Is this an example of orientation? Why or why not?

Yes, because there is a change in location in response to environmental information.

Conditioning that occurs when an animal learns to link two events is called _____ learning.

associative

Some of the characteristics used to describe biomes include precipitation and:

average temperature.

When would a researcher be MOST likely to observe resource partitioning?

between two sympatric species that eat similar-sized seeds

On land, _____, which are broad, ecologically uniform areas, are recognized by their characteristic vegetation that reflects adaptation of form and physiology to climate.

biomes

Population size can be influenced by.

births. deaths. immigration. emigration

A protostome is distinguished by a(n):

blastopore that becomes a mouth.

In general a larger biomass in primary producers for a trophic pyramid:

can support more biomass at higher trophic levels because more energy is available between the level of primary producer and primary consumer.

Which of the following would be considered a type of communication?

cardinals singing the plumage of a bird of paradise a lion marking its territory

The maximum number of individuals of a given population the environment can support is the environment's _____ for that population.

carrying capacity

Once a hemlock-spruce forest is established in Glacier Bay, it tends to remain relatively unchanged unless disturbed. This makes it the _____ for the region.

climax community

Examine Figure 44.1, below. According to this phylogeny, bilaterians (animals with bilateral symmetry) are most closely related to:

cnidarians.

Many plants have specialist pollinators. That is, the plant has evolved adaptations that only allow one type of pollinator access to nectar when pollinating. This is a result of:

coevolution.

Deserts can be found at 30° N and 30° S of the equator. If you visited the deserts in both regions you would see that the dominant plants look very similar. This is MOST likely the result of:

convergent evolution.

Annelids are characterized by: (Select all that apply.)

cylindrical, segmented bodies. extensive nervous systems. hydrostatic skeletons.

Amphibian population declines have been linked to:

habitat loss, pesticides and other toxins, and fungal disease.

Although all Anolis feed on insects and other invertebrates, they have evolved different feeding strategies that are reflected in:

habitat preference. skull morphology. behavior. leg morphology.

Which of the following would not be an example of associative learning?

habituation

In the classic fable of "the boy who cried wolf," the villagers who stopped listening to the shepherd boy who kept lying and telling them that a wolf was attacking the sheep were exhibiting the form of learning called:

habituation.

A _____ affects other members of the community in ways that are disproportionate to its abundance or biomass.

keystone species

A large population made up of smaller populations linked by migration is a:

metapopulation.

Arthropods are an incredibly successful group of animals. This is thought to be primarily due to the diversity in feeding appendages found in groups of arthropods. How did the diversity in feeding appendages arise?

modification of walking appendages into feeding in anterior-most segments

Which of the following is not a characteristic exclusively found in animals?

multicellularity chitin

According to this phylogeny, which of the following correctly lists the sequence in which multicellularity, tissues, and bilateral symmetry arose, from the oldest characteristic to the most recent?

multicellularity, tissues, bilateral symmetry

Some argue that any members of the microbiota that take up space on our body surfaces and do no harm to us are actually providing us a service because they prevent the colonization of harmful species. From this point of view, the relationship between the skin microbiota and their human host is:

mutualism.

In either freshwater or marine biomes, which regions would you expect to have the HIGHEST productivity?

near the surface where sunlight penetrates

The theory of island biogeography describes the number of species on an island as being determined by an equilibrium between the processes of immigration and extinction. Consider a small, far-offshore island and a large, near-shore island. Which island is expected to have a HIGHER equilibrium number of species?

near-shore, large island

Cnidarians are able to capture prey with the aid of _____, harpoon-like organelles that are often tipped with neurotoxins.

nematocysts

According to this phylogeny, the group marked "Bony fish" is:

paraphyletic.

Lampreys are known to attach themselves to fish. In doing so they rasp off a section of the fish with hard keratinized structures and "feed" on the blood and fluid that oozes into their oral cavity. Fish can survive with a lamprey attached, but they have to expend extra energy swimming with the lamprey attached. This association would be designated a:

parasitism.

In the experiments with moss patches described in your text, what were the two factors that affected insect extinction rates within patches?

patch size and patch connectivity (usable habitat corridors between patches)

An r-strategist will typically:

produce many small offspring.

Males of many species of ducks have very ritualized mating displays. The pattern and movements of their mating display:

provide a species-specific communication signal to females of their species.

Invasive species spread to new areas through all of following mechanisms EXCEPT:

purposeful importing. migratory birds. ballast water in ships. shipping of produce.

The amniotes include: (Select all that apply.)

reptiles. birds. mammals.

Measuring its costs and benefits in terms of energy spent and/or gained, predation:

results in a gain for one individual and a loss for the other.

Measuring its costs and benefits in terms of energy spent and/or gained, competition among individuals:

results in a loss for both individuals.

Members of the Ecdysozoa: (Select all that apply.)

secrete an external cuticle. molt during growth.

The enhancement of a response to a stimulus following a novel pre-stimulus is called:

sensitization.

Insects exchange gases through pores called _____, which connect to an internal system of tubes called _____, which are in turn connected to respiring tissues.

spiracles; tracheae

You are surveying biodiversity on a new island chain. You have counted the number of bat species on one island already. The next island is smaller and farther from the mainland than the one you have just surveyed. According to the theory of island biogeography, the total number of its bat species should be _____ than on the current island because the rate of immigration to the new island should be _____ and the rate of extinction should be _____. Refer to Figure 46.17.

smaller; lower; higher

Overlap of niches can be minimized through:

species evolving adaptations through selective pressure on competitive ability.

Consider two islands located an equal distance from the mainland (which is the colonization source). One island is large, the other is small. Which island will have a higher rate of change in species composition?

the small island

Which of the following BEST describes the Green Revolution?

the use of modern technology to increase crop production

Bilaterians develop specialized organs because they have:

three germ layers.

Triploblastic organisms give rise to _____ germ layers, called the _____.

three; ectoderm, mesoderm, and endoderm

Humans add about 150,000,000 tons of fixed nitrogen to the biosphere each year, primarily:

through the use of fertilizer.

Comparative embryology helped clarify the relationships among major groups of animals. Bilaterians, for example, are:

triploblastic

When the number of young produced at birth exceeds the number of adults that can be supported by available resources, this leads to natural selection.

true

Mammals are divided into three major groups based on:

where early development of the young occurs