Which of these five species originated earliest and appeared suddenly in the fossil record?
A) V
B) W
C) X
D) Y
E) Z

B) W

Which conclusion can be drawn from this evolutionary tree?
A) Gradualistic speciation and speciation involving punctuated equilibrium are mutually exclusive concepts; only one of them can occur.
B) Eldredge and Gould would deny that the lineages labeled X, Y, and Z could represent true species.
C) Assuming that the tip of each line represents a species, there are five extant (i.e., not extinct) species resulting from the earliest common ancestor.
D) A single clade (i.e., a group of species that share a common ancestor) can exhibit both gradualism and punctuated equilibrium.
E) V and W shared a common ancestor more recently than any of the other species.

D) A single clade (i.e., a group of species that share a common ancestor) can exhibit both gradualism and punctuated equilibrium.

Which of these five species is the extant (i.e., not extinct) species that is most closely related to species X, and why is this so?
A) V; shared a common ancestor with X most recently
B) W; shared a common ancestor with X most recently
C) Y; arose in the same fashion (i.e., at the same tempo) as X
D) Z; shared a common ancestor with X most recently, and arose in the same fashion as X
E) This tree does not provide enough information to answer this question.

A) V; shared a common ancestor with X most recently

Which of these evolutionary trees represents the situation described in the previous paragraph (Note: Yakuba (I) represents the island population, and yakuba (M) represents the mainland population)?

A. SEE IMAGE
B. SEE IMAGE
C. SEE IMAGE
D. SEE IMAGE

A. SEE IMAGE

Which of the following pairs are the best examples of homologous structures?
A) bones in the bat wing and bones in the human forelimb
B) owl wing and hornet wing
C) bat wing and bird wing
D) eyelessness in the Australian mole and eyelessness in the North American mole

A) bones in the bat wing and bones in the human forelimb

Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?
A) homologous; homologous
B) analogous; homologous
C) homologous; analogous
D) analogous; analogous

C) homologous; analogous

Of the following anatomical structures, which is homologous to the bones in the wing of a bird?
A) cartilage in the dorsal fin of a shark
B) bones in the hind limb of a kangaroo
C) chitinous struts in the wing of a butterfly
D) bony rays in the tail fin of a flying fish
E) bones in the flipper of a whale

E) bones in the flipper of a whale

Which of these conditions should completely prevent the occurrence of natural selection in a population over time?
A) All variation between individuals is due only to environmental factors.
B) The environment is changing at a relatively slow rate.
C) The population size is large.
D) The population lives in a habitat where there are no competing species present.

A) All variation between individuals is due only to environmental factors.

A trend toward the decrease in the size of plants on the slopes of mountains as altitudes increase is an example of
A) a cline.
B) a bottleneck.
C) relative fitness.
D) genetic drift.
E) geographic variation.

A) a cline.

Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing
A) nonrandom mating.
B) geographic isolation.
C) genetic drift.
D) gene flow.

D) gene flow.

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.3. What is the percentage of the population that is homozygous for this allele?
A) 0.09
B) 0.49
C) 0.9
D) 9.0
E) 49.0

D) 9.0

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the percentage of the population that is heterozygous for this allele?
A) 0.2
B) 2.0
C) 4.0
D) 16.0
E) 32.0

E) 32.0

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the frequency of individuals with AA genotype?
A) 0.20
B) 0.32
C) 0.42
D) 0.81
E) Genotype frequency cannot be determined from the information provided.

D) 0.81

In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple-flowering plants and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population?
A) 0.36
B) 0.64
C) 0.75
D) 0.80

D) 0.80

In the year 2500, five male space colonists and five female space colonists (all unrelated to each other) settle on an uninhabited Earthlike planet in the Andromeda galaxy. The colonists and their offspring randomly mate for generations. All ten of the original colonists had free earlobes, and two were heterozygous for that trait. The allele for free earlobes is dominant to the allele for attached earlobes.

If one assumes that Hardy-Weinberg equilibrium applies to the population of colonists on this planet, about how many people will have attached earlobes when the planet's population reaches 10,000?
A) 100
B) 400
C) 800
D) 1,000
E) 10,000

A) 100

A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?
A) 0.7
B) 0.49
C) 0.21
D) 0.42
E) 0.09

D) 0.42

Sexual reproduction
A) allows animals to conserve resources and reproduce only during optimal conditions.
B) can produce diverse phenotypes that may enhance survival of a population in a changing environment.
C) yields more numerous offspring more rapidly than is possible with asexual reproduction.
D) enables males and females to remain isolated from each other while rapidly colonizing habitats.
E) guarantees that both parents will provide care for each offspring.

B) can produce diverse phenotypes that may enhance survival of a population in a changing environment.

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

C) biological

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

D) biological

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

D) morphological

Dogs (Canis lupus familiaris) and gray wolves (Canis lupus) can interbreed to produce viable, fertile offspring. These species shared a common ancestor recently (in geologic time) and have a high degree of genetic similarity, although their anatomies vary widely. Judging from this evidence, which two species concepts are most likely to place dogs and wolves together into a single species?
A) ecological and morphological
B) ecological and phylogenetic
C) morphological and phylogenetic
D) biological and morphological
E) biological and phylogenetic

E) biological and phylogenetic

Which of the following factors weaken(s) the hypothesis of abiotic synthesis of organic monomers in early Earth's atmosphere?

1. the relatively short time between intense meteor bombardment and the appearance of the first life-forms
2. the lack of experimental evidence that organic monomers can form by abiotic synthesis
3. uncertainty about which gases comprised early Earth's atmosphere

A) 1 only
B) 2 only
C) 1 and 2
D) 1 and 3
E) 2 and 3

D) 1 (the relatively short time between intense meteor bombardment and the appearance of the first life-forms) and 3 (uncertainty about which gases comprised early Earth's atmosphere)

Traditionally, zoologists have placed birds in their own class, Aves. More recently, molecular evidence has shown that birds are more closely related to reptiles than their anatomy reveals. Genetically, birds are more closely related to crocodiles than crocodiles are to turtles. Thus, bird anatomy has become highly modified as they have adapted to flight, without their genes having undergone nearly as much change.

Taxonomically, what should be done with the birds?
A) The traditional stance is correct. Such dramatic morphological change as undergone by birds merits that the birds be placed in their own order, separate from the reptiles.
B) The birds should be reclassified, and their new taxon should be the subclass Aves. Genetic similarity trumps morphological dissimilarity.
C) The rest of the reptiles should be reclassified as a subclass within the class Aves.
D) Science is consensual. Taxonomy is a science. Variant classification schemes involving the birds should be tolerated until consensus is reached.

D) Science is consensual. Taxonomy is a science. Variant classification schemes involving the birds should be tolerated until consensus is reached.

Linnaeus was a "fixist" who believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with
A) classifying organisms using the morphospecies concept.
B) the scientific discipline known as taxonomy.
C) phylogenies.
D) nested, ever-more inclusive categories of organisms.
E) a hierarchical classification scheme.

C) phylogenies.

The various taxonomic levels (namely, genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of
A) how widely the organisms assigned to each are distributed throughout the environment.
B) their inclusiveness.
C) the relative genome sizes of the organisms assigned to each.
D) morphological characters that are applicable to all organisms.

B) their inclusiveness.

In the traditional phylogeny (A), the phylum Platyhelminthes is depicted as a sister taxon to the rest of the protostome phyla, and as having diverged earlier from the lineage that led to the rest of the protostomes. In the molecular phylogeny (B), Platyhelminthes is depicted as a lophotrochozoan phylum. What probably led to this change?
A) Platyhelminthes ceased to be recognized as true protostomes.
B) The removal of the acoel flatworms (Acoela) from the Platyhelminthes allowed the remaining flatworms to be clearly tied to the Lophotrochozoa.
C) All Platyhelminthes must have a well-developed lophophore as their feeding apparatus.
D) Platyhelminthes' close genetic ties to the arthropods became clear as their Hox gene sequences were studied.

B) The removal of the acoel flatworms (Acoela) from the Platyhelminthes allowed the remaining flatworms to be clearly tied to the Lophotrochozoa.

Match the numbered terms to the description that follows. Choose all appropriate terms.
1. autotroph
2. heterotroph
3. phototroph
4. chemotroph

a prokaryote that obtains both energy and carbon as it decomposes dead organisms & an organism that obtains both carbon and energy by ingesting prey
A) 1 only
B) 4 only
C) 1 and 3
D) 2 and 4
E) 1, 3, and 4

D) 2 (heterotroph) and 4 (chemotroph)

Match the numbered terms to the description that follows. Choose all appropriate terms.
1. autotroph
2. heterotroph
3. phototroph
4. chemotroph
an organism that relies on photons to excite electrons within its membranes
A) 1 only
B) 3 only
C) 1 and 3
D) 2 and 4
E) 1, 3, and 4

B) 3 only (phototroph)

Which measurement(s) would help determine absolute dates by radiometric means?
A) the accumulation of the daughter isotope
B) the loss of parent isotopes
C) the loss of daughter isotopes
D) Three of the responses above are correct.
E) Two of the responses above are correct.

E) Two of the responses above are correct.

A) the accumulation of the daughter isotope
B) the loss of parent isotopes

If a fossil is encased in a stratum of sedimentary rock without any strata of igneous rock (for example, lava, volcanic ash) nearby, then it should be
A) easy to determine the absolute age of the fossil, because the radioisotopes in the sediments will not have been "reset" by the heat of the igneous rocks.
B) easy to determine the absolute age of the fossil, because the igneous rocks will not have physically obstructed the deposition of sediment of a single age next to the fossil.
C) easy to determine, as long as there is enough metamorphic rock nearby.
D) difficult to determine the absolute age of the fossil, because the "marker fossils" common to igneous rock will be absent.
E) difficult to determine the absolute age of the fossil, because radiometric dating of sedimentary rock is less accurate than that of igneous rock.

E) difficult to determine the absolute age of the fossil, because radiometric dating of sedimentary rock is less accurate than that of igneous rock.

The ancestors of land plants were aquatic algae. Which of the following is not an evolutionary adaptation to life on land?
A) C₃ photosynthesis
B) a waxy cuticle
C) root hairs
D) xylem and phloem
E) guard cells

A) C₃ photosynthesis

Which of the following would be least likely to affect osmosis in plants?
A) proton pumps in the membrane
B) a difference in solute concentrations
C) receptor proteins in the membrane
D) aquaporins
E) a difference in water potential

C) receptor proteins in the membrane

Active transport of various materials in plants at the cellular level requires all of the following except
A) a proton gradient.
B) ATP.
C) membrane potential.
D) transport proteins
E) xylem membranes.

E) xylem membranes.

Given that early land plants most likely share a common ancestor with green algae, the earliest land plants were most likely
A) nonvascular plants that grew leafless photosynthetic shoots above the shallow fresh water in which they lived.
B) species that did not exhibit alternation of generations.
C) vascular plants with well-defined root systems.
D) plants with well-developed leaves.
E) species with a well-developed, thick cuticle.

A) nonvascular plants that grew leafless photosynthetic shoots above the shallow fresh water in which they lived.

Transpiration in plants requires all of the following except
A) adhesion of water molecules to cellulose.
B) cohesion between water molecules.
C) evaporation of water molecules.
D) active transport through xylem cells.
E) transport through tracheids.

D) active transport through xylem cells.

Which of the following statements about transport in plants is false?
A) Weak bonding between water molecules and the walls of xylem vessels or tracheids helps support the columns of water in the xylem.
B) Hydrogen bonding between water molecules, which results in the high cohesion of the water, is essential for the rise of water in tall trees.
C) Although some angiosperm plants develop considerable root pressure, this is not sufficient to raise water to the tops of tall trees.
D) Most plant physiologists now agree that the pull from the top of the plant resulting from transpiration is sufficient, when combined with the cohesion of water, to explain the rise of water in the xylem in even the tallest trees.
E) Gymnosperms can sometimes develop especially high root pressure, which may account for the rise of water in tall pine trees without transpiration pull.

E) Gymnosperms can sometimes develop especially high root pressure, which may account for the rise of water in tall pine trees without transpiration pull.

Plants do not have a circulatory system like that of some animals. If a water molecule did "circulate" (that is, go from one point in a plant to another and back in the same day), it would require the activity of
A) only the xylem.
B) only the phloem.
C) only the endodermis.
D) both the xylem and the endodermis.
E) both the xylem and the phloem.

E) both the xylem and the phloem.

At the conclusion of meiosis in plants, the end products are always four haploid
A) spores.
B) eggs.
C) sperm.
D) seeds.
E) gametes.

A) spores.

Which of the following is true in plants?
A) Mitosis occurs in gametophytes to produce gametes.
B) Meiosis occurs in sporophytes to produce spores.
C) The gametophyte is within the flower in angiosperms.
D) Mitosis occurs in gametophytes to produce gametes, and meiosis occurs in sporophytes to produce spores.
E) Mitosis occurs in gametophytes to produce gametes, meiosis occurs in sporophytes to produce spores, and the gametophyte is within the flower in angiosperms.

E) Mitosis occurs in gametophytes to produce gametes, meiosis occurs in sporophytes to produce spores, and the gametophyte is within the flower in angiosperms.

Microsporangia in flowering plants are located in the
A) stamen.
B) carpel.
C) petals.
D) sepals.
E) receptacle.

A) stamen.

Which of the following statements regarding flowering plants is false?
A) The sporophyte is the dominant generation.
B) Female gametophytes develop from megaspores within the anthers.
C) Pollination is the placing of pollen on the stigma of a carpel.
D) The food-storing endosperm is derived from the cell that contains two polar nuclei and one sperm nucleus.
E) Flowers produce fruits within the ovules.

B) Female gametophytes develop from megaspores within the anthers.

Where and by which process are sperm cells formed in plants?
A) meiosis in pollen grains
B) meiosis in anthers
C) mitosis in male gametophyte pollen tube
D) mitosis in the micropyle
E) mitosis in the embryo sac

C) mitosis in male gametophyte pollen tube

What is the difference between pollination and fertilization in flowering plants?
A) Fertilization precedes pollination.
B) Pollination easily occurs between plants of different species, whereas fertilization is within a species.
C) Pollen is formed within megasporangia so that male and female gametes are near each other.
D) Pollination is the transfer of pollen from an anther to a stigma. Fertilization is the fusion of haploid nuclei.
E) If fertilization occurs, pollination is unnecessary.

D) Pollination is the transfer of pollen from an anther to a stigma. Fertilization is the fusion of haploid nuclei.

The functional significance of porous septa in certain fungal hyphae is most similar to that represented by which pair of structures in animal cells and plant cells, respectively?
A) desmosomestonoplasts
B) gap junctionsplasmodesmata
C) tight junctionsplastids
D) centriolesplastids
E) flagellacentral vacuoles

B) gap junctionsplasmodesmata

In septate fungi, what structures allow cytoplasmic streaming to distribute needed nutrients, synthesized compounds, and organelles throughout the hyphae?
A) multiple chitinous layers in cross-walls
B) pores in cross-walls
C) complex microtubular cytoskeletons
D) two nuclei
E) tight junctions that form in cross-walls between cells

B) pores in cross-walls

Which of these paired fungal structures are structurally and functionally most alike?
A) conidia and basidiocarps
B) sporangia and hyphae
C) soredia and gills
D) haustoria and arbuscules
E) zoospores and mycelia

D) haustoria and arbuscules

you are given an organism to identify. It has a fruiting body that contains many structures with eight haploid spores lined up in a row. What kind of a fungus is this?
A) zygomycete
B) ascomycete
C) deuteromycete
D) chytrid
E) basidiomycete

B) ascomycete

Which of the following cells or structures are associated with asexual reproduction in fungi?
A) ascospores
B) basidiospores
C) zygosporangia
D) conidiophores
E) ascocarps

D) conidiophores

Which of the following has the least affiliation with all of the others?
A) Glomeromycota
B) mycorrhizae
C) lichens
D) arbuscules
E) mutualistic fungi

C) lichens

Lichens are symbiotic associations of fungi and
A) mosses.
B) cyanobacteria.
C) green algae.
D) Three of these responses are correct.
E) Two of these responses are correct.

B) cyanobacteria & C) green algae.

In both lichens and mycorrhizae, what does the fungal partner provide to its photosynthetic partner?
A) carbohydrates
B) fixed nitrogen
C) antibiotics
D) water and minerals
E) protection from harmful UV

D) water and minerals

Which of the following best describes the physical relationship of the partners involved in lichens?
A) Fungal cells are enclosed within algal cells.
B) Lichen cells are enclosed within fungal cells.
C) Photosynthetic cells are surrounded by fungal hyphae.
D) The fungi grow on rocks and trees and are covered by algae.
E) Algal cells and fungal cells mix together without any apparent structure.

C) Photosynthetic cells are surrounded by fungal hyphae.

If haustoria from the fungal partner were to appear within the photosynthetic partner of a lichen, and if the growth rate of the photosynthetic partner consequently slowed substantially, then this would support the claim that
A) algae and cyanobacteria are autotrophic.
B) lichens are not purely mutualistic relationships.
C) algae require maximal contact with the fungal partner in order to grow at optimal rates.
D) fungi get all of the nutrition they need via the "leakiness" of photosynthetic partners.
E) soredia are asexual reproductive structures combining both the fungal and photosynthetic partners.

B) lichens are not purely mutualistic relationships

The photosynthetic symbiont of a lichen is often
A) a moss.
B) a green alga.
C) a brown alga.
D) an ascomycete.
E) a small vascular plant.

B) a green alga.

A radula is present in members of which clade(s)?
A) chitons
B) bivalves
C) gastropods
D) cephalopods
E) both chitons and gastropods

E) both chitons and gastropods

This nudibranch, a type of sea slug, has many reddish cerata on its dorsal surface, as well as two, white-tipped rhinophores located on the head.

SEE IMAGE

The nontaxonomic term sea slug encompasses a wide variety of marine gastropods. One feature they share as adults is the lack of a shell. We might think, therefore, that they represent defenseless morsels for predators. In fact, sea slugs have multiple defenses. Some sea slugs prey on sponges and concentrate sponge toxins in their tissues. Others feed on cnidarians, digesting everything except the nematocysts, which they then transfer to their own skins. Whereas the most brightly colored sea slugs are often highly toxic, others are nontoxic and mimic the coloration of the toxic species. Their colors are mostly derived from pigments in their prey. There are also sea slugs that use their coloration to blend into their environments.

49) Which structure do sea slugs use to feed on their prey?
A) nematocysts
B) a sharp beak
C) an incurrent siphon
D) a radula
E) a mantle cavity

D) a radula

With which of the following statements would a biologist be most inclined to agree?
A) Humans and apes represent divergent lines of evolution from a common ancestor.
B) Humans evolved directly from Old World monkeys.
C) Humans represent the pinnacle of evolution and have escaped from being affected by natural selection.
D) Humans evolved from chimpanzees.
E) Humans and apes are the result of disruptive selection in a species of chimpanzee.

A) Humans and apes represent divergent lines of evolution from a common ancestor.

Which of the following statements about human evolution is correct?
A) Modern humans are the only human species to have evolved on Earth.
B) Human ancestors were virtually identical to extant chimpanzees.
C) Human evolution has occurred within an unbranched lineage.
D) The upright posture and enlarged brain of humans evolved simultaneously.
E) Fossil evidence indicates that early anthropoids were arboreal and cat-sized.

E) Fossil evidence indicates that early anthropoids were arboreal and cat-sized.

Tissues are composed of cells, and tissues functioning together make up
A) organs.
B) membranes.
C) organ systems.
D) organelles.
E) organisms.

A) organs.

Connective tissues typically have
A) many densely packed cells with direct connections between the membranes of adjacent cells.
B) a supporting material such as chondroitin sulfate.
C) the ability to shorten upon stimulation.
D) relatively few cells and a large amount of extracellular matrix.
E) the ability to transmit electrochemical impulses.

D) relatively few cells and a large amount of extracellular matrix.

A general rule relating the capacity of a specific animal's digestive system to provide adequate access to substrates for biosynthesis of cellular components, as well as fuel molecules needed for ATP production, is that the animal should have access to
A) a high-protein, low-carbohydrate diet.
B) a diet low in lipids and high in protein.
C) a low-calorie diet with a large intake of fluids, especially water.
D) a diet that matches the "food pyramid" for the species.
E) a diet that maximizes vitamins and minerals.

D) a diet that matches the "food pyramid" for the species.

An advantage of a complete digestive system over a gastrovascular cavity is that the complete system
A) excludes the need for extracellular digestion.
B) allows specialized functions in specialized regions.
C) allows digestive enzymes to be more specific.
D) allows extensive branching.
E) facilitates intracellular digestion

B) allows specialized functions in specialized regions

In the digestive system, peristalsis is
A) a process of fat emulsification in the small intestine.
B) voluntary control of the rectal sphincters regulating defecation.
C) the transport of nutrients to the liver through the hepatic portal vessel.
D) a common cause of loss of appetite, fatigue, and dehydration.
E) smooth muscle contractions that move food along the esophagus.

E) smooth muscle contractions that move food along the esophagus.

Which of the following organs is incorrectly paired with its function?
A) stomachprotein digestion
B) oral cavitystarch digestion
C) large intestinebile production
D) small intestinenutrient absorption
E) pancreasenzyme production

C) large intestinebile production

The molar teeth of herbivorous mammals are especially effective at
A) cutting.
B) ripping.
C) grinding.
D) splitting.
E) piercing.

C) grinding.

Which of the following animals is incorrectly paired with its feeding mechanism?
A) lionsubstrate feeder
B) baleen whalesuspension feeder
C) aphidfluid feeder
D) clamsuspension feeder
E) snakebulk feeder

A) lionsubstrate feeder

Which of the following pairs of mammalian blood vessels has blood that is the least similar in its gas content?
A) the pulmonary vein and the jugular vein
B) the veins from the right and left legs
C) the pulmonary artery and the vena cava
D) the pulmonary vein and the aorta
E) the inferior vena cava and the superior vena cava

A) the pulmonary vein and the jugular vein

The set of blood vessels with the slowest velocity of blood flow is
A) the arteries.
B) the arterioles.
C) the metarterioles.
D) the capillaries.
E) the veins.

D) the capillaries.

The set of blood vessels with the lowest blood pressure driving flow is
A) the arteries.
B) the arterioles.
C) the metarterioles.
D) the capillaries.
E) the veins.

E) the veins.

Histamines trigger dilation of nearby blood vessels as well as an increase in their permeability, producing
A) redness and heat only.
B) swelling only.
C) pain.
D) redness, heat, and swelling.
E) all of the signs of a major infection.

D) redness, heat, and swelling.

Which nitrogenous waste has the greatest number of nitrogen atoms?
A) ammonia
B) ammonium ions
C) urea
D) uric acid

D) uric acid

Excessive formation of uric acid crystals in humans leads to
A) a condition called diabetes, where excessive urine formation occurs.
B) a condition of insatiable thirst and excessive urine formation.
C) gout, a painful inflammatory disease that primarily affects the joints.
D) the absence of urea in the urine.
E) osteoarthritis, an inevitable consequence of aging.

C) gout, a painful inflammatory disease that primarily affects the joints.

The primary nitrogenous waste excreted by birds is
A) ammonia.
B) nitrate.
C) nitrite.
D) urea.
E) uric acid.

E) uric acid.

Birds secrete uric acid as their nitrogenous waste because uric acid
A) is readily soluble in water.
B) is metabolically less expensive to synthesize than other excretory products.
C) requires little water for nitrogenous waste disposal, thus reducing body mass.
D) excretion allows birds to live in desert environments.

C) requires little water for nitrogenous waste disposal, thus reducing body mass

Which of the following pairs of organisms excrete nitrogenous wastes in the form of uric acid?
A) mice and birds
B) insects and birds
C) lions and horses
D) humans and frogs
E) fish and turtles

B) insects and birds

A person with alkalosis will likely excrete urine that has abnormally high levels of
A) bicarbonate ions.
B) sodium ions.
C) glucose.
D) ammonia.
E) NaOH.

B) sodium ions.

Human urine is usually more acidic than most other body fluids because
A) hydrogen ions are actively moved into the filtrate.
B) the sodium transporter exchanges one hydrogen ion for each sodium ion.
C) excreted plasma proteins are nearly all acidic ions.
D) excreted amino acids are in abundance.
E) potassium and sodium exchange generates lots of acidity

A) hydrogen ions are actively moved into the filtrate.

If ATP production in a human kidney was suddenly halted, urine production would
A) come to a complete halt.
B) decrease, and the urine would be hypoosmotic compared to plasma.
C) increase, and the urine would be isoosmotic compared to plasma.
D) increase, and the urine would be hyperosmotic compared to plasma.
E) decrease, and the urine would be isoosmotic compared to plasma.

C) increase, and the urine would be isoosmotic compared to plasma.

Juxtamedullary nephrons can concentrate salt effectively in the renal medulla because of their long
A) loops of Henle.
B) distal convoluted tubules.
C) Bowman's capsules.
D) proximal convoluted tubules.
E) glomeruli.

A) loops of Henle.

Unlike an earthworm's metanephridia, a mammalian nephron
A) is intimately associated with a capillary network.
B) forms urine by changing fluid composition inside a tubule.
C) functions in both osmoregulation and excretion.
D) receives filtrate from blood instead of coelomic fluid.
E) has a transport epithelium.

D) receives filtrate from blood instead of coelomic fluid.

Which process in the nephron is least selective?
A) filtration
B) reabsorption
C) active transport
D) secretion
E) salt pumping by the loop of Henle

A) filtration

When female fruit flies mate with two different males on the same day,
A) the first male's sperm fertilizes all of the eggs.
B) the first male's sperm fertilizes most of the eggs.
C) the second male's sperm fertilizes most of the eggs.
D) the first and second males fertilize equal numbers of eggs.
E) none of the eggs become fertilized.

C) the second male's sperm fertilizes most of the eggs.

In male mammals, excretory and reproductive systems share
A) the testes.
B) the urethra.
C) the seminal vesicle.
D) the vas deferens.
E) the prostate.

B) the urethra.

Animals with reproduction dependent on internal fertilization need not have
A) any copulatory organs.
B) a receptacle that receives sperm.
C) behavioral interaction between males and females.
D) internal development of embryos.
E) haploid gametes.

D) internal development of embryos.

In close comparisons, external fertilization often yields more offspring than does internal fertilization. However, internal fertilization offers the advantage that
A) it is the only way to ensure the survival of the species.
B) it requires less time and energy to be devoted to reproduction.
C) the smaller number of offspring produced often receive a greater amount of parental investment.
D) it permits the most rapid population increase.
E) it requires expression of fewer genes and maximizes genetic stability.

C) the smaller number of offspring produced often receive a greater amount of parental investment.

Internal and external fertilization both
Internal and external fertilization both
A) produce single-celled zygotes.
B) occur only among invertebrates.
C) occur only among terrestrial animals.
D) depend on the use of intromittent copulatory organs.
E) occur only among birds.
B) occur only among invertebrates.
C) occur only among terrestrial animals.
D) depend on the use of intromittent copulatory organs.
E) occur only among birds.

A) produce single-celled zygotes.

Most flatworms, including parasitic liver flukes, are hermaphrodites that form zygotes as the result of
A) internal fertilization.
B) external fertilization.
C) parthenogenesis.
D) eggs and sperm mixing together in excreted feces.
E) eggs and sperm mixing together in wastewater.

A) internal fertilization.

At the time of fertilization, the complete maturation of each oogonium has resulted in
A) one secondary oocyte.
B) two primary oocytes.
C) four secondary oocytes.
D) four primary oocytes.
E) four zygotes.

A) one secondary oocyte.

Fertilization of human eggs usually takes place in the
A) ovary.
B) uterus.
C) vagina.
D) oviduct.
E) cervix.

D) oviduct.

Two contraceptive methods that are generally irreversible and which block the gametes from moving to a site where fertilization can occur are
A) the male condom and female condom.
B) the male condom and oral contraceptives.
C) vasectomy and tubal ligation.
D) coitus interruptus and rhythm method.
E) the diaphragm and subcutaneous progesterone implant.

C) vasectomy and tubal ligation.

As an embryo develops, new cells are produced as the result of
A) differentiation.
B) preformation.
C) cell division.
D) morphogenesis.
E) epigenesis.

C) cell division.

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?
A) first cell division → synthesis of embryo's DNA begins → acrosomal reaction → cortical reaction
B) cortical reaction → synthesis of embryo's DNA begins → acrosomal reaction → first cell division
C) cortical reaction → acrosomal reaction → first cell division → synthesis of embryo's DNA begins
D) first cell division → synthesis of embryo's DNA begins → acrosomal reaction → cortical reaction
E) acrosomal reaction → cortical reaction → synthesis of embryo's DNA begins → first cell division

E) acrosomal reaction → cortical reaction → synthesis of embryo's DNA begins → first cell division

The pattern of embryonic development in which only the cells lacking yolk subsequently undergo cleavage is called
A) arcadian development, which is typical of insects.
B) holoblastic development, which is typical of marsupial mammals.
C) meroblastic development, which is typical of humans.
D) holoblastic development, which is typical of amphibians.
E) meroblastic development, which is typical of birds.

E) meroblastic development, which is typical of birds.

A primitive streak forms during the early embryonic development of
A) birds, but not frogs or humans.
B) frogs, but not birds or humans.
C) humans, but not birds or frogs.
D) birds and frogs, but not humans.
E) humans and birds, but not frogs.

E) humans and birds, but not frogs.

If gastrulation was blocked by an environmental toxin, then
A) cleavage would not occur in the zygote.
B) embryonic germ layers would not form.
C) fertilization would be blocked.
D) the blastula would not be formed.
E) the blastopore would form above the gray crescent in the animal pole.

B) embryonic germ layers would not form.

The nucleus and most of the organelles in a neuron are located in the
A) dendritic region.
B) axon hillock.
C) axon.
D) cell body.
E) axon terminals.

D) cell body.

The point of connection between two communicating neurons is called
A) the axon hillock.
B) the dendrite.
C) the synapse.
D) the cell body.
E) the glia.

C) the synapse.

In a simple synapse, neurotransmitter chemicals are released by
A) the dendritic membrane.
B) the presynaptic membrane.
C) axon hillocks.
D) cell bodies.
E) ducts on the smooth endoplasmic reticulum.

B) the presynaptic membrane.

In a simple synapse, neurotransmitter chemicals are received by
A) the dendritic membrane.
B) the presynaptic membrane.
C) axon hillocks.
D) cell bodies.
E) ducts on the smooth endoplasmic reticulum

A) the dendritic membrane.

Neurotransmitters are released from axon terminals via
A) osmosis.
B) active transport.
C) diffusion.
D) transcytosis.
E) exocytosis.

E) exocytosis.

Neurotransmitters categorized as inhibitory are expected to
A) act independently of their receptor proteins.
B) close potassium channels.
C) open sodium channels.
D) close chloride channels.
E) hyperpolarize the membrane.

E) hyperpolarize the membrane.

Receptors for neurotransmitters are of primary functional importance in assuring one-way synaptic transmission because they are mostly found on the
A) axonal membrane.
B) axon hillock.
C) dendritic membrane.
D) mitochondrial membrane.
E) presynaptic membrane.

C) dendritic membrane.

The primary neurotransmitter from the parasympathetic system that influences its autonomic targets is
A) acetylcholine.
B) adenosine.
C) norepinephrine.
D) adrenaline.
E) dopamine.

A) acetylcholine.

The major inhibitory neurotransmitter of the human brain is
A) acetylcholine.
B) epinephrine.
C) glutamate.
D) nitric oxide.
E) GABA.

E) GABA.

The major excitatory neurotransmitter of the human brain is
A) acetylcholine.
B) epinephrine.
C) glutamate.
D) nitric oxide.
E) GABA.

D) nitric oxide.

Where are neurotransmitter receptors located?
A) the nuclear membrane
B) the nodes of Ranvier
C) the postsynaptic membrane
D) synaptic vesicle membranes
E) the myelin sheath

C) the postsynaptic membrane

Select the choice that correctly associates the organ with its embryonic sources.
A) anterior pituitary glandmesoderm and endoderm
B) thyroid glandmesoderm and ectoderm
C) adrenal glandectoderm and mesoderm
D) skinendoderm and mesoderm
E) brainmesoderm and endoderm

C) adrenal glandectoderm and mesoderm

The stretch receptors of the sensory neurons in the human knee-jerk reflex are located in the
A) gastrocnemius muscle, in the calf.
B) cartilage of the knee.
C) quadriceps, the flexor muscles on the ventral side of the thighs.
D) hamstring, the extensor muscles on the dorsal side of the thighs.
E) brain, the sensorimotor relay.

C) quadriceps, the flexor muscles on the ventral side of the thighs.

Afferent neuronal systems include the
A) sensory systems.
B) peripheral nervous system.
C) autonomic nervous system.
D) parasympathetic nervous system.
E) sympathetic nervous system.

A) sensory systems.

A systemic inflammatory response that is often life-threatening is
A) mild fever.
B) aches and dull pain.
C) septic shock.
D) high blood pressure.
E) increased white blood cell count.

C) septic shock.

A cow's herbivorous diet indicates that it is a(n)
A) primary consumer.
B) secondary consumer.
C) decomposer.
D) autotroph.
E) producer.

A) primary consumer

To recycle nutrients, an ecosystem must have, at a minimum,
A) producers.
B) producers and decomposers.
C) producers, primary consumers, and decomposers.
D) producers, primary consumers, secondary consumers, and decomposers.
E) producers, primary consumers, secondary consumers, top carnivores, and decomposers.

B) producers and decomposers.

What is secondary production?
A) energy converted by secondary consumers from primary consumers
B) solar energy that is converted to chemical energy by photosynthesis
C) food that is converted to new biomass by consumers
D) energy that is not used by consumers for growth and reproduction
E) growth that takes place during the second year of life in consumers

C) food that is converted to new biomass by consumers

The total biomass of photosynthetic autotrophs present in an ecosystem is known as
A) gross primary productivity.
B) standing crop.
C) net primary productivity.
D) secondary productivity.
E) trophic efficiency.

B) standing crop.

The amount of chemical energy in consumers' food that is converted to their own new biomass during a given time period is known as which of the following?
A) biomass
B) standing crop
C) biomagnification
D) primary production
E) secondary production

E) secondary production

One major advantage of using Arabidopsis thaliana as a model system for studies of plant form and function is its
A) fast generation time.
B) exceptionally large genome.
C) large seeds.
D) high tolerance to stress.
E) high mutation rate.

A) fast generation time.

Plants contain meristems whose major function is to
A) attract pollinators.
B) absorb ions.
C) photosynthesize.
D) produce more cells.
E) produce flowers.

D) produce more cells.

What is a major function of magnesium in plants?
A) to be a component of lignin-biosynthetic enzymes
B) to be a component of DNA and RNA
C) to be a component of chlorophyll
D) to be active in amino acid formation
E) to be required to regenerate phosphoenolpyruvate in C₄ and CAM plants

C) to be a component of chlorophyll

All of the following are primary functions of flowers except
A) pollen production.
B) photosynthesis.
C) meiosis.
D) egg production.
E) sexual reproduction.

B) photosynthesis.