Bio 2 Mastering Questions Practice

Under normal conditions, a pair of human kidneys processes what volume of blood each day?

1,600 L

Humans excrete: Aquatic animals excrete: Birds, insects, reptiles, etc. excrete:

1. Urea 2. ammonia 3. uric acid

Arrange the following five events in an order that explains the mass flow of materials in the phloem. 1. Water diffuses into the sieve tubes. 2. Leaf cells produce sugar by photosynthesis. 3. Solutes are actively transported into sieve tubes. 4. Sugar is transported from cell to cell in the leaf. 5. Sugar moves down the stem. 2, 4, 3, 1, 5 2, 4, 1, 3, 5 4, 2, 1, 3, 5 1, 2, 3, 4, 5

2, 4, 3, 1, 5

How does a flaccid cell differ from a turgid cell? How does a flaccid cell differ from a turgid cell? A flaccid cell has lower pressure potential. A flaccid cell has higher pressure potential. A flaccid cell has higher solute potential. A flaccid cell has lower solute potential.

A flaccid cell has lower pressure potential.

Which of the following is a component of the vertebrate central nervous system (CNS)? ANSWER All of the listed responses are correct. Brain Spinal cord Nerves Glia

All of the listed responses are correct.

Select the correct statement(s) about the transfer of food energy up the trophic levels from its source in autotrophs. Select all that apply. a. An organism feeds at only one trophic level. b. The length of a food chain is limited by the inefficiency of energy transfer along the chain. c. Few plants have adaptations to reduce feeding by herbivores.

b. The length of a food chain is limited by the inefficiency of energy transfer along the chain.

Identify the roles played by human gut bacteria. a. Human gut bacteria synthesize all essential vitamins required by humans. b. Ulcers are caused by the acid-tolerant bacterium Helicobacter pylori. c. The human appendix houses mutualistic bacteria that digest cellulose.

b. Ulcers are caused by the acid-tolerant bacterium Helicobacter pylori.

A fellow student brought in a leaf to be examined. The leaf was dark green, thin, had stoma on the lower surface only, and had a total surface area of ten square meters. Where is the most likely environment where this leaf was growing? a. the floor of a deciduous forest b. a tropical rain forest c. an oasis within a grassland d. a large, still pond

b. a tropical rain forest

Consider a population whose growth over a given time period can be described by the exponential model: dN/dt = rN. Select the correct statement about this population. a. A population with an r of 0 will have no births or deaths during the time period under consideration. b. A population with an r of 0.1 will decrease over time. c. A population with a positive value of r will grow exponentially.

c. A population with a positive value of r will grow exponentially.

Select the correct statement about essential nutrients. a. Due to their biochemical sophistication, humans have to ingest fewer essential nutrients than do other animals. b. All animals require an identical set of essential nutrients. c. Essential nutrients must be obtained from diet.

c. Essential nutrients must be obtained from diet.

With which of the following statements would a biologist be most inclined to agree? a. Humans evolved from chimpanzees. b. Humans represent the pinnacle of evolution and have escaped from being affected by natural selection. c. Humans and other apes represent divergent lines of evolution from a common ancestor. d. Humans and other apes are the result of disruptive selection in a species of chimpanzee.

c. Humans and other apes represent divergent lines of evolution from a common ancestor.

A population of ground squirrels has an annual per capita birth rate of 0.06 and an annual per capita death rate of 0.02. Calculate an estimate of the total number of individuals added to (or lost from) a population of 1000 individuals in one year. a. 120 individuals added b. 400 individuals added c. 20 individuals added d. 40 individuals added

d. 40 individuals added

Arrange the following taxonomic terms in order from most inclusive (most general) to least inclusive (most specific). 1. apes 2. hominins 3. Homo 4 anthropoids 5. primates a. 5, 1, 4, 2, 3 b. 5, 2, 1, 4, 3 c. 5, 4, 2, 1, 3 d. 5, 4, 1, 2, 3

d. 5, 4, 1, 2, 3

Which of the following statements regarding the future of populations in developing countries are correct? I) The fecundity is predicted to increase. II) Survivorship will increase. III) Overall population size will increase dramatically. IV) The number of offspring each year is predicted to remain high. a. only II and IV b. only I, II, and III c. only I and III d. only II, III, and IV

d. only II, III, and IV

Constipation can result from the consumption of a substance that _____. a. decreases water reabsorption in the small intestine b. speeds up movement of material in the large intestine c. stimulates peristalsis d. promotes water reabsorption in the large intestine

d. promotes water reabsorption in the large intestine

Historically inaccurate diagnosis of acid reflux disorders and gastric ulcers has been improved by _____. a. X-ray technology b. pH monitoring c. sonography d. screening for H. pylori infections

d. screening for H. pylori infections

The acidity of the stomach contents triggers the small intestine to secrete a hormone known as _____. a. cholecystokinin, or CCK b. histones c. TSH d. secretin e. pepsin

d. secretin

Many species of snakes lay eggs. However, in the forests of northern Minnesota, where growing seasons are short, only live-bearing snake species are present. This trend toward species that have live birth in a particular environment is an example of _____. a. sexual selection b. goal direction in evolution c. an exaptation d. species selection

d. species selection

The main reason polar regions are cooler than the equator is that _____. a. the polar atmosphere is thinner and contains fewer greenhouse gases b. the poles are permanently tilted away from the sun c. the poles are farther from the sun d. sunlight strikes the poles at a lower angle

d. sunlight strikes the poles at a lower angle.

Which of these was the first of the major events that stimulated an increase in the size of the human population? a. the Industrial Revolution b. the bubonic plague c. the discovery of antibiotics d. the advent of agriculture e. the discovery of vaccines

d. the advent of agriculture

Hybrid zones provide an opportunity to investigate _____. a. punctuated equilibrium b. mutations c. polyploidy d. the evolution of reproductive isolation e. allopatric speciation

d. the evolution of reproductive isolation

Which structure or compartment is separate from the apoplastic route? a. the cell wall of a root hair b. the cell wall of a mesophyll cell c. the lumen of a xylem vessel d. the lumen of a sieve tube

d. the lumen of a sieve tube

The observation that members of a population are uniformly distributed suggests that a. the size of the area occupied by the population is increasing. b. the members of the population are neither attracted to nor repelled by one another. c. resources are distributed unevenly. d. the members of the population are competing for access to a resource. e. the density of the population is low.

d. the members of the population are competing for access to a resource.

Why has the kingdom Protista been abandoned? a. Some protists are multicellular. b. The kingdom Protista is not monophyletic. c. Some protists are more closely related to plants, animals, or fungi than they are to other protists. d. Some protists are as small as prokaryotes. e. The second and third answers are correct.

e. The second and third answers are correct.

In evolutionary terms, an organism's fitness is measured by its _____. a. genetic variability b. stability in the face of environmental change c. health d. mutation rate e. contribution to the gene pool of the next generation

e. contribution to the gene pool of the next generation

Population ecologists follow the fate of same-age cohorts to a. determine if a population is regulated by density-dependent processes. b. determine a population's carrying capacity. c. determine the factors that regulate the size of a population. d. determine if a population's growth is cyclic. e. determine the birth rate and death rate of each group in a population.

e. determine the birth rate and death rate of each group in a population.

What situation most likely explains the occasional high frequency of certain inherited disorders among human populations established by a small population? a. gene flow b. bottleneck effect c. nucleotide variability d. mutation e. founder effect

e. founder effect

What is the most important factor that holds a gene pool of a species together and prevents speciation? a. sexual selection b. behavioral isolation c. hybridization d. prezygotic barriers e. gene flow

e. gene flow

Choose the list that presents the four stages of food processing in the order in which they naturally occur. a. digestion → ingestion → absorption → elimination b. ingestion → digestion → elimination → absorption c. ingestion → absorption → elimination → digestion d. absorption → digestion → ingestion → elimination e. ingestion → digestion → absorption → elimination

e. ingestion → digestion → absorption → elimination

Which of the following investigations is an example of the study of an abiotic factor? a. identifying food sources for an egret population b. the relationship between finch beak size and food availability on two different Galapagos Islands c. investigating how an elk population competes for food d. observing interactions among various organisms in a rainforest canopy e. investigating how the amount of annual precipitation affects the distribution of a tree species

e. investigating how the amount of annual precipitation affects the distribution of a tree species.

An organism's "trophic level" refers to _____. a. whether it is early or late in ecological succession b. the intensity of its competition with other species c. the rate at which it uses energy d. where it lives e. its food source

e. its food source

Gray matter of the nervous system differs from white matter in that ____________. ANSWER gray matter is primarily made up of neuron cell bodies, whereas white matter consists mainly of bundled axons gray matter makes up the brain, and white matter is found only in peripheral nerves gray matter makes up the brains of invertebrates, whereas white matter makes up the brains of vertebrates gray matter results from damage to white matter gray matter develops from white matter

gray matter is primarily made up of neuron cell bodies, whereas white matter consists mainly of bundled axons

Compared to a cell with few aquaporins in its membrane, a cell containing many aquaporins will _____. have a faster rate of active transport have a higher water potential have a lower water potential have a faster rate of osmosis

have a faster rate of osmosis

juxtamedullary nephron vs. cortical nephron

juxtamedullary is longer and goes deeper into the inner medulla of the kidney

longer loop of Henle means:

more water absorption. beneficial in water

Isosmotic relative to environment experience:

no net water loss by osmosis

The glia present throughout the vertebrate brain or spinal cord that surround axons and speed up electrical signals are called __________. ANSWER oligodendrocytes Schwann cells astrocytes microglia all of the listed responses are correct

oligodendrocytes

In the pressure-flow mechanism, loading of sucrose from companion cells to sieve-tube elements takes place through _____. facilitated diffusion sucrose-H+ antiporters plasmodesmata sucrose-H+ symporters

plasmodesmata

One of the functions of the __________ is monitoring breathing centers in the medulla. ANSWER pons cerebrum hypothalamus thalamus cerebellum

pons

Most of our nitrogen-containing waste products are a result of __________. protein metabolism drug use consumption of foods high in nitrates, such as green vegetables the body's attempts to maintain pH homeostasis metabolism of fatty foods

protein metabolism

An increase in the size of the hindbrain of vertebrates has been associated with an increased ability in ____________. ANSWER rapid, complex movement reasoning olfaction vision hearing

rapid, complex movement

Taking illegal amphetamines ("speed") can induce symptoms similar to __________. ANSWER schizophrenia Parkinson's disease bipolar disorder Alzheimer's disease none of the listed responses is correct

schizophrenia

A neuron that transmits an impulse to the central nervous system after the neuron is stimulated by the environment is called a(n) __________. ANSWER sensory neuron motor neuron interneuron parasympathetic neuron sympathetic neuron

sensory neuron

Which term describes an area where sugars are used or stored? Sink Stomata Source Leaves

sink

Mycorrhizae are _____. structures that minimize water loss from leaves mutualistic associations between plant roots and fungi structures that promote self-pruning in plants mutualistic associations between plants and nitrogen-fixing bacteria a type of leaf found in perennial grasses

structures that minimize water loss from leaves

Water flows into the source end of a sieve tube because _____. water pressure outside the sieve tube forces in water sucrose has been actively transported into the sieve tube, making it hypertonic sucrose has been transported out of the sieve tube by active transport the companion cell of a sieve tube actively pumps in water

sucrose has been actively transported into the sieve tube, making it hypertonic

The solute most abundant in phloem sap is _____. sugar water minerals amino acids hormones

sugar

The developing embryonic brain is shaped by __________. ANSWER the selective elimination in neurons and synapses differences in the rates of blood vessel growth pressures exerted by the growing skull variations in the levels of nutrients received across the placenta an oxygen gradient that promotes growth where oxygen is most concentrated

the selective elimination in neurons and synapses

Long-term potentiation (LTP) involves lasting changes in ____________. ANSWER the strength of signal transmission across synapses the length of the axons the number of neurons the number of neuronal synapses the mass of the brain

the strength of signal transmission across synapses

Loss of water from the aerial parts of plants is called _____. gas exchange dehydration respiration transpiration

transpiration

Xerophytes minimize water loss by _____. reducing the thickness of the leaf cuticle using the CAM pathway having leaves with a large surface-to-volume ratio using the C3 pathway developing a Casparian strip between their leaves and stem

using the CAM pathway

Ignoring all other factors, what kind of day would result in the fastest delivery of water and minerals to the leaves of an oak tree? very hot, dry, windy day cool, humid day cool, dry day warm, humid day

very hot, dry, windy day

Which of the following is not moved out of or into the filtrate of a nephron through active transport by epithelial cells? Water Nutrients NaCl H+ K+

water

Which of the following statements is an accurate description of the evolution of the vertebrate brain? ANSWER Birds and mammals have evolved a proportionally larger forebrain than have other vertebrate groups. In humans, the midbrain occupies a larger proportion of the brain than it does in any other vertebrate group. Except for humans, vertebrates have maintained a relatively constant ratio of brain-to-body mass. Only mammals possess a forebrain, midbrain, and hindbrain. Regional specialization of the brain is apparent only in vertebrate groups that have proportionally smaller brains.

Birds and mammals have evolved a proportionally larger forebrain than have other vertebrate groups.

What is the source of the filtrate produced in Bowman's capsule? ANSWER Blood in capillaries Urine Lymphatic fluid Cells of the kidney The loop of Henle

Blood capillaries

An animal would lose water to its environment through osmosis under which set of conditions? ANSWER Body fluids of 400 mOsm/L in an environment of 1,000 mOsm/L Body fluids of 1,100 mOsm/L in an environment of 1,000 mOsm/L Body fluids of 1,000 mOsm/L in an environment of 1,000 mOsm/L Body fluids of 400 mOsm/L in an environment of 300 mOsm/L Body fluids of 900 mOsm/L in an environment of 500 mOsm/L

Body fluids of 400 mOsm/L in an environment of 1,000 mOsm/L

What characterizes the rates of photosynthesis and transport in a plant on a dry cloudy day? The photosynthesis rate is high and phloem transport rates are low. The photosynthesis rate is low and stomata are open. Both the photosynthesis and transpiration rates are high. Both the photosynthesis and transpiration rates are low.

Both the photosynthesis and transpiration rates are low.

Which of the following is caused by the death of neurons in the brain that release dopamine? ANSWER Parkinson's disease Schizophrenia Alzheimer's disease Major depressive disorder None of the listed responses is correct

Parkinson's disease

Which would be present in an animal with a nerve net? ANSWER Radial symmetry Nerves Fused ganglia Ganglia Central nervous system

Radial symmetry

Which of the following is an action brought about by the sympathetic division of the autonomic nervous system? ANSWER Relaxation of lung bronchi Increase in gallbladder activity Increase in salivation Constriction of pupils All of the listed responses are correct.

Relaxation of lung bronchi

Which of the following statements is an accurate description of animal cognition? ANSWER Some birds can understand abstract concepts such as numbers. Mammals are the only animals considered to have cognitive abilities. Cognition depends on a highly convoluted cerebral cortex. Cognition is primarily a result of processes occurring in the hippocampus. All species rely on the same brain region for cognition.

Some birds can understand abstract concepts such as numbers.

Which of the following supports the finding that sugar translocation in phloem is an active (energy-requiring) process? Strong pH differences exist between the cytoplasm of the companion cell and the mesophyll cell. Sucrose occurs in higher concentrations in companion cells than in the mesophyll cells where it is produced. Movement of water occurs from xylem to phloem and back again. ATPases are abundant in the plasma membranes of the mesophyll cells.

Sucrose occurs in higher concentrations in companion cells than in the mesophyll cells where it is produced.

Many people have a tendency to gorge on rich, fatty foods. How could such a preference have evolved? a. Most people find fatty foods tasty and satisfying. b. Fatty foods are very rich in calories and consuming them is an efficient way to gain weight. c. In ancestral hunter-gatherer communities, individuals with a tendency to gorge on such foods when available would have had a selective advantage.

c. In ancestral hunter-gatherer communities, individuals with a tendency to gorge on such foods when available would have had a selective advantage.

Consider a population whose growth can be described by the logistic growth model: dN/dt = rmaxN[(K − N)/K]. Which of the following statements about this population is true? a. At low values of N, the logistic growth and exponential growth (dN/dt = rN) models predict similar population growth. b. K is a constant value. c. rmax declines as N increases.

a. At low values of N, the logistic growth and exponential growth (dN/dt = rN) models predict similar population growth.

Which of the following animals is paired with the correct excretory system unit? ANSWER a. Bird; kidney b. Fish; metanephridia c. Insect; protonephridia d. Flatworm; Malpighian tubule e. Earthworm; protonephridia

a. Bird; kidney

What is the correct path of filtrate through a nephron of the kidney as it is processed into urine? ANSWER a. Bowman's capsule, proximal tubule, descending limb of loop of Henle, thin segment of ascending limb, thick segment of ascending limb, distal tubule, collecting duct b. Collecting duct, descending limb of loop of Henle, thick segment of ascending limb, thin segment of ascending limb, proximal tubule, distal tubule, Bowman's capsule c. Collecting duct, Bowman's capsule, descending limb of loop of Henle, thick segment of ascending limb, thin segment of ascending limb, proximal tubule, distal tubule d. Bowman's capsule, proximal tubule, distal tubule, descending limb of loop of Henle, thick segment of ascending limb, thin segment of ascending limb, collecting duct e. Proximal tubule, descending limb of loop of Henle, thick segment of ascending limb, thin segment of ascending limb, distal tubule, collecting duct, Bowman's capsule

a. Bowman's capsule, proximal tubule, descending limb of loop of Henle, thin segment of ascending limb, thick segment of ascending limb, distal tubule, collecting duct

In which of the following portions of a nephron of the mammalian kidney does the filtrate have the highest osmolarity? a. Descending limb of the loop of Henle in the inner medulla b. Bowman's capsule c. Proximal tubule d. Distal tubule e. Collecting duct in the cortex

a. Descending limb of the loop of Henle in the inner medulla

Which of the following causes Earth's seasons? a. Earth's tilt on its axis b. ocean currents c. changes in the Earth's distance from the sun d. vertical air circulation e. global wind patterns

a. Earth's tilt on its axis

Which of the following best illustrates ecological succession? a. Grass grows on a sand dune, is replaced by shrubs, and then by trees. b. Decomposition in soil releases nitrogen that plants can use. c. Introduced pheasants increase, and native quail populations disappear. d. A mouse eats seeds, and an owl eats the mouse. e. Overgrazing causes a nutrient loss from soil.

a. Grass grows on a sand dune, is replaced by shrubs, and then by trees.

Which of the following statements about a population experiencing logistic growth is true? a. If N is greater than K, the population will shrink. b. If N is less than K, the population will not grow. c. If the K and N values are similar, the amount of available resources is high. d. If the K and N values are far apart, the population will grow very slowly.

a. If N is greater than K, the population will shrink.

Which of the following have an excretory system that functions without a filtration step? a. Insects b. Flatworms c. Earthworms d. Marine fishes e. Freshwater fishes

a. Insects

Consider two old-growth forests: one is undisturbed while the other is being logged. In which region are species likely to experience exponential growth, and why? a. Logged, because the disturbed forest affords more resources for increased specific populations to grow. b. Logged, because the various populations are stimulated to a higher reproductive potential. c. Old growth, because each of the species is well established and can produce many offspring. d. Old growth, because of stable conditions that would favor exponential growth of all species in the forest.

a. Logged, because the disturbed forest affords more resources for increased specific populations to grow.

The bile salts _____. a. emulsify fats in the duodenum b. are enzymes c. are manufactured by the pancreas d. are normally an ingredient of gastric juice

a. emulsify fats in the duodenum

As filtrate passes through the long loop of Henle, salt is removed and concentrated in the interstitial fluid of the kidney medulla. Because of this high salt concentration, the nephron is able to __________. ANSWER a. establish a hyperosmotic interstitial medullary concentration b. excrete the maximum amount of salt c. neutralize toxins that might accumulate in the kidney d. control the pH of the interstitial fluid e. excrete a large amount of water

a. establish a hyperosmotic interstitial medullary concentration

In a well-fed human eating a Western diet, the richest source of stored chemical energy in the body is _____. a. fat in adipose tissue b. protein in muscle cells c. glycogen in muscle cells d. glucose in the blood

a. fat in adipose tissue

When a woman has her gallbladder removed, she should probably reduce her consumption of _____. a. fats b. proteins and carbohydrates c. carbohydrates d. proteins

a. fats

Allele frequencies in a gene pool may shift randomly and by chance. What is this random shift called? a. genetic drift b. gene flow c. directional selection

a. genetic drift

The bed of capillaries in a vertebrate kidney where water, urea, and salts are filtered out of the blood is the __________. a. glomerulus b. Bowman's capsule c. collecting duct d. loop of Henle e. proximal convoluted tubule

a. glomerulus

During exponential growth, a population always _____. a. grows at its maximum per capita rate b. cycles through time c. quickly reaches its carrying capacity d. loses some individuals to emigration

a. grows at its maximum per capita rate.

Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships? The fossil record reveals an increased incidence of _____. a. hard parts b. organic material c. worm burrows d. larger animals

a. hard parts

When climbing a mountain, we can observe transitions in biological communities that are analogous to the changes _____. a. in biomes at different latitudes b. across the United States from east to west c. in an ecosystem as it evolves over time d. in a community through different seasons

a. in biomes at different latitudes

Bile is produced by the _____ and stored by the _____ until it is secreted into the small intestine. a. liver ... gall bladder b. pancreas ... gall bladder c. liver ... pancreas d. gall bladder ... liver e. esophagus ... stomach

a. liver ... gall bladder

Plants must always compromise between _____ and _____. a. maximizing photosynthesis ... minimizing water loss b. maximizing water loss ... minimizing H+ protons c. maximizing access to light ... minimizing intake of CO2 d. maximizing transport of minerals ... minimizing transport of sugars e. maximizing water absorption ... minimizing leaf area

a. maximizing photosynthesis ... minimizing water loss

A population's carrying capacity a. may change as environmental conditions change. b. can never be exceeded. c. can be accurately calculated using the logistic growth model. d. generally remains constant over time. e. increases as the per capita growth rate (r) decreases.

a. may change as environmental conditions change.

Secretin stimulates the _____ to secrete _____. a. pancreas ... bicarbonate b. pancreas ... pancreatic enzymes c. small intestine ... disaccharidases d. stomach ... bicarbonate e. liver ... liver enzymes

a. pancreas ... bicarbonate

An enlarged cecum is typical of _____. a. rabbits, horses, and herbivorous bears b. tubeworms that digest via symbionts c. humans and other primates d. carnivorous animals

a. rabbits, horses, and herbivorous bears

Which of these traits is most strongly associated with the adoption of bipedalism? a. repositioning of foramen magnum b. enhanced depth perception c. shortened hind limbs d. opposable big toe

a. repositioning of foramen magnum

What is a likely outcome of a moderate disturbance, such as a severe thunderstorm? Select all that apply. a. Loss of an equilibrium state of balance, leading to a less healthy community b. Reduced species diversity within a community c. Patches of different habitats within the landscape

c. Patches of different habitats within the landscape.

Which of the following is the first step in allopatric speciation? a. genetic drift b. polyploidy c. geographic isolation d. hybridization e. formation of a reproductive barrier

c. geographic isolation

Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna? a. embryos b. bilateral symmetry c. hard parts d. true tissues

c. hard parts

Evolution works by _____. a. converging on a particular phenotype b. "tinkering" with existing structures c. predicting the future d. molding the environment to conform to the organisms living in it e. constantly increasing complexity

b. "tinkering" with existing structures

Cattle are able to survive on a diet consisting almost entirely of plant material because cattle _____. a. manufacture all fifteen amino acids out of sugars in the liver b. re-ingest their feces c. have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs d. are autotrophic

c. have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

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

If you were to jog one kilometer a few hours after lunch, which stored fuel would you probably tap? a. blood proteins b. fat stored in adipose tissue c. liver glycogen and muscle glycogen d. muscle proteins

c. liver glycogen and muscle glycogen

The mammalian trachea and esophagus both connect to the a. rectum. b. epiglottis. c. pharynx. d. stomach. e. large intestine.

c. pharynx

What do animals ranging from corals to monkeys have in common? a. number of embryonic tissue layers b. a mouth and an anus c. presence of Hox genes d. type of body symmetry

c. presence of Hox genes

Which of these was the second of the major events that stimulated an increase in the size of the human population? a. the bubonic plague b. the advent of agriculture c. the Industrial Revolution d. the discovery of antibiotics e. the discovery of vaccines

c. the Industrial Revolution

Which equation represents the logistic growth rate of a population? Which equation represents the logistic growth rate of a population? a. ΔNΔt=rN b. ΔNΔt=rmaxN c. ΔNΔt=rMmaxN(K−N)K d. r=b−d

c. ΔNΔt=rMmaxN(K−N)K

astrocytes

blood-brain barrier

Which of the following substances is generally filtered from the blood by the kidneys? ANSWER All of the listed responses are correct. Water Sodium Urea Glucose

All of the above

Which of the following would be most likely to increase for an amphibian moving from the aquatic habitat it occupies as a larva to the terrestrial habitat it occupies as an adult? ANSWER Energetic cost of excretion Volume of urine produced Osmotic water gain Excretion of salt Excretion of ammonia

Energetic cost of excretion

Which of the following contributes to learning and memory storage in the brain? ANSWER Excitatory neurotransmitters released from presynaptic neurons into synapses Repeated, weak stimulation of receiving neurons A decline in long-term potentiation A decreased concentration of calcium ions entering receiving neurons through calcium channels Inactivation of the AMPA glutamate receptor into the postsynaptic membrane

Excitatory neurotransmitters released from presynaptic neurons into synapses

Which of the following statements is an accurate description of sleep? ANSWER Humans cannot live without sleep. The brain is largely inactive during sleep. Sleep occurs only in terrestrial animals. The brain does not receive external stimuli during sleep. Scientists currently lack any tools with which to investigate sleep.

Humans cannot live without sleep.

Which of the following statements is an accurate description of biological clocks? ANSWER In an unchanging environment, there is little variation in the periodicity of the human biological clock. The consistency of a biological clock depends on sensory information indicating when it is day and night. In humans, daily activity cycles maintained by the biological clock are adjusted by the amygdala to match environmental conditions. A biological clock is an adaptation that first arose in vertebrates. Only humans have their physiology regulated by a biological clock.

In an unchanging environment, there is little variation in the periodicity of the human biological clock.

Which of the following would not normally pass into a nephron of the kidney as a component of the filtrate? ANSWER Lymphocytes Salts Glucose Vitamins Nitrogenous wastes

Lymphocytes

A physician friend of yours tells you about a patient with a head injury who suddenly stopped breathing during the examination. What portion of the brain was probably injured? ANSWER Medulla oblongata Cerebrum Cerebellum Hypothalamus Pituitary

Medulla oblongata

Fundamental Niche versus Realized niche

The fundamental niche is the entire set of conditions of an area that the animal is supposed to occupy. The realized niche is the set of conditions of an area that the animals does occupy presently.

Which of the following statements about the distribution of sap throughout a plant is true? The mechanism that explains the movement of sugars throughout a plant is called the pressure-flow hypothesis. Companion cells form the conducting tissue for sap. The driving force for sugar movement is transpiration. The main component of phloem sap is glucose.

The mechanism that explains the movement of sugars throughout a plant is called the pressure-flow hypothesis.

Keystone species's absence would cause a major disruption in a community. True or False?

True.

Which of the following is a tube that carries urine from the kidneys to the urinary bladder in a mammal? ANSWER Ureter Loop of Henle Urethra Distal tubule Proximal tubule

Ureter

Which of the following statements about xylem transport is true? The xylem cells that conduct water and minerals are alive. Water and minerals enter the xylem by diffusion. Water and minerals move through the root cortex into the xylem and upward through the stem and into leaves. All water transported by the xylem is used for photosynthesis in the leaves.

Water and minerals move through the root cortex into the xylem and upward through the stem and into leaves.

Select the accurate statement about water potential. Adding solutes to water increases water potential. Free water moves from a region of lower water potential to a region of higher water potential. Water in a turgid cell has positive pressure potential.

Water in a turgid cell has positive pressure potential.

If a plant's stomata are closed and no transpiration is occurring, which of the following predictions is accurate? Without transpiration, the plant's cells will become flaccid. Without transpiration, the plant will be water deficient. Without transpiration, less water will be absorbed from the soil.

Without transpiration, less water will be absorbed from the soil.

Which of the following is a correct statement about a difference between xylem and phloem transport? Which of the following is a correct statement about a difference between xylem and phloem transport? Transpiration moves phloem sap but not xylem sap. Xylem sap moves from sugar source to sink, but phloem sap does not. Active transport moves xylem sap but not phloem sap. Phloem carries water and minerals; xylem carries organic molecules. Xylem sap moves up; phloem sap moves up or down.

Xylem sap moves up; phloem sap moves up or down.

Which of the following may result from resource partitioning? Select all that apply. a. Competing species may partition time, feeding at different times of day. b. A population's fundamental niche may be smaller than its realized niche. c. A population may have a smaller realized niche when it coexists with a competitor.

a and c

Which animal would most likely be an osmoconformer? a. Starfish (sea star) b. Sea trout c. Cane toad d. Seagull e. All of the listed responses are correct.

a. Starfish (sea star)

Which type of organism would have the least chance of long-term survival in the given environment? a. Stenohaline animals that move between fresh water and seawater b. Osmoconformers in seawater c. Euryhaline animals in fresh water d. Osmoregulators in seawater e. Euryhaline animals in seawater

a. Stenohaline animals that move between fresh water and seawater

True or false? Factors that determine the per capita rate of increase of a population include the age of breeding and the number of offspring produced each year. a. True b. False

a. True

What is a biome? a. a major type of ecosystem b. a specific set of abiotic factors c. a set of similar communities d. a major type of biosphere e. an area with a uniform distribution of organisms and abiotic environmental conditions

a. a major type of ecosystem

To survive, all animals must _____. a. balance consumption of food with use and storage of nutrients b. have a complete digestive system c. hibernate d. ingest nutrients from the environment every day of their lives e. digest plant material

a. balance consumption of food with use and storage of nutrients

The "essential nutrients" for proper human nutrition include _____. a. calcium, sodium, potassium, and other minerals b. cellulose c. all of the amino acids d. glucose e. active enzymes from plants and/or animals

a. calcium, sodium, potassium, and other minerals

Different types of food are eaten by various groups of animals, but it is usually true that _____. a. cellulose digestion in ruminant mammals occurs before the ingested foods reach the small intestine b. the intestines of carnivores tend to be longer than the intestines of herbivores of similar overall body size c. many carnivorous vertebrates house large populations of symbiotic bacteria and protists in special fermentation chambers in their stomachs d. animals typically produce enzymes that hydrolyze cellulose e. the teeth of herbivores tend to be sharper than the teeth of carnivores

a. cellulose digestion in ruminant mammals occurs before the ingested foods reach the small intestine

Which of the following choices includes all of the others in creating global terrestrial climates? a. differential heating of Earth's surface b. Earth's rotation on its axis c. global wind patterns d. ocean currents

a. differential heating of Earth's surface

Generalized global air circulation and precipitation patterns are caused by _____. a. rising, warm, moist air masses that cool and release precipitation as they rise and then, at high altitude, cool and sink back to the surface as dry air masses after moving north or south of the tropics b. the revolution of Earth around the sun c. polar, cool, moist high-pressure air masses from the poles that move along the surface, releasing precipitation along the way to the equator, where they are heated and dried d. air masses that are dried and heated over continental areas that rise, cool aloft, and descend over oceanic areas followed by a return flow of moist air from ocean to land, delivering high amounts of precipitation to coastal areas

a. rising, warm, moist air masses that cool and release precipitation as they rise and then, at high altitude, cool and sink back to the surface as dry air masses after moving north or south of the tropics

The pathway that a nervous signal travels in completing a typical vertebrate reflex is ____________. ANSWER a. sensors; sensory neurons; interneurons of the spinal cord; motor neuron b. sensors; sensory neurons; interneurons of the spinal cord; brain; motor neuron c. brain; motor neuron; interneurons of the spinal cord; sensory neurons d. brain; interneurons of the spinal cord; motor neurons; sensory neurons; sensors e. sensors; interneurons of the spinal cord; motor neurons; sensory neurons; brain

a. sensors; sensory neurons; interneurons of the spinal cord; motor neuron

The principle of competitive exclusion states that a. two species that have exactly the same niche cannot coexist in a community. b. competition in a population promotes survival of the best-adapted individuals. c. competition between two species always causes extinction or emigration of one species. d. two species cannot coexist in the same habitat. e. two species will stop reproducing until one species leaves the habitat.

a. two species that have exactly the same niche cannot coexist in a community.

The opening of stomata is thought to involve _____. active transport of water out of the guard cells movement of K+ from the guard cells decreased turgor pressure in guard cells an increase in the solute concentration of the guard cells

an increase in the solute concentration of the guard cells

All of the following processes occur in the nephron of the kidney except ________. ANSWER blood cell formation tubular secretion capsular filtration cellular respiration selective reabsorption

blood cell formation

Select the correct statement(s) about a terrestrial food chain. Select all that apply. a. Energy is transferred from decomposers to plants to herbivores to carnivores. b. About 1% of the energy stored in producers is converted to organic matter at the secondary consumer level. c. The total biomass of the top trophic level is greatest because the top consumers are large.

b. About 1% of the energy stored in producers is converted to organic matter at the secondary consumer level.

Which of the following statements about density-independent growth is true? a. Density-independent growth can continue indefinitely in nature. b. Density-independent growth is also known as exponential growth. c. A population that is experiencing density-independent growth levels off at the environment's carrying capacity. d. The per-capita rate of increase may exceed rmax during density-independent growth.

b. Density-independent growth is also known as exponential growth.

Select the correct statement about the global carrying capacity for the human population. a. The global carrying capacity for the human population is limitless because technological advances allow food supply to keep up with global population growth. b. Estimates of the global carrying capacity for the human population depend on resource use per capita. c. It is impossible to calculate the global carrying capacity for the human population.

b. Estimates of the global carrying capacity for the human population depend on resource use per capita.

Which of the following statements describing hominin evolution is/are correct? Select all that apply. a. The first hominin species evolved from chimpanzees. b. Homo sapiens is the only surviving member of a highly branched evolutionary tree of hominin species. c. Hominin species began to walk on two legs in order to free their hands to use tools.

b. Homo sapiens is the only surviving member of a highly branched evolutionary tree of hominin species.

Which of the following statements about human population in industrialized countries is incorrect? a. The survivorship curve is Type I. b. Life history is r-selected. c. Age distribution is relatively uniform. d. The population has undergone the demographic transition. e. Average family size is relatively small.

b. Life history is r-selected.

Bacteria in the human gut are which of the following? a. all pathogens b. both pathogens and mutualists c. all mutualists

b. both pathogens and mutualists

In a healthy person, after a large meal, the production of _____ will increase. After fasting, the production of _____ will increase. a. trypsin; trypsinogen b. insulin; glucagon c. glucagon; glucose d. glucagon; pepsinogen

b. insulin; glucagon

Which pair of terms most accurately describes life history traits for a stable population of wolves? a. semelparous; r-selected b. iteroparous; K-selected c. semelparous; K-selected d. iteroparous; N-selected e. iteroparous; r-selected

b. iteroparous; K-selected

Given that early land plants most likely share a common ancestor with green algae, the earliest land plants were most likely _____. a. species that did not exhibit alternation of generations b. nonvascular plants that grew leafless, photosynthetic shoots c. plants with well-developed leaves d.vascular plants with well-defined root systems

b. nonvascular plants that grew leafless, photosynthetic shoots

Over-the-counter medications for acid reflux or heartburn block the production of stomach acid. Which of the following cells are directly affected by this medication? a. goblet cells b. parietal cells c. chief cells d. smooth muscle cells

b. parietal cells

In the models that describe population growth, r stands for _____. a. a time interval b. per capita population growth rate c. carrying capacity d. total number of individuals in the population e. population density

b. per capita population growth rate.

In the digestive system, peristalsis is _____. a. the transport of nutrients to the liver through the hepatic portal vessel b. smooth muscle contractions that move food along the esophagus c. a process of fat emulsification in the small intestine d. voluntary control of the rectal sphincters regulating defecation

b. smooth muscle contractions that move food along the esophagus

Which of the following might be an investigation of microclimate? a. competitive interactions between various species of songbirds during spring migration b. the effect of sunlight intensity on species composition in a decaying rat carcass c. the effect of ambient temperature on the onset of caribou migration d. the seasonal population fluctuation of nurse sharks in coral reef communities

b. the effect of sunlight intensity on species composition in a decaying rat carcass

What is the importance of consuming an adequate amount of proteins in the diet? a. Proteins are necessary to produce urea and other important metabolites. b. They are most commonly used to meet energy demands of cells. c. Proteins serve a variety of functions, and the body does not store excess quantities of protein. d. They are used as cofactors for metabolic reactions and are required in minute quantities.

c. Proteins serve a variety of functions, and the body does not store excess quantities of protein.

Which aspects of a region's climate have the most impact on plants and animals? a. Moisture and wind. b. Sunlight and wind. c. Temperature and moisture. d. Soil composition and temperature.

c. Temperature and moisture

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 evolution has occurred within an unbranched lineage. c. The upright posture and enlarged brain of humans evolved separately. d. Human ancestors were virtually identical to extant chimpanzees.

c. The upright posture and enlarged brain of humans evolved separately.

Currently, how large is the worldwide population of humans relative to Earth's carrying capacity for humans? a. at the carrying capacity b. above the carrying capacity c. There is insufficient information to answer this question. d. below the carrying capacity e. either at or above the carrying capacity

c. There is insufficient information to answer this question.

Birth defects of the neural tube in humans _____. a. can be prevented by ingestion of more vitamin A during the periconception interval b. are not affected by nutritional considerations during pregnancy c. are reduced from about 6% without folic acid supplements in the periconception interval to about 1% when the supplements were taken d. result from excess sodium in the pregnant woman's diet e. are typically seen in 10-20% of male babies born in well-developed countries

c. are reduced from about 6% without folic acid supplements in the periconception interval to about 1% when the supplements were taken

Of the following, which is the most inclusive level of organization in nature? a. community b. cell c. biosphere d. population e. ecosystem

c. biosphere

According to the principle of competitive exclusion, two species cannot continue to occupy the same _____. a. range b. biome c. ecological niche d. territory e. environmental habitat

c. ecological niche

The term used to describe a harmless organism resembling a harmful one is _____. a. warning coloration b. aposematic coloration c. Müllerian mimicry d. Batesian mimicry e. cryptic coloration

d. Batesian mimicry

What are rain shadows? a. Dry regions on the windward side of mountain ranges. b. Wet regions on the leeward side of mountain ranges. c. Wet regions on the windward side of mountain ranges. d. Dry regions on the leeward side of mountain ranges.

d. Dry regions on the leeward side of mountain ranges.

The pancreas is involved in the digestion of _____. I) protein II) fat III) nucleic acids IV) carbohydrates a. I and III b. I, II, and IV c. II, III, and IV d. I, II, III, and IV

d. I, II, III, and IV

Which factor does not affect a habitat's carrying capacity? a. Number of nesting sites. b. Availability of food. c. Intensity of predation. d. Maximum number of individuals in a population.

d. Maximum number of individuals in a population.

Under which of the following conditions would a population most likely experience exponential growth? a. Large number of individuals in the starting population. b. Environment with a low carrying capacity. c. Habitat with limited resources. d. Young populations with few individuals.

d. Young populations with few individuals.

Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids. Both digestive processes __________. a. consume ATP b. require a low pH resulting from HCl production c. occur inside cells in most animals d. add a water molecule to break bonds

d. add a water molecule to break bonds

The _____ is the most efficient route of water movement in plants, while the _____ is the most select. a. transmembrane: symplast b. symplast apoplast c. apoplast: symplast d. apoplast: transmembrane

d. apoplast; transmembrane

Which level of ecological study focuses the most on abiotic factors? a. speciation ecology b. population ecology c. community ecology d. ecosystem ecology

d. ecosystem ecology

All protists are _____. a. unicellular b. symbionts c. mixotrophic d. eukaryotic

d. eukaryotic

As climate changes because of global warming, plant species' ranges in the northern hemisphere may move northward. The trees that are most likely to avoid extinction in such an environment are those that _____. a. produce well-provisioned seeds b. have seeds that become viable only after a forest fire c. disperse many seeds in close proximity to the parent tree d. have seeds that are easily dispersed by wind or animals

d. have seeds that are easily dispersed by wind or animals.

Which of the following is not a major activity of the stomach? a. enzyme secretion b. mucus secretion c. mechanical digestion d. nutrient absorption e. HCl secretion

d. nutrient absorption

When an animal cell is placed in a hypotonic solution and water enters the cell via osmosis, the volume of the cell increases until it bursts. This does not happen to plant cells, because _____. a. they have large central vacuoles, which provide abundant space for storage of incoming water b. certain gated channel proteins embedded in their plasma membranes open as osmotic pressure decreases, allowing excess water to leave the cell c. they have cell walls, which prevent the entry of water by osmosis d. they have cell walls, which provide pressure to counteract the pressure of the incoming water

d. they have cell walls, which provide pressure to counteract the pressure of the incoming water

In most cases, the two major climatic factors affecting the distribution of organisms in terrestrial ecosystems are _____. a. temperature and sunlight b. competitors and predators c. wind and water d. water and temperature e. predators and parasites

d. water and temperature

In humans, the frontal lobe of the brain handles functions associated with ____________. ANSWER decision making language comprehension hearing coordination of movement homeostasis

decision making

Which of the following neurotransmitters is most closely associated with schizophrenia, addiction, and Parkinson's disease? ANSWER Dopamine β-amyloid Glutamate Amphetamine None of the listed responses is correct.

dopamine

Osmoregulation in a freshwater fish would not include ___________. ANSWER drinking large amounts of water gaining water and some ions in food uptake of salt ions by gills osmotic water gain through gills excreting salt ions and large amounts of water in dilute urine

drinking large amounts of water

The limbic system is involved in __________. ANSWER emotion and memory speech and hearing vision sleep and wakefulness control of heartbeat and respiration

emotion and memory

Which tissue acts as a filter on the water absorbed by root hairs? Vascular tissue Epidermis Cortex Endodermis

endodermis

What is the main force by which most of the water within xylem vessels moves toward the top of a tree? osmosis in the root active transport of ions into the stele the force of root pressure evaporation of water through stoma

evaporation of water through stoma

The water lost during transpiration is a side effect of the plant's exchange of gases. However, the plant derives some benefit from this water loss in the form of _____. increased turgor and increased growth mineral transport and increased growth evaporative cooling and increased turgor evaporative cooling and mineral transport

evaporative cooling and mineral transport

Chloride cells in the gills of marine bony fishes play a role in which step of excretory system function? ANSWER Excretion Filtration Reabsorption Secretion All of the listed responses are correct.

excretion

Individuals suffering from bipolar disorder ____________. ANSWER experience periods of increased energy, overtalkativeness, and increased risk taking typically develop multiple personalities lack effective treatment options experience loss of motor control comprise 10% of the world's population

experience periods of increased energy, overtalkativeness, and increased risk taking

True or false? Root pressure can move water a long distance up the xylem because of the higher water potential of the xylem in comparison to the water potential in the surrounding cells. True False

false

In humans, the part of the brain that increases in size and complexity most significantly during the second and third month of embryonic development is derived from the embryonic __________. ANSWER forebrain forebrain and midbrain midbrain midbrain and hindbrain hindbrain

forebrain

One out of 10,000 babies born in North America is affected by cystic fibrosis, a recessive condition. Assuming that the North American human population is in Hardy-Weinberg equilibrium for this trait, what percentage of the population is heterozygous for this trait? (Remember the equation for a population in Hardy-Weinberg equilibrium: p2 + 2pq + q2 = 1.) a. 2% b. 0.01% c. 1%

a. 2%

Use the following description to answer the question(s) below. On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. Which two of the following have operated to increase divergence between mosquitofish populations on Andros? 1. improved gene flow 2. bottleneck effect 3. sexual selection 4. founder effect 5. natural selection 3 and 5 1 and 3 2 and 3 2 and 4

a. 3 and 5

The predatory bacterium Bdellovibrio bacteriophorus drills into a prey bacterium and, once inside, digests it. In an attack upon a Gram-negative bacterium that has a slimy cell covering, what is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey's cytoplasm? 1. membrane composed mostly of lipopolysaccharide 2. membrane composed mostly of phospholipids 3. peptidoglycan 4. capsule a. 4, 1, 3, 2 b. 1, 3, 4, 2 c. 2, 4, 3, 1 d. 1, 4, 3, 2

a. 4, 1, 3, 2

Identify the features that distinguish animals from organisms in other multicellular kingdoms. Select all that apply. a. Animals are ingestive heterotrophs. b. Animals have sensory organs at their anterior end. c. Animals are motile.

a. Animals are ingestive heterotrophs.

Endosymbiosis is an evolutionary theory that explains the origin of eukaryotes and suggests a specific order in which this might have occurred. Ancestral cells engulfed and then began to use the metabolic processes of the smaller cells. Based on shared core processes and features, which statement most accurately describes the order, the theory and the evolutionary implications for all organisms within domain Eukarya? a. As Earth was becoming more aerobic, mitochondria would have provided an advantage to host cells by converting "toxic" oxygen into energy for heterotrophic cells. Since mitochondria are found in all eukaryotes, these combinations likely evolved first. Photosynthetic eukaryotes probably acquired an autotrophic prokaryote, which developed an advantageous symbiotic relationship with the host cell. b. Ancestral heterotrophic eukaryotes most likely engulfed both a heterotrophic and an autotrophic prokaryote, whereas ancestral photosynthetic eukaryotes probably provided the host cell for the first mitochondria. Over time, natural selection favored these relationships and these cells became ancestors of all eukaryotes. c. All ancestral eukaryotes would have most likely consumed a nucleus-like prokaryote that eventually became the eukaryotic nucleus. These new eukaryotic cells would have had an advantage over prokaryotic cells by acquiring a nuclear command center for regulating cellular activities. d. As carbon dioxide levels were increasing over time, natural selection would have favored organisms that acquired a photosynthetic prokaryote to convert carbon dioxide into sugars. These would have likely been the first eukaryotic cells. At which point, these ancestral cells engulfed mitochondria-like prokaryotes that would have provided an even greater advantage for cells in this environment.

a. As Earth was becoming more aerobic, mitochondria would have provided an advantage to host cells by converting "toxic" oxygen into energy for heterotrophic cells. Since mitochondria are found in all eukaryotes, these combinations likely evolved first. Photosynthetic eukaryotes probably acquired an autotrophic prokaryote, which developed an advantageous symbiotic relationship with the host cell.

One hypothesis that has been proposed regarding the origin of life suggests that life evolved from an "RNA world" to todays "DNA world." Considering the properties of RNA and DNA molecules, which questions would direct an investigation of the most insightful test(s) of this hypothesis? a. Could RNA have provided a template for DNA assembly, thereby enabling a more stable molecule that is replicated more accurately? b. Is it likely that RNA molecules functioned as ribozymes to synthesize DNA from amino acids, and that this role was reversed when DNA became the information source? c. Is it likely that simple, yet stable RNA molecules served as a primitive precursor to a less stable DNA molecule that was more capable of storing more information? d. Since ribozymes could freely enter and leave the vesicles, could these molecules have brought external DNA into the cell as a less stable, but more reliable storage molecule of double-stranded DNA?

a. Could RNA have provided a template for DNA assembly, thereby enabling a more stable molecule that is replicated more accurately?

Select the correct statement(s) about animal body plans. Select all that apply. a. Development in all animals is determined by the unique family of Hox genes (or other similar homeobox genes). b. All triploblastic animals possess a coelom. c. In both protostomes and deuterostomes, the blastopore develops into the mouth.

a. Development in all animals is determined by the unique family of Hox genes (or other similar homeobox genes).

Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth. Which of these questions is currently the most problematic and would have the greatest impact on our understanding if we were able to answer it? a. How did RNA sequences come to carry the code for amino acid sequences? b. How could polymers involving lipids and/or proteins form membranes in aqueous environments? c. How can RNA molecules act as templates for the synthesis of complementary RNA molecules? d. How can amino acids, simple sugars, and nucleotides be synthesized abiotically?

a. How did RNA sequences come to carry the code for amino acid sequences?

How does diploidy help to preserve genetic variation? a. It allows recessive alleles that may not be favored in the current environment to be preserved in the gene pool by propagation in heterozygotes. b. It restricts the gene pool by chance events such as floods or other catastrophic events. c. It helps individual organisms make a greater contribution to the gene pool of the next generation. d. It allows the frequency of a recessive allele in a population to be predicted under certain conditions. e. It fosters the exchange of genes between different populations.

a. It allows recessive alleles that may not be favored in the current environment to be preserved in the gene pool by propagation in heterozygotes.

What is true of microevolution? a. It is the kind of evolution that can change the relative abundance of a particular allele in a gene pool over the course of generations. b. It is evolution that involves only tiny changes to DNA, such as point mutations, producing only small (if any) changes to phenotype. c. It is evolution that is restricted to individual organisms. d. It is evolution that results in the origin of small numbers of new species. e. It is evolution that influences only a small subset of the populations that comprise a species.

a. It is the kind of evolution that can change the relative abundance of a particular allele in a gene pool over the course of generations.

Which statement about natural selection on early Earth is correct? a. Natural selection could act on a population of proto-cells on early Earth, selecting for those that were stable and had self-replicating, catalytic RNA that allowed them to grow and divide to produce similar daughter proto-cells. b. Natural selection could only act on populations of living organisms that had DNA as their genetic material. c. Natural selection acted on populations of proto-cells on early Earth in order to make them more like modern living cells that have DNA as their genetic material.

a. Natural selection could act on a population of proto-cells on early Earth, selecting for those that were stable and had self-replicating, catalytic RNA that allowed them to grow and divide to produce similar daughter proto-cells.

Why do some scientists believe that RNA, rather than DNA, was the first genetic material? a. RNA has both information storage and catalytic properties. b. RNA could have evolved into DNA. c. All the proto-cells on early Earth contained RNA. d. RNA can replicate more accurately than DNA. e. RNA contains uracil in place of thymine

a. RNA has both information storage and catalytic properties.

Which of the following statements supports the hypothesis of "an RNA world" on early Earth? a. Some RNA molecules are important catalysts in modern cells. b. The oldest known fossils contain traces of RNA molecules. c. Single-stranded RNA molecules are linear and cannot form three-dimensional shapes.

a. Some RNA molecules are important catalysts in modern cells.

According to the endosymbiotic theory, why was it adaptive for the larger (host) cell to keep the engulfed cell alive, rather than digesting it as food? a. The engulfed cell provided the host cell with adenosine triphosphate (ATP). b. The host cell was able to survive anaerobic conditions with the engulfed cell alive. c. The engulfed cell provided the host cell with carbon dioxide. d. The engulfed cell allowed the host cell to metabolize glucose.

a. The engulfed cell provided the host cell with adenosine triphosphate (ATP).

Whatever its ultimate cause(s), the Cambrian explosion is a prime example of _____. a. adaptive radiation b. a large meteor impact c. evolutionary stasis d. mass extinction

a. adaptive radiation

House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of _____. a. allopatric speciation b. prezygotic isolation c. reinforcement d. sympatric speciation

a. allopatric speciation

Which of these primate groups is most closely related to humans? a. apes b. Old World monkeys c. lorises d. prosimians e. New World monkeys

a. apes

Two animals are considered members of different species if they _____. a. cannot mate and produce viable, fertile offspring b. look different c. are geographically isolated d. live in different habitats e. are members of different populations

a. cannot mate and produce viable, fertile offspring

Which of the following would you classify as something other than an animal? a. choanoflagellates b. sponges c. jellyfish d. coral

a. choanoflagellates

A researcher is trying to construct a molecular-based phylogeny of the entire animal kingdom. Assuming that none of the following genes is absolutely conserved, which of the following would be the best choice on which to base the phylogeny? a. collagen genes b. β-catenin genes c. genes involved in chitin synthesis d. genes involved in eye-lens synthesis

a. collagen genes

Use the following description to answer the question(s) below. On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about two hundred miles away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about fourteen million years ago. Using only the information provided in the paragraph, which of the following is the best initial hypothesis for how D. santomea descended from D. yakuba? a. habitat differentiation b. allopolyploidy c. sexual selection d. autopolyploidy

a. habitat differentiation

The original source of all genetic variation is _____. a. mutation b. independent assortment c. sexual reproduction d. recombination e. natural selection

a. mutation

What is the only evolutionary mechanism that consistently leads to adaptive evolution? a. natural selection b. neutral variation c. the bottleneck effect d. genetic drift e. gene flow

a. natural selection

Which of the following statements about hominin evolution is correct? As hominins have evolved, _____. a. sexual dimorphism was significantly reduced b. canine teeth have increased in size c. the foramen magnum has shifted farther back on the skull d. jaw size has increased e. they have developed longer fingers

a. sexual dimorphism was significantly reduced

Jams, jellies, preserves, honey, and other foods with high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment ____. a. undergo death as a result of water loss from the cell b. are unable to swim through these thick and viscous materials c. are obligate anaerobes d. are unable to metabolize the glucose or fructose, and thus starve to death

a. undergo death as a result of water loss from the cell

Use the information in the following paragraph to answer the question(s) below. A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. This bacterium's ability to survive in a human who is taking penicillin pills may be due to the presence of _____. 1. penicillin-resistance genes 2. a secretory system that removes penicillin from the cell 3. a Gram-positive cell wall 4. a Gram-negative cell wall 5. an endospore a. 2 or 3 b. 2, 4, or 5 c. 4 or 5 d. 1 or 5

b. 2, 4, or 5

Every few years a giant axe chops off the head of every person who is over 6 feet tall. How will this affect the human population? a. Gene flow will increase. b. Alleles that promote "tallness" will decrease in frequency. c. The mutation rate will increase. d. It will increase in number since shorter people use fewer resources than taller people. e. Genetic drift will play less of a role in the evolution of humans.

b. Alleles that promote "tallness" will decrease in frequency.

The earliest ancestors of about half of all extant animal phyla can be traced back to the _____ explosion. a. Carboniferous b. Cambrian c. Jurassic d. Devonian e. Pleistocene

b. Cambrian

Which feature of deuterostome development explains the formation of identical human twins? a. In deuterostomes, the blastopore becomes the anus. b. Deuterostomes have indeterminate development. c. Deuterostomes have radial cleavage.

b. Deuterostomes have indeterminate development.

Which of the following is the correct sequence of events in the origin of life? I. formation of protobionts II. synthesis of organic monomers III. synthesis of organic polymers IV. formation of DNA-based genetic systems a. I, III, II, IV b. II, III, I, IV c. II, III, IV, I d. I, II, III, IV

b. II, III, I, IV

Which of these is an example of temporal isolation? a. One species is found only in New York, the other only in London. b. One species is nocturnal, and the other species is not. c. The average weight of the individuals in one species is 45 kg; in the other species the average is 290 kg. d. One species performs a specific courtship dance. the other species does not. e. One is a type of primate, the other is a type of marsupial.

b. One species is nocturnal, and the other species is not.

What is the key difference between a coelom and a pseudocoelom? a. Pseudocoeloms arose early in animal evolution and evolved into coeloms. b. Only a coelom is fully lined with mesoderm tissue. c. A coelom is a true body cavity, whereas a pseudocoelom is a false coelom that is not fully functional.

b. Only a coelom is fully lined with mesoderm tissue.

_____ are the oldest known primate group. a. Apes b. Prosimians c. Anthropoids d. Hominids e. Monkeys

b. Prosimians

Which of the following is true of generalized bacteriophage transduction? a. The bacteriophage must enter the lysogenic cycle. b. The bacteriophage packages fragments of bacterial DNA into new phage particles. c. The bacteriophage chromosome has a region homologous to the bacterial chromosome.

b. The bacteriophage packages fragments of bacterial DNA into new phage particles.

The fruit fly Drosophila melanogaster has an allele that confers resistance to DDT and similar insecticides. Laboratory strains of D. melanogaster have been established from flies collected in the wild in the 1930s (before the widespread use of insecticides) and the 1960s (after 20 years of DDT use). Lab strains established in the 1930s have no alleles for DDT resistance. In lab strains established in the 1960s, the frequency of the DDT-resistance allele is 37%. Which statement is correct? a. Resistance to DDT evolved in some fruit flies in order to allow them to survive. b. The evolutionary fitness associated with the heritable trait of DDT resistance changed once DDT use became widespread. c. Alleles for DDT resistance arose by mutation during the period of DDT use because of selection for pesticide resistance.

b. The evolutionary fitness associated with the heritable trait of DDT resistance changed once DDT use became widespread.

How long does it take new species to form on Earth? a. millions of years b. The time required varies considerably. c. Speciation no longer takes place on Earth.

b. The time required varies considerably.

Which statement correctly describes the role of chance in evolution? a. Evolution by natural selection proceeds by an accumulation of changes that occur by chance. b. The ultimate source of new alleles is mutation, random changes in the nucleotide sequences of an organism's DNA. c. An allele that increases evolutionary fitness cannot be lost from a population by chance events.

b. The ultimate source of new alleles is mutation, random changes in the nucleotide sequences of an organism's DNA.

How are two different species most likely to evolve from one ancestral species? a. sympatrically, by a point mutation affecting morphology or behavior b. allopatrically, after the ancestral species has split into two populations c. allopatrically, due to extensive inbreeding d. sympatrically, due to extensive inbreeding

b. allopatrically, after the ancestral species has split into two populations

Radiometric dating _____. a. can be used to directly date fossils in sedimentary rock b. allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata c. allows us to determine an absolute, errorless date d. relies on the fact that the daughter isotope decays to the parent isotope at a constant rate e. only works on rocks younger than 75,000 years

b. allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata

A hybrid zone is properly defined as _____. a. an area where members of two closely related species intermingle, but gene flow is prevented by prezygotic barriers b. an area where mating occurs between members of two closely related species, producing viable offspring c. a zone where sterile hybrids form, kept separate by postzygotic barriers d. an area where the ranges of two closely related species overlap, but do not interbreed

b. an area where mating occurs between members of two closely related species, producing viable offspring

The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet again and _____. a. a decreasing number of viable, fertile hybrids is produced over the course of the next one hundred generations b. an increasing number of viable, fertile hybrids is produced over the course of the next one hundred generations c. no reproduction occurs in the hybrid zone d. an increasing number of infertile hybrids is produced over the course of the next one hundred generations

b. an increasing number of viable, fertile hybrids is produced over the course of the next one hundred generations

The following question are based on the observation that several dozen different proteins comprise the prokaryotic flagellum and its attachment to the prokaryotic cell, producing a highly complex structure. If the complex protein assemblage of the prokaryotic flagellum arose by the same general processes as those of the complex eyes of molluscs (such as squids and octopi), then _____. a. neither eyes nor flagella could have arisen by evolution because both are too complex to have evolved b. ancestral versions of this protein assemblage were either less functional or had different functions than modern prokaryotic flagella c. natural selection cannot account for the rise of the prokaryotic flagellum d. the need for more complex structure must have driven evolution

b. ancestral versions of this protein assemblage were either less functional or had different functions than modern prokaryotic flagella

The oldest fossils usually _____. a. are found in sediments formed during the Cenozoic era b. are found in the deepest strata c. contain more radioactive isotopes than younger fossils d. have the longest half-lives e. are found above younger fossils

b. are found in the deepest strata

A certain species of salamander was split into two populations by a wide, dry valley, and the populations began to diverge from each other. After a period of time, some members of the two populations began to interbreed in a hybrid zone at the southern end of the valley. Only weak reproductive barriers existed by this time, so the two populations could freely interbreed and re-establish gene flow. This outcome in a hybrid zone is known as _____. a. stability b. fusion c. reinforcement d. speciation e. punctuated equilibrium

b. fusion

If an organism has a relatively large number of Hox genes in its genome, it most likely _____. a. has Hox genes expressed in all cells of its body b. has a relatively complex anatomy c. has multiple paired appendages along the length of its body d. belongs to one of the first groups to evolve on Earth

b. has a relatively complex anatomy

Use the following information to answer the question(s) below. Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees. The two populations are _____. a. different species, under the phylogenetic species concept b. not different species, under the biological species concept c. different species, under the biological species concept

b. not different species, under the biological species concept

The approach to estimating phylogenetic trees is most like the approach of which species concept? a. biological species concept b. phylogenetic species concept c. morphological species concept

b. phylogenetic species concept

Most causes of speciation are relatively slow, in that they may take many generations to see changes, with the exception of _____. a. reinforcement b. polyploidy c. colonization d. natural selection

b. polyploidy

Among protostomes, which morphological trait has shown the most variation? a. number of embryonic tissue types (diploblasty vs. triploblasty) b. type of body cavity (coelom vs. pseudocoelom vs. no coelom) c. type of development (protostome vs. deuterostome) d. type of symmetry (bilateral vs. radial vs. none)

b. type of body cavity

The atmosphere of early Earth probably contained no O2 until the emergence of organisms that _____. a. had chloroplasts b. used water as an electron source for photosynthesis c. used hydrogen sulfide as an energy source d. were oxygen respiring e. were chemoautotrophic

b. used water as an electron source for photosynthesis

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. 0.09 c. 0.42 d. 0.49 e. 0.21

c. 0.42

Use the information in the following paragraph to answer the question(s) below. A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. In which feature(s) should one be able to locate a complete chromosome of this bacterium? 1. nucleolus 2. prophage 3. endospore 4. nucleoid a. 4 only b. 2 and 3 c. 3 and 4 d. 1 and 3

c. 3 and 4

For many years scientists believed that almost all animal lineages burst into being during the Cambrian era (just after the end of the Precambrian super eon). However, there have been many recent findings of animal-like fossils and "trace fossils" (fossils of an animal-like organisms movement) from the late Precambrian. Which of the following best explains why it took so long to realize there was animal-like life in the Precambrian? a. There were very few animals during this period. b. The global climate was such that there was poor fossilization in the Precambrian. c. Animals from the late Precambrian had soft bodies. d. There were many hard-shelled animals in the Cambrian.

c. Animals from the late Precambrian had soft bodies.

An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival? a. It has an endospore. b. It relies on photosystems that float freely in its cytosol. c. It engulfs organic material by phagocytosis or by absorption. d. It must have gained extra mitochondria when it lost its plastids.

c. It engulfs organic material by phagocytosis or by absorption.

The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when they mate among themselves, they are rarely successful in producing offspring. What can you infer from this information? a. The hybrids form a separate species under the biological species concept. b. These two species are likely in the process of fusing back into one species. c. Postzygotic isolation exists between the two frog species. d. Prezygotic isolation exists between the two frog species.

c. Postzygotic isolation exists between the two frog species.

A paleontologist finds a new tyrannosaur in a site she is excavating, and wishes to date the fossil. What is the most likely method she will use? a. She will measure the amount of the radioisotope uranium-238 in the stratum where she found the tyrannosaur. b. She will determine the fossil's age by measuring the ratio of carbon-14 to carbon-12 in the fossil. c. She will infer the age of the fossil by dating layers of volcanic rock above and below the stratum containing the fossil.

c. She will infer the age of the fossil by dating layers of volcanic rock above and below the stratum containing the fossil.

Select the correct statement about the evolution of animals. a. Approximately half the phyla of living organisms are found in Cambrian sediments. b. No animal fossils are found in strata formed before the Cambrian explosion. c. The oldest generally accepted fossils of large animals range in age from 565 to 550 million years old.

c. The oldest generally accepted fossils of large animals range in age from 565 to 550 million years old.

What do all deuterostomes have in common? a. Adults are bilaterally symmetrical. b. Embryos have pharyngeal pouches that may or may not form gill slits. c. The pore (blastopore) formed during gastrulation becomes the anus. d. All have a spinal column.

c. The pore (blastopore) formed during gastrulation becomes the anus.

You are the lucky student of a wacky professor who develops a time machine. He asks if you will test it with him. You get in and there is an immediate glitch-the date readout fails so that when you land you are not sure what era you are in. Your professor begins to panic, but you see something that tells you are in the Cenozoic era. Which of the following could it be? a. a bee pollinating a flower b. a water lily floating in a pond c. a rabbit eating a daisy d. masses of green ferns with dragonflies hovering above them

c. a rabbit eating a daisy

Arthropods invaded land about 100 million years before vertebrates did so. This most clearly implies that _____. a. arthropods evolved before vertebrates did b. vertebrates evolved from arthropods c. arthropods have had more time to coevolve with land plants than have vertebrates d. extant terrestrial arthropods are better adapted to terrestrial life than are extant terrestrial vertebrates

c. arthropods have had more time to coevolve with land plants than have vertebrates

In what respect do hominins differ from all other anthropoids? a. lack of a tail b. eyes on the front of the face c. bipedal posture d. opposable thumbs

c. bipedal posture

If the nucleotide variability of a locus equals 0%, what is the gene variability and number of alleles at that locus? a. Without more information, gene variability and number of alleles cannot be determined. b. gene variability > 0%; number of alleles = 2 c. gene variability = 0%; number of alleles = 1 d. gene variability = 0%; number of alleles = 0 e. gene variability = 0%; number of alleles = 2

c. gene variability = 0%; number of alleles = 1

Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception. a. evolutionary innovation b. an adaptive radiation in a group of organisms (such as plants) that another group uses as food c. genetic drift d. vacant ecological niches e. colonization of an isolated region that contains suitable habitat and few competitor species

c. genetic drift

Fossilized stromatolites a. formed around deep-sea vents. b. provide evidence that plants moved onto land in the company of fungi around 500 million years ago. c. resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays. d. all date from 2.7 billion years ago. e. contain the first undisputed fossils of eukaryotes and date from 2.1 billion years ago.

c. resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays.

The first genetic material on Earth was probably _____. a. DNA produced by reverse transcriptase from abiotically produced RNA b. oligopeptides located within protobionts c. self-replicating RNA molecules d. DNA molecules whose information was transcribed to RNA and later translated in polypeptides

c. self-replicating RNA molecules

The oxygen revolution changed Earth's environment dramatically. Which of the following took advantage of the presence of free oxygen in the oceans and atmosphere? a. the evolution of multicellular eukaryotic colonies from communities of prokaryotes b. the evolution of photosynthetic pigments that protected early algae from the corrosive effects of oxygen c. the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules d. the evolution of chloroplasts after early protists incorporated photosynthetic cyanobacteria e. the persistence of some animal groups in anaerobic habitats

c. the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules

Genetic drift is a process based on _____. a. mutation b. immigration c. the role of chance d. emigration e. differential reproductive success correlated to the relationship between a phenotype and the environment

c. the role of chance

Which of the following is true of secondary endosymbiosis? a. It is indicated by the presence of a double membrane surrounding the endymbiont. b. An organism containing one endosymbiont engulfs another organism, and that organism becomes an endosymbiont. c. It is indicated by the presence of a nucleomorph. d. An organism containing an endosymbiont is engulfed by another organism and becomes an endosymbiont. e. It is indicated by the presence of a mixotroph.

d. An organism containing an endosymbiont is engulfed by another organism and becomes an endosymbiont.

For many years scientists believed that almost all animal lineages burst into being during the Cambrian era (just after the end of the Precambrian super eon). However, there have been many recent findings of animal-like fossils and "trace fossils" (fossils of an animal-like organisms movement) from the late Precambrian. Which of the following best explains why it took so long to realize there was animal-like life in the Precambrian? a. There were many hard-shelled animals in the Cambrian. b. The global climate was such that there was poor fossilization in the Precambrian. c. There were very few animals during this period. d. Animals from the late Precambrian had soft bodies.

d. Animals from the late Precambrian had soft bodies.

Which listing of geological periods is in the correct order, from oldest to most recent? a. Permian, Cambrian, Cretaceous, Devonian b. Cambrian, Permian, Devonian, Cretaceous c. Devonian, Cambrian, Permian, Cretaceous d. Cambrian, Devonian, Permian, Cretaceous

d. Cambrian, Devonian, Permian, Cretaceous

A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A postdoctoral student thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus? a. See if it reproduces sexually. b. See if it is a eukaryote or prokaryote. c. Figure out whether it is autotrophic or heterotrophic. d. Look for cell walls under a microscope. e. Determine whether it is unicellular or multicellular.

d. Look for cell walls under a microscope.

Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans. a. gene flow b. mutation c. disease d. genetic drift e. natural selection

d. genetic drift

There are 40 individuals in population 1, all with genotype A1A1, and there are 25 individuals in population 2, all with genotype A2A2. Assume that these populations are located far from each other and that their environmental conditions are very similar. Based on the information given here, the observed genetic variation is most likely an example of a. discrete variation. b. disruptive selection. c. gene flow. d. genetic drift. e. directional selection.

d. genetic drift

Reinforcement is most likely to occur when _____. a. prezygotic isolating mechanisms are in place b. the environment is changing c. gene flow is low d. hybrids have lower fitness than either parent population

d. hybrids have lower fitness than either parent population

Natural selection changes allele frequencies because some _______ survive and reproduce more successfully than others. a. gene pools b. alleles c. species d. individuals e. loci

d. individual

Which of the following is (are) unique to animals? a. flagellated gametes b. heterotrophy c. the structural carbohydrate, chitin d. nervous system signal conduction and muscular movement

d. nervous system signal conduction and muscular movement

Hox genes are thought to play an important role in the development of different morphologies because _____. a. they paved the way for the development of multicellular organisms b. they affect the timing of development in the embryo c. they affect the timing of reproductive development in the organism d. they provide positional information in the embryo e. they affect the order of genes on certain chromosomes

d. they provide positional information in the embryo

Earth probably formed _____ years ago, and the first life evolved as early as _____ years ago. a. 3.9 million years ago ... 2.0 billion years ago b. Humans observed neither event, so there is no way to tell. c. 10 billion years ago ... 4.5 billion years ago d. 6,000 years ago ... 6,000 years ago e. 4.5 billion years ago ... 3.9 billion years ago

e. 4.5 billion years ago ... 3.9 billion years ago

How does continental drift affect living organisms? a. It causes climate change, which puts selective pressure on organisms. b. It causes changes in habitats, such as when large amounts of shallow marine habitat were lost in the formation of Pangaea. c. It may cause an increase or decrease in competition among different species. d. It happens so slowly that it does not affect living organisms. e. All but one of these are correct.

e. All but one of these are correct.

All animals can trace their lineage to a common ancestor that lived in the _____. a. Devonian b. Pliocene c. Cenozoic d. Jurassic e. Neoproterozoic era

e. Neoproterozoic era

How does the large amount of genetic variation observed in prokaryotes arise? a. The mutation rate in prokaryotes is much higher than in eukaryotes. b. They have extremely short generation times and large populations. c. They can exchange DNA with many types of prokaryotes by way of horizontal gene transfer. d. They have a relatively small genome. e. The second and third answers are correct.

e. The second and third answers are correct.

Crossing over, resulting in an increase in genetic variation, occurs between _____. a. nonsister chromatids of nonhomologous chromosomes b. sex cells and somatic cells c. sister chromatids of nonhomologous chromosomes d. sister chromatids of homologous chromosomes e. nonsister chromatids of homologous chromosomes

e. nonsister chromatids of homologous chromosomes

The earliest organisms were most likely _____. a. eukaryotic b. plants and fungi c. multicellular d. proto-cells e. prokaryotic

e. prokaryotic

According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool. a. mutation b. genetic drift c. immigration d. sexual selection e. sexual reproduction

e. sexual reproduction

The evolutionary effects of genetic drift are greatest when _____. a. sexual selection occurs b. the population size is large c. intraspecific competition is intense d. intraspecific competition is weak e. the population size is small

e. the population size is small

No two people are genetically identical, except for identical twins. The main source of genetic variation among human individuals is: a. geographic variation within the population. b. new mutations that occurred in the preceding generation. c. genetic drift due to the small size of the population. d. environmental effects. e. the reshuffling of alleles in sexual reproduction.

e. the reshuffling of alleles in sexual reproduction

Miller and Urey's experiments that attempted to recreate conditions on early Earth were significant because _____. a. they showed how radiometric dating could be used to give the absolute ages of rocks and fossils b. they showed how polymers could form spontaneously on a clay substrate c. proved the endosymbiotic theory d. they produced the first protocells e. they showed that organic molecules such as amino acids could be produced from inorganic molecules

e. they showed that organic molecules such as amino acids could be produced from inorganic molecules