BIO 122-EXAM 2
Which of the following is a natural pain reliever? (Concept 48.4)
endorphins -Endorphins are neuropeptides that function as natural analgesics, decreasing the perception of pain by the CNS.
There are advantages and disadvantages to adaptations. Animals that are endothermic are likely to be at the greatest disadvantage in _____.
environments with variable and limited food sources
In most animals, food is digested by __________, __________ are absorbed by body cells, and most energy-containing molecules are used to generate __________. (Concept 40.4)
enzymatic hydrolysis ... nutrients ... ATP -
Most of the exchange surfaces of multicellular animals are lined with _____.
epithelial tissue
Sheets of tightly packed cells that line organs and body cavities as well as external surfaces.
epithelial tissue
Opening all of the sodium channels, with all other ion channels closed (which is an admittedly artificial setting) should move its membrane potential to _____.
equilibrium potential for sodium (no net movement)
In which of the following pairs of populations is allopatric speciation most likely to occur? (Concept 24.2)
pine trees in Alaska and pine trees on the island of Madagascar -This is geographic isolation that could lead to allopatric speciation, for it is unlikely that pollen from one locale could get to the other locale.
Most causes of speciation are relatively slow in that they may take many generations to see changes, with the exception of ________.
polyploidy
In homeostasis in animals, a value maintained for a particular variable, such as body temperature or solute concentration.
set point
In the case of the Lake Victoria cichlids, sympatric speciation has been shown to be driven by __________. (Concept 24.2)
sexual selection -Experiments have shown that females select mates on the basis of coloration. This behavioral isolation may have been a major factor in the speciation of cichlids.
Neurons communicate by __________. (Concept 48.0)
short-distance chemical signals and long-distance electrical signals -These are the two types of signals that neurons use to communicate.
Which of the following animals would you expect to consume food at the highest rate (kilograms of food per kilogram of body weight per day)? (Concept 40.4)
shrew -Metabolic rates are highest for small organisms and during intense physical activity.
Food moves along the digestive tract as the result of contractions by _____.
smooth muscle
The operation of the sodium-potassium pump moves _____.
sodium ions out of the cell and potassium ions into the cell
The concentrations of ions are very different inside and outside a nerve cell due to _____.
sodium-potassium pumps
According to the concept of punctuated equilibrium, the "sudden" appearance of a new species in the fossil record means that ________.
speciation occurred rapidly in geologic time
If a new species of plant is to be produced by means of allopolyploidy from two parental species that are 2n = 4 and 2n = 8, how many chromosomes would you expect in the somatic cells of the new species? (Concept 24.2)
12 -The two gametes would be n = 2 and n = 4. They would combine for a total of 6, which after doubling would be 12.
You want to study divergence of populations, and you need to maximize the rate of divergence to see results within the period of your grant funding. You will form a new population by taking some individuals from a source population and isolating them so the two populations cannot interbreed. What combination of characteristics would maximize your chance of seeing divergence in this study? 1. Choose a random sample of individuals to form the new population. 2. Choose individuals from one extreme to form the new population. 3. Choose a species to study that produces many offspring. 4. Choose a species to study that produces a few, large offspring. 5. Place the new population in the same type of environment as the source population. 6. Place the new population in a novel environment compared to that of the source population.
2, 3, and 6
Rank the following in order from most general to most specific. 1. gametic isolation 2. reproductive isolating mechanism 3. sperm-egg incompatibility in sea urchins 4. prezygotic isolating mechanism
2, 4, 1, 3
Plant species A has a diploid number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be
28.
Use the following description to answer the question. 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
The following steps refer to various staged in transmission at a chemical synapse: 1. Neurotransmitter binds with receptors associated with the postsynaptic membrane. 2. Calcium ions rush into neuron's cytoplasm. 3. An action potential depolarizes the membrane of the presynaptic axon terminal. 4. The ligand-gated ion channels open. 5. The synaptic vesicles release neurotransmitter into the synaptic cleft. Which sequence of events is correct?
3 → 2 → 5 → 1 → 4
polyploidy
A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division.
Which of the following is a description of a behavior that helps warm the body? (Concept 40.3)
A falcon migrates from San Francisco to Brazil for the winter. -Brazil is on the equator, where winters are much warmer than in northern coastal California.
allopolyploid
A fertile individual that has more than two chromosome sets as a result of two different species interbreeding and combining their chromosomes.
hybrid zone
A geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry.
Which of the following statements is correct? (Concept 48.1)
A neuron only has a single axon. -Neurons have a single axon, an extension that transmits signals to other cells.
prezygotic barrier
A reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted.
postzygotic barrier
A reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults.
Which of the following statements about action potentials is correct?
Action potentials are propagated down the length of the axon.
In a hybrid zone, which of the following would tend to lead to reinforcement? (Concept 24.3)
All of the listed responses are correct. -All of these factors can reinforce the reproductive barriers between populations.
Which of the following is a mechanism by which neurotransmitters can be rapidly cleared from the synaptic cleft? (Concept 48.4)
All of the listed responses are correct. -The neurotransmitters are actively transported back into the presynaptic cells to be repackaged into synaptic vesicles. -Neurotransmitters are removed by simple diffusion. -The neurotransmitters are transferred to glia to be metabolized. -Neurotransmitters are removed by enzymatic hydrolysis of the neurotransmitter.
Which of the following statements is/are true of hormones? (Concept 40.1)
All of the listed responses are correct. -They act only on cells with receptors specific to that hormone. -They are chemical signals broadcast throughout the body. -They are relatively slow-acting compared to nerve impulses. -They are distributed by the bloodstream.
How are neurons structurally adapted to chemically transmit impulses to neighboring neurons? (Concept 48.4)
Axon terminals contain neurotransmitter within synaptic vesicles. -Numerous sacs, called synaptic vesicles, located in the cytoplasm at the tip of the presynaptic axon, release molecules of a neurotransmitter across the synaptic cleft, which bind to receptors embedded in the membrane of the postsynaptic cell.
Acetylcholinesterase is the enzyme that degrades acetylcholine. What effect on nerve transmission would occur following the administration of a chemical that inhibited acetylcholinesterase? (Concept 48.4)
Continuous excitatory postsynaptic potentials would occur in the postsynaptic neuron. -Because the neurotransmitter is not degraded, it continues to interact with the receptors on the postsynaptic membrane.
Which of the following is a characteristic of the nervous system but not the endocrine system? (Concept 40.1)
Communication usually involves more than one type of signal. -Signals are typically conducted electrically along the axons of neurons and chemically at the synapses between the neuron and target cell.
biological species concept
Definition of a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring but do not produce viable, fertile offspring with members of other such groups.
ecological species concept
Definition of a species in terms of ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment.
morphological species concept
Definition of a species in terms of measurable anatomical criteria.
Which statement is true regarding thermoregulation? (Concept 40.3)
Ectotherms generally do not conserve body heat as effectively as do marine mammals. -Ectotherms spend much less energy on adaptations that conserve heat than do marine endotherms such as whales.
Which of the following best illustrates homeostasis? (Concept 40.2)
Elevated blood CO2 stimulates faster breathing, which rids the body of excess CO2. -Homeostasis maintains an internal consistency by negative feedback; in this example, an increase in CO2 promotes its elimination.
In the late fall, bats hibernate in clusters with many bats pressed together and holding on to one another. Which of the following statements does NOT represent an advantage of this behavior? (Concept 40.3)
Huddling behavior helps bats stay warm while they feed. -This cannot be an advantage, because huddling behavior is not possible while bats fly and catch food. This represents a compromise of feeding and thermoregulation.
In the Lake Victoria cichlids, what appears to be contributing to fusion of different species? (Concept 24.3)
Females have a difficult time visually selecting males of the same species in the murky, polluted water. -Researchers are finding that sexual selection, which had been reinforcing reproductive barriers between species, is less effective in the murky water of the present-day lake.
Which of the following neurotransmitters typically has inhibitory effects? (Concept 48.4)
GABA (gamma-aminobutyric acid) -GABA appears to be the neurotransmitter at most inhibitory synapses.
What is the first thing that must happen in order for speciation to occur? (Concept 24.4)
Gene flow between populations must be interrupted. -Although several other factors come into play, as long as there is gene flow between populations, speciation is extremely unlikely.
Which of the following factors would not contribute to al-lopatric speciation?
Gene flow between the two populations is extensive.
At which point in the adaptation of a population is it clear that speciation has occurred?
Gene pool changes establish reproductive barriers between two populations. -This is an example of separate species being created.
Which of the following is a question about physiology? (Concept 40.0)
How is blood pressure affected by physical activity? -This question asks about the functional properties of the circulatory system.
How could you increase the magnitude of excitatory postsynaptic potentials (EPSPs) generated at a synapse? (Make an action potential more likely?)
Increase Na+ permeability.
Imagine that part of a population of South American finches is blown by a storm onto an island far offshore and manages to survive and reproduce there for a period of 10,000 years. After that period, a climate change results in lower sea levels and the reconnection of the island with the mainland. Members of the formerly isolated island finch population can now interact freely with members of the original mainland population. Which of the following observations would, by itself, lead you to conclude unequivocally that the island finch population had evolved into a distinct species, according to the biological species concept?
Individuals from the different populations sometimes mate with each other, but all of the resulting eggs are sterile. -The biological species concept defines a species as a population whose members interbreed successfully to produce viable, fertile offspring but who cannot produce viable, fertile offspring with members of other species.
Which of the following statements about the resting potential is true? (Concept 48.2)
Inside the cell, the concentration of potassium is much higher than the concentration of sodium. -The concentration of potassium is much higher inside the cell.
Which of the following statements is true? (Concept 48.2)
Ion channels are selectively permeable, permitting only certain ions to pass. -A potassium channel allows K+ to diffuse freely across the membrane, but not other ions, such as Na+.
In a resting potential, and example of a cation that is more abundant as a solute in the cytosol (interior) of a neuron than it is in the interstitial fluid outside the neuron is _____.
K+
Comparison of human fossils with living humans seems to show that there have been no significant physical changes in Homo sapiens in 30,000 to 50,000 years. What might an advocate of punctuated equilibrium say about this? (Concept 24.4)
Lack of change is consistent with the punctuated equilibrium model. -In punctuated equilibrium, new species change little after budding from their parent species.
A neurotransmitter receptor that triggers a signal cascade when bound.
Metabotropic receptor
According to the experiment of Diane Dodd, can adaptive divergence of allopatric fruit fly populations lead to reproductive isolation? (Concept 24.2)
No. After several generations, the formation of a reproductive barrier (behavioral isolation) was evident, but not absolute. -The starch flies were more apt to mate with other starch flies and the maltose flies were more apt to mate with other maltose flies, but some interbreeding still did occur.
Which of the following statements is correct? (Concept 48.1)
None of the listed responses is correct. -The vast majority of neurons in the brain are sensory neurons. -Sensory neurons transmit signals to muscle cells. -Synaptic cells nourish neurons, insulate the axons of neurons, and/or regulate the extracellular fluid surrounding the neurons. -The nucleus of a neuron is located in the axon hillock.
Lake Victoria, in Africa, is home to a group of related fishes known as cichlids. Many of these fishes are similar in appearance but have different feeding habits. What is the best method for scientists to determine conclusively whether the fish are members of a population that has a lot of variation or members of entirely different species? (Concept 24.1)
Observe the fish in their natural environment for possible instances of interbreeding leading to several generations of fertile offspring. -The biological species concept defines a species as a population whose members interbreed successfully to produce viable, fertile offspring but who cannot produce viable, fertile offspring with members of other species.
Which of the following is a benefit of multicellularity compared to organisms consisting of just one cell? (Concept 40.1)
Populations of cells in a multicellular body can be specialized for specific functions. -This is a benefit of multicellularity.
The membrane potential of a neuron at rest. On average this is around -70mV.
Resting potential
A transport protein in the plasma membrane of an animal cell that actively transports sodium out of the cell and potassium into the cell.
Sodium-potassium pump
When gene flow between two populations ceases, the potential for __________ exists.
Speciation -Reproductive isolation (the cessation of gene flow) is necessary for speciation.
Which of the following statements about the transmission across a typical chemical synapse is true? (Concept 48.4)
The binding of neurotransmitter molecules to receptors on the postsynaptic cell membrane results in changes to the behavior of the postsynaptic cell. -The binding of neurotransmitter molecules to receptors may increase or decrease the likelihood that the postsynaptic cell will generate an action potential.
Why are action potentials usually conducted in one direction?
The brief refractory period prevents reopening of voltage-gated Na+ channels.
reproductive isolation
The existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring.
allopatric speciation
The formation of new species in populations that are geographically isolated from one another.
sympatric speciation
The formation of new species in populations that live in the same geographic area.
Suppose that a group of male pied flycatchers migrated from a region where there were no collared flycatchers to a region where both species were present (see Figure 24.15). Assuming events like this are very rare, which of the following scenarios is least likely?
The frequency of hybrid offspring would decrease.
What happens when a resting neuron's membrane depolarizes?
The neuron's membrane voltage becomes more positive.
Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification?
The two forms interbreed often in nature, and their offspring have good survival and reproduction.
How many genes must change in order to form a new species? (Concept 24.4)
There is no set number of genes or loci that produces a new species. Genetic and environmental factors interact. -Research has shown that genetic changes can be few or many. Other factors such as geographic isolation, catastrophic events, pollution, the establishment of hybrid zones, and so on, will affect speciation in different organisms.
Many songbirds breed in North America in the spring and summer, and then migrate to Central and South America in the fall. They spend the winter in these warmer areas where they feed and prepare for the spring migration north and another breeding season. Two hypothetical species of sparrow, A and B, overwinter together in mixed flocks in Costa Rica. In spring, species A goes to the east coast of North America, and species B goes to the west coast. What can you say about the isolating mechanisms of these two species?
These two species mate in different climates.
The time interval between speciation events is typically __________. (Concept 24.4)
Times between speciation events vary widely and depend on generation times, causes of speciation, environmental factors, and chance. -Speciation may occur on many different time scales. Remember that mutations or meiosis, both of which are largely governed by chance, must first provide some traits that can lead to reproductive isolation.
Which of the following is an example of a postzygotic reproductive barrier?
Two fruit flies of different species produce sterile offspring. -This scenario represents reduced hybrid fertility.
A neurophysiologist is investigating nerve reflexes in two different animals: a crab and a fish. Action potentials are found to pass more rapidly along the fish's neurons. What is the most likely explanation?
Unlike the crab, the fish's axons are wrapped in myelin
An action potential is __________. (Concept 48.3)
a traveling wave of depolarization in the neuron membrane -An action potential is an all-or-none change in membrane potential that travels along the neuron.
Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal?
Voltage-gated calcium channels in the membrane open.
Which of the following statements is true? (Concept 40.3)
When your body temperature is too high, vasodilation in the skin helps to correct the situation because it redirects heat from the body core to the outside. -Vasodilation causes increased blood flow in the skin, which results in more heat being transferred to the environment, cooling the animal.
You are studying a large tropical reptile that has a high and relatively stable body temperature. How would you determine whether this animal is an endotherm or an ectotherm?
You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.
Which of the following is a function of your circadian rhythm? (Concept 40.2)
Your body temperature rises and falls every day. -Your biological clock maintains the rhythmic rise and fall of body temperature every 24 hours.
Which of the following animals uses the largest percentage of its energy budget for homeostatic regulation?
a desert bird
Acetycholine (a neurotransmitter) released into the junction between a motor neuron and a skeletal muscle binds to a sodium/potassium channel and opens it. This is an example of _____.
a ligand-gated channel
A columnar epithelial cell probably has what function? (Concept 40.1)
absorption and secretion -Columnar epithelia are involved in the production of secretory products, such as mucus, digestive juices, sweat, and oils, as well as absorption of nutrients.
Physiological adjustment to a change in an environmental factor.
acclimatization
One of the most common neurotransmitters. Heavily involved with motor movements, learning, and memory formation. Can be inhibited by sarin gas or botulism.
acetylcholine
The all or nothing response by a neuron when it is depolarized enough to clear the metaphorical wall of the axon hillock.
action potential
Which of the following is a list of connective tissues? (Concept 40.1)
adipose tissue, cartilage, bone, and blood -Connective tissues include loose and dense connective tissue, adipose tissue, cartilage, bone, and blood.
The Galápagos finches collected by Darwin are thought to have descended from a very small parent population. Different species of finches that are confined to only one or two islands most likely arose by __________. (Concept 24.2)
allopatric speciation -As the finches spread out to different islands and became isolated from each other, gene flow between them ceased, and new species arose.
The term endotherm refers specifically to __________. (Concept 40.3)
an animal that gets most of its body heat from its metabolism -Endotherms have special adaptations for conserving metabolic heat.
A common feature of action potentials is that they
are triggered by a depolarization that reaches the threshold.
According to the biological species concept, for speciation to occur, ________.
at least one gene, affecting one reproductive barrier, must change
The interplay of multiple excitatory and inhibitory inputs most affects what part of a neuron? (Concept 48.4)
axon hillock -The axon hillock is the neuron's integrating center.
What is the name of the epithelial cell surface that faces the outside of an organ? (away from the exchange surface)
basal
The metabolic rate of a resting, fasting, and nonstressed endotherm at a comfortable temperature.
basal metabolic rate
The amount of energy expended while an endothermic organism is resting, unstressed, and not actively digesting or growing is called its __________. (Concept 40.4)
basal metabolic rate -Basal metabolic rate refers to the amount of energy an endothermic organism needs to merely survive.
Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian Islands have different elaborate courtship rituals. These rituals involve fighting other males and making stylized movements that attract females. What type of reproductive isolation does this represent?
behavioral isolation
Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?
biological
Plasma, a fluid containing water, salts, and dissolved proteins, is the extracellular matrix of __________. (Concept 40.1)
blood -Blood plasma is the fluid matrix of blood tissue.
Which of the six major types of connective tissue has a rigid matrix that contains collagen and calcium salts? (Concept 40.1)
bone -The matrix of bone is hard but not brittle because of the collagen fibers included in the bone matrix.
Ligaments connect __________ to __________. (Concept 40.1)
bones ... bones -Fibrous connective tissue is found in tendons, which connect muscles to bones, and in ligaments, which connect bones at joints.
Microscopic analysis of an unknown tissue sample reveals the presence of chondrocytes, indicating that the sample was probably taken from __________. (Concept 40.1)
cartilage -Chondrocytes secrete the matrix found in cartilage.
A neuron consists of many components. Name three. (Concept 40.1)
cell body, dendrites, and axon -These are the three basic parts of a neuron.
Suppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that
cells X and Y express different receptor molecules for this particular neurotransmitter.
Cells that secrete the proteins that make cartilage strong yet flexible are called __________. (Concept 40.1)
chondrocytes -right answer feedback:Correct. Chondroitin sulfate and collagen are secreted by chondrocytes, cells confined to scattered spaces in the matrix called lacunae.
If a person were to travel to a time zone that was several hours ahead of their own, they may experience tiredness known as jet lag. Jet lag is due to a disruption of _____.
circadian rhythm
What are ganglia? (Concept 48.0)
clusters of nerve cell bodies -A ganglion is a cluster of nerve cell bodies that carries out higher-order processing.
An animal for which an internal condition conforms to (changes in accordance with) changes in an environmental variable.
conformer
Animal tissue that functions mainly to bind and support other tissues, having a sparse population of cells scattered through an extracellular matrix.
connective tissue
The body tissue that consists largely of material located outside of cells is
connective tissue. -
Which of the following tissues bind and support other tissues in the body? (Concept 40.1)
connective tissues -Connective tissues connect, bind, and support other tissues in the body.
On a cold day, blood vessels in the skin __________. (Concept 40.3)
constrict, reducing heat loss from blood at the surface -Because blood vessels in the skin lie close to the surface of the body, they give off heat to the external environment easily. Constricting blood vessels in the skin reduces heat loss.
At the neuromuscular junction, the neurotransmitter acetylcholine (ACh) is degraded by acetylcholinesterase. If a neurophysiologist applies the naturally occurring acetylcholinesterase inhibitor, onchidal (produced by the mollusc Onchidella binneyi), to a synapse, what would you expect to happen?
convulsions due to constant muscle stimulation
Blocking potassium ion channels in a mammalian cell membrane would __________. (Concept 48.2)
decrease the magnitude of the membrane potential -Closing the potassium channels would prevent K+ from diffusing freely across the membrane, thus holding positively charged ions inside the cell, but Na+ would continue to flow into the cell along its concentration gradient, making the membrane potential less negative.
"Striated" is a description that would apply to which kind of animal tissue? (Concept 40.1)
muscle -Some types of muscle cell are striated.
The part of a neuron that carries nerve impulses toward the cell body is called a(n) __________. (Concept 48.1)
dendrite -The dendrite is defined as the part of the neuron that carries an impulse toward the cell body.
Action potentials are generated along a neuron because __________. (Concept 48.3)
depolarization of the membrane at one point causes an increase of permeability to sodium at the next point -An influx of sodium depolarizes the membrane and opens more sodium channels, causing still more depolarization; this is an example of positive feedback.
Food processing and the absorption and distribution of nutrients within your body are mainly accomplished by the __________ systems. (Concept 40.1)
digestive and circulatory -The digestive system breaks down foods and selectively absorbs nutrients, which are then distributed by the circulatory system.
Referring to organisms for which external sources provide most of the heat for temperature regulation.
ecothermic
Which of the following correctly pairs up a type of synapse and its characteristic? (Concept 48.4)
electrical synapse ... gap junctions -Electrical synapses contain gap junctions.
Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The __________ would have the highest total annual energy expenditure, and the __________ would have the highest energy expenditure per unit mass.
elephant; mouse
Which of the following systems is correctly paired with one of its parts? (Concept 40.1)
endocrine system ... thyroid gland -The thyroid gland is part of the endocrine system.
The sodium-potassium pump __________. (Concept 48.2)
expels sodium from the cell -The sodium-potassium pump is a channel protein that expels sodium from the cell, exchanging it for potassium.
Ligaments are a type of __________. (Concept 40.1)
fibrous connective tissue -Both ligaments and tendons are fibrous connective tissue made of densely packed, nonelastic collagen fibers; they are strong and flexible.
It is a cold day in the lecture hall. When you rest your arm on the cool laminated desktop at your seat, heat is transferred __________. (Concept 40.3)
from your body to the desk by conduction -Conduction is the direct transfer of heat between molecules of the environment and those of the body surface. Heat is always conducted from a body of higher temperature to one of lower temperature.
Other than predation by introduced Nile perch, the most likely explanation for the recent decline in cichlid species diversity in Lake Victoria is ________.
fusion
Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. Pollen grains (which contain sperm cells) from one species are unable to germinate and make pollen tubes on female ovules (which contain egg cells) of the other species. These two juniper species are kept separate by ________.
gametic isolation
Which of the following evolutionary mechanisms does NOT contribute to the process of allopatric speciation? (Concept 24.2)
gene flow -Gene flow between populations tends to homogenize the populations, reducing the likelihood of speciation occurring.
Cells that provide metabolic and structural support to the neurons are called __________. (Concept 48.1)
glia -These cells support neurons in different ways (depending on type).
Cells of the nervous system that act to support and optimize the functions of neurons. An example would be the cells that form they myelin sheath.
glial cells
Use the following information to answer the question. 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. What keeps the two populations separate?
habitat isolation
The wolf, his coat glowing in the early spring sunshine, sat atop a cold boulder after unsuccessfully pursuing a plump jackrabbit. He continued to pant while __________. (Concept 40.3)
heat radiated from his tired body -Heat would radiate away from his body; heat would also radiate from the sun to him.
Sweating __________. (Concept 40.3)
helps the body thermoregulate -Sweating is an effective method of thermoregulation through evaporative cooling.
The body's automatic tendency to maintain a constant and optimal internal environment is termed as _____.
homeostasis
What is an increase in the magnitude of the membrane potential called? (Concept 48.3)
hyperpolarization -Hyperpolarization results from any stimulus that increases either the outflow of positive ions or the inflow of negative ions.
For a neuron with an initial membrane potential at -70 mV, an increase in the movement of potassium ions out of that neuron's cytoplasm would result in the _____.
hyperpolarization of the neuron
Neurotransmitters categorized as inhibitory are expected to ________.
hyperpolarize the membrane
The temperature-regulating center of vertebrate animals is located in the _____.
hypothalamus
During a fever, the __________ readjusts the set point of the body to a __________ temperature. (Concept 40.3)
hypothalamus ... higher -The hypothalamus is the main thermostat in the body.
A new species can arise in a single generation __________. (Concept 24.2)
if a change in chromosome number creates a reproductive barrier -This most often happens in plants.
An animal's inputs of energy and materials would exceed its outputs
if it is growing and increasing its mass.
A drug that causes potassium to leak out of a neuron, increasing the positive charge on the outside, would __________. (Concept 48.3)
inhibit transmission of nerve signals by the neuron -The additional positive charge to the outside of the neuron would cause a hyperpolarization of the membrane.
Which of the following is specifically a part or a function of the central nervous system? (Concept 48.1)
integration -Integration is the interpretation of sensory signals and the formulation of responses, and it occurs in the central nervous system.
The fluid filling the spaces between cells in most animals.
interstitial fluid
In a cool environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm _____.
invests little energy in temperature regulation
Schwann cells make up the __________. (Concept 48.3)
myelin sheath in axons of the PNS (peripheral nervous system) -In the peripheral nervous system, supporting cells called Schwann cells wrap many axons with an insulating myelin sheath.
A neurotransmitter receptor that allows for ion flow when bound.
ionotropic receptor
Compared with a smaller cell, a larger cell of the same shape has
less surface area per unit of volume.
A receptor that opens or closes in response to being bound by a neurotrasmitter
ligand-gated receptor
Where in the body would you be most likely to find secretory cells shaped like dice? (Concept 40.1)
lining glandular tissue of the thyroid and salivary glands -These glands, as well as the tubules of the kidney, are lined with cuboidal epithelium.
Sometimes two phenotypically different populations interbreed to a limited extent, so that it is difficult to determine whether they are clearly separate species. This is not a concern to scientists because this __________. (Concept 24.1)
may indicate that the formation of a new species is in progress -This could indicate that although a reproductive barrier is becoming established, it is not yet complete.
Which of the following reproductive barriers actually prevents individuals of closely related species from copulating successfully?
mechanical isolation -With mechanical isolation, mating cannot occur successfully due to incompatibility of reproductive parts.
The "threshold" potential of a membrane is the _____.
minimum depolarization needed to operate the voltage-gated sodium and potassium channels
Snake behavior in Wisconsin changes throughout the year. For example, a snake is _____.
more active in summer because it can gain body heat by conduction
As animals have evolved large body size, they have also evolved adaptations to improve exchange of energy and materials with the environment. For example, in many larger organisms, evolution has favored lungs and a digestive tract with ________.
more branching or folds
According to the punctuated equilibria model,
most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species.
All animals, whether large or small, have _____.
most of their cells in contact with an aqueous medium
When a jogger starts to run, the rate at which his muscles produce CO2 rises sharply. But the CO2 in his blood rises only slightly before he starts to breathe faster and his heart starts beating stronger. Soon his increased rate of CO2 production is balanced by an increased rate of CO2 removal. This would be an example of __________ feedback because the jogger's circulatory and respiratory systems are __________. (Concept 40.2)
negative ... acting to oppose the increase of CO2 from the set point or normal range -In negative feedback, a change in the variable being monitored triggers the control mechanism to decrease the deviation from the set point or normal range.
What kind of feedback most directly maintains homeostasis? Why is this? (Concept 40.2)
negative, because it tends to keep a system at a desirable set point or normal range -In negative feedback, a change in the variable being monitored triggers the control mechanism to counteract further change in the same direction.
The __________ system and the __________ system work together to coordinate and control physiological processes in most animals.
nervous ... endocrine -Together, these systems coordinate and control the physiology of animals.
By definition, an ectotherm __________. (Concept 40.3)
obtains most of its heat from its environment -Many ectotherms regulate body heat through behavioral methods such as basking in the sun, seeking shade, or generating heat through movement.
Saltatory conduction means that the membrane potential changes __________. (Concept 48.3)
only at the nodes of Ranvier -The action potential does not propagate over the length of the myelinated axon but jumps from node of Ranvier to node of Ranvier, skipping the myelinated regions of membrane between the nodes.
Complete the following word association: Albatross is to organism as intestine is to __________. (Concept 40.1)
organ -The intestine is a specific type of organ, just as an albatross is a specific type of organism.
Bone-forming cells are called __________. (Concept 40.1)
osteoblasts -Osteoblasts deposit the matrix of bone.
A form of regulation in which an end product of a process speeds up that process; in physiology, a control mechanism in which a change in a variable triggers a response that reinforces or amplifies the change. Think contractions during childbirth.
positive feedback
Threshold is of great significance in the physiology of neurons. What happens if threshold is NOT reached? (Concept 48.3)
positive-feedback depolarization will not occur -Stimuli that do not depolarize the membrane to the level of the threshold do not generate action potentials.
In descriptions of synapse organization, which type of cell is the transmitting neuron and which type of neuron, muscle, or gland cell receives the signal? (Concept 48.1)
presynaptic ... postsynaptic -Pre- and postsynaptic cells are named for their position around the synapse.
Prezygotic barriers __________.
prevent fertilization of gametes from members of closely related species -Prezygotic barriers act prior to fertilization to prevent interbreeding between sibling species.
Three species of frogs, Rana pipiens, Rana clamitans, and Rana sylvatica, all mate in the same ponds, but they pair off correctly because they have different calls. This is a specific example of a __________ barrier, called __________.
prezygotic ... behavioral isolation -It occurs before fertilization and is due to different reproductive behaviors in sibling species.
In humans, making more serotonin available to brain cells typically __________. (Concept 48.4)
produces an effect on mood -Dopamine and serotonin are widespread in the brain and affect sleep, mood, attention, and learning.
Myosin and actin are __________. (Concept 40.1)
proteins that play a major role in muscle contraction -Myosin and actin proteins are the two chief components of myofibrils. They play a key role in muscle contraction.
One-way synaptic transmission occurs because ________. (best answer)
receptors for neurotransmitters are mostly found on the postsynaptic membrane
Which of the following conditions is necessary for speciation to occur? (Concept 24.2)
reproductive isolation -The biological species concept hinges on reproductive isolation.
A chemical that affects neuronal function but is not stored in presynaptic vesicles is ________.
retrograde neurotransmitters
An example of an ecothermic organism that has few or no behavioral options when it comes to its ability to adjust its body temperature is a _____.
sea star living deep in the ocean
If your fingers touch a hot stove and you suddenly pull back, you have experienced a reflex. What is the correct order of the information processing in this reflex? (Concept 48.1)
sensory input, integration, motor output -After a sensor detects a painful stimulus, the information is integrated in the CNS (central nervous system) and an appropriate response, the contraction of the muscles resulting in you removing your hand from the hot stove, is carried out via motor output.
A neuron that transmits an impulse to the central nervous system after the neuron is stimulated by the environment is called a(n) __________. (Concept 48.1)
sensory neuron -Sensory neurons communicate information between sensory receptors and the central nervous system about the external and internal environments.
The three stages of information processing in animals include _____.
sensory reception, an integrating center, and effectors (motor neurons)
The largest unit within which gene flow can readily occur is a
species.
Which of the following are types of cell found in epithelial tissues? (Concept 40.1)
squamous, cuboidal, and columnar cells -This question asks about the functional properties of the circulatory system.
Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species that lived side by side in parts of their ranges. However, recent books show them as eastern and western forms of a single species, the yellow-rumped warbler. Apparently, the myrtle warbler and Audubon's warbler __________.
successfully interbreed and produce fertile offspring
The gap between an axon terminal and dendrite across which neurons communicate via neurotransmitters.
synapse
The point of connection between two communicating neurons is called the _____.
synapse
There are two groups of pine trees that appear to be very similar phenotypically and genotypically. However, one releases pollen in January, when the female structures of that group are receptive, and one in March. What kind of reproductive barrier is this?
temporal isolation - Temporal isolation occurs when two similar species have sexual readiness at different times.
Two species of water lilies in the same pond do not interbreed because one blooms at night and the other during the day. The reproductive barrier between them is an example of __________.
temporal isolation -The gametes of species that breed during different times of the day, different seasons, or different years do not have an opportunity to combine and create a zygote.
A small number of birds arrive on an island from a neighboring larger island. This small population begins to adapt to the new food plants available on the island, and their beaks begin to change. About twice a year, one or two more birds from the neighboring island arrive. These new arrivals ________.
tend to slow adaptation to the new food plants
Interstitial fluid is __________. (Concept 40.1)
the fluid that fills the spaces between cells -The interstitial spaces are those around individual cells.
Where are neurotransmitter receptors located?
the postsynaptic membrane
In mammals, GH (growth hormone) is an endocrine signal that stimulates repair and growth of various tissues. Which of the following would be required for a tissue to respond to growth hormone?
the presence of a growth hormone receptor on the responding tissue
In a simple synapse, neurotransmitter chemicals are released by _____.
the presynaptic axon terminal
Most cells are microscopic because at this small size, __________. (Concept 40.1)
the ratio of surface area to cell volume is maximized -Cells obtain all of their nutrients and gases across their plasma membranes. Because volume increases at a faster rate than surface area, larger cells are limited by the area available for diffusion.
The period in which an axon membrane CANNOT generate an action potential is called __________. (Concept 48.3)
the refractory period -A membrane cannot act during the refractory period because its gates will not open.
Penguins, seals, and tuna have body forms that permit rapid swimming, because _____.
the shape is a convergent evolutionary solution, which reduces drag while swimming
According to the punctuated equilibrium model of evolution, __________. (Concept 24.4)
the tempo of evolution consists of abrupt episodes of speciation among long periods of equilibrium -This is the exact description of the punctuated equilibrium model of evolution.
An integrated group of cells with a common structure, function, or both.
tissue
During the night, the dormouse forages and eats, but during the day, its body temperature and heart rate drop significantly. This is an example of what physiological process? (Concept 40.4)
torpor -Torpor is a physiological state in which metabolism is slowed temporarily; the decrease in heart rate and body temperature each day in the dormouse is an example of this state.
Both the endocrine and nervous systems transmit information around an animal's body. Which of the following is a characteristic of nervous system signals?
travel quickly, allowing rapid transmission of signals
An ion channel that opens or closes in response to the membrane potential. Commonly found in an axon.
voltage-gated ion channel
Which of the following would increase the rate of heat exchange between an animal and its enviroment?
wind blowing across the body surface
Which of the following would increase the rate of heat exchange between an animal and its environment?
wind blowing across the body surface