review Flashcards
(141 cards)
1
Q
Chromosomes condense. The spindle apparatus
begins to form, and polar microtubules overlap each other
A
Prophase
2
Q
In cells of many organisms, the nuclear envelope
disintegrates. Microtubules attach to the kinetochores
of chromosomes and begin moving them to the middle of the
spindle.
A
Prometaphase
3
Q
All the chromosomes are positioned in the middle
of the spindle. The spindle is anchored to the cell membrane
by astral microtubules.
A
Metaphase
4
Q
Sister chromatids are pulled apart by the disassembly
of kinetochore microtubules at the kinetochore. The
separated chromatids are now daughter chromosomes. The
spindle poles are moved farther apart to fully separate the replicated
chromosomes.
A
Anaphase
5
Q
Telophase
A
Daughter chromosomes are fully separated and
are clustered at opposite poles of the spindle. A nuclear envelope
forms around each set and the chromosomes de-condense.
6
Q
How Do Cells Replicate?
A
when a cell divides it must copy its chromosomes, separate the copies, and divide the cytoplasm to generate daughter cells such that each carries the same chromosomal complement as the parent.
7
Q
interphase consists of s phase
A
is when chromosomes are replicated and gap phases called g1 and g2 when cells grow and prepare for division
8
Q
eukaryotic cells divide by cycling through four phases
A
g1, s , g2, and M and enter a non replication phase called g0
9
Q
eukaryotic cells divide by
A
alternating between interphase and M phase.
10
Q
Which statement about the daughter cells following mitosis and cytokinesis is correct?
A
They are genetically identical with each other and with the
parent cell
11
Q
Progression through the cell cycle is regulated by oscillations in
the concentration of which type of molecule?
A
cyclins
12
Q
After the S phase, what comprises a single chromosome
A
two sister chromatids
13
Q
What major events occur during anaphase of mitosis
A
Sister chromatids separate, and the spindle poles are pushed farther apart.
14
Q
What evidence suggests that during anaphase, kinetochore
microtubules shorten at the kinetochore
A
Daughter chromosomes were observed to
move toward the pole faster than do the marked regions
of fluorescently labeled kinetochore microtubules.
15
Q
Under normal conditions, what happens to the cell cycle if the chromosomes fail to separate properly at anaphase?
A
The cycle would arrest in M phase, and cytokinesis
would not occur.
16
Q
Identify at least two events in the cell cycle that must be completed successfully for daughter cells to share an identical complement of chromosomes.
A
For daughter cells to have identical complements
of chromosomes, all the chromosomes must be
replicated during the S phase, the spindle apparatus
must connect with the kinetochores of each sister
chromatid in prometaphase, and the sister chromatids
of each replicated chromosome must be partitioned
in anaphase and fully separated into daughter cells
by cytokinesi
17
Q
Explain how microinjection experiments supported the hypothesis
that specific molecules in the cytoplasm are involved in the
transition from interphase to M phase. What was the control for
this experiment?
A
Microinjection
experiments suggested that something in the cytoplasm
of M-phase cells activated the transition from
interphase to M phase. The control for this experiment
was to inject cytoplasm from a G2-arrested oocyte into
another G2-arrested oocyte
18
Q
Why are most protein kinases considered regulatory proteins?
A
Protein kinases
phosphorylate proteins. Phosphorylation changes a
protein’s shape, altering its function (activating or
inactivating it). As a result, protein kinases regulate the
function of proteins.
19
Q
Why are cyclins called cyclins? Explain their relationship to MPF activity
A
Cyclin concentrations
change during the cell cycle. At high concentration,
cyclins bind to a specific cyclin-dependent kinase (or
Cdk), forming a dimer. This dimer becomes active
MPF by changing its shape through the phosphorylation
(activating site) and dephosphorylation (inhibitory
site) of Cdk
20
Q
A particular cell spends 4 hours in G1 phase, 2 hours
in S phase, 2 hours in G2 phase, and 30 minutes in M phase. If a
pulse–chase assay were performed with radioactive thymidine on
an asynchronous culture, what percentage of mitotic cells would
be radiolabeled after 9 hours?
A
adding up each phase allows you to determine
that the cell cycle is 8.5 hours long. After 9 hours,
the radiolabeled cells would have passed through a full
cycle and be in either S phase or G2—none would have
entered M phase
21
Q
When fruit fly embryos first begin to develop, a large cell is
generated that contains over 8000 nuclei that are genetically identical with one another. What is most likely responsible for this
result?
A
The embryo passes through
multiple rounds of the cell cycle, but cytokinesis does not occur during M phases
22
Q
What is most likely responsible for the reduction in death rates
over the past several years in cancers of the breast and prostate?
How is this related to the development of cancer?
A
Early detection of
cancers leads to a greater likelihood of survival. The
widespread implementation of breast and prostate exams
allows for the identification and removal of benign
tumors before they become malignant.
23
Q
Cancer is primarily a disease of older people. Further, a group
of individuals may share a genetic predisposition to developing
certain types of cancer, yet vary a great deal in time of onset—or
not get the disease at all. What conclusion could be drawn based
on these observations? How does this relate to the requirements
for a cell to become cancerous?
A
Cancer
requires many defects. Older cells have had more time
to accumulate defects. Individuals with a genetic predisposition
to cancer start out with some cancer-related defects,
but this does not mean that the additional defects
required for cancer to occur will develop
24
Q
In multicellular organisms, nondividing cells stay in G0 phase. For the
cell, why is it better to be held in G1 rather than S, G2, or M phase
A
G1 cells have not replicated their DNA in preparation for
division.
25
In the roundworm Ascaris, eggs and sperm have two
| chromosomes, but all other cells have four. Observations such asthis inspired which important hypothesis?
Before gamete formation, a special type of cell division leads to a halving of chromosome number.
26
What are homologous chromosomes?
chromosomes that are similar in their size, shape, and gene
| content
27
What is a bivalent?
a group of four chromatids produced when homologs synapse
28
What is an outcome of genetic recombination
the new combination of maternal and paternal chromosome
| segments that results when homologs cross over
29
What proportion of chromosomes in a human skin cell are
| paternal chromosomes
1/2
30
Meiosis II is similar to _____.
mitosis.
31
Explain the relationship between homologous chromosomes and
| the relationship between sister chromatids
Homologous chromosomes are similar in
size, shape, and gene content, and originate from different
parents. Sister chromatids are exact copies of a
chromosome that are generated when chromosomes are
replicated (S phase of the cell cycle
32
Lay four pens and four pencils on a tabletop, and imagine that they
represent replicated chromosomes in a diploid cell where n = 2.
Explain the phases of meiosis II by moving the pens and pencils
around. (If you don’t have enough pens and pencils, use strips of
paper or fabric.)
The four pens
represent the chromatids in one replicated homologous
pair; the four pencils, the chromatids in a different homologous
pair. To simulate meiosis II, make two “haploid
cells”—each with a pair of pens and a pair of pencils
representing two replicated chromosomes (one of each
type in this species). Line them up in the middle of the
cell; then separate the two pens and the two pencils in
each cell such that one pen and one pencil go to each of
four daughter cell
33
Meiosis is called a reduction division, but all the reduction occurs during meiosis I—no reduction occurs during meiosis II. Explain
why meiosis I is a reduction division but meiosis II is not.
Meiosis I is a reduction
division because homologs separate—daughter cells
have just one of each type of chromosome instead of
two. Meiosis II is not a reduction division because sister
chromatids separate— daughter cells have unreplicated
chromosomes instead of replicated chromosomes, but
still just one of each type.
34
Dogs have 78 chromosomes in their diploid cells. If a diploid dog
cell enters meiosis, how many chromosomes and chromatids will
be present in each daughter cell at the end of meiosis I?
39 chromosomes and 78 chromatids
35
Triploid (3n) watermelons are produced by crossing a tetraploid
(4n) strain with a diploid (2n) plant. Briefly explain why this
mating produces a triploid individual. Why can mitosis proceed
normally in triploid cells, but meiosis cannot
Tetraploids
produce diploid gametes, which combine with a haploid
gamete from a diploid individual to form a triploid
offspring. Mitosis proceeds normally in triploid cells
because mitosis doesn’t require forming pairs of chromosomes.
But during meiosis in a triploid, homologous
chromosomes can’t pair up correctly. The third set of
chromosomes does not have a homologous partner to
pair with
36
Some plant breeders are concerned about the susceptibility of
asexually cultivated plants, such as seedless bananas, to new strains
of disease-causing bacteria, viruses, or fungi. Briefly explain their
concern by discussing the differences in the genetic “outcomes” of
asexual and sexual reproduction
Asexually produced individuals
are genetically identical, so if one is susceptible to a new
disease, all are. Sexually produced individuals are genetically
unique, so if a new disease strain evolves, at least
some plants are likely to be resistant
37
The gibbon has 44 chromosomes per diploid set, and the siamang
has 50 chromosomes per diploid set. In the 1970s a chance
mating between a male gibbon and a female siamang produced an
offspring. Predict how many chromosomes were observed in the
somatic cells of the offspring. Do you predict that this individual
would be able to form viable gametes? Why or why not
The gibbon would have 22 chromosomes in
each gamete, and the siamang would have 25. Each somatic
cell of the offspring would have 47 chromosomes.
The offspring should be sterile because it has some
chromosomes that would not form homologous pairs at
prophase I of meiosis.
38
Meiosis results in a reassortment of maternal and paternal
chromosomes. If n = 3 for a given organism, there are eight
different combinations of paternal and maternal chromosomes. If
no crossing over occurs, what is the probability that a gamete will
receive only paternal chromosomes?
1/8
39
Some researchers hypothesize that older women are less responsive
to triggers of spontaneous abortion than younger women. How
could the data shown in Figure 13.13, which graphs a mother’s age versus the incidence of Down syndrome, be used to support this
hypothesis?
Aneuploidy is
the major cause of spontaneous abortion. If spontaneous
abortion is rare in older women, it would result in a
higher incidence of aneuploid conditions such as Down
syndrome in older women
40
A species of rotifer, a small freshwater invertebrate, abandoned sexual reproduction millions of years ago. A remarkable feature
of the rotifer’s life cycle is its ability to withstand extreme drying. When the rotifer’s watery environment dries out, so does there rotifer, and it can be blown in the wind to a new environment. Once blown to water, the rotifer rehydrates and resumes an active life. A major pathogen of these rotifers is a species of fungus. Some scientists hypothesize that fungus-infected rotifers rid themselves of the pathogen when they dry.
Design an experimental study to test this hypothesis.
41
when mendal began his work there were two leading hypothesis of inheritance
blending inheritance and the inheritance of
| acquired characteristics.
42
In studies of how traits are inherited, what makes certain species
candidates for model organisms?
They are easy to maintain, have a short life cycle, produce
many offspring, and yield data that are relevant to many other
organisms
43
Why is the allele for wrinkled seed shape in garden peas
| considered recessive?
The trait associated with the allele is not expressed in
| heterozygotes.
44
The alleles found in haploid organisms cannot be dominant or
| recessive. Why?
Dominance and recessiveness describe which allele is expressed
in phenotype when different alleles occur in the same individual
45
Why can you infer that individuals that are “pure line” are
| homozygous for the gene in question?
Because no other phenotype is ever observed in a pure-line
| population, this implies that only one allele is present
46
The genes for the traits that Mendel worked with are either
located on different chromosomes or so far apart on the same
chromosome that crossing over almost always occurs between
them. How did this circumstance help Mendel recognize the
principle of independent assortment?
Otherwise, his dihybrid crosses would not have produced a
| 9 : 3 : 3 : 1 ratio of F2 phenotypes.
47
What is meant by the claim that Mendel worked with the simplest
possible genetic system?
Discrete traits, two alleles, simple dominance and recessiveness,
no sex chromosomes, and unlinked genes are the simplest
situation known.
48
Mendel’s rules do not correctly predict patterns of inheritance
for tightly linked genes or the inheritance of alleles that show
incomplete dominance. Does this mean that his hypotheses are
incorrect?
No, it just means that his hypotheses are limited to certain
| conditions.
49
The artificial sweetener NutraSweet consists of a phenylalanine
molecule linked to aspartic acid. The labels of diet sodas that
contain NutraSweet include a warning to people with PKU. Why?
People with PKU have to avoid phenylalanine in their diet.
50
When Sutton and Boveri published the chromosome theory of
inheritance, research on meiosis had not yet established that
paternal and maternal homologs of different chromosomes
assort independently. Then, in 1913, Elinor Carothers published
a paper about a grasshopper species with an unusual karyotype:
One chromosome had no homolog (meaning no pairing partner
at meiosis I); another chromosome had homologs that could be
distinguished under the light microscope. If chromosomes assort
independently, how often should Carothers have observed each of
the four products of meiosis shown in the following figure?
The four types of gametes should be observed to occur at equal
frequencies.
51
Which of the following is the strongest evidence that a trait might
be influenced by polygenic inheritance
The trait shows quantitative variation.
52
In peas, purple flowers are dominant to white. If a purpleflowered,
heterozygous plant were crossed with a white-flowered
plant, what is the expected ratio of genotypes and phenotypes
among the F1 offspring? If two of the purple-flowered F1 offspring
were randomly selected and crossed, what is the expected ratio of
genotypes and phenotypes among the F2 offspring?
3/4; 1/256 (see BioSkills 5 in Appendix B); 1/2
(the probabilities of transmitting the alleles or having
sons does not change over time). 14
53
In garden peas, yellow seeds (Y) are dominant to green seeds
(y), and inflated pods (I) are dominant to constricted pods (i).
Suppose you have crossed YYII parents with yyii parents.
Draw the F1 Punnett square and predict the expected F1
phenotype(s).
List the genotype(s) of gametes produced by F1 individuals.
Draw the F2 Punnett square. Based on this Punnett square,
predict the expected phenotype(s) in the F2 generation and the
expected frequency of each phenotype.
Yes—there would be
some individuals with yellow seeds and constricted pods
and with green seeds and inflated pods
54
How can biological fitness be estimated
Count the number of healthy, fertile offspring produced by
| different individuals in a population
55
Some traits are considered vestigial because they
| existed long ago.
false
56
What is an adaptation?
a trait that improves the fitness of its bearer, compared with
individuals without the trait
57
Why does the presence of extinct forms and transitional features
in the fossil record support the pattern component of the theory of
evolution by natural selection?
It supports the hypothesis that species change over time.
58
Traits that are derived from a common ancestor, like the bones of
human arms and bird wings, are said to be _____.
homologous
59
According to data presented in this chapter, which of the following
statements is correct?
Populations—not individuals—change when natural selection
| occurs.
60
Why don’t the biggest and strongest individuals in a population
always produce the most offspring?
In some environments, being big and strong lowers fitness.)
61
Explain how artificial selection differs from natural selection
Artificial selection is determined by human choice and
is goal directed, whereas natural selection is the unplanned
differential reproductive success of individuals
that vary in their heritable traits
62
Random mating
This condition was enforced by picking
gametes from the gene pool at random. Individuals were not
allowed to choose a mate.
63
The model assumed that all members of
the parental generation survived and contributed equal numbers
of gametes to the gene pool, no matter what their genotype.
No natural selection
64
No genetic drift (random allele frequency changes)
The
model assumed that alleles were picked in their exact frequencies
p and q, and not at some different values caused by
chance—that is, the model behaved as though the population
was infinitely large. For example, allele A1 did not “get lucky”
and get drawn more than 70 percent of the time.
65
No gene flow
No new alleles were added by immigration or lost
through emigration. As a result, all of the alleles in the offspring
population came from the original population’s gene pool
66
The model didn’t consider that new A1s or A2s
| or other, new alleles might be introduced into the gene pool
No mutation
67
In a population of 2500, how many babies would you
expect to have cystic fibrosis, a homozygous recessive condition, if
the frequency of the dominant allele is 0.9 and the population is at
Hardy–Weinberg equilibrium?
d; freq(A1) = 0.9, so freq(A2) = 0.1. Freq(A2A2)
| = q2 = (0.1)2 = 0.0
68
In what sense is the Hardy–Weinberg principle a null hypothesis?
It defines what genotype and allele frequencies
should be expected if evolutionary processes and
nonrandom mating are not occurring.
69
Why isn’t inbreeding considered an evolutionary process?
It does not change allele frequencies.
70
Why is genetic drift aptly named?
It causes allele frequencies to drift up or down randomly.
71
What does it mean when an allele reaches “fixation”?
It has a frequency of 1.0.
72
Gene flow can either increase or decrease the
| average fitness of a population
true
73
Mutation is the ultimate source of genetic variability. Why is this
statement correct?
Mutation is the only source of new alleles.
74
which prevents
| individuals of different species from mating;
prezygotic
75
postzygotic
in which the offspring of matings between members of different species do not survive or reproduce.
76
Which studies in this chapter represent direct observation of
speciation? Which are indirect studies of historical speciation
events
Direct observation: Galápagos finch colonization,
apple maggot flies, Tragopogon allopolyploids,
maidenhair ferns. Indirect studies: snapping shrimp,
sunflowers.
77
What distinguishes a morphospecies?
It has distinctive characteristics, such as size, shape, or
| coloration
78
When the ranges of two different species meet, a stable “hybrid
zone” occupied by hybrid individuals may form. How is this
possible
Hybrid individuals may have intermediate characteristics that are
advantageous in a given region.
79
Which of the following describes vicariance?
A population is fragmented into isolated subpopulations.
80
Why are genetic isolation and genetic divergence occurring in
apple maggot flies, even though populations occupy the same
geographic area?
Different populations feed and mate on different types of fruit.
81
The biological species concept can be applied only to which of the
bird species living today
82
Why is “reinforcement” an appropriate name for the concept that
natural selection should favor divergence and genetic isolation if
populations experience postzygotic isolation?
The selected traits reinforce differences that evolved while the
populations were isolated from one another.
83
Gene flow increases the divergence of populations.
False
84
Choose the best definition of a fossil
any trace of an organism that lived in the past
85
What is the difference between a branch and a node on a
| phylogenetic tree?
A branch is a population through time; a node is where a
| population splits into two independent populations
86
Which of the following best characterizes an adaptive radiation?
A single lineage diversifies rapidly, and descendant populations
occupy many habitats and ecological roles
87
The dinosaurs (other than birds) went extinct
during the asteroid impact at the K–P boundary because they were
poorly adapted to their ecological niches
False
88
Which of the following is an example of homoplasy?
streamlined bodies in dolphins and ichthyosaurs
89
Monophyletic groups are identified by shared,
| derived traits.
True
90
How do the molecules that function as electron donors and those
that function as electron acceptors differ
Electron donors have relatively high potential energy; electron
acceptors have relatively low potential energy
91
What do some photosynthetic bacteria use as a source of electrons
instead of water?
b. hydrogen sulfide (H2S
92
What is distinctive about the chlorophylls found in different
photosynthetic bacteria?
their absorption spectra
93
What are organisms called that use inorganic compounds as electron donors in cellular respiration
lithotrophs
94
Certain aerobic bacteria in the presence of oxygen
| can convert nitrogen gas to ammonia
false
95
Unlike plant cell walls that contain cellulose, bacterial cell walls are
composed of _____.
peptidoglycan
96
What has metagenomic analysis allowed researchers to do for the
first time
study organisms that cannot be cultured ( grown in lab)
97
Which of the following is true of the parasite that causes malaria in
humans?
It undergoes meiosis immediately following zygote formation
98
Why are protists considered paraphyletic?
They include some but not all descendants of their most recent
common ancestor
99
What material is not used by protists to manufacture hard outer
coverings
lignin
100
What does amoeboid motion result from?
interactions among actin, myosin, and ATP
101
According to the endosymbiosis theory, what type of organism is
the original ancestor of the chloroplast?
a cyanobacterium
102
All protists are unicellular.
false
103
The most important primary producers in marine ecosystems
| are _____.
diatoms
104
Multicellularity is defined in part by the presence of distinctive cell
types. At the cellular level, what does this criterion imply
Different cell types express different genes.
105
Land plants may have reproductive structures that (a) protect
gametes as they develop, (b) allow sperm to be transported in the
absence of water, (c) provide stored nutrients and a protective coat
so that offspring can be dispersed by wind away from the parent
plant, and (d) provide nutritious tissue around seeds that facilitates
dispersal by animals. Name each of these four structures, and state
which land plant group or groups have each structure
a) Gametangia are found in all land plant groups except
angiosperms; (b) pollen is found in gymnosperms
and angiosperms; (c) seeds are found in gymnosperms
and angiosperms, (d) fruit is found in angiosperms.
106
What does it mean to say that a life cycle is gametophyte dominant
versus sporophyte dominant
In a gametophyte-dominant life cycle, the gametophyte
is larger and longer lived than the sporophyte
and produces most of the nutrition. In a sporophytedominant
life cycle, the sporophyte generation is the
larger, longer-lived, and photosynthetic phase of the life
cycle.
107
Which of the following groups is definitely monophyletic?
green plants
108
The appearance of cuticle and stomata correlated with what event
in the evolution of land plants?
growth on land
109
What is a pollen grain?
male gametophyte
110
What do seeds contain?
embryo and nutritive tissue
111
In the life cycle of an angiosperm, the egg
is one of the cells formed by mitosis in the ovule.
112
Which of the following statements is not true?
a. Green algae in the lineage called Charophyceae are the closest
living relatives of land plants.
b. The nonvascular plants form a monophyletic group.
c. The horsetails and the ferns form a distinct lineage. They have
vascular tissue but reproduce via spores, not seeds.
d. According to the fossil record and phylogenetic analyses,
angiosperms evolved before the gymnosperms. Angiosperms are
the only land plants with vessels.
According to the fossil record and phylogenetic analyses,
angiosperms evolved before the gymnosperms. Angiosperms are
the only land plants with vessels.
113
Explain how pores in septa of certain fungi allow mycelia to
| become larger.
Pores in septa allow nutrients to move from regions
| of acquisition to regions of mycelial growth.
114
The mycelial growth habit leads to a body with a high surfacearea-
to-volume ratio. Why is this important
Mycelia have a large surface area for absorption.
115
What is plasmogamy
fusion of the cytoplasm from different mating types, without
| nuclear fusion
116
The hyphae of arbuscular mycorrhizal fungi (AMF) form bushy
structures after making contact with the plasma membrane of a
root cell. Why?
They increase the surface area available for the transfer of
| nutrients.
117
What does it mean to say that a hypha is dikaryotic?
Two independent nuclei, derived from different individuals, are
present in each cell.
118
Symbiotic partnerships in which one partner benefits and the
| other is unaffected are called _____.
commensal
119
The Greek root ecto means “outer.” Why are ectomycorrhizal fungi,
or EMF, aptly named?
Their hyphae form dense mats that envelop roots but do not
| penetrate the cell walls.
120
Lawns are sometimes fertilized with nitrate that can be washed
into neighboring woodlots by rain. If the trees in that woodlot are
associated with EMF, what effect might the excess nitrate have on
the fungi and/or trees?
The trees may take up the nitrate directly into their roots and rely less on the fungi.
121
```
What synapomorphy (shared, derived trait) distinguishes animals
as a monophyletic group, distinct from choanoflagellates?
```
multicellularity
122
All coelomates are triploblasts
True
123
In _____, the mouth develops before the anus; but in _____, the
anus develops before the mouth.
protostomes, and deuterostomes
124
Why do some researchers maintain that the limbs of all animals
are homologous
Homologous genes, such as Dll, are involved in their
| development.
125
In a tube-within-a-tube body plan, what is the interior tube?
endoderm
126
Which of the following characteristics does not apply to
| cnidarians
have a central nervous system
127
Which of the following is an example of homology (similarity due
to common ancestry)?
cnidocytes (stinging cells) in jellyfish and sea anemones
128
You have a unique opportunity to explore a pristine coral reef
in the South Pacific. You come across a small organism that you
do not recognize and that is not in your field guide. Which of
the following suites of characteristics would be most helpful in
identifying the organism’s phylum?
radial symmetry, sessile, two tissue layers.
129
The transition from water to land reduced
| protostome diversity
False
130
What is a lophophore?
a specialized filter-feeding structure
131
Why is it logical that Platyhelminthes have flattened bodies?
A flat body provides a large surface area for gas exchange, which
compensates for their lack of gas-exchange organs
132
What is the function of the arthropod exoskeleton?
It provides protection and functions in locomotion
133
One trait that is shared by the Lophotrochozoa and Ecdysozoa
| is_____.
Both groups are bilaterally symmetric triploblasts
| with the protostome pattern of development.
134
Which protostome phylum is distinguished by having body
| segments organized into tagmata
Arthropoda
135
Put the following phyla in order from least diverse
(in terms of number of named species) to most diverse: Annelida,
Mollusca, Arthropoda, Rotifera
Rotifera, Annelida, Mollusca, Arthropoda
136
The increase in red blood cell count in tourists
| visiting Tibet is an example of acclimatization.
True
137
______tissues form the interface between the inside of an animal’s
body and the environment.
epithelial
138
As an animal gets larger, which of the following occurs?
Its volume grows more rapidly than its surface area.
139
Which of the following best describes the set point in a
| homeostatic system?
the target or “normal” value of the parameter in question
140
What does it mean to say that an animal is a heterothermic
| endotherm?
Its body temperature varies, but most of its heat is produced by
its own tissues.
141
Which of the following is an advantage that ectotherms have over
endotherms of the same size?
They require much less food.
