Create an account
the process in which CO2 in the atmosphere intercepts and absorbs reflected infrared radiation and reflects it back to Earth is known as
when one species was removed from a tidepool, the species richness became significantly reduced. the removed species was probably a
which of the following is an example of an ecosystem?
zebras, cheetahs, and antelope living on the African savanna
carrying capacity is
the number of animals or people a given area of land or water can support over time
which of the following is a likely graphic outcome of a population of deer introduced to an island with an adequate herbivory and without natural predators, parasites, or disease?
grows at first, then makes a straight vertical line on time
an ecological footprint is a construct that is useful
for a person living in a developed nation to consider to make better choices when using global food and energy resources
the greatest cause of the biodiversity crisis that includes all of the others is
overpopulation by humans
how is habitat fragmentation related to biodiversity loss?
populations of organisms in fragments are smaller and, thus, more susceptible to extinction
what is the term for a top predator that contributes to the maintenance of species diversity among its animal prey?
extinction is a natural phenomenon. it is estimated that 99% of all species that ever lived are now extinct. why then do we say that we are now in a biodiversity crisis?
the current rate of extinction is high and human activities threaten biodiversity at all levels
which of the following describes carbon dioxide, methan, and water vapor re-reflecting infrared radiation back toward earth?
which of the following causes an increase in the intensity of UV radiation reaching the earth?
a depletion of the atmospheric ozone
subtraction of which of the following will convert gross primary productivity into net primary productivity?
the energy used by autotrophs in respiration
which of the following is true of detrivores?
they convert organic materials from all trophic levels to inorganic compounds usable by primary producers
In a tide pool, 15 species of invertebrates were reduced to eight after one species was removed. The species removed was likely a(n)
Dwarf mistletoes are flowering plants that grow on certain forest trees. They obtain nutrients and water from the vascular tissues of the trees. The trees derive no known benefits from the dwarf mistletoes. Which of the following best describes the interactions between dwarf mistletoes and trees?
Use the surviorship curves in Figure 53.1 to answer the following questions. Which curve best describes survivorship in elephants?
Use the survivorship curves in Figure 53.1 to answer the following questions. Which curve best describes survivorship in marine mollusks?
You are observing a population of lizards when you notice that the number of adults has increased and is higher than previously observed. One explanation for such observation would include
In which of the following terrestrial biome pairs are both dependent upon periodic burning?
Chaparral and savanna
Generalized global air circulation and precipitation patterns are caused by
Rising, warm, moist air masses 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 main reason polar regions are cooler than the equator is because
Sunlight strikes the poles at a lower angle
Which of the following are important biotic factors that can affect the structure and organization of biological communities?
Sow bugs become more active in dry areas and less active in humid areas. This is an example of
A chemical produced by an animal that serves as a communication to another animal of the same species is called
To increase the effectiveness of exchange surfaces in the lungs and in the intestine, evolutionary pressures have
Increased surface area
The heartworms that can accumulate with the hearts of dogs and other mammals have a pseudocoelom, an alimentary canal, and an outer covering that is occasionally shed. To which phylum does the heartworm belong?
A radially symmetrical animal that has two embryonic tissue layers probably belongs to which phylum?
You are trying to identify an organism. It is an animal, but it does not have nerve or muscle tissue. It is neither diploblastic nor triploblastic. It is probably a
In addition to seeds, which of the following characteristics are unique to the seed-producing plants?
Which of these taxa contains species that produce potent toxins that can cause extensive fish kills, contaminate shellfish, and poison humans?
Which of these is the most common compound in the cell walls of gram-positive bacteria?
Which of the following pairs are the best examples of homologous structures?
Bat wing and human hand
One species mates at the season when daylight is increasing from 13 hours to 13 hours, 15 minutes; another species mates at the season when daylight is increasing from 14 hours to 14 hours, 15 minutes.
What is generally true of two very closely related species that have diverged from each other quite recently?
They share a common ancestor recently in evolutionary time
Fossil evidence indicates that horses have gradually increased in size over geologic time. Which of the following terms best describes this?
Which of the following statements best summarizes evolution as it is viewed today?
It is the differential survival and reproduction of the most-fit phenotypes
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.4. What is the percentage of the population that is homozygous for this allele?
Each of the following has a better chance of influencing gene frequencies in small populations than in large populations, but which one most consistently requires a small population as a precondition for its occurrence?
Which of these is the smallest unit that natural selection can change?
A population's gene frequency
Which statement best describes the evolution of pesticide resistance in a population of insects?
Offspring of insects that are genetically resistant to the pesticide become more abundant as the susceptible insects die off
Natural selection is based on all of the following except
Individuals adapt to their environments and, thereby, evolve
Darwin's mechanism of natural selection required long time spans in order to modify species. From whom did Darwin get the concept of Earth's ancient age?
What was the prevailing notion prior to the time of Lyell and Darwin?
Earth is 6,000 years old and populations are unchanging
What does the operon model attempt to explain?
The coordinated control of gene expression in bacteria
Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes
Excision of introns
A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is
3' UCA 5'
What is meant by the description "antiparallel" regrarding the strands that make up DNA?
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand
Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
What is the mechanism for the production of genetic recombinants?
Crossing over and independent assortment
Males are more often affected by sex-linked traits than females because
Males are hemizygous for the X chromosome
Huntington's disease is a dominant condition with late age of onset in humans. If one parent has the disease, what is the probability that his or her child will have the disease?
A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?
The F1 offspring of Mendel's classic pea cross always looked like one of the two parental varieties because
One allele was completely dominant over another
Chiasmata are what we see under a microscope that let us know which of the following is occuring?
Which of the following occurs in meiosis but not in mitosis?
Synapsis and allignment of tetrads at metaphase plate
Which of the following is true of a species that has a chromosome number of 2n = 16?
There are 8 homologous pairs
The formation of a cell plate is beginning across the middle of a cell and nuclei are re-forming at opposite ends of the cell. What kind of cell is this?
A plant cell undergoing cytokinesis
A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei each containing how many chromosomes?
Which term describes centromeres uncoupling, sister chromatids separating, and the two new chromosomes moving to opposite poles of the cell?
From the perspective of the cell receiving a message, the three stages of cell signaling are
Signal reception, signal transduction, and cellular response
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?
The synthesis of ATP
When oxygen is releaed as a result of photosynthesis, it is a by-product of which of the following?
Splitting the water molecules
In any ecosystem, terrestrial or aquatic, what group(s) is (are) always necessary?
Producers and primary consumers
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
ATP and NADPH
For each molecule of glucose that is metabolized by glycolysis and the citic acid cycle, what is the total number of NADH + FADH2 molecules produced?
The oxygen consumed during cellular respiration is involved directly in which process or event?
Accepting electrons at the end of the electron transport chain
When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a hydrogen ion) the molecule becomes
When you have a severe fever, what may be a grave consequence if this is not controlled?
Change in the folding of enzymes
Which of the following is true of enzymes?
They accelerate the rate of chemical reactions and many activities in living organisms require multiple enzymes
Why is ATP an important molecule in metabolism?
It provides energy coupling between exergonic and endergonic reactions
The sodium-potassium pump is called an electrogenic pump because it
Contributes to the membrane potential
A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water, equal to the volume of blood lost, is transferred directly into one of his veins. What will be the most probable result of this transfusion?
The patient's red blood cells will swell because the blood fluid is hypotonic compared to the cells
Which of the following types of molecules are the major structural components of the cell membrane?
Phospholipids and proteins
Which of the following relationships between cell structures and their respective functions is NOT correct?
Chloroplasts: Chief sites of cellular respiration
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
At which bond would water need to be added to achieve hydrolysis of the peptide back to its component amino acid? Refer to Figure 5.6 to answer the following questions.
All of the following statements concerning saturated fats are true except
They have multiple double bonds in the carbon chains of their fatty acids
Which of the following solutions has the greatest concentration of hydrogen ions [H+]?
Gastric juice pH 2
The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
What is the difference between covalent bonds and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms, and ionic bonds involve the electrical attraction between atoms
About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?
Carbon, hydrogen, nitrogen, and oxygen
For most ecosystems, _________ is (are) the ultimate source of energy, and energy leaves the ecosystem in the form of _________.
Please allow access to your computer’s microphone to use Voice Recording.
Having trouble? Click here for help.
We can’t access your microphone!
Click the icon above to update your browser permissions and try again
Reload the page to try again!Reload
Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
Please upgrade Flash or install Chrome
to use Voice Recording.
For more help, see our troubleshooting page.
Your microphone is muted
For help fixing this issue, see this FAQ.
Star this term
You can study starred terms together