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In the late 1960’s, Robert Paine conducted landmark studies on diversity in the rocky intertidal zone comparing the species diversity in control plots with diversity in experimental plots from which he removed the top predator, sea stars. After 5 years, 15 species of intertidal invertebrates lived in the control plots, while the experimental plots were dominated by only two species, one mussel and one barnacle. Why did species diversity most likely remain high in the presence of a predator?
a. The sea star kept the mussel and barnacle populations low enough to prevent competitive exclusion from occurring.
b. The sea star kept the mussel and barnacles from developing a mutualistic relationship. That, in turn, kept their populations low.
c. The mussel and the barnacle parasitized the sea star, keeping populations low enough to prevent competitive exclusion from occurring.
d. The sea star developed a mutalistic relationship with the mussel and barnacle, keeping their populations low and preventing competitive exclusion from happening.
2. _____ can have similar effects on population sizes as predators; that is, keeping populations below carrying capacity and limiting competitive exclusion.
b. Interspecific competitors
c. Facultative mutualists
e. Obligate mutualists
Five species of ants can be found on aspen sunflowers (Helianthella quinquenervis), which live in wet mountain meadows of the Rocky Mountains. The aspen sunflowers provide nectar to the ants in special structures called extrafloral nectaries. The ants, in turn, protect the sunflowers from other insects. The ants, however, are not found solely on the sunflowers—they can be found tending aphids on other flower species and collecting nectar from other species as well. This, then, is an example of a(n):
a. obligate mutualism
b. obligate antagonism
c. facultative mutualism
d. facultative antagonism
In a pond, tadpoles eat algae and fish eat the tadpoles. Above the pond, grasshoppers eat grass and, at night, are preyed upon by bats. Other bats eat the fish that eat the tadpoles. In this community, the fish-eating bats are:
a. primary producers.
b. primary consumers.
c. secondary consumers.
d. tertiary consumers.
In the Sierra Nevada Mountains of California there are many populations of the checkerspot butterfly Euphydryaseditha. You notice that females of one population lay their eggs near the tip of a plant’s stem (population A). Females of another population in the same area lay their eggs at the base of the stem on a different type of plant (population B). The young hatch out as caterpillars; they live on the host plant and eat its leaves. If we want to know only whether or not a population is getting larger or smaller, what are the variables we need to know?
births deaths emigration immigration
You are surveying biodiversity on a new island chain. You have counted the number of bird species on one island already. The next island is larger and closer to the mainland than the one you have just surveyed. According to the theory of island biogeography, the total number of its bird species should be ______ than on the current island because the rate of immigration to the new island should be ______ and the rate of extinction should be ______.
Phylogenies suggest that Anolis lizards colonized Hispaniola:
b. two or three times.
c. four or five times.
d. five or six times.
e. a dozen times or more.
Male peacocks have tail feathers that make up about 60% of their body length. During the mating season they shake these feathers in front of females. Longer feathers produce a larger rustling sound for a given shaking rate, but they are also heavier, and thus require more energy to shake at a given rate than shorter feathers. This suggests that ______________.
a. selective pressures will continue selection for longer and longer peacock tails
b. selective pressures will always result in shorter peacock tails to reduce the energetic cost of shaking
c. there are selective pressures against too long or too short of a tail, which results in the variable tail lengths
Some types of fish have specialized cells called electrocytes that generate an electric field around their body using specialized Na+ channels they produce and insert into their plasma membrane. As sodium channels are proteins, this behavior __________________.
a. has a genetic basis because proteins are produced through gene expression
b. is a learned behavior
c. is dependent on environmental conditions
d. does not change regardless of input from the environment
e. does not have a genetic basis because proteins are produced independent of the genome
Salamanders are amphibians with very interesting mating rituals. The males perform species specific dances that attract females to mate. Male salamanders deposit spermatophores (mucus packets filled with sperm) on leaves, twigs, or the ground and guide females over them so females can take them up into their cloaca. Mating dances like this result in internal fertilization in many salamander species. Which of the following statements best explains why salamanders are not entirely terrestrial?
a. Salamanders require water for gas exchange.
b. Salamanders simply lay their eggs near the water in which they live.
c. Internal fertilization is the first necessary step toward non-dependence on water for reproduction.
d. Salamanders do not produce amniotic eggs; therefore, they require water for reproduction because eggs need protection from desiccation.
Gastrulation results in the formation of:
a. a bilaminar embryo consisting of the epiblast and the hypoblast.
b. a trilaminar embryo consisting of the epiblast, the mesoblast, and the hypoblast.
c. a gastrula consisting of a trilaminar embryo.
d. a trilaminar embryo consisting of ectoderm, endoderm, and mesoderm.
e. a bilaminar gastrula consisting of the epiblast and the hypoblast.
Why do mitochondria and chloroplasts have small genomes?
a. They have small genomes because their bacterial ancestors did.
b. They have small genomes because they do not need many genes to function.
c. They have small genomes because they lack non-coding DNA.
d. They have small genomes because over time, much of their nucleic acid has migrated to the host cell nucleus.
Which one of the following correctly lists features of eukaryotic cells that distinguish them from prokaryotic cells?
a. a dynamic cytoskeleton, dynamic system of membranes, relatively limited metabolic capabilities
b. a dynamic cytoskeleton, dynamic system of membranes, flexible, wide-ranging metabolic capabilities
c. a dynamic cytoskeleton that permits cellular movement, the ability to carry out photosynthesis, and the ability to switch from haploid to diploid stages in their life cycle
Of all the green algae, which are most closely related to land plants?
d. red algae.
Pollinating insects are in part responsible for _____ diversity.
a. flowering plant
c. predatory insect
e. none of these
The water-to-land transition was achieved through a series of significant morphological and physiological changes. Which of the following did not contribute to the transition?
a. The ability to breathe air.
b. The evolution of appendages that could support the weight of the body.
c. The evolution of jaws for better prey capture and feeding.
If current changes in ocean temperature and pH caused a mass extinction of today’s reef-building organisms,
a. we would see an unprecedented mass extinction, unlike anything the earth has experienced in the past.
b. we would see one more in a series of mass extinctions that have wiped out reefs at least 3 times since the first reefs appeared over 500 million years ago.
c. we would see one more in a series of mass extinctions that have wiped out reefs at regular intervals – roughly every 10 million years since the first reefs were formed over 500 million years ago.
d. we would see the second great mass extinction of reefs; the only previous such extinction took place at the end of the Permian.
Human ABO blood groups are determined by a single gene with 3 alleles: A, B, and O. In a sample of 300 individuals, 100 are blood type A and genotype AA, 100 are blood type B and genotype BO, and 100 are blood type O and genotype OO. What are the allele frequencies?
a. 33.3% A, 33.3% B, 33.3% O
b. 33.3% A, 33.3% B, 66.6% O
c. 33.3% A, 16.6% B, 50% O
d. 25% A, 25% B, 50% O
e. 50% A, 25% B, 25% O
A population of charmingly charismatic rodents, population A, lives on a small island. The population consists of 100,000 individuals and it has been isolated for over ten thousand years. Do you expect to find that all individuals of A genetically identical?
The majority of an individual fungus lives “in” its food source. What characteristics of the fungal growth form make this a necessity?
a. Fungi have a high ratio of surface area to volume and are highly susceptible to dessication.
b. Fungi have a low ratio of surface area to volume and are highly susceptible to dessication.
c. Fungi require the stimulus of “pushing” through the substrate to stimulate growth.
d. Fungi require more nutrients than other organisms, and large amounts of nutrients can only be acquired by living in a host.
Imagine that sexual reproduction could occur between hyphae that were the same mating type. How might this affect rates of evolution in fungi?
a. Rates of evolution would be lower because genetic variation would be lower.
b. Rates of evolution would be higher because more novel genetic combinations are generated through sexual reproduction.
c. Rates of evolution would stay the same because as long as sexual reproduction is occurring, it does not matter if it is between individuals of the same or different mating type.
A researcher is looking at different petri dishes containing the yeast C. albicans. In the first dish she evaluates, she notices that the yeast do not form hyphae. Is this a mutant strain of yeast?
a. Yes, as the lack of hyphae denotes pathogenic yeast.
b. Yes, as yeast typically form hyphae.
c. No, as yeast do not normally form hyphae.
d. No, as yeast always form rhizoids and not hyphae.
Which one of the following organisms has coenocytic organization?
d. green algae (Codium and Caulerpa)
Organisms that are dependent on oxygen for cellular respiration depend on which of the following processes to move oxygen into cells?
a. simple diffusion
b. active transport
d. facilitated diffusion
Most plants are firmly rooted in place and are not mobile. Which of the following is not
an adaptation to this condition?
a. growth by mitosis
b. the presence of hairs, spines, and toxins
c. the ability to survive long periods of unfavorable conditions
d. cell walls
In a phylogenetic tree, a node or branching point represents:
a. the common ancestor from which the descendent species diverged.
b. the species in the fossil record from which the descendent species diverged.
c. one of the descendent species in the phylogeny.
d. the ancestral species from which all species in the phylogeny arose.
e. A node could be any of these, depending on the nature of the phylogenetic tree.
To be useful for phylogenetic reconstruction, a taxonomic character must exhibit which of the following properties? (Select all that apply.)
a. It must vary among the taxa being analyzed, but not within individual taxa.
b. It must have a genetic basis.
c. It must be anatomical.
d. It must be molecular (DNA or protein).
e. None of the above.
*a. It must vary among the taxa being analyzed, but not within individual taxa.
*b. It must have a genetic basis.
Recall that the bullhorn acacia forms a symbiosis with Pseudomrymex. ferruginea
ants. A researcher takes an acacia seed and plants it in an area without P. ferruginea. What will happen to this acacia plant?
a. It will immediately form a symbiotic relationship with ants native to the area.
b. It will begin producing alkaloids and terpenes to deter herbivores.
c. It will begin to produce hairs on its leaves to deter herbivores.
d. Without P. ferruginea, the plant won’t form any new defenses and will be eaten by herbivores.
All plants that produce chemical compounds to deter herbivores make the same compounds.
A plant’s fitness is directly related to its ability to deter predators; the more it invests in defenses, the higher its fitness.
Plants from which of the following groups died off as angiosperms diversified and became more abundant? Select all correct choices.
Which taxonomic group of land plants still in existence today was the dominant group of land plants when the angiosperms began their rapid increase in speciation and distribution?
b. ferns and horsetails
Which of these plants are phylogenetic sister group to the pine trees and apple trees?
b. wheat and mosses
c. mosses and ferns
d. wheat and ferns
What are advantages of root meristems originating at the pericycle, rather than at other root structures (e.g., the epidermis)? (Select all that apply.)
a. New roots form only at the tips of pre-existing roots, reaching deep-water sources.
b. New roots are directly connected to the xylem and phloem of pre-existing roots.
c. New roots form outside of the Casparian strip and can absorb more nutrients.
d. New roots can sprout from any location (i.e., not just nodes) on pre-existing root
Auxin moves between cells through a process called polar transport. Auxin molecules move from one cell to the next through PIN proteins. However, their movement is unidirectional. What accounts for this unidirectional movement?
a. PIN proteins are only found on the basal side of the cell.
b. PIN proteins are only found on the apical side of the cell.
c. Auxin diffuses down its concentration gradient. The concentration of auxin molecules decreases as you move down the stem away from the apical meristem.
d. Auxin moves independently of its concentration gradient because the presence of the PIN protein provides a channel that auxin can “leak” through to get into adjacent cells.
A researcher creates a mutant pea plant in which cytokinins are overexpressed and gibberellic acid is underexpressed. What is the most likely phenotype of this mutant pea plant?
a. The pea plant would be shorter with more branches compared to wild-type plants.
b. The pea plant would be taller with more branches compared to wild-type plants.
c. The pea plant would be shorter with fewer branches compared to wild-type plants.
d. The pea plant would be taller with fewer branches compared to wild-type plants.
Which of the following processes do not require plants to spend energy? Choose all that apply.
a. water transport through xylem
b. carbohydrate transport through phloem
c. C3 photosynthesis
d. C4 photosynthesis
e. nutrient transport across endoderm cells
A researcher determines that her favorite plant has a symbiotic relationship with fungi. Upon closer examination, she notices that fungal cells form a sheet enclosing the root epidermis, but no arbuscules are present. Of what type of relationship is this an example? (Select all correct answer options.)
Stomatal closure is passive because ______________.
a. K+ and Cl– diffuse from high to low concentration
b. water diffuses from low to high concentration
c. ATP is required
d. it conserves leaf hydration
a. K+ and Cl– diffuse from high to low concentration
During photosynthesis, _____ is reduced to _____. .
a. water; carbon dioxide
b. carbon dioxide; glucose
c. oxygen; water
d. glucose; oxygen
e. carbon dioxide; oxygen
Which of the following could be true if a plant cell is exposed to a toxin that makes the thylakoid membrane freely permeable to hydrogen ions? (choose all that apply)
a. There would be no ATP available to drive carbohydrate synthesis in the Calvin cycle.
b. There would be no ATP needed to split water molecules early in the light-dependent pathway.
c. There would be no ATP produced in the chloroplasts to power photosynthesis in the absence of light energy.
d. ATP generated by the mitochondria would be used to power photosynthesis, so the plant cells would not have enough ATP left to supply the many other processes that require it.
e. The amount of NADPH in the chloroplast would increase.
f. The amount of carbohydrate produced would increase.
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