Alligators excavate holes in the bottom of bodies of water. During times of severe drought these holes act as refugia for various aquatic organisms that might perish if there were no water available. Thus, alligators in this system can be classified as a(n)
A. keystone species.
B. symbiotic species.
C. sympatric species.
D. allopatric species.
E. refugistic species.
A. keystone species.
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The zoo decides to keep all of Gus and Ida's descendants under zoo conditions for the next 30,000 years. They breed only with each other. You visit the zoo in 30,000 years and see their offspring
Do you expect their offspring, which are alive in 30,000 years, to be identical in genotype and phenotype to Gus and Ida? Keep in mind, polar bears start reproducing when they are between 5 and 10 years old, and adult females give birth to two cubs every 2-3 years. A. Yes, because evolution only occurs in nature. B. Yes, because they had a small population to begin with (only two bears), so there was little genetic variation to start. C. No, because mutation would occur occasionally and there are selective pressures that exist in artificial as well as natural environments. D. Maybeâ€"it depends on mutation rates and strength of selective pressures.
In some rocky intertidal habitats, the barnacle Chthamalus can survive across the same depths as can the barnacle Balanus
However, where the two occur together, Chthamalus adults are found only in the more stressful upper portions of the habitat where they are more prone to desiccation. This is an example of: A. the mutualistic form of symbiosis. B. intraspecific competition reducing the size of Chthamalus' fundamental niche to a smaller realized niche. C. mutualism reducing the size of Balanus' realized niche to a smaller fundamental niche. D. competitive exclusion reducing the size of Chthamalus' fundamental niche to a smaller realized niche. E. competitive exclusion expanding the size of Balanus' realized niche to a larger fundamental niche.
Which of the following sequences of skeletal muscle proteins is correctly listed from smallest to largest?
A) actin, titin, nebulin, myosin B) actin, myosin, nebulin, titin C) titin, nebulin, actin, myosin D) myomesin, myosin, titin, nebulin E) actin, myosin, titin, troponin
If a person has a recessive allele for a disorder and that allele is masked by the presence of a normal dominant allele, this person
A. is homozygous for the disease. B. cannot produce gametes. C. has the disease but cannot pass this disease to their offspring. D. is termed a carrier. E. is termed a linkage group.