Uplift and formation of a mountain range divides a freshwater snail species into two isolated populations. Erosion eventually lowers the mountain range and brings the two populations together again, but when they mate, the resulting hybrids all produce sterile young. This scenario is an example of
a. sympatric speciation
b. punctuated equilibrium
c. allopatric speciation
d. the gradual model of speciation
Answer: c. allopatric speciation
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Sometimes a prokaryotic activator protein interacts with a small molecule in the cell and undergoes a change in shape that alters its affinity for binding to DNA. This change in shape is an example of an ____ effect
Fill in the blank with the appropriate word.
Which of the following statements is false?
A. The use of antibiotics causes mutations in bacteria for antibiotic resistance. B. Once evolved, antibiotic resistance can be passed between different species of bacteria. C. Failure to complete a course of antibiotics selects for pathogens that are least susceptible to antibiotics. D. Some diseases, such as tuberculosis, have strains that are so antibiotic resistant that they are essentially untreatable. E. None of the answer options is false.
A genotype refers to
A) the alleles present in an individual. B) expression patterns of certain genes. C) the environmental components of a trait. D) the number of chromosomes that a person has.
Select all the ways lymph moves in one direction through lympatic vessels. Select all that apply
A) skeletal muscle contraction B) presence of one-way valves C) pumping of the heart D) movement of synergistic bacteria