Uplift and formation of a mountain range divide 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) allopatric speciation.
C) incomplete speciation.
D) diversifying speciation.
Answer: B
You might also like to view...
Which of the following offers the best description of neural transmission across nearly all mammalian synaptic clefts?
A. Neural impulses involve the flow of K+ and Na+ across the cleft. B. Neural impulses travel across the gap as electrical currents. C. Neural impulses cause the release of chemicals that diffuse across the cleft. D. Neural impulses travel across the cleft in both directions. E. The calcium within the axons and dendrites of nerves adjacent to a synapse acts as the neurotransmitter.
The electron transport system
A. requires a membrane. B. utilizes the nuclear membrane of eukaryotes. C. utilizes the mitochondrial membrane of prokaryotes. D. generates a concentration gradient of protons. E. requires a membrane AND generates a concentration gradient of protons.
How did researchers explain the smaller size of sexual maturity for guppies in some Trinidad streams?
a. Some low-quality streams have small carrying capacities, which forces guppies to reach sexual maturity more quickly b. Smaller streams require that individual fish be smaller at sexual maturity. c. Smaller sexually mature guppies were those that had hybridized with killifish, another small fish found in Trinidad. d. When predators select larger fish, the smaller fish reaching sexual maturity will experience increased fitness.
Which one of the following steps of the scientific method should come only after a hypothesis has been formed?
A. question formulation B. resource exploration C. experimentation D. observation