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Terms in this set (1127)

A, C, and D
The geological fossil record generally agrees quite well with phylogenetic reconstruction from DNA sequence comparisons. Scientists now use one to help resolve ambiguities in the other.
Biological evolution refers only to populations - change in the frequency of heritable variants in a population over generations. Therefore, it cannot apply to an individual (unless studying the population of microbes in the individual's gut, or the population of cancer cells in an individual patient's tumor).
Although genetic variants that may not be useful at the time may be useful in an altered environment of the future, they are not maintained in anticipation of such changes, because no organism or population can predict the future. Predictable, recurring changes (day/night, seasons) are a different story.
Changing environments do not induce new mutations (unless we're talking about exposure to mutagens), and they certainly do not induce new mutations that are favorable for adaptation. Changing environments select among pre-existing genetic variants in the population.
Evolution and natural selection are constrained by the variants that exist in the population. These variants in turn are constrained and influenced by the prior evolutionary history of the organism. For example, the optimal design for humans may be to have another pair of eyes in the back of our heads, or another pair of arms, but that kind of genetic variation is not possible given the constraints of mammalian body plans, which are constrained by tetrapod body plans, that evolved upon a framework of vertebrate body plans.
Two types of sticklebacks (fish), benthic and limnetic, live in Paxton Lake, British Columbia. The benthic type has the same number of chromosomes as the limnetic type. Researchers working on the sticklebacks have made the following observations:

1.Limnetic and benthic sticklebacks differ in number of dorsal spines, number of lateral plates, and presence of a pelvic girdle.
2.Limnetic and benthic stickleback males build their nests in the same region on the nearshore lakebottom of Paxton Lake. However, benthic males select heavily vegetated areas while limnetic males select bare areas of the lake bottom. Limnetic and benthic males differ in courtship behaviors.
3. When given a choice in laboratory experiments, male and female benthics and limnetics choose to mate with their own kind.
4. Benthics are stout-bodied fish with wide mouths that feed on invertebrates in the mud in the shallow margins of the lake. Limnetics are slim-bodied fish with narrow mouths that feed on zooplankton in the center of the lake.
5. 1-2% of sticklebacks in Paxton Lake are natural hybrids.
6. Lab-bred hybrid fish were released in a small BC lake that lacked a resident stickleback population. 20 years later, a small, healthy population of sticklebacks is well established in the lake.

Which pieces of information provided are necessary and sufficient to assess if the benthic and limnetic sticklebacks of Paxton Lake represent separate species according to the biological species concept?

Numbers 1-6.
All except number 1
Numbers 2, 4, 6
Number 6 only.
Numbers 5 and 6.