Natural Selection unit test
A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.
Stabilizing selection
Hardy-Weinberg equations
Convergent evolution
Frequency-dependent selection
Sexual selection
Heritability requirement
Adaptive radiation
Artificial selection
Variation as the raw material
Antibiotic and pesticide resistance
Mass extinction and its effects
Phylogenetic tree
Short answer 1. Define or explain: Speciation
3 ptsShort answer 2. Define or explain: Gene flow
3 ptsShort answer 3. Define or explain: Natural selection
3 ptsShort answer 4. Define or explain: Molecular clock
3 ptsFree response
4 ptsTwenty million years ago the Caribbean Sea and the Pacific Ocean were connected and water flowed freely between them; many of the same marine species were found in both areas. Over millions of years the land now called the Isthmus of Panama formed, eventually closing the connection and creating two separate bodies of water. The ecology of the two marine habitats was dramatically altered: warm Caribbean water could no longer flow west, so the Pacific water cooled and became more nutrient-rich while the Caribbean water became warmer. The same land formation connected two continents, North America and South America. Many North American land animal species migrated to South America after the isthmus formed and occupied niches similar to those of South American species.
(a) Describe the genetic evidence that evolution is occurring in a population.
(b) Explain how the isolation of marine species by the formation of a land barrier can lead to divergent evolution of those species.
(c) Predict the effect the formation of the isthmus had on resource availability for South American species.
(d) Justify your prediction in part (c).