Exam 4 2010 SA Key


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1 SHORT ANSWER QUESTIONS: You MUST answer ONLY 4 of these questions. Draw an X through the Q you are choosing not to answer. SA 1 . Tropical forests are biomes of spectacular natural beauty and remarkable species diversity (10 points total, A-D) A) What do biologists mean when they talk about a latitudinal gradient in species diversity and provide an example of evidence that such a gradient exists? (2 pt.) Species diversity increases towards the equator (or declines with increasing latitude, or increases with decreasing latitude) (1). The species richness (or biodiversity) of [birds, fish, plants, insects, pretty much all taxa] declines as you move away from the equator towards the poles (1). B) What two abiotic factors are suggested to contribute to species richness in the tropics (1 pt.), what term do we use to describe their combined effects (1 pt.) and with what ecosystem process are they associated? (1 pt.) Rainfall (1/2) and temperature (or solar energy) (1/2) Evapotranspiration (1) Net Primary Production (1) C) An estimated 250 million people on earth use “shifting cultivation” as their major form of agriculture. Describe the 3 components of a typical shifting agriculture system (3 pt.) Clearing of land for planting (1) Growing crops on the land until fertility declines (1) Then leaving the land fallow so that it recovers (1) D) Name two ecological consequences of tropical deforestation (2 pt.) Many are possible, including (1 point each for two total): Declining biodiversity Soil erosion Loss of carbon sequestration Increase in atmospheric C0 2 pool leading to climate change
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2 SA 2 . The phylum Chordata includes a wide diversity of animal species from tunicates to birds (10 points total, A-D). A) Tunicates are representatives of a very early branch within the phylum Chordata but are not vertebrates. What four structural characteristics do tunicates possess that confirm their membership in the Phylum Chordata (2 pt.)? Are tunicates Deuterostomes or Protostomes? (1 pt.)? Notochord (1/2), hollow dorsal nerve cord (1/2), pharyngeal slits (1/2), post-anal tail (1/2) Deuterostomes (1) B) The evolution of jaws in the vertebrates was a major innovation that allowed the harvesting of food by biting. From what structure(s) did vertebrate jaws evolve (1 pt.)? In what group of organisms are the fin bones homologous with the tetrapod limb (1 pt)? (anterior) gill arches (1) Lobe-finned fishes (or coelacanths, or lungfish) (1) C) The first tetrapods evolved during the Devonian period. What habitats/organisms became available on land at this time that facilitated the evolution of the tetrapods (2pt.)? extensive forests and/or marshes and/or swamps were available (2)
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This note was uploaded on 05/29/2010 for the course BIO 171 taught by Professor Josephinekurdziel during the Winter '08 term at University of Michigan.

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