chapter 8 test review

chapter 8 test review - Exploring Environmental Issues 1301...

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Exploring Environmental Issues 1301, Dr. Marcum Test 2 review sheet CHAPTER 8 – Biodiversity What are genetic, species and ecosystem diversity, and why are they important? - genetic diversity: differences in DNA composition and among individuals within species and populations. - Species diversity: species richness and relative abundance. - Ecosystem diversity: number and variety of ecosystems, or the diversity of biotic community types and habitats. Why isn’t it easy to know how many species are on Earth? - Some of them have probably not been discovered yet. - Some are difficult to identify. What is the Latitudinal Gradient, and why does it occur? - The latitudinal gradient can be described like this: as one moves closer to the equator, species richness increases. - Why does it occur? Towards the equator, there is more solar energy, heat, and humidity, which may lead to more plant growth and the ability of an ecosystem to support more animal life. Also, climate is relatively stable and ensures the coexistence of many species. Describe previous mass extinctions, and why this one (the 6th) is fundamentally different from the others. - Ordovician, Devonian, Permo-Triassic, End-Triassic, Cretaceous-Tertiary. - The most severe was at the end of the Permian, when close to 54% of all families, 90% of all species, and 95% of marine species went extinct. - The best-known: the end of the Cretaceous, when an apparent asteroid impact brought an end to the dinosaurs and many other groups. -
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This note was uploaded on 05/05/2008 for the course ENV 1301 taught by Professor Larrylehr during the Spring '07 term at Baylor.

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chapter 8 test review - Exploring Environmental Issues 1301...

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