CHAPTER 34 The Biosphere: An Introduction to Earth's Diverse Environments

1. CHAPTER 34The Biosphere: An Introduction to Earth's Diverse Environments Modules 34.7 – 34.11

2. AQUATIC BIOMES 34.7 Oceans occupy most of Earth's surface • Oceans cover about 75% of the Earth's surface • Light and the availability of nutrients are the major factors that shape aquatic communities

3. The saltiness of estuaries ranges from less than 1% to 3% • They provide nursery areas for oysters, crabs, and many fishes • They are often bordered by extensive coastal wetlands • Estuaries are productive areas where rivers meet the ocean Figure 34.7A

4. Salt marshes, sand and rocky beaches, and tide pools are part of the intertidal zone • It is often flooded by high tides and then left dry during low tides • The intertidal zone is the wetland at the edge of an estuary or ocean, where water meets land Figure 34.7B

5. Intertidal zone • Abiotic conditions dictate the kinds of communities that ocean zones can support Continental zone Photiczone Pelagiczone Benthiczone(seafloor) Aphoticzone Figure 34.7C

6. It supports highly motile animals such as fishes, squids, and marine mammals • Phytoplankton and zooplankton drift in the pelagic zone • The benthic zone is the ocean bottom • It supports a variety of organisms based upon water depth and light penetration • The pelagic zone is the open ocean

7. Photosynthesis occurs here • The aphotic zone is a vast, dark region of the ocean • It is the most extensive part of the biosphere • Although there is no light, a diverse and dense population inhabits this zone • The photic zone is the portion of the ocean into which light penetrates

8. They support a huge diversity of invertebrates and fishes • Coral reefs are easily degraded by • pollution • native and introduced predators • human souvenir hunters • Coral reefs are found in warm tropical waters above the continental shelf Figure 34.7D

9. 34.8 Freshwater biomes include lakes, ponds, rivers, streams, and wetlands • Lake and pond communities are shaped by • light • temperature • the availability of nutrients and dissolved oxygen

10. A river environment changes greatly between its source and its mouth • Temperature, nutrients, currents, and water clarity vary at different points Figure 34.8A

11. Wetlands are among the richest biomes in terms of species diversity Figure 34.8B

12. TERRESTRIAL BIOMES 34.9 Terrestrial biomes reflect regional variations in climate • Climatic differences, mainly temperature and rainfall, shape the major biomes that cover Earth's land surface • Biomes tend to grade into each other • Within each biome there is local variation • This gives vegetation a patchy, rather than uniform, appearance

13. Major terrestrial biomes 30º N Equator 30º S Tropical forest Polar and high-mountain ice Temperate deciduous forest Savanna Chaparral Coniferous forest Desert Temperate grassland Tundra (arctic and alpine) Figure 34.9

14. 34.10 Tropical forests cluster near the equator • Several types of tropical forests occur in the warm, moist belt along the equator Figure 34.10

15. Large-scale human destruction of tropical rain forests continues to endanger many species • It may also alter world climate • The tropical rain forest is the most diverse ecosystem on Earth

16. 34.11 Talking About Science: Ecologist Arial Lugo studies tropical forests in Puerto Rico • The Luquillo Experimental Forest in Puerto Rico allows ecologists to study the effects of disruption on tropical forests • It contains deforested as well as still-forested areas Figure 34.11B

17. He and other scientists have offered valuable insight into the peril these forests face as well as the promise they hold • Studies indicate that tropical forests recover from natural disasters much more readily than they do from human destruction • The forest ecologist Dr. Ariel Lugo has been one of the key scientists at the Luquillo Experimental Forest Figure 34.11A