1 / 62

Chapter 34

Chapter 34. The Biosphere: An Introduction to Earth's Diverse Environments. A Mysterious Giant of the Deep Deep-sea submersibles are revealing the diversity of life beneath the ocean Giant squid Hydrothermal vent communities

libra
Download Presentation

Chapter 34

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 34 The Biosphere: An Introduction to Earth's Diverse Environments

  2. A Mysterious Giant of the Deep • Deep-sea submersibles are revealing the diversity of life beneath the ocean • Giant squid • Hydrothermal vent communities • Animals, such as tube worms, living on energy produced by chemoautotrophic bacteria • Ecology is the scientific study of the interactions of organisms with their environments

  3. Video: Hydrothermal Vent Video: Tubeworms

  4. 34.1 Ecologists study how organisms interact with their environment at several levels • Organism • Individual organisms interacting with the environment • Population • Group of individuals of the same species living in a particular geographic area

  5. Community • All the populations of different species that inhabit a particular area • Ecosystem • All the biotic and abiotic components in a certain area • Ecological research is conducted in the field as well as in the lab and with models

  6. THE BIOSPHERE • 34.2 The biosphere is the total of all of Earth's ecosystems • The biosphere is the global ecosystem • Atmosphere to an altitude of several kilometers • Land down to 3,000 m beneath Earth's surface • Oceans to a depth of several kilometers • The biosphere is self-contained and characterized by patchiness

  7. CONNECTION • 34.3 Environmental problems reveal the limits of the biosphere • No part of the biosphere is untouched by human activities • Current awareness of the biosphere's limits stems from past environmental practices • Rachel Carson warned of the effects of pesticides in 1962

  8. 34.4 Physical and chemical factors influence life in the biosphere • Major abiotic factors determine the biosphere's structure and dynamics • Solar energy • Water • Temperature • Wind • Disturbances such as fire, hurricanes

  9. 34.5 Organisms are adapted to abiotic and biotic factors by natural selection • Species exist in a given place because they evolve there or disperse there • Unique adaptations that fit a particular environment allow organisms to survive there • Example: pronghorns • Organisms vary greatly in their ability to tolerate fluctuations and long-term changes in their environment

  10. 34.6 Regional climate influences the distribution of biological communities • Because of its curvature, Earth receives an uneven distribution of solar energy • The tilt of the Earth's axis causes the seasons of the year • Globe's position relative to the sun changes through the year • The tropics experience the least seasonal variation in solar radiation

  11. LE 34-6a North Pole 60°N Low angle of incoming sunlight 30°N Tropic of Cancer Sunlight strikes most directly 0° (equator) Tropic of Capricorn 30°S Low angle of incoming sunlight 60°S South Pole Atmosphere

  12. LE 34-6b March equinox (equator faces sun directly) June solstice (Northern Hemisphere tilts toward sun) Constant tilt of 23.5° December solstice (Northern Hemisphere tilts away from sun) September equinox

  13. Uneven heating of the Earth sets up patterns of precipitation and prevailing winds • Doldrums are near the equator • Trade winds dominate the tropics • Seasonal climate variation and more moderate temperatures exist in the temperate zones • Prevailing winds are major global air movements

  14. LE 34-6c Descending dry air absorbs moisture Descending dry air absorbs moisture Ascending moist air releases moisture Trade winds Trade winds Doldrums 0° 23.5° 23.5° 30° 30° Temperate zone Tropics Temperate zone

  15. LE 34-6d 60°N 30°N 30°S

  16. Ocean currents have a profound effect on regional climates • Generally modify climate of nearby land • Landforms can also affect local climate • Variations in climate determine the character of the world's biomes

  17. LE 34-6e Fresno 104° 40 miles Death Valley 119° Paso Robles 93° Bakersfield 106° Pacific Ocean Burbank 86° San Bernardino 101° Santa Barbara 75° Key Riverside 91° Los Angeles (Airport) 74° 70s (°F) Santa Ana 84° Palm Springs 104° 80s 90s 100s 110s San Diego 75°

  18. LE 34-6f Wind direction East Pacific Ocean Sierra Nevada Coast Range

  19. AQUATIC BIOMES • 34.7 Oceans occupy most of Earth's surface • Abiotic factors influencing the distribution of aquatic biomes • Light • Distance from shore • Availability of nutrients • Oceanic zones • Intertidal zone: where land meets ocean

  20. Pelagic zone: open ocean • Contains phytoplankton and zooplankton • Benthic zone: seafloor • Photic zone: illuminated regions of the pelagic and benthic zones • Photosynthesis occurs • Aphotic zone: vast, dark region underlying the photic zone • Most extensive part of the biosphere

  21. LE 34-7b Intertidal zone 0 Photic zone 200 m Pelagic zone Continental shelf Benthic zone (seafloor) Aphotic zone 2,500–6,000 m

  22. Continental shelf: submerged part of a continent • Coral reef: found in warm waters above continental shelf • Biologically very diverse • Estuary: area where freshwater stream or river merges with ocean • Among the most productive biomes on Earth

  23. Wetland: area that is transitional between an aquatic and terrestrial ecosystem • Aquatic communities are environmentally threatened Video: Coral Reef Video: Clownfish and Anemone

  24. 34.8 Freshwater biomes include lakes, ponds, rivers, streams, and wetlands • Light has a significant effect on freshwater biomes • All but the most shallow ponds and lakes have photic and aphotic zones • Temperature creates stratification of water • Availability of nutrients and dissolved oxygen influence organic growth • Nitrogen and phosphorus runoff create algal blooms

  25. Rivers and streams support communities quite different from those of lakes and ponds • Freshwater wetlands range from swamps to marshes and bogs • Great ecological and economic value

  26. TERRESTRIAL BIOMES • 34.9 Terrestrial biomes reflect regional variations in climate • Many biomes are named for climatic features and predominant vegetation • Each biome is also characterized by the organisms adapted to that environment • The distribution of biomes depends largely on climate • Within each biome there is local variation

  27. LE 34-9 30°N Tropic of Cancer Equator Tropic of Capricorn 30°S High mountains Tropical forest Temperate grassland Savanna Temperate broadleaf forest Polar ice Coniferous forest Desert Tundra Chaparral

  28. 34.10 Tropical forests cluster near the equator • Rainfall generally determines the type of vegetation in a tropical forest • Tropical rain forests are the most complex of all biomes • Very high diversity • Complex structure • Human impact is of great concern

  29. 34.11 Savannas are grasslands with scattered trees • Savannas are dry and warm • Frequent fires inhibit invasion by trees • Large grazing animals migrate during seasonal droughts

  30. 34.12 Deserts are defined by their dryness • Deserts are the driest terrestrial biomes • Can be hot or cold • Cycles of growth and reproduction are keyed to rainfall • Animals are adapted to drought and extreme temperatures • Desertification is a significant environmental problem

  31. 34.13 Spiny shrubs dominate the chaparral • The chaparral is a region of dense, spiny shrubs with tough, evergreen leaves • In midlatitude coastal areas • Cool, rainy winters and dry, hot summers • Vegetation adapted to periodic fires

More Related