Ch. 15 The Biosphere

1. Ch. 15The Biosphere

2. 15.1 biosphere • Part of Earth where life exists • All of Earth’s ecosystems • Biota – all living things in biosphere • Abiotic factors NOT included • Ex: water, air, rocks

3. Earth’s systems • 1) Biosphere • 2) Hydrosphere – water, ice, water vapor • 3) Atmosphere – the air around earth • 4) Geosphere – features of surface • Continents, rocks, sea floor, all below surface

4. Ecosystems are linked • Change in one sphere affects others • Ex: • What could result if plants are removed from a riverbank? • How does this affect the other spheres?

5. Gaia hypothesis • Proposed by James Lovelock • United Kingdom • Considers Earth itself a kind of living organism • Recognizes connections and feedback loops between biotic and abiotic factors • More CO2 = more plants • More plants = more O2 • More O2 = few plants • Cycle continues • Earth is NOT a thinking being!

6. 15.2 climate • Prevailing weather of a region • Includes: • Ave temp • Ave precipitation • Relative humidity • Seasonal variations

7. Microclimate • Small, specific climate within a larger climate • Very important to life • Ex: hole in rotting log • Grassy meadow • Top of tree • San Francisco

8. 3 Climate zones • Ave temp and precipitation determine • 1) polar • 2) tropical • 3) temperate

9. What determines climate? • Sun • Air and water movement • Landmasses

10. sunlight • Rays most intense (thus hottest) where strikes directly • Region near equator = most sun • Polar regions = least sun • Rays strike at lower angle/less intense • Earth’s axis • More tilted away from sun = less light = colder

11. Air and water • Movement caused by Sun when it heats Earth • Warm = less dense • Rises • Cools as it rises; releases moisture • Currents – movement in water • Connected to: • Water temp • Air movement • Earth’s rotation • Salt levels

12. Landmasses • Land heats up and cools more quickly that water • Coastal areas = smaller changes in temperature • Water evaporates faster from water than land • Coastal areas = more humid and more precipitation • Mountains– air cools as it rises • Side facing wind = wet • Downside of wind = rain shadow – area of decreased precipitation

13. Adaptations • Organisms adapt to survive • Ex: • Frog p. 433 • What enables it to survive so well? • Polar bear?

14. 15.3 Biomes • Characterized by climate and plants • 6 major biomes • Broad • Can be divided more specifically • Ice caps and mountains are NOT biomes

15. 1) Tropical rain forest • Warm temp • Lots of precipitation • Thick forests • Limiting factor = Sunlight • Little reaches ground <1% • Infertile soil • Canopy – tops of trees • Many animals • Epiphyte – plant that grows above ground (ex: on trees)

16. 2) Grassland • 2 Types • A)Tropical (Savannas) • Africa, S. America, Australia • Grasses 3-7 ft. tall • Some shrubs • Limiting factor = rainfall • Rainy and dry season • Hoofed animals dominate biome

17. 2) Grassland • B)Temperate • S. Africa, E. Europe, N. America • 20-35” rain/snow per year • Most in spring/early summer • Dry and warm summers • Many animals live below ground • Fires are common • Some seeds need fire to germinate

18. 3) Desert • Very dry (arid) • <10” precipper year • Many nocturnal animals • Plants = cacti-like or have deep roots • 4 types

19. 3) Desert • A) Hot • >100°F • Precip falls as rain • B) Semiarid • Temps rarely exceed 100°F • C)Coastal • 25°-95°F • D) Cold • Precip mostly snow

20. 4) Temperate • Distinguishable seasons • 2 Types: • A) Deciduous forest • Trees drop leaves/go dormant • 30-59” precip • Spread evenly thru year • Hot summer/cold winter

21. 4) Temperate • B) Rain forest - • Long wet season/short, dry summer • >98” precip • Evergreens dominate • Coniferous – retain needles all year

22. 5) Taiga • = Boreal forest • Cooler climates • Cold, long winter • Short, humid summers • 12-33” precip per year • Coniferous forest dominant

23. 6) Tundra • Subzero temps • North latitudes • Long winter • < 5” precip • Permafrost – permanently frozen ground • Barren • Few plants and animals

24. Minor biomes • Ex: Chaparral (Mediterranean shrubland) • Hot, dry summer • Cool, moist winter • Along S. CA coast • 15-40” rain • Read p. 438

25. Polar ice caps • No soil • No plant community • Permanently frozen • NOT a biome • Ex: Antarctica, parts of Greenland, N. Pole

26. Mountains • NOT a biome • Rich biodiversity • As elevation increases, life characteristics change • Represents various biomes • Ex: grassland at bottom • Deciduous forest in middle • Tundra at top

27. 15.4 Marine Ecosystems • Oceans • Separated into zones • Use following abiotic conditions: • Sunlight • Temp • Salinity • Turbidity (murkiness) • Depth • Water Chemistry

28. Ocean zones • Dif systems used: • 1) separates pelagic zone (open sea)from benthic zone (floor) • 2) presence of light • Photic zone vs. aphotic zone (depths) • 3) 4 zones made using: • Distance from shore • Water depth

29. System #3: 4 major Zones • 1) Intertidal – land bw high and low tide • Ex: Beach and tidal pools • Variety of conditions • Organisms must adapt • 2)Neritic – from intertidal to continental shelf • Depth = few cm to >200m

30. System #3: 4 major zones • 3) Bathyal – edge of neritic to base of continental shelf • Greek = deep • 200m to 2000m • Turbid; lots of silt • High pressure • Burrowing animals thrive

31. System #3: 4 major zones • 4) Abyssal – below 2000m • Greek = bottomless • Complete darkness • Deep sea vents • Support life • Chemosynthetic organisms • Base of food web • Strange organisms • Some make own light

32. Neritic zone life • < 1/10th of ocean • 40x more biomass than rest of ocean • Plankton – tiny, free-floating organisms • Includes: • Zooplankton – Animals • Phytoplankton - photosynthetic protists • Ex: algae • Base of food chain • Estimate produce up to 70% of all oxygen

33. Coastal habitats • Shallow waters of neritic zone • Coral reefs – tropical climate • Mutualistic relationship w algae • Algae = nutrients for reef • Reef = home for algae • Reef = mostly dead skeletons • Support lots of life • Over 400 dif species of coral • Delicate • Sensitive to pollution, temperature • Artificial reefs • Ex: shipwrecks

34. Coastal habitats • Kelp forests – cold, nutrient-rich water • = seaweed forests • Grow up to ~100 ft • High productivity • Habitat: • Ex: small invertebrates • Sea lions

35. 15.5 Freshwater • Estuary – where river flows into ocean • Salt and freshwater • Partially enclosed • Nutrient rich • Tide changes water levels • Highly productive ecosystem • Comparable to rain forest and coral reef • Contain lots of decomposers • Home to many endangered species

36. Estuaries • 75% of fish we eat depend on • “nurseries of the sea” • Fish spawn • Young mature • Birds migrate/layover here • Threats: • Humans • Development • Pollution • Erosion • Up to 80% have been lost in U.S.

37. Freshwater • Moving and standing water • Wetlands – standing water • Very productive • Help maintain clean water • Filters and renews underground supply • Ex: Bogs, marshes, swamps • ID by plant communities

38. Freshwater • Factors that affect life here • pH • Oxygen levels • Water temp • Water flow • How would a tadpole in a pond differ from that in a fast moving river?

39. Watershed • Region of land that drains into a body of water • Where lakes, streams, and ponds originate

40. 3 Freshwater zones • Lakes and ponds • Some may not have all • 1) Littoral – similar to intertidal • Between high and low water marks on shoreline • Well-lit • Warm • Shallow • Diverse organisms: • Invertebrates • Water plants

41. 3 freshwater zones • 2) Limnetic (pelagic) – open water farther from shore • Lots of plankton • 3) Benthic - bottom • Less sunlight • Many decomposers

42. Water “turn over” • Water differs in temp • “layers” separated by thin zone called thermocline • Water most dense at 39° F • When reaches this temp, it sinks below other water whether warmer or colder • Moving all year • Mixes nutrients from bottom