Ch. 3: Communities and Biomes

1. Ch. 3: Communities and Biomes

2. What is Climate? • Weather • Day-to-day condition of the Earth’s atmosphere at a particular time and place • Climate • Refers to the average year-after-year conditions of temperature and precipitation in a particular region

3. The Greenhouse Effect • Carbon dioxide, methane, water vapor, and a few other atmospheric gases trap heat energy and maintain Earth’s temperature range • Greenhouse Effect • Natural situation in which heat is retained by this layer of greenhouse gases

5. The Effects of Latitude on Climate • As a result of differences in latitude and thus the angle of heating, Earth has three main climate zones: polar, temperate, and tropical

6. Climate Zones

7. Heat Transport in the Biosphere • The unequal heating of the Earth’s surface drives wind and ocean currents, which transport heat throughout the biosphere

8. Biotic and Abiotic Factors • Biotic factors • Include all living organisms that inhabit and environment. • Abiotic factors • The nonliving parts of an organism’s environment. • Examples: • Air currents, soil, temperature, light and moisture • These factors typically determine species survival.

9. Succession: Changes over Time • Ecological Succession • The orderly, natural changes and species replacements that take place in the communities of an ecosystem • Eventually a climax community (a stable, mature community that undergoes little or no change in species) results.

11. Primary Succession – the sequential development of living communities from bare rock • Example – volcano erupting • Pioneer species – the first species to populate the area • Secondary Succession – occurs when communities are disrupted • Examples – forest fire, hurricane

14. Biomes • Biome • A complex of terrestrial communities that covers a large area • Characterized by certain soil and climate conditions and particular plants and animals. • Tolerance • Ability to survive and reproduce under conditions that differ from their optimal conditions.

15. The Major Biomes • Includes: • Tropical rain forest, tropical dry forest, tropical savanna, desert, temperate grassland, temperate woodland and shrubland, temperate forest, northwestern coniferous forest, boreal forest, and tundra. • Two climate factors, temperature and precipitation, are the major limiting factors for the formation of terrestrial biomes.

16. Tropical Rain Forest • Home to more species of organisms than any other place on earth • Warm temperatures (25°C), wet weather (200 cm – 600 cm per year) • Lush plant growth • Located near the equator • Vertical layering (ground, understory, & canopy)

17. Tropical Rain Forest (cont.) • Plants: hardwoods (mahogany), orchids, moss and ferns • Animals: monkeys, birds, bats, chameleons, snakes, jaguar, ants, termites, and earthworms • Soil not nutrient rich

19. Tropical Dry Forest • Rainfall is highly season • Trees lose their leaves during the dry season - deciduous • Located just above and below the equator • Plants: deciduous trees, orchids and bromeliads, and aloes • Animals: tigers, elephants, rhinoceroses, termites, snakes and monitor lizards

20. Tropical Savanna • Characterized by a cover of grasses • Spotted with isolated shrubs and trees • Compact soils and fairly frequent fires • Plants: tall perennial grasses, trees and shrubs • Animals: lions, leopards, cheetahs, hyenas, jackals, elephants, giraffes, zebras, eagles, ostriches, and termites

21. Desert • Driest biome: less than 25cm of precipitation annually • Plants: cacti and small shrubs • Animals: desert tortoises, snakes, coyotes, hawks, owls, roadrunners, lizards, and scorpions

23. Grassland “Breadbaskets of the World” • Large community covered with grasses and similar small plants • Experience a dry season • Contains fewer than 10 – 15 trees per hectare • Animals: grazing animals (bison), coyotes, wolves, prairie dogs, insects, birds and reptiles • Plants: any type of grasses (oats, rye, wheat)

25. Temperate Woodland and Shrubland • Semiarid climate • Characterized by open woodlands, large areas of grasses and wildflowers with oak trees • Plants: evergreen shrubs, herbs • Animals: coyotes, foxes, bobcats, mountain lions, blacktailed deer, rabbits, quails, lizards and snakes

26. Temperate Forest • Between 70 – 150 cm of precipitation annually • Top layer of soil is very rich • Plants: Dominated by broad leaved deciduous hardwoods, conifers, flowering shrubs, ferns • Animals: squirrels, deer, rabbits, mice, black bears, bluejays, and salamanders This is where we live.

28. Northwestern Coniferous Forest • Moist air from the Pacific Ocean provides abundant rainfall • Located along the northern California coast • Plants: Douglas fir, Sitka spruce, western hemlock, redwoods • Animals: bears, elk and deer, beavers, owls, bobcats and weasels

29. Boreal Forest (Taiga) • Along the northern edge of the temperate zone • Winters are bitterly cold but summers are mild • Acidic nutrient-poor soil • Plants: spruce, fir, berry-bearing shrubs • Animals: lynxes, timber wolves, moose, beavers, migratory birds

31. Tundra • Treeless land with long summer days and short periods of winter sunlight • Temperatures never rise above freezing for long • Permafrost – permanently frozen ground under the topsoil • Thin topsoil can only support shallow-rooted grasses and other small plants; lacks nutrients

32. Tundra • Process of decay is slow because of cold temperatures • Short growing season • Plants: grasses, dwarf shrubs, & cushion plants • Animals: migratory waterfowl, shore birds, musk ox, artic foxes, caribou and lemming

35. Aquatic Ecosystems • Aquatic ecosystems are determined primarily by the depth, flow, temperature, and chemistry of the overlying water.

36. Freshwater Ecosystems • Two main types: • Flowing-water ecosystems • Rivers, stream, creeks and brooks • Originate in mountains or from an underground water source • Upstream: insect larvae, catfish, trout • Downstream: turtles, beavers and river otters

37. Two main types: (cont.) • Standing-water ecosystems • Lakes and ponds • Water is usually circulating within them • Organisms: plankton ( tiny, free-floating organisms) • Phytoplankton – algae • Zooplankton – animal-like that feed on phytoplankton

38. Freshwater Wetlands • Wetland – an ecosystem in which water either covers the soil or is present at or near the surface of the soil for part of the year • Water may be flowing or standing and can be freshwater, salt water or brackish • 3 main types: bogs, marshes and swamps

39. Estuaries • Estuaries • wetlands formed where rives meet the sea • Affected by the high and low tide • Producers: plants, algae and bacteria • Detritus – organic matter that provides food for clams, worms and sponges • Serve as spawning grounds for shrimp and crabs

40. Salt marshes • temperate-zone estuaries dominated by salt-tolerant grasses • Located along eastern North America from Maine to Georgia • Mangrove swamps • Coastal wetlands along the tropical regions including Florida (Everglades) and Hawaii • Plants: salt-tolerant trees and seagrasses • Serve as nurseries for fish and shellfish

42. Marine Ecosystems • Photic zone – shallow enough for sunlight • Photosynthesis occurs here through algae and other producers • Aphotic zone – deeper water that never receives sunlight • Chemosynthetic autotrophs live here

43. Marine Ecosystems (continued) • Marine biologists divide the oceans into zones based on the depth and distance from the shore. • Intertidal zone • Coastal ocean • Open ocean

45. Marine Ecosystems (continued) • Intertidal Zone • Organisms that live here are exposed to regular and extreme changes in their surroundings • Submerged twice a day and exposed to air, sunlight, and temperature changes rest of the day. • Zonation- prominent horizontal banding of organisms that live in a particular habitat

47. Marine Ecosystems (continued) • Coastal Ocean • Extends from the low-tide mark to the outer edge of the continental shelf (relatively shallow border that surrounds the continents) • Located in the photic zone and is rich in plankton and other organisms • Kelp forests – named for the giant brown algae that can grow up to 50 cm a day • Most productive coastal ocean communities

48. Marine Ecosystems (continued) • Coral Reefs • Named for the coral animals whose hard, calcium carbonate skeletons make up their primary structure • Most diverse and productive environment • Thrive only in brightly lit areas within 40 meters of the surface

49. Marine Ecosystems (continued) • Open Ocean • Begins at the edge of the continental shelf and extends outward • Largest of the marine zone (covers more than 90% of the surface of the world’s oceans) • Depth is from 500 m to 11,000 m • Organisms exposed to high pressure, frigid temperatures, and total darkness

50. Marine Ecosystems (continued) • Open Ocean (continued) • Has very low levels of nutrients and supports only the smallest producers • Most of the Earth’s photosynthetic production occurs in the part of the open ocean in the photic zone (due to the enormous area) • Common organisms: squid, octopus, whale, dolphins, swordfish, variety of fish