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Communities and Biomes

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Presentation on theme: "Communities and Biomes"— Presentation transcript:

1 Communities and Biomes

2 Community Collection of several interacting populations that inhabiting a common environment.

3 Abiotic factors and biotic factors determine an organisms ability to survive

4 (food availability, temperature, and predators)
Limiting Factors Environmental factors that affect the organism’s ability to survive in its environment. (food availability, temperature, and predators)

5 Limiting Factors Biotic or abiotic
Restrict existence, numbers, reproduction or distribution of an organism. Factors that limit one population in a community, may indirectly effect another E.g. Lack of water limits grass growth—reducing seed growth, mice need seeds for food, no food, populations reduce.

6 Ranges of Tolerance Organisms ability to withstand fluctuations in biotic and abiotic environmental factors Populations varies according to its tolerance for environmental changes.


8 Succession Orderly, natural changes and species replacements that take place in communities over time.

9 Succession Occur in stages; different species at different stages create conditions that are suitable for some organisms and not suitable for others. Difficult to observe; happen over long periods of time.

10 Primary Succession Initial colonization of new sites
Lava from volcano; Avalanche Pioneer species—First species in the area (e.g. Lichen) Climax Community—A stable, mature community that undergoes little or no change in species. Over time as a community or organisms change and develop (additional habitats emerge, new species move in, and old species disappear) Areas become forest of vines, trees, and shrubs, inhabited by birds and other forest-dwelling animals. Gradual changes over time.


12 Pioneer species colonize
Growth continues until community becomes fairly stable. Pioneering organism dies, decaying into soil. Presence of soil makes it possible for weedy plants, small ferns, and insects to become established Soil builds up, seeds borne by wind blow into soil, and begin to grow Area becomes forest of vines, trees, and shrubs. Birds and other animals.

13 Secondary Succession Sequence of changes that take place after a community is disrupted by natural disaster or human actions.

14 Secondary Succession Gradual changes over time
Area previously contained life Land that contains SOIL Different pioneer species May have same climax community, with similar climate. Faster to develop because soil exist.


16 Biomes: Large areas that have characteristics of climax communities

17 Biome Factors Altitude and Latitude Temperature and Precipitation
Major limiting factors

18 Biomes Aquatic Biomes—Marine, Freshwater, Estuaries (3/4 of Earth’s surface covered by aquatic biomes) Terrestrial Biomes—Tundra, Taiga, Desert, Grassland, Deciduous Forest, Tropical Rain Forest.



21 Marine Biomes Oceans Photic Zone—Portion of marine biome that is shallow enough to penetrate sunlight (coastlines-Shore, beaches, mudflats) Aphotic Zone—Deeper waters that do not receive sunlight. (Deep, least explored oceans) Phos—Light (Greek) A—without (Greek)


23 Marine Life Largest amounts of biomass (living materials) though often very small Whales, seals, sea otters, sea cows Kelp, algae, sea grass



26 Estuary Bay, sound, fjord, salt marshes, wetlands
Freshwater mixes with salt water (some land) Brackish Water ( more salt than freshwater; but less than marine) Salinity ranges Amount of freshwater vs.. Saltwater Tides Biodiversity

27 Estuary Life Eelgrass, smooth cordgrass, sea lavender
Shiner Perch, Starry Flounder Orange Striped Jellyfish, Purple Shore Crab, Scallop Predators—cranes and other birds Decay of dead organisms is quick, nutrients recycled through food web.


29 Tides: Gravitational pull of sun and moon cause the rise and fall of ocean tides.

30 Intertidal zone—Portion of the shoreline that lies between the high and low tide lines
Size depends on slope of the land and tide height. High levels of sunlight, nutrients and oxygen (But productivity may be limited by waves/tides) Differ in rockiness and wave actions Snails, sea stars, mussels, barnacles, clams, worms, crabs

31 Tide Pools: Pools of water left when the water recedes at low tide, can land lock organisms until next tide. Vary greatly in nutrient and oxygen levels


33 Ocean Bottom/Photic Zone
Less affected by waves and tides Nutrients washed from the land by rainfall contribute to abundant life and high productivity. Plankton—Small organisms that live in waters of photic zone.**removal great impact Autotrophs—diatoms Heterotrophes—juvenile stages of many marine animals.

34 Ocean Bottom/Aphotic Zone
Almost 90 % of ocean is > than a km deep. Animals living there far and few, depend on photic zone where plankton live for food (directly or indirectly) Fish adapted to darkness and scarcity of food


36 Freshwater Biomes Major abiotic factors: temperature and light
Not enough sunlight penetrates to bottom to support photosynthesis few aquatic plants or algae grow Population density lower Bacteria break down dead organisms and recycle nutrients.

37 Freshwater Life Concentric bands of species Cattails, sedges
Tadpoles, aquatic insects, turtles, worms, crayfish, beetles, dragonflies, minnows, bluegill, carp.


39 Terrestrial Biomes


41 Tundra Treeless land; long summer days; short periods of winter sunlight Temperatures never rise above freezing

42 Underneath topsoil is a layer of permanently frozen ground. (Mammoths)
Permafrost Underneath topsoil is a layer of permanently frozen ground. (Mammoths)

43 Tundra Organisms Shallow-rooted grasses (sedges), small plants, reindeer moss (lichen) Soil lacking in nutrients; decay process slow due to cold temperatures. Mosquitoes, lemmings, weasels, artic foxes, snowshoe hares, musk oxen, caribou, reindeer.


45 Taiga/Boreal Forest South of tundra Warmer and wetter than tundra
Climatic conditions—long, severe winters, short, mild summers. Canada, Northern Europe, Asia. Permafrost absent Topsoil—decaying coniferous needles Pines/evergreens (acidic and poor in minerals)

46 Taiga Organisms PLANTS Northern coniferous (cone bearing) forest
Larch, fir, hemlock, spruce trees Fire/Logging disrupts taiga-first trees to re-colonize are birch, aspen, or other deciduous species. ANIMALS Raccoons, bears, lynxes, wolves, ruff-legged buzzards, caribou, ox, artic fox


48 Desert Arid region Sparse to almost nonexistent plant life
Less than 25 cm of precipitation annually Atacama Desert (Chile)—one of dryest places in the world.

49 Desert Organisms PLANTS
Drought-resistant trees—mesquites, cacti, creosote bush ANIMALS Lizards, tortoises, snake, coyotes, hawks, owls, roadrunners, scorpions.


51 Grasslands/Prairies/ Steppes/Pampas/Savannas
Large communities covered by grasses and similar small plants Yellowstone National Park Fewer than 10 to 15 trees per HECTARE! (a unit of surface, or land, measure equal to 100 areas, or 10,000 square meters: equivalent to Most terrestrial area Higher biological diversity than desert—more than 100 species per acre.

52 Animals: herd animals, fox, prairie dogs, coyotes, weasels, Red-tailed Hawks, bison, lions, antelope and lynx. Plants: buffalo grass, ryegrass, foxtail, wild oats, and purple needlegrass Wildflowers: wild indigos, clovers, sunflowers, goldenrods, blazing stars, and asters Species


54 Temperate Forests Many types Precipitation: 70 to 150 cm annually
Dominated by broad-leaved Hardwood tress that lose their foliage annually. Soil—top layer rich in humus and deep layer of clay. Animals—Black bears, deer, squirrels, salamanders, mice, blue jays Plants—birch, hickory, oak, beech and maple.

55 Tropical Rain Forest More species of organisms anywhere
Warm temperatures (25C), high humidity, and abundant rain fall, lush plant growth Biodiversity makes important protect Near equator Precipitation: 200 cm annually (some 600 cm)

56 Why so many species in rain forest?: Hypothesis
Location near equator—not covered with ice during last ice age—more time to evolve Warm weather, do not drop leaves, year round growing conditions for plants, creates greater food supply, therefore supports more organisms. Provide a multitude of possible habitats for diverse organisms. More layers allowing more for organisms to exist. (Many organisms find their niche)

57 Tropical Rain Forest Continued
Nutrients are tied up in living materials (few soil) Decomposers do their work Rainforest trees have roots and mycorrhizae that enable them to absorb nutrients. Trees are cut for their hardwoods (mahogany), for farming, and to produce grasslands for cattle.


59 Layers of the Rain Forests

60 EMERGENT LAYER Highest layer. Tallest trees. Resemble umbrellas
Researcher built towers and aerial walkways in the trees. Birds, butterflies and small monkeys live with bats, snakes and bugs.

61 Kapok Tree Brazil Nut Tree

62 CANOPY Trees : meters Only a few taller trees push to make the emergent layer Treetops stop a lot of the light from entering the forest. Protects the soil from erosion from rains. Birds, monkeys, frogs, and sloth, as well as lizards, snakes and many insects

63 Howler Monkey Spider Monkey

64 Understory Trees that reach the canopy.
Wait until a gap appears which they can then grow into. Small, thin trunks. 20 meters tall. This layer is the home to birds, butterflies, frogs and snakes.

65 hummingbirds

66 SHRUB LAYER Grows between the smaller trees of the understory and the forest floor. ferns and small shrubs

67 FOREST FLOOR Very dark (Estimated that only 2% of the sunlight actually reaches the floor) Layer of leaves, twigs and dead plants, which rot down quickly to provide nutrients for the plants (Home to invertebrates and microorganisms, which quickly rot down this surface layer) The soil is very sandy with only a thin layer of rotting vegetation. Without the trees, the soil quickly loses its ability to support plants and turns to desert-like conditions.

68 Rainforest floor Organisms
Plants—Ferns and Mosses Animals—tigers and elephants in Asia, gorillas and leopards in Africa and tapirs and jaguars in South America.

69 Amazon River Dolphin


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