Community Collection of several interacting populations that inhabiting a common environment.
Abiotic factors and biotic factors determine an organisms ability to survive
Limiting Factors Environmental factors that affect the organism’s ability to survive in its environment. (food availability, temperature, and predators)
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.
Ranges of Tolerance Organisms ability to withstand fluctuations in biotic and abiotic environmental factors Populations varies according to its tolerance for environmental changes.
Succession Orderly, natural changes and species replacements that take place in communities over time.
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.
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.
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.
Secondary Succession Sequence of changes that take place after a community is disrupted by natural disaster or human actions.
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.
Biome Factors • Altitude and Latitude • Temperature and Precipitation • Major limiting factors
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.
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)
MarineLife • Largest amounts of biomass (living materials) though often very small • Whales, seals, sea otters, sea cows • Kelp, algae, sea grass
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
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.
Tides: Gravitational pull of sun and moon cause the rise and fall of ocean tides.
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
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
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.
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
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.
Freshwater Life • Concentric bands of species • Cattails, sedges • Tadpoles, aquatic insects, turtles, worms, crayfish, beetles, dragonflies, minnows, bluegill, carp.
Tundra • Treeless land; long summer days; short periods of winter sunlight • Temperatures never rise above freezing
Permafrost Underneath topsoil is a layer of permanently frozen ground. (Mammoths) http://news.bbc.co.uk/2/hi/science/nature/6284214.stm
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.
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)
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
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.
Desert Organisms PLANTS • Drought-resistant trees—mesquites, cacti, creosote bush ANIMALS • Lizards, tortoises, snake, coyotes, hawks, owls, roadrunners, scorpions.