Ecology chapters 2-5 Ecology ( oikos: home) The scientific study of the interactions of organisms with their environments Factors Abiotic and biotic factors drive natural selection The organism that best fits the environment has the advantage to pass on it’s genes Key Abiotic Factors: Sunlight, Water, Temperature, Soil, Wind, Sever Disturbances Organisms/Environment Interaction Organism: Single organism Population: Single species Community: All living organisms Ecosystem: Abiotic & Biotic Biome: Large group of ecosystems that share the same climate Biosphere: Earth’s ecosystem Ecosystem Interactions Habitat: Area where an organism lives Niche: An organisms role in the environment (Food, shelter, reproduction) Biome, ecosystem, habitat, niche Competition Competitive exclusion principle: No two species can occupy the same niche at the same time. Interspecific: Competition between different species Intraspecific: Competition between individuals of the same species Predation Adaptations Predation: One organism pursues and consumes another organism Coevolution: When one organism changes the organism that depends on it must change also. Camouflage (crypsis) Chemical defense (aposmatic) Batesian mimicry Symbiosis Parasitism: One benefits, one is harmed Commensalism: One benefits, other is nether helped or harmed Mutualism: Both benefits Energy Flow & Chemical Cycling Energy flow: The passage of energy through an ecosystem Energy must be added Chemical cycling: The circular movement of materials within an ecosystem Chemicals are recycled Energy in an ecosystem Autotrophs: Collects energy from sunlight or inorganic substances to produce food Heterotrophs: energy from consuming other organisms Herbivore: Eats only producers (plants) Carnivores: Eat other heterotrophs Omnivours: Eat heterotrophs and autotrophs Detritovors: Eat dead organisms (worms) Decomposers: Final release of chemicals (fungus) Trophic Structure Food chain: The sequence of food transfer from trophic level to trophic level Producers, primary consumers, secondary consumers, tertiary consumers, quaternary consumers Detritivours, decomposers Food Chain vs Food Web Food web: Network of interconnected food chains Everything is dependent on other organisms Energy Pyramid Energy supply limits the length of the food chain Biomass: The amount of organic matter in an ecosystem Cycles in the Biosphere Matter: Anything that takes up space and has mass Nutrient: Chemicals that an organism must obtain from the environment to sustain life Biogeochemical cycles: Water, carbon, nitrogen phosphorus Global Water Cycle Driven by heat from the sun Three major processes: Precipitation, Evaporation, Transpiration Carbon Cycle Cycle of photosynthesis and cellular respiration Plants take in CO2 from the atmosphere and convert it to organic material. Animals take in organic material and release CO2 Nitrogen Cycle Atmospheric nitrogen can not be taken directly by animals Certain plants and bacteria must convert it to a form animals can take in Nitrates Community Ecology Range of tolerance: The variations of physical & chemical factors that support a population Limiting factors: Factors that sets the carrying capacity of the population Ecological Succession Primary succession - new environments (Volcanoes, glaciers, strip mines) Secondary succession - communities were destroyed or displaced Fires, farming Climax community - forest Climate Regional climate influences the distribution of biological communities Climate often determines the distribution of communities Earth's global climate patterns are largely determined by the input of solar energy and the planet's movement in space Microclimate: Small-scale differences in a climate (Under a rock or log) Climate Distribution Earth’s tilt causes the seasons Tropics: Between 23.50 north and 23.50 south Temperate zone: Latitudes between tropics and arctic circle Polar zones: North of 66.50 N & south of 66.50 S Wind Patterns Doldrums: Air currents rising from the equator causes area of light winds (horse latitudes) Trade winds: Descending air mass heading back to equator Prevailing winds: combined effects of rising and lowering air masses Westerlies: Winds from west to east Ocean Currents Greenhouse Effect Greenhouse effect: The trapping of heat by gasses in the upper troposphere Greenhouse gasses: Water vapor, carbon dioxide, methane, and nitrous oxide Natural occurrence Allowed life on Planet Earth Excess gasses from burning fossil fuels is causing global warming Biomes Biomes are major terrestrial ecosystems that cover large regions of the Earth Tropical forest, Savanna, Desert, Chaparral, Temperate grassland, Temperate deciduous forest, Coniferous forest, Tundra, Tropical Rain Forest Equatorial, 11-12 hours daylight, Greater than 200 cm of rain per year, Most complex biome, Temperature: 24oC – 27oC Savanna Precipitation: 50-130 cm, Temperature: 20oC-30oC, Grasses & scattered trees, Frequent fires, Large herbivores Desert Regions of descending air (30o north & 30o south), Precipitation: 2-26 cm, Temperature: high 20oC, 49oC ,low -18oC, 10oC, Warm days cold nights, Rain Shadow,Rate of evaporation exceeds precipitation Chaparral (shrubland) Precipitation: 38-100 cm, Temperature: 10oC – 40oC, Dense, spiny shrubs, Cool ocean currents, Mild rainy winters, long hot summers, Mediterranean & southern California Temperate Grasslands Precipitation: 50-89 cm, Mostly treeless, cold winters, Seasonal droughts, fires, grazing Temperate Deciduous Forest Precipitation: 75-150 cm, 35o to 50o latitude, Broadleaf trees (oak, beech, hickory, maple, birch), Very cold winters, hot summers, High rain fall Coniferous Forest Precipitation: 30-84 cm, Cone-bearing trees (spruce, pine, fir), Taiga: Northern (boreal) forests, Harsh winters, mild summers, Thin acidic soil, Fire needed Tundra Precipitation: 15-25 cm, Permafrost, Extremely cold, Brief summer, Arctic and alpine Freshwater Life Zones Littoral zone: Top shallow sunlight area from the shore to depth which rooted plants stop growing Limnetic zone: Open sunlight layer to the depth light can penetrate Profundal zone: Deep open water where light cannot penetrate, low O2 levels Benthic: Bottom of the lake Types of Lakes Oligotrophic: Nutrient poor lakes, Deep, Steep banks, Clear with little sediments, Young lakes Eutrophic: Nutrient rich lakes, Shallow, Shallow banks, Murky, Older lakes Vertical Stratification The photic zone is the portion of the ocean into which light penetrates Photosynthesis occurs here The aphotic zone is a vast, dark region of the ocean It is the most extensive part of the biosphere Although there is no light, a diverse and dense population inhabits this zone Estuaries are productive areas where rivers meet the ocean The saltiness of estuaries ranges from less than 1% to 3% They provide nursery areas for oysters, crabs, and many fishes They are often bordered by extensive coastal wetlands Saltwater Life Zones Coastal wetlands: Land areas covered with water all or part of the year Inlets, bays, sounds, mangrove forest swamps, salt marshes Wide fluctuations in temperature and salinity Mangrove forest swamps Buffers from storms, Filter water, Build new land Marine Zonation Neritic zone: low tide line to continental shelf The intertidal zone is the wetland at the edge of an estuary or ocean, where water meets land Salt marshes, sand and rocky beaches, and tide pools are part of the intertidal zone It is often flooded by high tides and then left dry during low tides Pelagic Biomes The pelagic zone is the open ocean It supports highly motile animals such as fishes, squids, and marine mammals Phytoplankton and zooplankton drift in the pelagic zone The benthic zone is the ocean bottom It supports a variety of organisms based upon water depth and light penetration Coral Reefs Coral reefs are found in warm tropical waters above the continental shelf They support a huge diversity of invertebrates and fishes Coral reefs are easily degraded by pollution, native and introduced predators human souvenir hunters Hydrothermal Vents Openings in ocean floor that spew mineral-rich, superheated water Primary producers are chemoautotrophic bacteria; use sulfides as energy source Population Characteristics Population density: Number of organisms per unit area Population distribution (dispersion): Clumping (most common) Uniform Random Density Factors Density-dependent factors: Population-limiting factors whose effects depends on population density. Food, nest site Density-independent factors: Abiotic factors that control population Climate, weather Population Growth Cycles Boom-bust cycle: A rapid increase in population followed by a sharp decline Usually found in a predator-pray situation Lynx & snowshoe hares Exponential Growth The rate of expansion of a population under ideal conditions when the whole population multiplies by a constant factor during constant time intervals. Exponential growth model: Gives a picture of unregulated growth of a population Logistic Growth Model A description of population growth that is slowed by limiting factors. Population limiting factors: Environmental factors that restrict population growth Carrying capacity: Number of individuals that the environment can maintain with no net increase or decrease. World Population Growth Overall population growth has slowed from 2.2% to 1.25%. (0.6 by 2050 predicted) Death rate has fallen more than birth rate ~ 219,000 new people per day 97% in developing nations China: 1.3 billion people (20%) India: 1.1 billion people (17%) U.S.A.: 294 million people (4.6%) Human Population Growth Demography: Study of population size, density, distribution, movement, birth and death rate Population growth rate: Birthrate – deathrate + migration rate = PGR (%) 10 Diversity Biodiversity: The number of species in a given area Genetic diversity: The variety of genes in the gene pool Ecosystem diversity: The variety of ecosystems in the biosphere Threats to Biodiversity Background extinction: Local environmental changes cause a low number of species to go extinct (~ 1-5 species per 1 million) Mass extinction: Widespread sometimes global in which 25% to above 70% of the species goes extinct Mass depletion: Extinction rate is higher than background extinction but does not reach mass extinction rates Habitat destruction, Habitat fragmentation, Introduced species, Overexploitation, Pollution Biological magnification: The concentration of a toxin is greatly increased the further it is passed up the food chain Rachel Carson was one of the first to perceive the global dangers of pesticide abuse Carson documented her concerns in the 1962 book Silent Spring This book played a key role in the awakening of environmental awareness Eutrophication Enrichment of a body of water with nutrients Can occur naturally over long time span Can be triggered by pollutants Acid Precipitation Acid rain: Sulfur & nitrogen from burning fossil fuels combine with water, forming sulfuric and nitric acid Mainly caused from the burning of coal for the generation of electricity, Denatures plant enzymes, Kills fish Conserving Biodiversity Natural resources Renewable resources Nonrenwable resources Sustainability: Using just enough resources so as not to effect the next generation Restoring Ecosystems Bioremediation: Using living organisms to detoxify a polluted area Biological augmentation: Using natural predators to a degraded ecosystem Fixing the Problem Focusing on hot spots Understanding an organisms habitat Balancing the demands for resources Planning for a sustainable future Buffer zones Sustainable development GETTING INVOLVED!!!!!!!!!!!!!