BSCI Review Guide ECOLOGY Ecology is the study of the effects of the environment on living organisms the effect of living organisms on the environment and the effects of living organisms on each other Plant ecology is the interaction among plants and between plants and the environment Population is all members of a single species living together Habitat is the location where the population is found the address of an organism Niche are the functional role an organism plays in the ecosystem it encompasses habitat plus relationships with other organisms in the ecosystem Plant community is when different populations of plants live together in the same geographical area The dominant species are the most influential species in the community They control the structure and species composition of the community Physical factions include light wind and humidity Chemical factors include nutrients pH Ecosystem is the functional unit of study in the environment A community with all its living organisms are biotic Non living organisms are abiotic Abiotic factors include non living components of the environment climate light soil inorganic substance biogeochemical cycles carbon water nitrogen phosphorus Carbon cycle CO2 enters plants through photosynthesis carbon is relases back to the air through respiration fossil fuels formed from remains humans upset the carbon cycle through global deforestation and more CO2 released through burning of fuels carbon dixiode acts as heat trap capturing sunlight and the consequence is global warming Water cycle water enters the atmosphere as vapor from the land and transpiration from plants vapor condenses to rainfall into rivers streams oceans Nitrogen cycle nitrogen gas fixed by bacteria in plant root plants assimilate N and incorporate into organic nitrogen compounds animals assimilate N by ingesting plants animal waster and organic N compounds broken down Legumes play the role of nitrogen fixiation through their roots nitrogen fixing bacteria convert absorbed nitrogen into usable form symbiotic relationship Phosphorous cycle Biotic organisms are many organisms in a community Organisms interact in food chain producers photosynthesis 1st order consumers herbivores 2nd order consumers carnivores Each step in the food chain is a trophic level where energy is lost at each level Food web are multiple interactions between several food chains theres usually more than one producer and more than one primary consumer Consumers have alternative food sources Plant succession is a series of predictable changes over time in the kinds of plants growing in an area ecosytems mature and change with time and ecosystems are determined by the physical parameters in the environment An an ecosystems ages kinds of organisms change until a stable type of community forms Initial stages are unstable and have a high rate of replacement later stages are more stable and have a low rate of change Climax community is a relatively stable community at the end of succession In equilibrium with the environment Permanent until major change Varies depending on conditions Primary succession is when plants become established on land completely devoid of soil and vegetation example new volcanic islands Ex Forest habitats o Lichens mosses grasses shrubs trees ferns o Each stage prepares for the next invasion of species o Pioneer species are the first they form the soil eventually community is mature climax o Primary succession begins as pioneer species lichens and mosses invade bare rock climax community is spruce fir and birch forest Secondary succession is natural forces or human intervention destroying the existing vegetation fire flooding logging agriculture when the disturbance stops the community begins secondary succession and goes back to climax community Takes place 5 to 10 times faster than primary succession because soil is aready in plane Abiotic factors affect the nature of plant community weather temperature humidity o Affected by plant community o Tropical rain forests vegetation creates the rainfall through plant transpiration when trees removed rain fall stops new climax community often desert shrubs Ex Mount St Helens volcano o After 1980 eruption Soil is the portion of Earth s surface of disintegrated rock and organic materials humus It provides esstential nutrients to all plants water and minerals Soil is influenced by Climate Topography Parent material soil particles occurring naturally in inorganic material Time Soil texture 3 kinds of particles sand silt clay most important Organic matter humus is decomposing organic matter in soil Soil pH acid or basic soil influences soil fertility and nutrient availability Best soil is neutral or slightly acidic BIOMES Biomes are the largest terrestrial divisions of the biosphere The are large distinct ecosystems climax communities for huge regions of the land They are recognized and defines by distinctive vegetation animal life climate and soil conditions They are largely controlled by climate o Temperature how hot cold and the length of the season o Precipitation rain snow annual precipitation and seasonal distribution o Wind humidity light fire soil Role of climate o Global and ever changing o Seasons are determined by the tilt of the earth 23 5 o Solar energy at the equator vs at higher latitiudes o Differences in atmospheric heating create winds drive global patterns Elevation Altitude with climate o Weather patterns move west to east o Precipitation is influenced by physiographic features like mountains oceans o Elevation is altitude that influences biomes high in mountains colder AQUATIC BIOMES Aquatic biomes are the types of plants and animals reflect the temperature depth of body of water available nutrients and salinity of the environment Examples include tropical marine temperate marine and freshwater The Chesapeake Bay is an estuary An estuary is a body of water open to the sea but with a large input of fresh water from the land Productive ecosystem because of lots of light Salinity least salty in the spring because of rain and snowfall Nutrients feed the primary producers of ecosystem they are washed off land and bring on tides Botany of Bay All either algae or angiosperms Phytoplankton o Unicellular algar form the basis of the food chain o Exist in great quantites o Diatoms and Dinoflagettes o Diatoms food of oysters form diatomaceous earth deposits are algae with silicon in walls that are usually found in cooler waters they