BSCI124 Unit 4 Review Sheet ECOLOGY PLANT SUCCESSION Ecology study of the effects of the environment on living organisms living organisms on the environment and living organisms on other living organisms Population members of a single species living together Habitat location where the population is the address Niche the functional role an organism plays in the ecosystem Plant community different plants living together Dominant species most influential species in the community ex Redwood forest Abiotic Factors Climate light soil inorganic substances cycles Carbon Cycle C02 enters plants by photosynthesis carbon released through respiration or combustion of fuels humans upset the carbon cycle 1 global deforestation 2 more CO2 released due to burning fuels Water Cycle Water enters the atmosphere as vapor from the land and transpiration from plants Vapor condenses rainfall into rivers and oceans Nitrogen Cycle gas is fixed by bacteria in plant root nodules plants incorporate N into organic nitrogen compounds Animals assimilate N by ingesting plants Animal waste and organic nitrogen compounds are broken down Plant Succession series of predictable changes over time in the kinds of plants growing in an area Ecosystems change with time and the kind of organisms change until a stable community forms Initial stages unstable high rate of replacement Later stages low change more stable Climax Community relatively stable community at the end of succession 1 in equilibrium with the environment 2 permanent 3 varies depending on conditions Primary Succession when plants become established on land completely devoid of soil and vegetation Soil portion of Earth s surface of disintegrated rock and organic materials humus Each stage prepares the way for the next invasion of species pioneer species are the first inhabitants and form the soil that thickens and community reaches climax Lichens mosses grasses shrubs trees ferns Secondary Succession natural forces or human intervention destroy the existing vegetation fire flooding logging agriculture when the disturbance stops community begins secondary succession back to climax community Secondary succession can take place 5 to 10 times faster than primary succession abiotic factors affect the nature of the plant community weather temperature humidity Ex forest fire is secondary volcanic islands are primary because they are barren rock and have no soil so they start from scratch Plant community affects abiotic factors vegetation creates the rainfall through plant transpiration when trees are removed rainfall stops and land becomes arid resulting new climax community is often desert Soil provides essential nutrients to all plants product of the living environment and is influenced by climate topography parent material time Parent material soil particles of naturally occurring inorganic material Soil texture all soils contains 2 kinds of particles sand silt clay most Important it holds nutrients for plants Organic Matter humus is decomposing organic matter in the soil Soil pH acid low pH or basic high pH soil influence soil fertility and nutrient availability the best soil is neutral or slightly acidic pH TERRESTRIAL BIOMES What is a biome They are the largest terrestrial divisions of the biosphere all places on Earth where organisms are found Biomes are large distinct ecosystems recognized and defined by distinctive vegetation and animal life specific plants and animals climate soil conditions Biome distribution is largely controlled by climate 1 temperature how hot or cold it gets and the length of the growing season 2 precipitation annual rain or snow and seasonal distribution 3 wind humidity light fire soil type Role of Climate daily and seasonal cycles influence prevailing winds climate is global and every changing seasons of the year are determined by the tilt of the earth solar energy at the equator vs at higher latitudes differences in atmospheric heating create winds drive global patterns of atmospheric circulation Elevation altitude in North America weather patterns move from west to east precipitation is influenced by physiographic features like mountains rivers and oceans Elevation altitude influences biomes cooler temperature high in the mountains favor biomes similar to biomes near North Pole 1 Tundra land without trees northernmost land biome around the arctic circle very cold and very dry freezing temperatures can occur any day of the year rarely over 60degrees short growing season 60 100 days year soil is wet shallow or with permanently frozen soil permafrost Plants are perennials and short grass like plants no trees very short growing season lichens mosses Animals migratory birds wolves fox polar bear reindeer wolves very LOW biodiversity and productivity very sensitive to human disruption and takes a long time to recover slow growth 2 Boreal forest taiga Northern forest occupies 17 of the Earth s land and surface area largest biome area near the Arctic Circle Alaska Canada and Great Lakes Climate severe winters extreme colds 58 degrees and little precipitation short growing season Soil is wet and may have deep permafrost nutrient poor Soil may be acidic due to decomposing needles vegetation is mostly trees especially pines 3 Temperate Deciduous Forest 4 Grasslands widely scattered throughout the world prairie Great Plains conifers fir spruce birch aspen Ground is covered in lichens and mosses flowers uncommon Animals caribou wolves fox bear moose mink migratory birds hunting is leading to a loss of species Mineral exploitation lumbering and clear cutting has threatened the biome Eastern North America like Maryland climate has higher precipitation longer growing season 120 250 days yr extreme temperatures 40 degrees to 110 degrees prolonged winters hurricanes and freezing rain can cause damage to vegetation Soil is more acidic and fertile lower layer is deep and rich in clay and topsoil is rich in humus Dominant plans a northeast maple beech trees b south oak and chestnut trees c west oak and hickory Deciduous leaves fall off seasonally Animals deer moose buffalo and bear were common but not anymore due to hunting No deciduous forests are undisturbed due to extensive logging Clear cutting of forests for agriculture and exotic weed species and fungi has altered the flora Soil erosion and depletion makes it hard for native plants to repopulate Erosion results in silting and deposition in wetlands Climate very low rainfall especially in