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Introduction to Ecology. Ecology. Study of “Homes” Interaction of living or Biotic and non-living or Abiotic. Areas of Study. Ecological Levels. Biome: are the major habitats types found on Earth
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Ecology • Study of “Homes” • Interaction of living or Biotic and non-living or Abiotic
Ecological Levels • Biome: are the major habitats types found on Earth • Ecosystem: The relationships of a smaller group of organisms with each other and their environment. • Community The relationships between groups of different species. For example, the desert communities consist of rabbits, coyotes, snakes, birds, mice and such plants as saguaro cactus (Carnegia gigantea), Ocotillo, creosote bush, etc.. • Populations: Groups of individuals of the same species in a limited geographic area. This can be as simple as a field of flowers, which is separated from another field by a hill or other area where none of these flowers occur. • Species: Groups of similar individuals who tend to mate and produce viable, fertile offspring. We often find species described not by their reproduction (a biological species) but rather by their form (anatomical or form species).
Ecosystems • Defined as all the abiotic and biotic communities that are found in an area • Associations largely determined by climate and soils • These determine plant communities • Plant communities determine animal communities that can live in an area • Some are defined by geological units • Different levels of ecosystems • Some variation depending on source
Biomes • Biomes are the major habitats (ecosystem) types found on Earth • They are defined by both abiotic (non living) and biotic (living) components • Ecosystems include all living organisms in an area as well as its physical environment (including plants, animals, fungi,microorganisms, soil, rocks, minerals, atmosphere, water source and climate) functioning together as a unit.
Abiotic Factors • Rainfall and temperature over time determine climate • Climate determines which plant communities can live in terrestrial biomes • This in turn determines animal communities • Soil, wind, light and other physical factors are also important
Tropical Forest • latitudes 23.5 degrees N and 23.5 degrees S. • Temperature - 20-25° C varies little • Precipitation is evenly distributed throughout the year, annual rainfall exceeding 2000 mm. • Soil is nutrient-poor and acidic. Decomposition is rapid and soils are subject to heavy leaching.
Canopy is multilayered allowing little light penetration. • Flora is highly diverse: as many as 100 different tree species per km • orchids, bromeliads, vines, ferns, • numerous birds, bats, small mammals, and insects.
Tropical Rain Forest -soils are generally unfertile -nutrients and carbon stored in plant biomass, not soils -canopy trees up to 55 m tall -largest biome, on an area basis
Tropical Savanna/Seasonal Forest • Grass with scattered trees • found in the tropics (but > 10° latitude) Africa, India , South America, Australia • Wet and dry season • 50-127 cm per year • pronounced dry season with <5 cm rainfall in some months • Grazing mammals, large and small predators; many birds insects, reptiles
Tropical Savanna/Seasonal Forest -fire & grazing by animals also contribute to predominance of grasses -scattered trees and grass
Temperate Forest • Temperature varies from -30° C to 30° C. • Precipitation (75-150 cm) even throughout year. • distinct winter season, frost a defining feature • summer season usually moist with precipitation > evapotranspiration • Soil is fertile, enriched with decaying litter. • Canopy allows light to penetrate, richly diversified understory vegetation • Flora is characterized by trees with broad leaves that are lost annually • Fauna - squirrels, rabbits, skunks, birds, deer, mountain lion, bobcat, timber wolf, fox, and black bear.
Temperate Forest -relatively large tree biomass -also called the deciduous forest, but contains evergreen needle trees as well
Temperate Grasslands • Prairies – Large areas of N and S America and S Africa (tall grass) • Steppes of Russia (short grass; very cold winters • Mostly grass; few trees and shrubs except along waterways • Similar to tropical savanna’s but with more variation in temperature from summer to winter • potential evapotranspiration > precipitation during summer months • Fires important to diversity • Wildflowers abundant • Grazers and their predators
Temperate Grassland/Shrubland -scattered trees and shrubs -trees are short statured -fire & grazing by animals also contribute to predominance of grasses, but that depends on climate
Deserts • Rainfall less than 50 cm • May be hot and dry, semiarid, cold, or chaparral (coastal) • Few mammals and few large animals • Plants adapted to lack of water – cacti and succulents • Cool at night due to reflection of sand so has wide swings in temperature • Coarse sandy or rocky soils
Deserts • Hot and Dry • Semi arid- dry summers and little rainfall in winter • Cold deserts • Coastal deserts or chaparrel • Rainfall < 50cm • Plants and animals specialized for low water • Soils have abundant nutrients and little organic matter
Desert -thorny plants -other adaptations to conserve water
Chapparal -mild winters -seasonal rainfall, winter rain, summer drought -maritime influence: cold ocean currents continental winds
Chapparal -sclerophyllous plants -adaptations to fire
Boreal Forest (Taiga) • 50-60 degees N; > 4 month growing season • Temperatures very low. • Precipitation primarily in the form of snow, 40-100 cm • Soil is thin, nutrient-poor, and acidic. • Flora cold-tolerant evergreen conifers with needle-like leaves • Fauna - woodpeckers, hawks, moose, bear, weasel, lynx, fox, wolf, deer, hares, chipmunks, shrews, and bats.
Boreal Forest -10-20 m trees evergreen needle and deciduous -second largest biome, on an area basis -fire dominated, but on longer timescale than grassland -more nutrients and carbon stored in soils than plants
Tundra • High latitudes or altitude • < 2 month growing season • Very cold; Precipitation 15-25cm • Very shallow soil and permafrost • Low plants and lichens • Animals adapted to cold; many hibernate • Reptiles and amphibians rare
Tundra – Mountain Tops and Arctic • Extremely cold climate and winds • Low biotic diversity • Simple vegetation structure low shrubs, mosses, and lichens • Limitation of drainage • Short season of growth and reproduction • Energy and nutrients in the form of dead organic material • Large population oscillations
Tundra - no trees - sedges, low shrubs, & mosses - permafrost present
