Ecology • The study of interaction among organisms and between organisms and their environment
Universe Galaxies Biosphere Solar systems Planets Earth Biosphere Ecosystems Ecosystems Communities Populations Realm of ecology Organisms Communities Organ systems Organs Tissues Cells Populations Protoplasm Molecules Atoms Organisms Subatomic Particles Fig. 3-2, p. 51
Widely separated regions share similarities • Biome = major regional complex of similar communities recognized by • Plant type • Vegetation structure
A variety of factors determine the biome • The biome in an area depends on a variety of abiotic factors • Temperature, precipitation, atmospheric circulation, soil • Climatographs • A climate diagram showing an area’s mean monthly temperature and precipitation • Similar biomes occupy similar latitudes
Desert • Minimal precipitation • Some deserts are bare, with sand dunes (Sahara) • Some deserts are heavily vegetated (Sonoran) • They are not always hot • Temperatures vary widely • Saline soils • Nocturnal or nomadic animals • Plants have thick skins or spines
DESERT BIOMES • Variations in annual temperature (red) and precipitation (blue) in tropical, temperate and cold deserts. Figure 5-12
Boreal forest (taiga) • Canada, Alaska, Russia, Scandinavia • Variation in temperature and precipitation • Cool and dry climate • Long, cold winters • Short, cool summers • Poor and acidic soil • Few evergreen tree species • Moose, wolves, bears, migratory birds
Tropical rainforest • Central America, South America, southeast Asia, and west Africa • Year-round rain and warm temperatures • Dark and damp • Lush vegetation • Variety of animals and tree species, but in low numbers • Very poor, acidic soils
Temperate deciduous forest • Deciduous trees lose their leaves each fall and remain dormant during winter • Mid-latitude forests in Europe, East China, Eastern North America • Fertile soils • Forests = oak, beech, maple
Temperate grasslands • More extreme temperature difference between winter and summer • Less precipitation • Also called steppe or prairie • Once widespread throughout parts of North and South America and much of central Asia • Much was converted for agriculture • Bison, prairie dogs, antelope, and ground-nesting birds
Savanna • Grassland interspersed with trees • Africa, South America, Australia, India • Precipitation only during rainy season • Water holes • Zebras, gazelles, giraffes, lions, hyenas
Tundra • Canada, Scandinavia, Russia • Minimal precipitation • Nearly as dry as a desert • Seasonal variation in temperature • Extremely cold winters • Permafrost: permanently frozen soil • Few animals: polar bears, musk oxen, caribou • Lichens and low vegetation with few trees
Chaparral • Mediterranean Sea, California, Chile, and southern Australia • High seasonal • Mild, wet winters • Warm, dry summers • Frequent fires • Densely thicketed, evergreen shrubs
Tropical dry forest • Tropical deciduous forest • India, Africa, South America, northern Australia • Wet and dry seasons • Warm, but less rainfall • Converted to agriculture • Erosion-prone soil
Temperate rainforest • Coastal Pacific Northwest region • Great deal of precipitation • Coniferous trees: cedar, spruce, hemlock, fir • Moisture-loving animals • Banana slug • The fertile soil is susceptible to erosion and landslides • Provides lumber and paper
Altitudes create patterns • Vegetative communities change along mountain slopes • In the Andes, a mountain climber would begin in the tropics and end up in a glacier • Hiking up a mountain in the southwest U.S. is analogous to walking from Mexico to Canada
Biodiversity Definition • The many forms of life found on the Earth. “Wildness” • Genetic Diversity – the variety of genetic make-up w/in a single species • Species Diversity – the variety of species in different habitats on the Earth
Photosynthesis Producers: Basic Source of All Food • Most producers capture sunlight to produce carbohydrates by photosynthesis: • The process in which glucose is synthesized by plants.
Producers • An organism that uses solar energy (green plant) or chemical energy (some bacteria) to manufacture its food.
Consumers: Eating and Recycling to Survive • Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. • Herbivores • Primary consumers that eat producers • Carnivores • Primary consumers eat primary consumers • Third and higher level consumers: carnivores that eat carnivores. • Omnivores • Feed on both plant and animals.
Decomposition • As plant or animal matter dies it will break down and return the chemicals back to the soil. • This happens very quickly in tropical rainforest which results in low-nutrient soils. • Grasslands have the deepest and most nutrient rich of all soils
Decomposer (scavenger, detritivore) • An organism that digests parts of dead organisms, cast-off fragments, and wastes of living organisms. Ex. bacteria and fungi.
Decomposers and Detrivores • Decomposers: Recycle nutrients in ecosystems. • Detrivores: Insects or other scavengers that feed on wastes or dead bodies. Figure 3-13
Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Heat Solar energy Heat Heat Producers (plants) Decomposers (bacteria, fungi) Consumers (herbivores, carnivores) Heat Heat Fig. 3-14, p. 61
Primary Consumer (herbivore) • An organism that feeds directly on all or parts of plants.
Secondary Consumer (carnivore) • An organisms that feeds only on primary consumers. Most are animals, but some are plants (Venus fly-trap).
Tertiary Consumer (carnivore) • Animals that feed on animal-eating animals. Ex. hawks, lions, bass, and sharks.
Quaternary Consumer (carnivore) • An animal that feeds on tertiary consumers. Ex. humans.
Food Webs/Chains • Purpose – determines how energy & nutrients move from one organism to another through the ecosystem • Arrows – point from the producer to the consumer
First Trophic Level Second Trophic Level Third Trophic Level Fourth Trophic Level Tertiary consumers (top carnivores) Secondary consumers (carnivores) Producers (plants) Primary consumers (herbivores) Heat Heat Heat Solar energy Heat Heat Heat Heat Detritivores (decomposers and detritus feeders) Heat Fig. 3-17, p. 64
Structure • Shows the decrease in usable energy available at each succeeding trophic level in a food chain or web.
10% Rule • We assume that 90% of the energy at each energy level is lost because the organism uses the energy. (heat) • It is more efficient to eat lower on the energy pyramid. You get more out of it! • This is why top predators are few in number & vulnerable to extinction.
Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs • In accordance with the 2nd law of thermodynamics, there is a decrease in the amount of energy available to each succeeding organism in a food chain or web.
Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs • Ecological efficiency: percentage of useable energy transferred as biomass from one trophic level to the next. Figure 3-19
Energy Flow & Feeding Relationships • Direction: grain steer human • Measurement – samples are taken, dried, & weighed
Predator • An organisms that captures & feeds on parts or all of another animal.
Prey • An organisms that is captured & serves as a source of food for another animal.
Description • Two kinds of organisms, such as lions and zebras, are said to have a predator-prey relationship.
Cycle • See graph (page 203 and 204)
Importance in Population Control • Predators usually kill the sick, weak or aged. • This helps to let the rest of the prey have greater access to the available food supply. • It also improves the genetic stock.
SPECIES INTERACTIONS: COMPETITION AND PREDATION • Species can interact through competition, predation, parasitism, mutualism, and commensalism. • Some species evolve adaptations that allow them to reduce or avoid competition for resources with other species (resource partitioning).