Domain 2 Ecology

What is Ecology? Ecology is the scientific study of interactions between organisms and their environments. Ecology reveals relationships between the nonliving and the living parts of an ecosystem. Abiotic factors are non-living chemical and physical factors in the environment such as water, atmospheric gases, soil, temperature, light, space, shelter, and wind. The biotic factors include all of the living organisms with which an organism might interact. Each organism in an ecosystem lives in a particular place (habitat) and plays a particular role (niche). There are many type of interactions including competition, predation, and symbiosis.

Types of Symbiosis Mutualism-both species benefit from the relationship. Commensalism-one organism benefits and the other is not affected. Parasitism-one organism lives inside or on another organism and harms it.

Predation Predation occurs when one organism (the predator) kills and consumes another organism (prey) or uses its nutrients without killing it.

On the graph, when predators are fewer in number, the numbers of prey rise. Predators respond by reproducing more. As the population of predators rises, more prey are killed and their numbers fall. Many of the predators then die. Video Clip

Matter and Energy Sunlight is the main energy source for life on Earth. The need for energy to power life’s processes drives every organism’s interaction with its environment.

Matter and Energy Flow in Ecosystems A food chain is one path of matter and energy flow in an ecosystem. Each level of consumption in a food chain is called a trophic level. a. The source of all food is photosynthesis by autotrophs, mainly plants. They are called producers because only they can manufacture food from inorganic raw materials. b. Food produced by autotrophs is consumed by heterotrophs . Heterotrophs are known by other names. herbivores eat plants and are called primary consumers. carnivores feed on herbivores and are called secondary consumers. carnivores that feed on other carnivores are tertiary consumers. omnivores eat both herbivores and carnivores decomposers are organisms which break down and consume dead organisms and their wastes

Food Web all the possible feeding relationships at each trophic level in a community interconnected food chains

Food Web What is missing from this food web? decomposers

Ecological Pyramid A graphical representation of the trophic levels within an ecosystem. The producer level is at the base of the pyramid with the consumer levels above. Video

Energy Pyramid compares the total amount of energy available in each trophic level. Approximately 10% of the energy available is passed from one level to the next. 90% is used by the organisms for their life activities or lost as heat to the environment.

Biomass Pyramid compares the total weight of the organisms in each trophic level. Video Clip

Numbers Pyramid compares the number of individuals in each trophic level. Video Clip

Exponential Growth individuals in a population reproduce at a constant rate. occurs under ideal conditions Will show a j-shaped curve

Logistic Growth occurs when a population’s growth slows or stops following a period of exponential growth. occurs when resources become less available Will show a s-shaped curve

Logistic Growth

Biomes: areas with similar abiotic factors (temperature, rain, soil), plant, and animal species Dominant plants Dominant animals Climate Interesting facts Tundra Lichens and mosses caribou dry, cold; short growing season permafrost Taiga coniferous forest (pine, spruce, fir trees) moose, elk, snowy owl long, dark, snowy winters and warm, short summers Area south of the tundra Temperate forest deciduous trees (oak, hickory, and maple) Squirrels, deer 4 distinct seasons; moderate rainfall covers much of the U.S. and Europe Desert cacti reptiles, nocturnal mammals hot days, cold nights; very little rainfall sandy soil Grassland grasses Prairie dogs, bison long periods of drought Savannah, steppes Tropical rainforest orchids sloths, and birds lots of rainfall; constant warm temperature most biodiversity

Comparison of Rainfall in the Major Land Biomes