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Ecology—the study of the interaction between organisms and their environment I. Feeding relationships A.Autotrophs=producers MAKE their own food Ex: plants, algae, some bacteria B.Heterotrophs=consumers Eat other organisms; do NOT make their own food Types of Consumers: 1. Herbivore—only eat plants 2. Carnivore—kill and eat other animals 3. Omnivore—eat both plants and animals 4. Scavenger—eat dead animals 5. Decomposer—(also called saprobe/ saprophyte)—break down and absorb nutrients from dead organisms II. Survival relationships A. Predation (Predator-prey)— Predator hunts and eats prey. B. Competition—occurs when 2 species fight for the same limited resources Predators Competition C. Symbiosis-2 species living together; at least one depends on the other Types of Symbiosis: 1. Mutualism—BOTH species benefit (mutually beneficial!) Ex: clownfish & sea anemone flower & bee cattle & white birds Mutualism 2. Commensalism—One species benefits and the other is NOT AFFECTED Ex: orchid & tree human & eyelash mites Commensalism 3. Parasitism—One species benefits and the other is HARMED. Ex: tick on a dog mistletoe in a tree mosquitoes on humans Parasites III. Matter and Energy relationships A. Food Web— expresses ALL possible feeding relationships in a community Food Web example B. Food chain— one path in a food web Food chain example 1. A food chain MUST start with a producer. 2. Arrows are used to show the direction of energy transfer. 3. A food chain does NOT typically have more than 5 levels. Why are food chains this short? • Only about 10% of the energy at each level is passed to the next level. C. Trophic level—represents a feeding step in a food web 1. First trophic level—producer 2. Second—herbivore/omnivore 3. Third—carnivore/omnivore 4. Fourth—carnivore/omnivore 5. Fifth—carnivore/ omnivore/decomposer D. Ecological or energy pyramids— describe energy conversion in an ecosystem 1. The SOURCE of energy for all pyramids is the SUN. 2. The BASE of the pyramid is PRODUCERS. 3. The TOP is the top CARNIVORE or omnivore. 4. Biomass—the total mass of all organisms at any one level in the pyramid 5. Biological Magnification— the concentration of toxic substances increases as it moves up the food chain *Will be highest in top level IV. The Organization of Life A. Organism—3 Things that affect organisms: 1. habitat—where it lives 2. niche—its way of life 3. trophic level—its feeding level in the food chain Niche B. Population—all members of the same species that live in a certain area --Animal population is also called a breeding group. Populations A group of individuals of one species usually Aoccupying group of individuals of one species a defined usually occupying a defined area. area. C. Community—All populations in a certain area D. Ecosystem—the biotic and abiotic factors interacting in an area 1. biotic—living things 2. abiotic—nonliving things Ex: water, soil, temperature, precipitation Ecosystem E. Biome—A large area defined by the presence of certain plants and animals Biomes Permafrost F. Biosphere— the area on Earth where life exists (the SURFACE) Biosphere V. Geochemical Cycles Water Cycle Nitrogen Cycle Carbon Cycle Carbon Cycle Oxygen Cycle Types of Lakes Oligotrophic Eutrophic Estuary • Place where freshwater, such as a river, meets the sea • Ex: bay, swamp, marsh, bayou VI. Homeostasis in Communities A. Carrying capacity—the largest number of organisms from a species that can be supported by the environment Ex: There is only enough food for a certain number of deer. Why Hunting is Legal B. Limiting Factor—any living or nonliving thing that restricts the existence, numbers, reproduction, or distribution of organisms Ex: food available, temperature Why These Animals Live Only in Certain Places C. Tolerance—the ability to withstand fluctuations (changes) in environmental factors --There is a range of conditions (temp., amt. of food, etc.) in which organisms can survive. D. Succession—orderly, natural changes that take place in a community *climax community—a stable, mature community that undergoes little to no succession 2 Types of Succession: 1. Primary—establishment & development of an ecosystem in an area that was previously UNINHABITED Lichens and algae on bare rock Succession of plant species on abandoned fields in North Carolina. Pioneer species consist of a variety of annual plants. This successional stage is then followed by communities of perennials and grasses, shrubs, softwood trees and shrubs, and finally hardwood trees and shrubs. This succession takes about 120 years to go from the pioneer stage to the climax community. From http://www.physicalgeography.net/fundamentals/9i.html on 10-6-10 2. Secondary-REESTABLISHMENT of a damaged ecosystem in an area where the soil was left intact Secondary Succession—Illustration of (1) a climax forest (2) destroyed by wildfire and (3) and (4) its eventual recovery. Secondary succession occurs in an area where life once existed but has then been destroyed. (Reproduced by permission of The Gale Group)