Ecology
Ecology - the study of how living things interact with each other and their environment
Biotic Factors - the living parts of a habitat
Abiotic Factors - the non-living parts of a habitat examples: moisture, sunlight, oxygen, temperature, and soil They determine what living things can survive in a given environment
Ecologists examine interrelationships between biotic and abiotic factors in an ecosystem Wolves in Yellowstone *
Levels of Organization in an Environment: Organism Population Community Ecosystem Biome Biosphere
Organism - a living thing An organism obtains food, water, shelter, and other things it needs to live, grow, and reproduce from its environment
Population - a group of organisms of the same species living in the same place at the same time that interbreed compete for food, water, mates, and other resources
Some species have adaptations to reduce competition within a species ex. frogs and tadpoles/ butterflies and caterpillars; different food requirements at different stages of life cycle
Community - all of the different interacting populations that live together in an area A change in one population will cause changes in the other populations (rabbits and hawks) There is some competition between populations for food and other resources (lions and hyenas)
Ecosystem - a community of organisms that live in a particular area, along with their nonliving (abiotic) surroundings terrestrial ecosystems are on land aquatic ecosystems are found in freshwater or salt water (marine)
Biome - a group of ecosystems with similar climates and organisms - ex. rain forest, desert, tundra, grassland, deciduous forest
Biosphere - the portion of the Earth that supports life; spans from the bottom of the ocean to high in the atmosphere
Niche - the role an organism plays in the community
Habitat - the place where an organism lives Several species can share the same habitat since every habitat is divided into separate niches
Producer (autotroph) - an organism that can make its own food uses energy from the sun or energy stored in chemical compounds to make its own food includes plants, algae, and some bacteria
Consumer (heterotroph) - an organism that obtains energy by feeding on other organisms
Herbivore - a consumer that eats only plants includes grazing, seed-eating, and algae eating animals
Carnivore - a consumer that eats only animals
Scavenger - a carnivore that feeds on the bodies of dead organisms
Omnivore - a consumer that eats both plants and animals
Decomposer - an organism that breaks down wastes and dead organisms recycle nutrients from organic matter fungi, bacteria, earthworms
Food Chain - a series of events in which one organism eats another and obtains energy nutrients and energy move from producers to consumers to decomposers arrows show the direction of energy flow
each organism in a food chain represents a feeding step or trophic level (producer, 1 st order consumers, 2 nd order consumer, etc.)
food chains can only have 3-5 links energy is lost as heat at each link* a food chain shows only one possible route for matter and energy
Food Web - the pattern of overlapping food chains in an ecosystem
A food web is a more accurate model than a food chain since most organisms depend on more than one species for food.
3 Main Types of Interactions Between Organisms - competition, predation, and symbiosis
Competition - organisms compete against each other for the same limited resource most competition is limited to individuals of the same species since they have the same niche
Predation - an interaction in which one organism kills another organism for food predator kills prey is killed
population size of predator and prey species will rise and fall in cycles
Symbiosis - a close relationship between organisms of different species where at least one species benefits means living together
Commensalism - a symbiotic relationship in which one species benefits and the other species is neither harmed nor benefitted (+/0) ex. small bird living in a woodpecker s abandoned nest, barnacles on whales, etc.
Mutualism - a symbiotic relationship in which both species benefit (+/+) ex. stinging ants and acacia tree, plants and insect pollinators
Parasitism - a symbiotic relationship in which one organism benefits at the expense of the other (+/-) parasites usually harm, but don t kill, their hosts ex. ticks, fleas, and tapeworms
Natural Selection - the process in which traits that make an individual better suited to its environment become more common in a species
Survival of the Fittest - organisms that have those desirable traits tend to survive and produce more offspring
Desirable traits change if the environment changes ex. peppered moths
Adaptation - a behavior or physical characteristic that allows an organism to live successfully in its environment Organisms have adaptations for obtaining food, protection, and reproduction
Limiting Factor - an environmental factor that limits population size (food, water, space, weather, etc.)
Carrying Capacity - the largest population (# of one species) that an area can support
Energy and Matter in Ecosystems Energy lost as heat in an ecosystem is replenished by the sun
Matter is recycled in ecosystems The atoms of carbon, hydrogen, oxygen, nitrogen, etc. are the same atoms that have been on Earth since life began
Water Cycle - condensation, precipitation, evaporation...
plants absorb and animals drink water plants and animals lose water through transpiration (plants) and respiration (animals) decomposition also releases water back into the atmosphere
Carbon Cycle - CO 2 gas found in the atmosphere and the oceans is used by plants to make energy-rich sugars; these sugars are broken down by living things and CO 2 is released as a byproduct
Photosynthesis - the process in which organisms use the energy from sunlight to convert water and carbon dioxide into sugar and oxygen 6CO 2 + 6H 2 O + sunlight C 6 H 12 O 6 + 6O 2
Cellular Respiration - organisms break down sugars to release the energy found in food C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + energy released
Photosynthesis and cellular respiration are opposite reactions the reactants of one are the products of the other one stores energy and one releases energy
Solar energy chemical energy mechanical energy