What is Ecology? scientific study of interactions among organisms and between organisms and their environment
Biosphere Combined portions of the planet in which all of life exists, including land, water and air or atmosphere Extends from 8 kilometers above Earth’s surface to 11 kilometers below the surface of the ocean
Interactions and Interdependence Interactions within the biosphere produce a web of interdependence between organisms and the environment in which they live
Levels of Organization Individual: interactions between an organism and its surroundings cottontail rabbit Population: groups of individuals that belong to the same species and live in the same area group of cottontail rabbits
Levels of Organization Communities: different populations that live together in a defined area rabbits, coyotes, ravens, lizard Ecosystem: collection of all the organisms that live in a particular place, together with their nonliving, or physical, environment rabbits, coyotes, ravens, lizard, rocks, dirt, climate, water
Levels of Organization Biome: group of ecosystems that have the same climate and dominant communities desert, tundra, tropical rain forest Biosphere: planet Earth
Ecological Methods Three approaches to ecological research: Observing: Use of 5 senses to ask ecological questions Experimenting: Used to test hypotheses artificial environment in a lab within natural ecosystems
Ecological Methods Modeling: Used to gain insight into complex phenomena such as the effects of global warming may include mathematical formulas based on data collected through observation and experimentation predictions tested by further observations and experiments
Energy Flow Energy flows from the sun or inorganic compounds to producers. Consumers eat producers to get energy. The primary source of energy on Earth is the sun!!
Producers Autotrophs – “self feed” Use sunlight to create carbohydrates via photosynthesis Ex – Plants, algae and some bacteria Some bacteria create organic compounds from inorganic chemicals – Chemosynthesis Live in remote places.
Trophic Levels Each step in a food chain or food web 1 st level = producers 2 nd, 3 rd, or higher levels = consumers Usually no more than 5 levels because 90% of energy is lost at each level.
Ecological Pyramid A diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web. Energy, biomass, and population numbers can all be represented by a pyramid.
Nitrogen Cycle N 2 in Atmosphere NH 3 NO 3 - and NO 2 -
Nitrogen Cycle 78% of Earth’s atmosphere is Nitrogen gas = N 2 Nitrogen containing products: Ammonia (NH 3 ) Nitrate ions (NO 3 -) Nitrite ions (NO 2 -) Nitrogen is needed for protein and nucleic acid synthesis
Nitrogen Cycle Converting nitrogen gas into ammonia is called nitrogen fixation. Only certain types of bacteria can do this. Plants use the converted products (NH 3, NO 3 -,& NO 2 -) to make plant proteins. Some bacteria convert nitrates into nitrogen gas (denitrification).
Phosphorus is important for the formation of DNA and RNA molecules. Phosphorus is not very common and does not enter the atmosphere, instead it is found mostly on land in rock and soil.
Primary Productivity The rate at which producers create organic matter. Determines the size of the community. Limited by availability of nutrients. Land – phosphorus (P), nitrogen (N), potassium (K) Marine – nitrogen Fresh water - phosphorus
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