What is Ecology? The study of how organisms interact with each other and their environment. Environmental conditions include: Biotic factors (living) Abiotic factors (nonliving)

Levels of Organization

- All of a species in an area - All biotic factors in an area Definitions: - One organism - All of a species in an area - All biotic factors in an area - All biotic and abiotic factors in an area - A major region - All regions of the Earth where life exists forest, grassland, freshwater, marine, desert, and tundra

Sunlight is the main energy source for life on earth. Energy Flow Sunlight is the main energy source for life on earth.

Autotroph An organism that is able to capture energy from sunlight or chemicals and use it to produce its own food Also called a producer Who: all plants, some algae and bacteria

Heterotroph An organism that obtains food by consuming other living things Also called a consumer Herbivore: eat plants Carnivore: eats animals Omnivore: eats both plants and animals

Detritivore: scavengers that feed on remains and other dead matter Ex. Mites, earthworms, snails, crabs Decomposer: break down organic matter Ex. Bacteria, fungi

Feeding Relationships Energy flows through an ecosystem in one direction. Trophic level: each step in a food chain or food web Food chain: a series of steps in which organisms transfer energy by eating and being eaten

Food Web Network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem

Also called: Tertiary Consumers ----- Secondary Consumers Primary Consumers ------- Autotrophs *The arrows mean energy transfer; the arrrow go towards the organism eating G here

Ecological Pyramid An illustration of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web Energy Biomass Numbers

Pyramid of Energy Organisms consume others to gain energy for life processes (respiration, movement, reproduction) Only about 10% of the energy consumed is stored in their tissues and available for the next trophic level

Where Does That Energy Go?

Pyramid of Biomass The total amount of living tissue at each level D here

Pyramid of Numbers The number of individual organisms at each level

Biogeochemical Cycles Matter is recycled. A process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another Nutrients and water may be outside or inside organisms.

Water Cycle Water moves between oceans, atmosphere, and land. Transpiration: loss of water from a plant through its leaves

Carbon Cycle Primary source of carbon in our atmosphere??? Photosynthesis Cellular Respiration Burning fossil fuels Decomposition of dead matter Primary source of carbon in our atmosphere???

Which 3 processes return carbon to the environment? Respiration Burning fossil fuels decomposition What process removes carbon from the environment and incorporates it into living things?

The dangerous Greenhouse effect CO2 is a gas that hold in heat Too much CO2 (combustion, respiration, and decomposition) increases CO2 traps more heat global warming 

Nitrogen Cycle Primary source of nitrogen? Atmosphere! 78% is nitrogen Bacteria are essential to obtaining nitrogen from the atmosphere. Primary source of nitrogen? Atmosphere! 78% is nitrogen

Primary source of nitrogen? Atmosphere! 78% is nitrogen

Nitrogen fixation Certain kinds of bacteria can convert nitrogen gas into nitrogen compounds (ammonia) that plants can absorb and use These bacteria live in the soil and on the roots of legumes Denitrification: soil bacteria that reverse this process