Unit 3

What is Ecology?  The Scientific study of the interaction among organisms and between organisms and their environment. Ernst Harckel coined the term ecology based on the Greek word for house. Harckel saw the earth and its various environments as “houses” with each of its organisms playing a role (interacting) to keep the “houses” going.

Houses…..  Nature’s “houses” come in many sizes from single cells to the entire planet.  The largest of nature’s houses is called a biosphere.  Biosphere- the part of earth in which life exists including land, water(11km), and air or atmosphere(8km).

Levels of Organization  Biosphere (largest) Biome-group of ecosystems that have the same climate and dominant communities. ○ Ecosystem-collection of all the organism that live in a particular place, together with non-living things. Community-assemblage of different populations that live together in a defined area. -Population-group of individuals of the same species that live in the same area. -Individual (species)-a group of organisms so similar that they can breed and produce fertile offspring. (smallest)

How do ecologists study the biosphere??  Three Ecological Methods of Study. Observing: What lives here? How many? Etc. Experimenting: Imitation of natural environments Modeling: Create models using computer or mathematical formulas

Energy Flow in the Biosphere  Sunlight: The main source of energy for all living things on earth.  Producers: An organism that can capture energy from the sun and use it to produce food (autotroph). Photosynthesis- uses light to make food (Phototrophs) Chemosynthesis- uses inorganic molecules (Chemotrophs)  Consumers: An organism that relies on other organisms for its energy (heterotroph).

Consumers Cont….  Types of Heterotrophs Herbivores- Eat only plants (ex. Cow). Carnivores- Eat only other animals (ex.Owl). Omnivores- Eat both plants and animals (ex. Humans). Detritvores- Feed on detritus, dead or decaying materials (snails, crabs). Decomposers- Breaks down dead organic matter (bacteria). Sunlight  Autotrophs (producers)  Heterotrophs (consumers)

Energy continued….  Feeding Relationships: Energy flows through an ecosystem in one direction from the sun or inorganic compounds to autotrophs and then to heterotrophs. Food Chain: Series of steps in an ecosystem in which organisms transfer energy by eating and being eaten. Food Web: Network of complex interactions formed by the feeding relationships among organisms in an ecosystem. ○ Trophic Levels The steps in a food chain or web.

Food Web Ex.

Ecological Pyramids  A diagram that shows the relative amounts of energy or matter within each trophic level in a food chain. Energy pyramid- shows relative amount of energy available at each trophic level. Biomass pyramid-total amount of living tissue within a trophic level.

Cycle of Matter  Recycling in the biosphere- Unlike the one-way flow of energy within a biosphere, matter is recycled. Water Cycle Nutrient Cycle (Biochemical cycles) ○ Carbon Cycle (key ingredient in living things) ○ Nitrogen Cycle Needed to make amino acids 78% of the Earth’s air ○ Phosphorus Cycle Essential for DNA and RNA

Water Cycle  Evaporation- Liquid  Gas  Transpiration- evaporation from the leaves of plants  Precipitation- The release of condensed liquid from clouds  Condensation- Gas  Liquid  Runoff- Precipitation runs along surface of ground until it enters a river or stream.  Seepage- Rain water seeps into the soil and becomes ground water.

Nutrient Cycle Carbon CycleNitrogen Cycle

Four Types of Processes that Impact the Biosphere  Biological-Take up carbon and release oxygen (ex. photosynthesis & respiration)  Geochemical-Erosion and volcanic activity that release carbon dioxide.  Mixed Biogeochemical- Decomposition of dead organisms, underground pressure that leads to formation of coal.  Human Activities- Release CO2 into the air by cutting and burning forests, burning fossil fuels.

Nutrient Limitations  Primary Productivity Rate at which producers make organic matter. Controls the amount of nutrients available.  Limiting Nutrients Scarce nutrients, limits organism’s growth. Farmers use fertilizer to try and fix this problem. Can have sudden increase in limiting nutrients usually in aquatic ecosystems due to runoff. ○ Algae Bloom