Environmental Science Chapter 5 – How Ecosystems Work

Photosynthesis Plants use energy from the sun to make their own food… carbohydrates

Producer An organism that makes its own food through photosynthesis or chemical sources; also called an autotroph.

Consumers An organism that gets its energy by eating other organisms, either producers or consumers; also called a heterotroph. Therefore, consumers get their energy indirectly.

Herbivores Obtain their energy only from producers.

Carnivores Obtain their energy only from other consumers.

Eating Insects http://video.nationalgeographic.com/video/player/places/culture-places/food/us_insects.html

Omnivores Obtain their energy from both producers & consumers.

Decomposers Fungi & bacteria break down organisms in an ecosystem & returns nutrients to soil, water, & air

Trophic Level Each step through which energy is transferred in a food chain If a fish eats a plant, and then a bird eats the fish, only about 10% of the energy from the original plant is available for the bird.

Nitrogen & Nitrogen Fixing Bacteria Makes up approximately 78% of our atmosphere Only certain kinds of bacteria found in the roots of legumes can transfer nitrogen from the atmosphere into chemical compounds suitable to build proteins

Succession Is possible because newer species make environment less suitable for previous species.

Primary Succession Begins where there is no soil Examples: new islands created by volcanoes, rocks exposed by glacial retreat, or any other surface that has not previously supported life Much slower than Secondary Succession

Lichen Often a pioneer species in primary succession Breaks rock down into soil

Secondary Succession More common than Primary Succession Occurs on a surface where an ecosystem previously existed but is disrupted by humans, animals, or natural processes Examples: Storms, Floods, Earthquakes, Forest Fires, Volcanoes

Benefits of Forest Fires & Prescribed Burns Fires benefit some forest communities by allowing some trees to release seeds, clearing away deadwood, & encouraging new growth. http://player.discoveryeducation.com/index.cfm?guidAssetId=AE93A354-4B1C-438B-80AA-83AFAF835050&blnFromSearch=1&productcode=US

Climax Community Final & Stable Community that develops during succession.

Old Field Succession Occurs when farmland is abandoned. Taller grasses eventually replace pioneer weeds. After approximately 150 year, a tall mature oak forest is likely to form.

Where would a scientist be least likely to study primary succession? New Volcanic Island Gravel Filled Valley Abandoned Parking Lot Tropical Rain Forest

Where would a scientist be least likely to study primary succession? New Volcanic Island Gravel Filled Valley Abandoned Parking Lot Tropical Rain Forest

Where would a scientist be most likely to study secondary succession? Breaking Down of Bare Rock by Lichen Pioneer plants Growing in a Glacial Valley Appearance of Weeds in Concrete Cracks A Forest Burned Down By Fire

Where would a scientist be most likely to study secondary succession? Breaking Down of Bare Rock by Lichen Pioneer plants Growing in a Glacial Valley Appearance of Weeds in Concrete Cracks A Forest Burned Down By Fire

Carbon Cycle Process by which carbon is cycled between the atmosphere, land, water, & organisms.

Carbon Cycle Humans impact the carbon cycle by burning fossil fuels that release carbon dioxide into the air. (Global Warming)

Carbon Cycle Plants impact carbon cycle by enabling carbon to enter ecosystem through photosynthesis.