Chapter 3: The Biosphere. Objectives Identify the levels of organization Describe the methods used to study ecology Identify the source of energy for life processes Trace the flow of energy through living systems
An individual living thing
Members of one species that interbreed and live in the same place at the same time.
the Earth that
All organisms depend upon other living things and nonliving things to meet their needs, such as:
Thus, an interdependence exists among organisms and the environment
plants, and algae
Also called producers
their energy and food supply
Heterotrophs that eat plants (1st order consumers)
They come in many sizes!
Eat both plants and animals
Ex: humans, raccoons, bears
Animals that feed on animal remains and dead matter (collectively called detritus)
EX: mites, earthworms, snails, crabs
Break down decaying matter
Ex: bacteria and fungi
Each organism represents a trophic level, a step in the food chain.
Natural Food Chain
Sun Grass Rabbit Snake Hawk
The arrows show the direction that energy is transferred
*78% of the atmosphere is composed of nitrogen
*Living things cannot use nitrogen in the atmospheric form
*Lightening and some bacteria convert nitrogen to usable forms, then producers use them to make proteins. Consumers then eat the producers and reuse the nitrogen to make their own proteins!
*When organisms die, decomposers return nitrogen to the soil and it is either reused or converted into nitrogen gas and returned to the atmosphere.
Primary Productivity—rate at which an organic matter is created by producers
Process can be limited by a lack of nutrients
A polar bear, its fur stained with algae, stands in its cage at Higashiyama Zoo in Nagoya, central Japan, Saturday, Sept. 6, 2008. Three polar bears at the zoo changed their colors in July after swimming in a pond with an overgrowth of algae, prompting many questions from visitors concerned about whether the animals are sick or carrying mold, a zoo official said. Credit: AP Photo/Kyodo News, Shuzo Shikano