How living things interact with their environment Ecology – study of how living things interact with one another and with their environment

Ecosystem – Living and non-living things that interact in a particular area The type of place an organism lives is the ecosystem, the specific part of the ecosystem that meets the organism’s needs is its habitat: • Forest Ecosystem – woodpeckers habitat is different from that of a mushrooms

Biotic vs. Abiotic Biotic Factors – the living parts of an ecosystem Abiotic Factors – the nonliving parts of an ecosystem Examples: water, oxygen, temperature, air currents Soil and sunlight

Water Water is an important abiotic factor because most organisms are made up of 50-95% water. Respiration, photosynthesis, digestion, and other important life processes can take place only in the presence of water.

Soil Soil helps to determine which plants and other organisms live in that location. Most soil is a combination of sand, clay, and humus. Soil type is determined by the amounts of sand, clay and humus in the soil. Humus: the decayed remains of dead organisms. The greater the humus content, the more fertile the soil

Light and Temperature Through the process of photosyntheisis, the radiant energy of sunlight is transformed into chemical energy that drives virtually all of life’s processes. How much sunlight is available affects where green plants and other photosynthetic plants live. Most organisms can survive only if their body temperatures stay within the range of 0°C to 50°C.

Biotic Factors Abiotic factors don’t provide everything an organism needs for survival. Example: mushrooms would not be able to grow without the decaying bodies of other organisms to feed on. Example: honeybees couldn’t survive without pollen from flowers. Organisms depend on other organisms for food, shelter, protection or reproduction. Living or once living organisms in the environment are called biotic factors.

Interactions Among Living Organisms Characteristics of Populations Population Size: the # of individuals in the population. Usually individuals are too widespread or move around too much to be counted so the population size is estimated. The # of organisms of one species in a small section is counted. This is used to estimate the population of the larger area. size of the population is always changing. The rate of change in a population varies from population to population.

Population Spacing: How the organisms are arranged in a given area. Population Density: the # of individuals in a population that occupy a definite area. Population Spacing: How the organisms are arranged in a given area. Ex. Evenly spaced, randomly spaced, or clumped together

Limiting Factors Any biotic or abiotic factor that limits the # of individuals in a population. A LF can affect other populations in the community indirectly. Ex. A drought might reduce the # of seed producing plants in a forest. Fewer plants means that food can become a LF for deer that eat the plants and the bird that feeds on the seeds of these plants. LF may include: Food,Shelter,Water,Space,Disease, Parasitis, Predation,Nesting Sites.

Limiting Factors Affecting the Everglades Water Flow Pesticides and Herbicides Invasive species