Interactions: Environment and Organisms

Ecological Concepts  Environment  Limiting factors

Environment What do we mean by environment? Everything that affects an organism during its life time Every environment is made-up of 2 parts Abiotic- the non-living parts of the ecosystem (rocks, land, energy, processes) Biotic- the living parts of the ecosystem ( birds, fish, trees)

Name all the abiotic and biotic factors you see in this environment

Limiting Factors  What are limiting Factors?  A restriction of necessary resources (water, light, nutrients, oxygen) which keep an organisms population regulated  Ex: the amount of sunlight available for plants in Seattle to grow. Limiting Factors can be abiotic or biotic

Community and Ecosystem Interactions  Major Roles of Organisms in Ecosystems  Energy Flow Through Ecosystems  Food Chains and Food Webs

Major Roles of Organisms in Ecosystem Energy is supplied to ecosystems by the sun  Producers: organisms that are able to use sources of energy to make complex organic molecules from simple inorganic substances in their environment  Consumer: Uses organic matter as a source of food  Primary Consumer: Eats plants directly  Secondary Consumer: Animals that eat other animals  Decomposer: Organisms that use nonliving organic matter as a source of energy

Energy Flow Through Ecosystem  Ecosystems are stable, self-regulating units  Producers trap solar energy and convert it, through the process of photosynthesis, into usable energy for the rest of the ecosystem  The Energy is stored in the form of chemical bonds within the producers  The energy is transferred from the producer to the consumer when eaten

 Every time energy is transferred from one organism to another you go up a trophic level  Trophic Level:  The position an organism occupies in a food chain  Approximately 90% of the energy in each trophic level is transferred into heat and used for life process for that organism(non-useful)  That means only 10% can be used by the next trophic level when eaten (useful)

Populations  How many organisms are in each trophic level in a stable ecosystem?

How do we measure how much energy transfers from one organism to the next? Biomass: The weight of living material  It is difficult to measure energy, but collecting and weighing organisms at each trophic level correlates to the 10:90 ratio of usable:nonusable energy.

Food Chains and Food Webs  What is a Food Chain?  The passage of energy from one trophic level to another  Turn to your neighbor and draw out a food chain an owl is a part of.

Photosynthesis Vs. Cellular Respiration  What is Photosynthesis?  How does it occur?  How is it a part of a stable ecosystem?  What is Cellular?  How does it occur?  How is it a part of a stable ecosystem?

 What is a Food Web?  Several food chains overlapping and intersecting  Now in pairs draw a food web that an owl would be a part of

Effects  Direct Effect: An affect between two individuals  Indirect Effect: An affect that occurs because of another interaction that didn’t involve the individual directly

Summary  An environment consists of abiotic and biotic factors. The interactions and processes that go on between the abiotic(non-living) and biotic(living) factors are what make up an ecosystem.