North American Wildlife Principles of Ecology

What is Ecology The branch of biology that describes relationships between organisms and the environment.

The Laws of Ecology Law of conservation of matter: Matter can not be created or destroyed, only changed from one form to another. First law of energy: Energy cannot be created or destroyed only converted to different forms. Second law of energy: Every time energy is converted to another form some energy is lost as heat.

Why do we care about these laws? Conservation of matter applies to waste. Conservation of matter applies to toxic chemicals like pesticides. First law of energy applies to energy flow through an ecosystem. Second law of energy applies to animal systems and makes life possible. Main Idea: We cannot continue to use more energy then the earth can replace.

Natural Cycles Since matter cannot be created or destroyed elements are cycled through the ecosystem Major important cycles: Carbon, Nitrogen, Water

The Carbon Cycle Most abundant element in living organisms CO2 is given off by respiration and taken in during photosynthesis. Fossil fuels are composed of carbon decay that has been under pressure for long periods of time. Problems from too much fossil fuel burning.

Nitrogen Cycle Most abundant element in the atmosphere Form proteins in plants and animals Important in molecules like DNA Nitrogen Fixation: is a process in which nitrogen gas is converted to useable nitrates.

Water Cycle Why is water important? Required for all life Control temperature Dissolves nutrients

Energy Flow through Ecosystem Represented by food chain or food web. What's the difference?

Organization of Organisms Producer- we always start here. An organism that can create its own food (AKA Autotroph) Primary Consumer- the first eater. Plant eaters (AKA Herbivores) Secondary Consumer- the eater of the eater. Meat eaters (AKA Carnivores) Decomposers- final step, bacteria that breaks organic tissue from plants/animals that have died.

What have we forgotten? Omnivores-??? The opposite of Autotrophs are Heterotrophs. Who can tell me what heterotroph means? An Example???

Review Questions??? Define and explain the first law of energy? List some factors that make water important to all living things. Describe the organization of a food chain. Explain how a food chain is different from a food web. Give an example of a secondary consumer.