Ecology

Ecology

Vocabulary:

• Ecology - The study of how organisms fit into their environment.
• Community - The organisms which live in a particular environment.
• Habitat - Physical location of a community
• Ecosystem - Self-sustaining collection of organisms & their physical environment.
• Diversity - a measurement of the number of organisms inhabiting an ecosystem

Energy in ecosystems:

• Life in any ecosystem is driven by the flow of energy.
• All energy entering the earth's Biome is from the sun.
• Living things are divided into 3 major categories based on how they obtain their energy

1. Producers - Obtain energy from their surroundings (eg.light)
2. Consumers - Obtain energy from consuming other organisms
3. Decomposers - Obtain energy from consuming wastes.

• Energy in an ecosystem always flows from producers to consumers
• Organisms are assigned "trophic levels" according to how many "steps" they are away from the source of their energy.
• Autotrophs (like plants) occupy the first level since they obtain their energy directly from the source
• Herbivores occupy the second level, since they obtain their energy from eating the autotrophs.
• Carnivores occupy all higher levels, since they obtain energy from eating herbivores (and other carnivores)
• Omnivores can occupy more than one trophic level since they can eat all of the above.

Note: All organisms above the the first trophic level are known as heterotrophs since they cannot make their own food, but must obtain it by consuming other organisms.

• Energy flow across trophic levels is inefficient - Energy is lost between each level.
• Only about 1/10 makes it from 1 level to the next.

Food Webs
Energy moves through an ecosystem in a complex pattern. The interactions of energy flow is best viewed as a food web.