Ecology Review

The branch of Biology that describes relationships between organisms and the environments in which they live

Principles

• The law of conservation of matter:

• Matter can be changed from one form to another

• but it cannot be created or destroyed

1st law of energy

• Energy cannot be created or destroyed but can be converted from one form to another– Radiant energy – sun– Chemical energy – photosynthesis– Kinetic energy – animal movement– Thermal energy – creating heat

2nd law of energy

• Every time energy is converted from one form to another, energy is lost in the form of heat

Energy Cycle

• The fundamental source of energy in almost all ecosystems is radiant energy from the sun

• energy and organic matter are passed along an ecosystem's food chain.

• Organisms are classified based upon the number of energy transfers through a food web

Primary Production

• Photoautotrophic production of organic matter represents the first energy transfer in ecosystems

2nd Trophic Level

• Consumption of a plant by a herbivore is the second energy transfer,

• Herbivores occupy the second trophic level,

• also known as secondary production.

Consumers

• Consumer organisms that are one, two, or three transfers from autotrophs are classified as primary, secondary, and tertiary consumers.

Energy Loss

• Moving through a food web, energy is lost during each transfer as heat, as described by the second law of thermodynamics.

Energy Loss

• Consequently, the total number of energy transfers rarely exceeds four or five;

• with energy loss during each transfer, little energy is available to support organisms at the highest levels of a food web.