Principles of Ecology

Ecosystems are made up of: Biotic factors, such as plants, animals, fungi Abiotic factors, such as air, wind, fire, water Both factors occur together in one area. An ecosystem can vary in size from a pond, a fish bowl or an entire desert.

Levels of organization: Community is made up of the living factors of an ecosystem. Ecosystem is made up of the living factors as well as the abiotic factors such as wind, water, air, etc. Biome is a much larger, regional or global community of organisms characterized by climatic conditions, exp.: desert, forest, tundra, etc.

Organisms are classified based upon how they get their energy. Producers: from the sun Consumers: from other organisms Decomposers: from dead organisms

Keystone Species A species in an ecosystem that determines that ecosystems overall health and stability is called a keystone species. This species has a large effect on the stability of that ecosystem. Examples are: beavers, salmon, sea otter, lion, mangrove plants, etc.

Keystone Species Keystone:

Biodiversity Biodiversity is the variety of living things in an ecosystem. The greater the biodiversity the greater the stability of that ecosystem to withstand changes. The lower the biodiversity the greater the likelihood that a loss of one organism will alter the balance in that ecosystem.

Low biodiversity

Biodiversity and Keystone Species

Energy in Ecosystems 1. Producers capture energy from the sun or from chemicals. Autotrophs when the sun is the source of energy Chemotrophs when chemicals are the source of energy. 2. Consumers are organisms that rely upon other organisms to get there energy.

Photosynthesis: 6H2O + 6CO2 C6H12O6 + 6O2

Chemosynthesis Producers can also be classified as chemotrophys. Chemotrophys produce their energy not from the sun but from chemicals such as hydrogen, sulfur, and magnesium.

Food Chains/Webs Food chains “link” species together based upon their feed behavior. Food webs, on the other hand, shows the complex relationship among many species, both plant and animal.

Food Web

Types of Consumers Herbivores, eat only plants: cows, rabbits, elephants, etc. Carnivores, eat only meat: you and me, bunny rabbits, Donald Duck, you get the idea. Omnivores eat both plants and animals. Detritivores break down dead organic matter Decomposers break down organic matter into smaller components.

Feeding Relationships A specialists is an organisms that can eat only one type of food. A generalists is an organism that can eat a variety of different foods.

Numbers Weight Calories

Pyramid of Energy, calories

Abiotic Factors

Examples of abiotic factors: Oxygen Sunlight Fire Water

Cycling of Matter Matter can be cycled through an ecosystem in a number of forms in what is known as the biogeochemical cycle (bio = life; geo = earth) Water (hydrologic) cycle Nitrogen cycle: bacteria Carbon cycle ( photosynthesis & cell resp. ) Phosphorous cycle

Water Cycle The three states of matter are: gas, liquid, and solid Water takes the form of all three. Clouds are the gas phase Water is the liquid phase Ice is the solid phase

Water Cycle

Nitrogen Cycle

Nitrogen Cycle The atmosphere is made up of 78% nitrogen, N2. Animals cannot use N2. Animals must rely upon bacteria and plants for their N2. Bacteria and plants “fix” this atmospheric N2 into ammonia, ammonium or nitrate.

Nitrogen Fixing Bacteria Bacteria fix atmospheric nitrogen into a form which can be converted or used by plants. Animals eat these plants and thereby, receive the nitrogen needed for protein and nucleic acids (DNA/RNA).

Carbon Cycle

Carbon Cycle Carbon is released into the environment in the form of carbon dioxide from cellular respiration. Carbon is also released through the use of fossil fuels (oil, coal, natural gas). Carbon is removed from the environment through photosynthesis to form glucose.

Carbon Cycle

The End