Introduction to Ecology and Energy Flow Ecology and Food Webs

What is Ecology? Ecology is the scientific study of interactions among organisms and between organisms and their environment, or surroundings. The word “ecology” was coined in 1866 by a German Biologist, Ernst Haeckel. It comes from the Greek word oikos, meaning house.

Interactions Nature’s “houses” come in different sizes –Biosphere  all the combined portions of the planet. This is the largest “house” and includes all existing life, land, water, air, and the atmosphere. There are interactions within the biosphere that produces a web of interdependence betweeen organisms and their environment.

Levels of Organization Species  a group of organisms so similar to one another that they can breed and produce fertile offspring Population  group of individuals that belong to the same species and live in the same area Community  assemblage of different populations that live together in a defined area

Levels of Organization Ecosystem  a collection of all the organisms that live in a particular place together with their non-living, or physical environment. Biomes  a group of ecosystems that have the same climate and similar dominant communities.

Energy Flow The flow of energy through an ecosystem is one of the most important factors that determines the system’s capacity to sustain life. Sunlight is the main energy source for life on Earth.

Producers Organisms that can capture energy from the sunlight or chemicals and use that energy to produce food are autotrophs. They use energy from the environment to assemble simple inorganic compounds into complex organic molecules.

Consumers Heterotrophs are organisms that rely on other organisms for their energy and food supply. They are also known as consumers. –Herbivores- eat only plants –Carnivores – eat animals –Omnivores – eat plants and animals –Detritivores- eat dead plants and animals –Decomposers- break down organic matter

Feeding Relationships Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers) Food chain is a series of steps in which organisms transfer energy by eating and being eaten.

Feeding Relationships When the feeding relationships among the various organisms in an ecosystem form a network of complex interactions, it is called a food web. It links all the food chains in an ecosystem together. Each step in a food chain or food web is called a trophic level. Each consumer depends on the trophic level below it for energy.

Ecological Pyramid The amount of energy or matter in an ecosystem can be represented by an ecological pyramid.It shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web. Three types: –Energy pyramid, Biomass pyramid, pyramid of numbers

Energy Pyramid Only about 10% of the energy available within one trophic level is transferred to organisms at the next trophic level.

Biomass Pyramid Biomass Pyramid represents the total amount of potential food available for each trophic level in an ecosystem. Biomass is the total amount of living tissue within a given trophic level

Pyramid of Numbers Represents the number of individual organisms at each trophic level.