Ecology

What is Ecology? Ecology is the study of interactions among organisms (biotic factors) and between organisms and their environment (abiotic factors). Biotic factors- all the living things in the environment Abiotic factors- all the nonliving things in the environment ex. Temperature, light, water, soil

Levels of Organization Species is a group of organisms so similar to one another that they can breed. Population are a group of individuals (of one type of species) that belong to the same species that interbreed and live in the same area. For example, all foxes living in an area form a population. Another example, all dandelions growing in an area form another population.

Levels of Organization Communities are assemblages of the different populations that live together in a defined area. All the foxes, dandelions, grasshoppers, snakes, hawks, deer, and skunks living in one area (forest) each form their individual populations, but together make up a community. Ecosystem is a collection of all the organisms that live together in a particular place as well as their nonliving or physical environment. Ex. Forest or ocean

Levels of Organization Biome is a group of ecosystems that have the same climate and similar dominant communities. ex. Tropical rainforest, temperate deciduous forest Biosphere Biosphere contains the combined portions of the planet in which life exists, including land, water, and air or atmosphere.

Energy Flow Sunlight is the main source of energy for life on Earth. Some types of organisms rely on the energy stored in inorganic chemical compounds. Autotrophs Autotrophs (producers) use energy from the environment to fuel assembly of simple compounds into complex organic molecules.

Energy Flow Autotrophs The best know autotrophs are those that harness the power of the sun through photosynthesis (a.k.a. plants) They use this energy to convert carbon dioxide and water into oxygen and glucose. The second type of autotrophs use chemical energy to make carbohydrates. This is performed by several types of bacteria.

Energy Flow Consumers Heterotrophs (consumers) rely on other organisms for their energy and food. Herbivores obtain energy by eating plants. Carnivores eat animals. Omnivores eat both plants and animals. ex. Humans or bears Detritivores feed on the remains of plants, animals and other dead matter. ex. earthworms Decomposers breaks down organic matter. ex. Fungus or bacteria Scavenger- feeds upon dead material ex. vulture fungus

Feeding Relationships Energy flow through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers). Food Chains are a series of steps in which organisms transfer energy by eating or being eaten. Food webs show the complex interactions within an ecosystem. Each step in a food chain or web is called a trophic level. Producers make up the first step, consumers make up the higher levels.

Food Chain

Food Web

Ecological Pyramids An ecological pyramid is a diagram that shows the relationship amounts of energy or matter contained within each trophic level in a food web or food chain. Energy Pyramid only 10% of the energy available within one trophic level is transferred to organisms at the next trophic level ( a lot of energy is used for metabolism of food and is given off as heat as well so it is not available to pass on to the next energy level

Energy pyramid

Pyramids Continued Biomass pyramids show the total amount of living tissue available at each trophic level. This shows the amount of tissue available for the next trophic level. Numbers pyramid shows the number of species at each trophic level. Because each trophic level harvests only about one tenth of the energy from the level below, it can support only about one 10 th the amount of living tissue.

Biomass pyramid

Cycles of Matter Unlike the one-way flow of energy, matter is recycled within and between ecosystems. These cycles are the water cycle, Nutrient Cycle, Carbon Cycle, nitrogen cycle and phosphorus cycle.