Levels of Organization

Levels Within Levels An ecosystem is a collection of all the organisms that live in a particular place, together with their nonliving, or physical, environment. Within an ecosystem, there are several levels of organization. Your school and its grounds are similar to an ecosystem. 1. What living things are found in and around your school? 2. What nonliving things are found in your school? 3. Into what large groups are the students in your school divided? 4. Into what smaller groups are these large groups divided? 5. Are these groups ever divided into even smaller groups? If so, what are these groups?

What is Ecology? Study of interactions among 1. Organisms (Living-Living) 2. Organisms and their environment (Living-Nonliving)

Species- a group of similar organisms that can breed and produce fertile offspring.

3-2 Ecological Levels of Organization Section 3-1 Go to Section:

Levels of Organization Individual- one organism (living) Ex a moose

Levels of Organization Population- groups of individuals that belong to the species and live in the same area. (living-living same species) Ex many moose

Levels of Organization Community- groups of different populations (more than one population or different groups of species) Ex many groups of moose beavers, trees, grass (all living)

Levels of Organization Ecosystem- all organisms in a particular area along with the nonliving. (living and nonliving) Ex many groups of moose beavers, trees, grass, rocks, water, mountains

Levels of Organization Biome- group of ecosystems that have the same climate and similar dominant communities Biomes: tropical rain forest, tropical dry forest, tropical savannah, temperate grassland, desert, temperate woodland and shrubland, temperate forest, northwestern coniferous forest, boreal forest (taiga), tundra, mountains and ice caps

Levels of Organization Biosphere- all of the planet where life exhists, includes land, water, and, air Life extends 8 km up and 11 km below the surface

What shapes an ecosystem? Biotic factors- biological (living) influences on ecosystem Ex. Interactions between organisms, predation, symbiosis, etc. Abiotic factors- nonliving influences on ecosystems Ex. Temperature, precipitation, nutrient availability, sol type, sunlight.

Biotic- anything living

Abiotic- anything non-living

Habitat vs. Niche Habitat- an area where an organism lives Niche- full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions. Includes where in the food chain it is, where an organism feeds Habitat is like an address in an ecosystem and a niche is like an occupation in an ecosystem.

Community Interactions when organisms live together in an ecological community they interact constantly. Three types of interactions Competition Predation Symbiosis

Competition- competing for resources occurs due to a limited number of resources Resource- any necessity of life. water, nutrients, light, food. Competitive exclusion principle- no two species can occupy the same niche in the same habitat at the same time

Predation Predation- when an organism captures and feeds on another organism. Predator- hunter Prey- hunted

Symbiosis Symbiosis- any relationship where two species live closely together. (3 types) Mutualism Commensalism Parasitism

Symbiosis Mutualism- both species benefit from a relationship. Lichens (fungus and Algae) One example is the lichens, little non-descript patches of stuff you see growing on rocks and tree bark. This is a symbiosis, consisting of a fungus and an alga. The fungus provides a protective home for the algae, and gathers mineral nutrients from rainwater and from dissolving the rock underneath. The alga gathers energy from the sun. There are thousands of species of lichen in the world; actually thousands of species of fungi with just a few species of algae which can form a partnership with almost any of them.

Symbiosis Commensalism – One member of a symbiotic relationship benefits and the other is neither helped or harmed Ex. Holes used by bluebirds in a tree were chiseled out by woodpeckers after it has been abandoned .

Symbiosis Parasitism- One creature benefits and one creature is harmed Ex tapeworm. Feeds in a humans intestines absorbing his/her nutrients.

Energy Flow (Trophic Levels) Producers- make their own food Consumers- get energy from consuming producers or other consumers

Producers Producers- capture energy from sunlight or chemicals and use the energy to produce food. Producers are autotrophs- they make food from their environment

Autotrophs Get energy from the sun-by photosynthesis Get energy without light- by chemosynthesis

Consumers Consumers are heterotrophs- get energy from other organisms

Types of Consumers Herbivores- eat only plants Carnivores- eat animals Omnivores- eat both plants and animals Detritivores- eat dead matter (plants and animals)

Feeding Relationships Energy flows through an ecosystem in one direction from: 1. the sun or inorganic compounds 2. To autotrophs (producers) 3. To heterotrophs (consumers) Decomposers get energy from decomposing dead organisms

Food Web- A network of feeding relationships. Food Chain- a series of steps in which organisms transfer energy by eating or being eaten. Third Level Consumers Second Level First Level (Primary) Food Web- A network of feeding relationships. (More realistic than a food chain)

Trophic levels Each step in a food chain or a food web is called a trophic level. Producers are the first trophic level Consumers are the second, third, or higher trophic level Each trophic level depends on the one below for energy Third Level Consumers Second Level First Level (Primary)

Energy Pyramid Only part of the energy stored in one level can be passed to the next- most energy is consumed for life processes (respiration, movement, etc., and heat is given off) Only 10% of the energy available within one trophic level is transferred to organisms in the next trophic level

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