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 shrub land, temperate forest, northwestern coniferous forest, boreal forest (taiga), tundra, mountains and ice caps
Levels of Organization • Biosphere- all of the planet where life exists, includes land, water, and, air • Life extends 8 km up and 11 km below the surface
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, soil type, sunlight. What shapes an ecosystem?
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. Clownfish uses a sea anemone as shelter which does not harm the sea anemone
Symbiosis • Parasitism- One creature benefits and one creature is harmed • Ex tapeworm. Feeds in a humans intestines absorbing his/her nutrients.
Producers- capture energy from sunlight or chemicals and use the energy to produce food. Producers are autotrophs- they make food from their environment photosynthesis Get energy from the sun Consumers- get energy from consuming producer Consumers are heterotrophs- get energy from other organisms Energy Flow (Trophic Levels)
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 Chain- a series of steps in which organisms transfer energy by eating or being eaten. Food Web- A network of feeding relationships. (More realistic that 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
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.
Ecological succession occurs in a community over a period of time Start at 1:05 What is Succession? • Ecosystems are constantly changing 2. As change occurs, older inhabitants usually die out and new organism move in 3. Some changes within an ecosystem are predictable Primary succession- occurs on land where no soil exists.
Primary Succession Mosses and grasses begin to take root in thin soil layer that formed from decaying lichens… Lichens begin to grow on bare rock. When they die, they leave behind organic matter… Newly exposed rock is barren and lifeless… Tree seedlings and shrubs begin to grow.
Secondary succession- occurs when a disturbance changes an existing community without removing the soil