Chapter 2: Principles of Ecology

Ecology The study of the interactions between organisms and their environment Includes both Biotic (living) and abiotic (nonliving) factors Abiotic factors might include: Temperature Water availability/quality Terrain (mountains, flat land, etc.) Soil chemistry Etc.

Levels of Ecological organization Individual Population=members of same species in an area Community=interacting populations Ecosystem=communities and abiotic factors Biosphere=portion of planet that supports life

Important! Within populations and communities, there is competition for limited resources (i.e. food, water, shelter, etc.)

2 types of ecosystems Terrestrial= on, under, or near land Aquatic=in water These ecosystems do occasionally overlap (pelicans, frogs, etc)

Habitat vs. Niche Habitat=where an organism lives Niche=role or position of the organism in the habitat

Symbiosis Sym=together (think “symmetry”) Bio=life Means “living together” 3 main types, defined by how they impact one another

Mutualism (+/+) Both organisms are benefitted

Commensalism (+/0) One organisms gets a benefit, the other is unaffected

Parasitism (+/-) One organism is benefitted, the other is harmed Usually does not kill host, because it relies on it for survival

Nutrition and Energy Flow Terms: Autotroph: “Auto”=Self “troph”=nourishment Makes its own energy (producers) Typically photosynthesis, can also be chemosynthesis Heterotroph: “Hetero”=other A.k.a. consumers Get energy from consuming other living matter (ex. Animals, fungi) Decomposers/Detritivore/Scavengers (technically heterotrophs) Break down dead/dying matter (ex. Fungi)

Types of Heterotrophs Herbivore-only eats plants Carnivore=“only” eats other animals Omnivore=eats plants and animals Scavengers=consumes dead organisms Detritivore=decomposes animal and plant pieces and feces (large) Decomposer=Absorb and break down remains of dead organisms (small)

Trophic Levels Feeding step in energy chain Begin with autotrophs 1st order heterotroph (herbivore) 2nd order heterotroph (carnivore or omnivore) 3rd order heterotroph (carnivore or scavenger) Decomposer (everything ends with decomposers!)

How energy moves through an ecosystem Food chain-simple diagram showing where energy goes Producer (Autotroph)→Primary Consumer (Herbivore)→Secondary consumer (carnivore)→Decomposer NOTE: Arrows show where the ENERGY is going, not what is eating what

Food web More complex Shows “all possible” feeding relationships More realistic, but seldom perfect

Energy Pyramids Recall, Law of Conservation of Energy Cannot be created or destroyed Can change forms Model to show how much energy is available at each level 10% can move on The rest is lost to the environment as heat (metabolism) Biomass-mass of living matter at each level