INTRODUCING BIOGEOGRAPHY

“Ecology” oikos : home; that which is held in common Study of the interrelationship of living plants and animals with their non-living environment. Energy/heat is common to both.

Ecosystem Combination of living organisms (biotic) with the non-living (abiotic) surroundings.

Biotic Components organized in communities Community: group of interlocking populations of plants and animals in a habitat. Habitat: place in which an organism is suited to live. Niche: functional “role” of organism in ecosystem.

Habitats of Canadian boreal forest Community in upland habitat: red squirrels, pine and spruce trees, mushrooms, lichens, wolves, etc. Niche of red squirrel: Spreads seeds in the forest

Abiotic components cycle through the earth-atmosphere Nutrient cycles –Oxygen, nitrogen, carbon cycles, etc. Water cycle Energy : solar converted into other forms

Recall solar radiation budget…solar radiation budget 69% insolation absorbed.  converted to other forms of energy  follows one of two pathways: 1.HEAT PATH (>99%) 2.ORGANIC PATH (< 1% )

HEAT PATH converted to heat by atmosphere,oceans, land surfaces. hydrologic system, nutrient cycles, atmospheric circulation ORGANIC PATH converted to organic compounds in plants. the energy that drives ALL LIFE ON EARTH!

HOW does energy flow through ecosystems??????

FOOD CHAIN Sequence in which energy flows through trophic levels (successive consumer stages).

Fourth-order consumer Primary Producer green plants; photosynthetic bacteria and algae Primary consumer Secondary consumer Tertiary consumer heterotrophs autotrophs

AUTOTROPHS : manufacture living (organic) tissue from non-living (inorganic) chemicals HETEROTROPHS rely on autotrophs

Grazing Chain (above ground) Detritus Chain : the decomposers who consume dead organic matter (detritus)

Underground food web (detritus food chain)

On average, 10 times as much energy flows through the detritus chain as through the grazing chain.

ENERGY PYRAMID Energy passed from one trophic level to the next Only 10% of energy from each level gets passed along to the next level. Log scale

Where does the “wasted” energy go??? It is used in respiration.

Energy transfer Green plants contain CHLOROPHYLL –reflects green; absorbs all other colors absorption of light = absorption of energy PHOTOSYNTHESIS: CO 2 + H 2 O + energy  C 6 H 12 O 6 + Oxygen (sun) Glucose: carbohydrate Only autotrophs can do this!

RESPIRATION –Plants and animals derive energy C 6 H 12 O 6 +Oxygen  CO 2 + H 2 O + energy Heterotrophs do this. Animals, roots, microorganisms in soil

Primary productivity Gross primary productivity: rate at which energy is stored in organic chemicals by primary producers in photosynthesis. In respiration, carbohydrates are broken down and energy is released; remaining carbohydrates can become plant tissue. Net primary productivity: rate at which energy is stored in plant tissue. Gross P.P. = Respiration + Net P.P.