INTRODUCING BIOGEOGRAPHY
Dec 29, 2015
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 Componentsorganized 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 componentscycle through the earth-atmosphere
• Nutrient cycles– Oxygen, nitrogen, carbon cycles, etc.
• Water cycle
• Energy : solar converted into other forms
Recall 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 PATHconverted to heat by
atmosphere,oceans, land surfaces.hydrologic system, nutrient cycles, atmospheric
circulation
ORGANIC PATHconverted 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 Producergreen plants;photosyntheticbacteria and algae
Primary consumer
Secondary consumer
Tertiary consumer
hete
rotro
ph
sauto
trop
hs
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:CO2 + H2O + energy C6H12O6 + Oxygen
(sun) Glucose: carbohydrate
Only autotrophs can do this!
RESPIRATION– Plants and animals derive energyC6H12O6 +Oxygen CO2 + H2O +
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.