The Balance of the Living World. Ecology is the study of the distribution and interactions of...
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Transcript of The Balance of the Living World. Ecology is the study of the distribution and interactions of...
The Balance of the Living World
Ecology is the study of the distribution and interactions of living communities with each other and the abiotic habitat.
It is an objective science based on the collection of field observations and experimental data.
Environmentalism is a way of thinking that places maintaining the richness and balance of nature as a top priority.
It is a subjective belief system based on an emotional response to information provided by ecology
Biosphere Ecosystem Community Population Individual
A single of member of a species
Chimpanzee, Pan troglodytes
A group of individuals that belong to the same species, live in the same area, and breed with others in the same group.
Scalloped hammerhead, Sphyrna lewini
The many different species that live together in a given area.
A collection of populations in a habitat.
An ecological system encompassing a community and all the physical
aspects of its habitat.
The sum total of all ecosystems
autotroph Self-feeder, uses environmental energy to
create organic molecules ex. plant, algae, cyanobacteria Common name: producer
chemoautotroph Self-feeder, uses non-organic chemicals (H2S)
as energy source ex. bacteria surrounding ocean vents Common name: producer
heterotroph Other-feeder, consumes living organisms for
energy needs Ex. Insects, zooplankton, mammals, etc. Common name: consumer
saprotroph obtains energy by secreting enzymes outside
body and absorbing digested remains of once living organisms
Ex. Fungi and bacteria Common name: decomposer
The trophic level of an organism is its position in the food chain
Primary Producer The foundation of the trophic pyramid (food
chain) Primary Consumer
Heterotrophic feeders of producers Typically herbivores (eat photosynthetic
organisms) Secondary Consumer
Obtains energy from the primary consumer Typically carnivores or omnivores.
Tertiary Consumer, etc.
The collection of all the food chains in a given area
A food web describes the predator-prey relationships of a given community
It is a model of the energy flow through a living system
Very rarely does the model accurately represent the full collection of organisms
First Law of Thermodynamics: Energy can be transferred and
transformed, but it cannot be created or destroyed.
Second Law of Thermodynamics Every energy transfer or transformation
increases the entropy of the universe Ordered forms of energy are at least partly
converted to heat.
Microorganismsand other
detritivores
Tertiaryconsumers
Secondaryconsumers
Detritus Primary consumers
Sun
Primary producers
Heat
Key
Chemical cycling
Energy flow
Nutrient Cycling
Defined as the amount of light energy converted to chemicalchemical energy, i.e., the total amount of organic matter made by producers, during any given time period.
Globally, primary producers create approximately 10 billion tons of organic 10 billion tons of organic materialsmaterials per year.
Gross Primary Production (GPP) is the total primary production in an ecosystem
Net Primary Production (NPP) is the GPP minus the energy used by primary producers for respiration (R)
NPP = GPP - R
NPP represents the storage of chemical energy that will be available to consumers in the ecosystem.
NPP can be expressed as: Energy per unit area per unit time (J/m2/yr) Biomass (weight; usually dry weight) of
vegetation added per unit area per unit time (g/m2/yr)
Standing crop: total mass of photosynthetic organisms present at a given time
NPP: amount of new biomass added in a given time period
Open oceanContinental shelf
Upwelling zonesExtreme desert, rock, sand, ice
Swamp and marshLake and stream
Desert and semidesert scrubTropical rain forest
Temperate deciduous forestTemperate evergreen forest
Tropical seasonal forest
SavannaCultivated land
EstuaryAlgal beds and reefs
Boreal forest (taiga)Temperate grassland
Woodland and shrublandTundra
0.40.4
1.01.31.51.61.71.82.42.72.93.33.54.7
0.30.10.1
5.265.0
Freshwater (on continents)
TerrestrialMarine
Key Percentage of Earth’ssurface area
Average net primaryproduction (g/m2/yr)
6050403020100 2,5002,0001,5001,0005000
Percentage of Earth’snet primary production
2520151050
125
2,500
3601,500
5003.090
900600
800
2,200
600
250
1,6001,2001,300
2,000
700140
0.3
7.99.19.6
5.43.5
0.67.1
4.93.8
2.3
24.45.6
1.20.9
0.10.040.9
22
North Pole
60°N
30°N
South Pole
Equator
60°S
30°S
60°W 60°E 120°E120°W180° 0° 180°
High R O Y G B I V Low
How much energy is passed to the next level of a food chain relative to what is available.
Energy transfer between trophic levels is usually < 20% efficient
Defined as: amount of chemical energy in consumer’s food that is converted to their own biomass during a given time period
How much mass is gained compared to how much food is eaten.
NET SECONDARY NET SECONDARY PRODUCTION = PRODUCTION = 33J33J
Growth (new biomass)
Cellularrespiration
Feces100 J
33 J
67 J
200 J
Plant materialeaten by caterpillar
Production Efficiency = Net Secondary Production Assimilation of Primary Production
33J100J = 33%
Note that energy lost as undigestible material does not count toward assimilation.
Growth (new biomass)
CellularrespirationFeces
100 J33 J
67 J
200 J
Plant materialeaten by caterpillar
The percentage of food intake (energy) that is converted to new biomass
Birds & Mammals (endotherms) ~ 1-3%
Fish ~ 10% Insects ~ 40%
• Trophic Efficiency = Y/X x 100• Usually ranges from 10% – 20%.• i.e., 80% – 90% energy available at one trophic level is not transferred to the next trophic level.• This loss is multiplied over the length of the food chain.
1,000,000 J of sunlight
10,000 J
1,000 J
100 J
10 JTertiaryconsumers
Secondaryconsumers
Primaryconsumers
Primaryproducers
Size of each block is proportional to the net production, expressed in energy units.
Trophic level Dry weight(g/m2)
Tertiary consumers
Secondary consumers
Primary consumers
Primary producers
1.5
11
37
809
Most biomass pyramids show a sharp decrease in biomass at successively higher trophic levels, as illustrated by data from a bog at Silver Springs, Florida.
Size of each block is proportional to the standing crop (total dry weight of all organisms) at each trophic level.
Carbon, Nitrogen, Potassium, Water, Phosphorous
Energy is used to maintain highly ordered homeostasis with organisms
Basic materials of living organisms: Carbon Nitrogen Oxygen Phosphorus
CO2 + H2O C6H12O6 + O2
sunlight
Only occurs in autotrophs (animals that make their own food)
CO2 + H2O + ATPC6H12O6 + O2
Happens in all eukaryotic cells (everything but bacteria)Yes, that means both animals and plants
sugar
Carbon Dioxide required for photosynthesis Plants take CO2 from the air. Carbon can be found…
1. in atmosphere, 2. dissolved in water, 3. in living organisms,4. or deposited at CaCO3 (limestone) or fossil fuels
Decomposition, combustion, and respiration returns C to atmosphere as CO2
Atmospheric and Ocean CO2
Plants Animals
Fossil Fuels
photosynthesis
respirationcombustion
Limestone(plankton)
erosion
N is a major component of proteins, the basic functional unit of the cell.
Most N is found in atmosphere as N2
Only a few bacteria can use N2 and turn it into forms of N that plants can use.
Animals get their N from the food they eat.
Other bacteria turn organic N from urea and dead organisms back into N2
N2 (79% of atmosphere)
Animals PlantsUrea Death Bacteri
a, soil
Bacteria
Bacteria
N2
NH3NO3
N2
NH3
NO3