lec 9 BSC 202 Energy ecosystems presentation versi

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Energy in Ecosystems: 

Energy in Ecosystems

Slide2: 

Ecosystem Processes --Energy Flow Solar Radiation Herbivore Decomposers Autotroph Carnivore 1. Sun as an energy source 2. Energy Fixed by plants 3. Energy flow to heterotrophs

The Sun as an Energy Source : 

The Sun as an Energy Source How does the sun make energy? Solar energy is generated by fusion

The composition of the Sun : 

The composition of the Sun 81.76 % hydrogen 18.17 % helium trace of other elements 0.07%

E = mc2: 

E = mc2 + + + + Fuse four hydrogen nuclei Helium 4 + loss of mass (matter) + release of energy Intense Heat (1,000,000 degrees Celsius) and Pressure

The sun converts matter to energy: 

The sun converts matter to energy 4.1 billion tons of matter per second How old is the sun? How long can it last?

The sun converts matter to energy: 

The sun converts matter to energy We can rest easy for a long time!

The sun is a medium sized star 93,000,000 miles from the earth. : 

The sun is a medium sized star 93,000,000 miles from the earth. How does solar energy reach us? Electromagnetic energy What is electromagnetic energy?

Slide9: 

Electromagnetic Waves Packets of Energy Following a Wave Pattern

What Make Electromagnetic Waves Different?: 

What Make Electromagnetic Waves Different? Trough to Trough Crest to Crest

Measuring Wavelengths : 

Measuring Wavelengths Meter = 3.3 feet (39.37 in.) 1/100 meter = centimeter (0.3937 in.) 1/1000 meter = millimeter (0.0397 in. 1/1000,000 meter = micron (0.0000397 in.) 1/1000,000,000 meter = millimicron (nanometer) (0.0000000397 in.) Abbreviations used: cm = centimeter, nm = nanometer, in. = inch

Electromagnetic Spectrum from the sun: 

Electromagnetic Spectrum from the sun Vary in wave length from: AM radio (200-600 m), FM radio (0.18- 5.5 m) Microwaves (30 cm to 0.3 cm) Infrared (0.1 cm - 800 nm) Visible light (400 - 800 nm) Ultraviolet (400 nm - 10 nm) X-rays (less than 10 nm)

Mostly electromagnetic energy between 100 and 4,000 nanometers transfers solar energy to the earth : 

Mostly electromagnetic energy between 100 and 4,000 nanometers transfers solar energy to the earth 7-8 % ultraviolet (100-400 nanometers) 43 % visible (400-700 nanometers) 49-50 % (700+ nanometers) Infrared Microwaves Radio waves

Slide15: 

X-rays UV White light Micro and radio waves

Ultraviolet Radiation: 

Ultraviolet Radiation Ultraviolet radiation Wave length Greater than x-ray 10 nm Less visible light – 10 to 400 nm

Three Categories of Ultraviolet Radiation : 

Three Categories of Ultraviolet Radiation UV-C less than 280 nanometers to x-rays (10 nm) stratospheric ozone absorbs all UV-B 280-320 nm ozone absorbs some UV-A 320-400 nm ozone absorbs none

Slide18: 

Shorter wave length of UV are more dangerous to living organisms

Slide19: 

Response to UV radiation (Erythemal –sunburn) UV-C 10 -280- nm UV-B 280-320 nm UV-A 320-400 nm C 1 10 100 1000 10000 B A

Slide20: 

Three Categories of Ultraviolet Radiation UV-C less than 280 nanometers to x-rays (10 nm) stratospheric ozone absorbs all UV-B 280-320 nm ozone absorbs some UV-A 320-400 nm ozone absorbs none

UV-B Radiation Effects : 

UV-B Radiation Effects Penetrates skin about 1 mm Needed for formation of vitamin B3 Cataracts Causes: sunburn and tanning wrinkling & aging of skin Cause skin cancer (malignant melanoma) disrupts DNA Metastasizes Melanocyte (melanin) USA 54,000 cases & 7,000 deaths annually

Malignant Melanoma: 

Malignant Melanoma Malignant Melanoma Normal Mole Malignant Melanoma Irregular Edge Color Less Uniform Appears to be spreading into the skin

UV-B Radiation Effects: 

UV-B Radiation Effects Suppress the immune system Plants: stunts growth & bleach chlorophyll

Commercial Tanning: 

Commercial Tanning Most use UV A Is it safe? Experts say no UV A causes same health concerns as UV B but less dangerous

Solar (Sun) Radiation on the earth’s surface: 

Solar (Sun) Radiation on the earth’s surface Most short-wave radiation filtered out stratospheric ozone Most medium and longer waves reach the earth’s surface (400-4,000 nanometers) Atmosphere is relatively transparent to visible light (400-700 nanometers) Maximum energy output -visible portion of the spectrum Used by plants in photosynthesis

Re-radiated Energy From the Earth : 

Re-radiated Energy From the Earth Energy radiated from the earth peaks 8,000 to 13,000 nanometers (8-13 microns) Atmosphere has strong absorbency 8,000 to 13,000 nanometer range

The sun’s energy is radiated in all direction into space : 

The sun’s energy is radiated in all direction into space Only 1/2,000,000,00 of the sun’s energy reaches the earth What happens to energy reaching the earth’s atmosphere? Sun Earth

Flow of Energy to and from the Earth: 

Flow of Energy to and from the Earth In coming solar radiation 100% Cloud Emissivity 66% Albedo 34% (Reflected) Photosynthesis 0.023% Heating: 42% Evaporation 23% Wind & Waves 1% Reflected (Albedo) + Emissivity = 100%

Solar Radiation Used by Plants: 

Solar Radiation Used by Plants 1. Visible light - 400-700 nanometers most concentrated energy 2. Peaks at red and blue light

Gross Primary Production: 

Gross Primary Production = the accumulation of energy or dry matter by plants (autotrophs) through the process of photosynthesis

Efficiency of Gross Primary Production: 

Efficiency of Gross Primary Production = energy fixed by gross primary production Energy in incident sunlight Incident sunlight = energy striking the leaves Efficiency of photosynthesis varies from about 0.5 to 3.5%

Primary Production: 

Primary Production Gross Primary Production = total amount of energy fixed or biomass produced by plants Net Primary Production = Gross Primary Production minus plant respiration Productivity = the rate of accumulation of energy or biomass (g/m2/yr or kcal/m2/yr)

Comparison of Net Primary Productivity (kcal/m2/year) For Natural Ecosystems Productivity is the rate of energy or biomass accumulation: 

Comparison of Net Primary Productivity (kcal/m2/year) For Natural Ecosystems Productivity is the rate of energy or biomass accumulation Ecosystem Climate Productivity Desert Arid 400 Ocean ------ 800 Forests Deciduous Temperate 4,800 Coniferous Temperate 11,200 Tropical Rainforest Tropical 20,000

Comparison of Net Primary Productivity for Agricultural Systems (kcal/m2/year): 

Comparison of Net Primary Productivity for Agricultural Systems (kcal/m2/year) Agricultural Crop Climate Productivity Annual Temperate 8,800 Perennial Temperate 12,000 Annual Tropical 12,000 Perennial Tropical 30,000a a(sugar cane)

Energy Flow Beyond the Producer: 

Energy Flow Beyond the Producer Food Chains = an energy transfer system through living organisms with repeated eating and being eaten

Types of Food Chains: 

Types of Food Chains Grazing Food Chain 1. Starts with an autotroph 2. Grass Rabbit Fox Detritus Food Chain 1. Starts with detritus (dead material) 2. Types of detritivores a. Detritus Feeder (Holozoic) b. Decomposers (fungi and bacteria)

Energy Consumed in grazing and detritus food chains: 

Energy Consumed in grazing and detritus food chains Amount of Net Primary Consumed Detritus Grazing Ecosystem Tropical rain forest 93% 7% Temp. deciduous forest 95% 5% Grassland 90% 10% Ocean 60% 40%

Trophic Level Concept: 

Trophic Level Concept Definition Plants or detritus are the first trophic level

Short Food Chain (Three Trophic Levels): 

Short Food Chain (Three Trophic Levels) Grass (Autotroph) Deer (Herbivore) Wolf (Carnivore) Third Trophic Level Second Trophic Level First Trophic Level

Laws of Thermodynamics (First Law): 

Laws of Thermodynamics (First Law) Energy can be converted from one form of energy to another but the amount of energy remains the same.

Slide42: 

First Law of Thermodynamics Solar Energy Green Plant (autotroph) Heterotrophs 1-3% 10% Energy (Heat Randomly Distributed) 97-99% 90% Solar Energy = Chemical energy in autotroph and Heterotroph + Randomly distributed heat Energy No Net Loss of Energy

Second Law of Thermodynamics: 

Second Law of Thermodynamics Any transformation of energy will go from a concentrated to a dispersed form Energy available to be used is constantly being diminished

Slide44: 

Second Law of Thermodynamics Solar Energy Green Plant (autotroph) Heterotrophs 1-3% 10% Lost Energy (Heat Randomly Distributed) 97-99% 90% Energy Available to be used is constantly diminished 100% 1-3% 0.1-0.3%

Energy Transformation in Food Chains: 

Energy Transformation in Food Chains As energy moves through a food chain Constant loss of energy of high utilization Constant gain of energy of low utilization (heat) 10% of the energy at one trophic level is transferred to the next

SUMMARIZING FOOD CHAINS AND TROPHIC LEVELS : 

SUMMARIZING FOOD CHAINS AND TROPHIC LEVELS PYRAMID OF NUMBERS PYRAMID OF BIOMASS PYRAMID OF ENERGY

PYRAMID OF NUMBERS BLUEGRASS PASTURE: 

PYRAMID OF NUMBERS BLUEGRASS PASTURE AUTOTROPH 5,542,424 708,624 3 HERBIVORE CARNIVORE GRASS GRASSHOPPER BIRD

Slide48: 

PYRAMID OF BIOMASS BLUEGRASS PASTURE (LB/ACRE) AUTOTROPH 4,190 54 1 HERBIVORE CARNIVORE GRASS GRASSHOPPER BIRD

PYRAMID OF ENERGY: 

PYRAMID OF ENERGY SOLAR ENERGY PLANT AUTOTROPH DEER HERBIVORE LION CARNIVORE 1 10 100 10,000 CALORIES 9,900 CALORIES 90 9 Energy Lost