Download - Ch 54 - Ecosystems
![Page 1: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/1.jpg)
Ch 54 - Ecosystems
![Page 2: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/2.jpg)
What is an ecosystem?
• All organisms in a community and the abiotic factors they interact with
![Page 3: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/3.jpg)
Physical Laws & Energy
• Law of conservation of energy – energy cannot be created or destroyed, only transferred or transformed
• 2nd law of thermodynamics – every exchange of energy increases the entropy of the universe
• Thus ecosystems need a constant supply of energy
![Page 4: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/4.jpg)
Energy flow in ecosystems
• Energy flows through the ecosystem –one way
• Sun is primary source of energy
![Page 5: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/5.jpg)
Trophic levels
• Autotrophs – primary producers – plants, phytoplankton
• Heterotrophs – consumers– Primary consumers – herbivores– Secondary consumers – carnivores that eat
herbivores– Tertiary consumers – carnivores that eat other
carnivores
![Page 6: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/6.jpg)
• Decomposers/Detritivores- get energy from detritus– prokaryotes & fungi are main decomposers– Decomposition connects all trophic levels
– http://www.countrysideinfo.co.uk/rabbita.htm– http://vimeo.com/21216124
![Page 7: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/7.jpg)
KeyChemical cyclingEnergy flow
Sun
Heat
Primary producers
Primaryconsumers
Secondary andtertiary consumers
Detritus
Microorganismsand other
detritivores
![Page 8: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/8.jpg)
Primary production
• Most ecosystems - primary production is the amount of light energy converted to chemical energy by autotrophs during a given time period
• In a few ecosystems, chemoautotrophs are the primary producers
![Page 9: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/9.jpg)
GPP vs. NPP
• Gross primary production – total primary production
• Net primary production:• = GPP minus energy used by primary
producers for respiration• On average NPP is ½ of GPP• This is the amount of energy available to consumers
![Page 10: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/10.jpg)
Net primary production(kg carbon/m2yr)
3
2
0
1
Global net primary production
![Page 11: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/11.jpg)
Primary production in Aquatic systems• Factors:
– Light limitation– Nutrient limitation
Commonly nitrogen & phosphorous
• Eutrophication– Process where bodies of water receive too many
nutrients, which results in excessive plant growth, reducing oxygen concentration & water clarity
![Page 12: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/12.jpg)
Primary production in Terrestrial ecosystems
• Factors– Temperature– Moisture– Nutrients
![Page 13: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/13.jpg)
Plant adaptations for nutrients
• Symbiotic relationships:• Nitrogen fixing bacteria –
– Convert N2 to NH3 – Rhizobium forms nodules on roots of
legumes
• Mycorrhizae -– Host plant provides fungus with sugar– Fungus increases surface area for water
uptake, and supplies plant with minerals absorbed from soil
![Page 14: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/14.jpg)
Secondary production
The amount of chemical energy from food that is converted to a consumer’s biomass
![Page 15: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/15.jpg)
Trophic efficiency
• 10% rule• Only 10% of energy available at one trophic
level is transferred to the next trophic level
• 90% of energy is not transferred:– Not eaten, lost through respiration, contained in
feces– http://science.howstuffworks.com/life/27995-assi
gnment-discovery-energy-flow-video.htm
![Page 16: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/16.jpg)
![Page 17: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/17.jpg)
Pyramid of energy
![Page 18: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/18.jpg)
![Page 19: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/19.jpg)
Biogeochemical Cycles
Matter gets recycled
![Page 20: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/20.jpg)
Phosphorus Cycle
![Page 21: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/21.jpg)
![Page 22: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/22.jpg)
![Page 23: Ch 54 - Ecosystems](https://reader033.vdocuments.mx/reader033/viewer/2022051402/56815ecc550346895dcd5218/html5/thumbnails/23.jpg)
Carbon Cycle