1. Unit III: Ecosystem Ecology
Chapters 3 Part I: Energy Transfer

2. Chapter Objectives List the basic components of an ecosystem
Describe how energy flows through ecosystems.
Describe how carbon, nitrogen, and phosphorus cycle within ecosystems
Explain how ecosystems respond to natural and anthropogenic disturbances
Discuss the values of ecosystems and how humans depend on them

3. I. Ecosystems
Particular location on Earth distinguished by its particular mix of interacting biotic and abiotic components,
Components of an ecosystem are interrelated
Each ecosystem interacts with surrounding ecosystems through the exchange of energy and matter

4. Sustain Life on Earth:
One-way flow of high-quality energy from the sun, through living things in their feeding interactions, into the environment as low quality (heat) energy and eventually back into space.
Cycling of Nutrients (atoms, ions, molecules) through the biosphere. Law of Conservation of Matter governs nutrient cycling process.
Gravity: allows planet to hold onto atmosphere and helps movement and cycling of chemicals through air, water, soil, organisms

5. II. Energy Flows Through Ecosystems
Producers (autotrophs)
Photosynthesis
6CO2 + 6H2O + light energy C6H12O6 + 6O2
Producers –Make own food from compounds and energy obtained from environment. Most capture sunlight to produce carbs by photosynthesis. on land mostly vascular plants/water phytoplankton
Decomposers – mostly bacteria, some fungi, consumers that complete breakdown of and recycling or organic matter. They release these nutrients into soil and water, to be used by producers.
Detrivores=live off detritus-extract

6. Anaerobic Respiration / Fermentation
C6H12O6 + 6O CO2 + 6H2O + Energy (38 ATP)
Anaerobic Respiration / Fermentation
Breakdown of glucose in absence of oxygen.
C6H12O C2H5OH (ethanol) + energy
C6H12O C3H6O3 (lactic acid) + energy
Products are methane (CH4), ethyl alcohol ( C2H6O) and acetic acid (C2H4O2)
In aerobic respiration one molecule of glucose can generate 38 molecules of ATP, in anaerobic respiration about 2 molecules of ATP are released per one molecule of glucose

7. Chemosynthesis:
Chemosynthetic microbes grow on and below the seafloor and even within other animals at the vents
A process in which certain microbes use chemicals in the vent water to produce energy. They in turn form the base for an entire food chain of animals.
Chemosynthesis is the process by which certain microbes create energy by mediating chemical reactions.They make carbs from hydrogen sulfide (H2S) So the animals that live around hydrothermal vents make their living from the chemicals coming out of the seafloor in the vent fluids! Because they are a local food source, hydrothermal vents typically have high biomass, in stark contrast to the very sparse distribution of animals outside of vent areas where animals are dependent on food dropping down from above.
Consumers: all other organisms . Omnivore

9. III. Trophic Levels, Food Chains and Food Webs
Consumers: Heterotrophs
1o, 2o, 3o
Herbivore
Carnivore
Omnivore
Scavenger
Detrivore
Acid, Poop, and Barf: Vultures' Secret Weapons
Biomes-major eco divisions determined by relationship between altitude and temperature and precipitation/characterized by distinct climate andlife forms that have adapted.
Abiotic-sun, temp, precip, wind, latitude, altitude, nutrients
ROT-range of abiotic conditions in which an organism (species) can survive.LOT-the existence, abundance, distributino of species whithin an ecosystem determined by whether physical and chemical factors fall within range of tolerance
Limiting Factor: A variable that influences that growth, abundance and distribution of a population
Example: car manufacturing-if a part is in short supply than cars can only be produced at the rate that part is available, even if there is an abundance of other car parts. In an exosystem is could be sun, temp., water, oxygen,availability of nutrients

10. Decomposers: break organic compounds down into inorganic substances.
Fruit and vegetable Decomposition
Bacteria/Fungi
Detrivores: Comsume detritus to optain energy. Earthworm, Beetles, Millipedes, Sow Bug
Diverstiy: Genetic, Species, Ecological
Decomposers: recycle nutrients. Secrete enzymes that digest or degrade dead organisms into simpler INORGANIC compounds
Scavangers-Feed of dead organisms killed by others or die naturally nutrients from partly decomposed organic matter.

12. Food Webs & Energy Flow
© Brooks/Cole Publishing Company / ITP

13. V. Productivity
Different Ecosystems use solar energy to produce and use biomass at different rates.
To understand how ecosystems function must understand where energy comes from and how it is transferred
Gross Primary Productivity-GPP total amount of energy that producers in an ecosystems capture via photosynthesis over a given amount of time
GPP: Rate at which producers convert solar energy to chemical energy as biomass.
NPP: Producers must use some of the biomass they produce to grow, reproduce and stay alive. What are these processes called? (Respiration) The rate at which producers use photosynthesis to store energy – rate at which they use some for aerobic respiration is the net. It is a measure of how fast producers can supply food to consumers.

14. Energy captured minus the energy respired by producers is Net Primary Productivity: NPP
NPP=GPP-R

15. Why Productivity is Important
The amount of sunlight that reaches a lake determines how much algae can live in the lake
Amount of Algae determine the number of zooplankton the lake can support
Size of zooplankton population determines size of fish population

17. Measuring Productivity
Rarely does photosynthesis occur w/o respiration.
Measure production of CO2 in dark
(only produced-no photo means no uptake/loss of CO2)
Measure uptake of CO2 in sunlight.
(being produced and used)
CO2 taken up in photosynthesis = CO2 taken up in sunlight + CO2 produced in dark

18. Factors Limiting Primary Productivity
The planet’s NPP limits the number of consumers-including humans, that can survive on earth.
Solar Radiation alone does not determine Primary Productivity
Temperature:
Relationship between forest net primary productivity and annual temperature.
Precipitation
Increasing Precipitation increases productivity

19. Energy Transfer Efficiency and Trophic Pyramids
The energy in an ecosystem can be measure in terms of biomass (total mass of all living matter)
NPP establishes the rate at which biomass is produced over a given amount of time.
The amount of biomass present in an ecosystem at a particular time is standing crop
Not all energy contained in a trophic level is in a usable form-not digestible

21. Problem 1% solar energy striking a producer captured by photo
60% of GPP lost to respiration
40% of GPP supports the growth and reproduction of producers
A North American Forest has a GPP of 2.5 kg C/m2/year
How much is “lost” to respiration?
What is the NPP?

22. An acre of cropland could produce 1,000 kg of soybeans.
If that is fed to people, how much biomass is available?
Of fed to a cow, how much biomass do we get from the beef?
Since 1 kg of soybeans contains 2.5 as many calories as 1kg of beef, 1 acre of land can produce 25 more calories when used for soybeans than beef.