Presentation on theme: "Energy Flow. ENERGY Energy is the ability to do work and transfer heat. Kinetic energy – energy in motion heat, electromagnetic radiation Potential."— Presentation transcript:
ENERGY Energy is the ability to do work and transfer heat. Kinetic energy – energy in motion heat, electromagnetic radiation Potential energy – stored for possible use batteries, glucose molecules
Electromagnetic Spectrum Many different forms of electromagnetic radiation exist, each having a different wavelength and energy content. Figure 2-11
Fig. 2-11, p. 43 Sun Nonionizing radiationIonizing radiation High energy, short Wavelength Wavelength in meters (not to scale) Low energy, long Wavelength Cosmic rays Gamma Rays X rays Far infrared waves Near ultra- violet waves Visible Waves Near infrared waves Far ultra- violet waves Micro- waves TV waves Radio Waves
Electromagnetic Spectrum Organisms vary in their ability to sense different parts of the spectrum. Figure 2-12
Fig. 2-12, p. 43 Energy emitted from sun (kcal/cm 2 /min) Wavelength (micrometers) Ultraviolet Visible Infrared
ENERGY LAWS: TWO RULES WE CANNOT BREAK The first law of thermodynamics: we cannot create or destroy energy. We can change energy from one form to another. The second law of thermodynamics: energy quality always decreases. When energy changes from one form to another, it is always degraded to a more dispersed form. Energy efficiency is a measure of how much useful work is accomplished before it changes to its next form.
Fig. 2-14, p. 45 Chemical energy (food) Solar energy Waste Heat Waste Heat Waste Heat Waste Heat Mechanical energy (moving, thinking, living) Chemical energy (photosynthesis)
Producers: Basic Source of All Food Most producers capture sunlight to produce carbohydrates by photosynthesis:
Producers: Basic Source of All Food Chemosynthesis: Some organisms such as deep ocean bacteria draw energy from hydrothermal vents and produce carbohydrates from hydrogen sulfide (H 2 S) gas.
Photosynthesis: A Closer Look Chlorophyll molecules in the chloroplasts of plant cells absorb solar energy. This initiates a complex series of chemical reactions in which carbon dioxide and water are converted to sugars and oxygen. Figure 3-A
Fig. 3-A, p. 59 Sun Chloroplast in leaf cell Light-dependent Reaction Light-independent reaction Chlorophyll Energy storage and release (ATP/ADP) Glucose H2OH2O Sunlight O2O2 CO 2 6CO 2 + 6 H 2 O C 6 H 12 O 6 + 6 O 2
Consumers: Eating and Recycling to Survive Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. Herbivores Primary consumers that eat producers Carnivores Primary consumers eat primary consumers Third and higher level consumers: carnivores that eat carnivores. Omnivores Feed on both plant and animals.
Decomposers and Detrivores Decomposers: Recycle nutrients in ecosystems. Detrivores: Insects or other scavengers that feed on wastes or dead bodies. Figure 3-13
Fig. 3-13, p. 61 Scavengers Powder broken down by decomposers into plant nutrients in soil Bark beetle engraving Decomposers Long-horned beetle holes Carpenter ant galleries Termite and carpenter ant work Dry rot fungus Wood reduced to powder Mushroom Time progression
Aerobic and Anaerobic Respiration: Getting Energy for Survival Organisms break down carbohydrates and other organic compounds in their cells to obtain the energy they need. This is usually done through aerobic respiration. The opposite of photosynthesis
Aerobic and Anaerobic Respiration: Getting Energy for Survival Anaerobic respiration or fermentation: Some decomposers get energy by breaking down glucose (or other organic compounds) in the absence of oxygen. The end products vary based on the chemical reaction: Methane gas Ethyl alcohol Acetic acid Hydrogen sulfide
Two Secrets of Survival: Energy Flow and Matter Recycle An ecosystem survives by a combination of energy flow and matter recycling. Figure 3-14
ENERGY FLOW IN ECOSYSTEMS Food chains and webs show how eaters, the eaten, and the decomposed are connected to one another in an ecosystem. Figure 3-17
Fig. 3-17, p. 64 Heat Detritivores (decomposers and detritus feeders) First Trophic Level Second Trophic Level Third Trophic Level Fourth Trophic Level Solar energy Producers (plants) Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores)
Food Webs Trophic levels are interconnected within a more complicated food web. Figure 3-18
Fig. 3-18, p. 65 Humans Blue whaleSperm whale Crabeater seal Elephant seal Killer whale Leopard seal Adelie penguins Emperor penguin PetrelFish Squid Carnivorous plankton KrillHerbivorous plankton Phytoplankton
Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs In accordance with the 2 nd law of thermodynamics, there is a decrease in the amount of energy available to each succeeding organism in a food chain or web.
Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs Ecological efficiency: percentage of useable energy transferred as biomass from one trophic level to the next. Figure 3-19
Fig. 3-19, p. 66 Heat Decomposers Tertiary consumers (human) Producers (phytoplankton) Secondary consumers (perch) Primary consumers (zooplankton) 10 100 1,000 10,000 Usable energy Available at Each tropic level (in kilocalories)
Productivity of Producers: The Rate Is Crucial Gross primary production (GPP) Rate at which an ecosystem’s producers convert solar energy into chemical energy as biomass. Figure 3-20
Fig. 3-20, p. 66 Gross primary productivity (grams of carbon per square meter)
Net Primary Production (NPP) NPP = GPP – R Rate at which producers use photosynthesis to store energy minus the rate at which they use some of this energy through respiration (R). Figure 3-21
Fig. 3-21, p. 66 Photosynthesis Sun Net primary production (energy available to consumers) Growth and reproduction Respiration Energy lost and unavailable to consumers Gross primary production