3 Ecosystems and Energy
Overview of Chapter 3 What is Ecology? The Energy of Life Laws of Thermodynamics Photosynthesis and Cellular Respiration Flow of Energy Through Ecosystems Producers, Consumers & Decomposers Ecological Pyramid Ecosystem Productivity
Ecology Ernst Haeckel (developed the concept in 19 th Century) eco house & logy study of Literally means The study of one s house The study of interactions among & between organisms in their abiotic environment Biotic - living environment Includes all organisms Abiotic - non living or physical environment The abiotic factors SWATS: Soil, Water, Air, Temperature, and Sunlight.
Ecologists - are interested in the levels of life above that of organism. Species - A group of similar organisms whose members freely interbreed Population a group of organisms of the same species that live in the same area at the same time. Community - All the populations of different species that live and interact in the same area at the same time Ecosystem - A community and its physical (abiotic) environment
Ecosystem Is a system which all of the biological, physical & chemical components of an area from a complex, interacting network of energy flow & materials cycling. Regulate global cycles of water, carbon, nitrogen phosphorus and sulfur essential to survival. Landscape Ecology Sub-discipline of ecology Studies ecological process over a large area Includes several interacting ecosystems
Biosphere-Contains earth s communities, ecosystems and landscapes, and includes: Atmosphere gaseous envelope surrounding earth Hydrosphere earth s supply of water Lithosphere soil and rock of the earth s crust
Energy The ability or capacity to do work Types of Energy Chemical, Thermal, Mechanical, Nuclear, Electrical, and Radiant/Solar (below)
Energy Energy exists as: Potential energy (stored energy) Kinetic energy (energy of motion) Potential energy is converted to kinetic energy as arrow is released from bow The Study of energy and its transformation is called Thermodynamics
Thermodynamics System a group of atoms, molecules or objects being studied. Closed System Does not exchange energy with surroundings (rare in nature) Open System exchanges energy with surroundings
Laws of Thermodynamics First Law of Thermodynamics Energy cannot be created or destroyed; it can change from one form to another Second Law of Thermodynamics When energy is converted form one form to another, some of it is degraded to heat Heat is highly entropic (disorganized) Energy conversion is never 100% efficient (lost as heat = Increase in Entropy (disorder))
Photosynthesis (plants, algae & some bacteria) Biological process by which energy from the sun (radiant energy) is transformed into chemical energy of sugar molecules. Sun energy chemical energy & Sugar 6 CO 2 + 12 H 2 O + radiant energy C 6 H 12 O 6 + 6 H 2 O + 6 O 2 Glucose (Carbohydrate)
Cellular Respiration (aka. aerobic respiration) Chemical energy captured in photosynthesis is released. Energy Made by photosynthesis is used by cells to do work C 6 H 12 O 6 + 6 O 2 + 6 H 2 O 6 CO 2 + 12 H 2 O + energy Plants, bacteria, fungus, fish animals use this living systems of hydrothermal vents gets more complicated
Photosynthesis, Cellular Respiration & Chemosynthesis Chemosynthesis Hydrothermal Vents Process by which each produced from inorganic items (Hydrogen 2012 John Wiley sulfide & Sons, Inc. & All Oxygen) rights reserved.
Food Chains- The Path of Energy Flow Energy from food passes from one organisms to another based on their Trophic Level An organism s position in a food chain is determined by its feeding relationships First Trophic Level: Producers Second Trophic Level: Primary Consumers Third Trophic Level: Secondary Consumers Fourth Trophic Level: Tertiary Consumers Decomposers are found at all levels
Energy Flow Through Ecosystems Passage of energy in one way direction through an ecosystem Consumers = heterotrophs / 1 0 consumer = Herbivores 2 0 & 3 0 consumers = Carnivores or (Omnivores) Herbivore
Ecological Pyramids Graphically represent the relative energy value of each trophic level Important: large amount of energy is lost between trophic levels to heat Three main types Pyramid of numbers Shows the number of organisms at each trophic level Pyramid of biomass Quantitative estimate of total mass of living material Pyramid of energy Energy content (expressed as Kcal/m 2 @ trophic level)
Pyramid of Numbers Illustrates the number of organisms at each trophic level Fewer organisms occupy each successive level Does not indicate: biomass of organisms at each level amount of energy transferred between levels
Pyramid of Biomass Illustrates the total biomass at each successive trophic level Biomass: measure of the total amt of living material 90% reduction in biomass through trophic levels
Pyramid of Energy Illustrates how much energy is present at each trophic level and how much is transferred to the next level Most energy dissipates between trophic levels Explains why there are so few trophic levels
Ecosystem Productivity Gross Primary Productivity (GPP) Total amount of energy that plants capture and assimilate in a given period of time Net Primary Productivity (NPP) Plant growth per unit area per time Represents the rate at which organic material is actually incorporated into the plant tissue for growth GPP cellular respiration = NPP Only NPP is available as food to organisms
Variation in NPP by Ecosystem
Human Impact on NPP Humans represent 0.5% of land-based biomass, but use 32% of land-based NPP! This may contribute to loss of species (extinction) This represents a threat to planet s ability to support both human & non-human inhabitants