Ecological Organization • Ecos = Home – Ecology = study of the home – Ecological = Pertaining to the home
Spheres of Organization • Biosphere –Sphere of Life –Life cycle
• Hydrosphere –Sphere of Water –Water cycle
• Lithosphere –Sphere of Rocks –Rock cycle
• Atmosphere –Sphere of Air –Weather cycle
Biosphere
Lithosphere
Hydrosphere
Atmosphere
Ecosphere • All four spheres and the interactions between them! • Examples of Interactions –Biosphere and Hydrosphere –Lithosphere and Hydrosphere –Biosphere and Atmosphere –Lithosphere and Hydrosphere –Hydrosphere and Atmosphere
Interactions
Levels of Biological Organization • • • • • • •
Cells (lowest level) Tissues Organs Organ Systems Individuals Populations Communities (highest level)
Biosphere
Ecosystems
Communities
Populations
Organisms
Ecosystems • Systems of the ecosphere • Communities and their physical environments – Fundamental interactions of organisms with energy and matter at the highest levels of biological organization
Ecosystems • Basic operational units of the ecosphere • Maintained by fundamental interactions of organisms with energy and matter at the highest levels of biological organization
Ecosystem • A total environment, biotic and abiotic, that is somewhat self-contained and selfsustaining. • Requires an input of energy and materials to sustain life • Capable of recycling elements reducing demand for them
Ecosystem Trophic Structure • Feeding relationships influence the passage of energy and materials within ecosystems
Trophic Levels
Producers • Photoautotrophs • Energy and materials both enter the biotic portion of ecosystems by the action of producers
Consumers • Heterotrophs • Energy and materials are both transferred between species in ecosystems by the action of consumers
Levels of Consumption • 1o Consumers= eat producers – Includes all herbivores
• 2o and higher level Consumers= eat other consumers – Includes all carnivores
Food Chain • A linear relationship of predators and prey where each prey species has one predator species and each predator species has one prey species
Food Chain Diagram • In a food chain diagram the arrows point from the prey to the predator • Example: phytoplankton--->zooplankton--->whale
Food Chain
Food Web • A complex set of relationships between predators and prey. • Prey species have 2 or more predator species • Predator species have 2 or more prey species
Food Web Diagram • The arrows point from the prey to the predator. • The producers are placed at the bottom with the herbivores just above them, and the carnivores at the top
Food Web
Food Web vs. Food Chain
Energy and Ecosystems • Energy flows through an ecosystem • Open system with a continuous input and an equivalent continuous output
Energy Passes Along the Chain
Energy Supply • Most ecosystems rely on the unlimited supply of sunlight capturing it by photosynthesis • Energy captured during photosynthesis is stored in the chemical bonds of the molecules synthesized during the process
Idealized diagram illustrating photosynthesis for a green plant (tree) and generalized reaction.
Energy Utilization • Most of the captured energy is used by the autotrophs to maintain their lives and is lost as heat • About 10% is used for growth and reproduction being transformed into producer biomass
Biomass • Weight of living tissues • Wet weight or Dry weight
Available Energy • The energy in producer biomass is transferred to herbivores and then to carnivores. • Energy transfers are by ingestion, digestion, absorption and assimilation.
Energy Losses • Energy is lost from an ecosystem in the form of heat and the chemical energy in wastes and dead organisms that are transported out of the ecosystem
Energy Transfer • Energy transfers between trophic levels are only 10% efficient with 90% lost as heat • 10% of the energy is found in the biomass of animals in the next trophic level
Energy Losses • Not all prey items are eaten some die and about 10% of their energy goes into decomposer biomass • Digestion and absorption is not complete
Eltonian Pyramid • Graphical representation of the energy relationships of trophic levels in an ecosystem • Represent the decreasing standing crop at higher trophic levels
Pyramid Diagram 3 0 Consumers 0
2 Consumers 0
1 Consumers
Producers
Standing Crop • The amount (of individuals, biomass, or energy) present at any one moment in time
Pyramid Diagrams • Trophic levels are arranged with the producers at the base of the pyramid and the consumers in increasingly higher levels up the pyramid • The width of the pyramid at any trophic level indicates the size of the standing crop
Pyramid Types • Numbers: Represents the number of individuals of each trophic level • Biomass: Represents the weight of living tissue of each trophic level in kilograms • Energy: Represents the energy content of each trophic level in calories
Pyramid Relationships • The energy content and biomass of a single individual increases moving up the pyramid although the total energy and biomass of the trophic level decreases
Materials and Ecosystems • Materials cycle in an ecosystem • Semi-closed system with limited input and output of elements and continuous recycling between the biotic and abiotic portions • The degree of recycling determines how closed the system is.
Basic parts of a cycle.
Hydrologic Cycle
Source of Materials • The Reservoir is the source of materials from outside the ecosystem • It is often the water or atmosphere but is sometimes sediments or rock and can be another ecosystem
Recycling of Materials • Occurs between the organisms of the system and an abiotic Exchange Pool which is usually in the water or sediments inside the ecosystem
Decomposition • Decomposers release materials from the biotic portion of the ecosystem to the exchange pool or reservoir
Regeneration • Mineralizing bacteria regenerate inorganic materials by transforming released materials in a way that makes them available to photoautotrophs
