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





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


Levels of Biological Organization • • • • • • •

Cells (lowest level) Tissues Organs Organ Systems Individuals Populations Communities (highest level)






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


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

Nitrogen Cycle

Phosphorus Cycle

Carbon Cycle