Ecosystems and the Ecosystems and the BiosphereBiosphere

Ecology UnitNewark Academy Summer Session 2014

Advanced Credit BiologyMonkemeier

The sun is the ultimate source of The sun is the ultimate source of energy for all life on Earth.energy for all life on Earth.

All organisms need energy to carry out essential functions such as growth, movement, maintenance, repair and reproduction.

In an ecosystem,

energy flows from the sun to autotrophs , then to organisms that eat the autotrophs, then to organisms that feed on other organisms.

ProducersProducers

Organisms that capture the sun’s energy and transform it into chemical energy contained within organic compounds are known as autotrophs.

Some bacteria undergo chemosynthesis to manufacture their own organic compounds. Chemosynthesis is a process that manufactures organic molecules using energy from inorganic molecules.

Organisms that manufacture organic compounds using either photosynthesis or chemosynthesis are known as PRODUCERS.

ProducersProducers

Terrestrial Ecosystems Aquatic Ecosystems

Plants are major producers

Photosynthetic protists and bacteria are major producers

Gross Primary ProductivityGross Primary Productivity

Gross Primary ProductivityGross Primary Productivity

Gross primary productivity is the rate at which energy is produced (by producers mainly through photosynthesis) in an ecosystem.

In other words: Gross primary productivity is the rate at which producers in an ecosystem capture the sun’s energy and transform it into chemical energy contained within sugars.

Sugars made by PhotosynthesisSugars made by Photosynthesis

Plants metabolize some of their manufactured sugars during cellular respiration.

Plants also utilize some of their manufactured sugars to grow, repair and reproduce.

The sugars made by PRODUCERS increases the BIOMASS in the ecosystem.

BiomassBiomass

Biomass is all of the ORGANIC MATERIAL in an ecosystem. It includes the bodies of plants, animals, etc.

ONLY energy stored as biomass is available to other organisms in the ecosystem.

Ecologists measure the productivity of an ecosystem by measuring the rate at which BIOMASS accumulates in a specific ecosystem.

NET PRIMARY PRODUCTIVITYNET PRIMARY PRODUCTIVITY

The rate at which biomass accumulates within an ecosystem is known as NET PRIMARY PRODUCTIVITY.

NPP is typically expressed in units of energy per unit area per year. (kcal/m2/y)

NPP = GPP – Rate of respiration of producers

Comparative Productivity of Comparative Productivity of EcosystemsEcosystems

ConsumersConsumers

Heterotrophs: all heterotrophs rely upon ingestion or absorption of organic compounds made by other organisms (ultimately made by producers)

Heterotrophs = ConsumersHerbivores, carnivores, omnivores

are all forms of Consumers.

Consumers that RECYCLEConsumers that RECYCLE

DETRITIVORES are consumers that feed on the “wastes” of an ecosystem such as dead bodies of organisms, fallen vegetation and wastes of animals.

DECOMPOSERS cause decay by breaking down the complex molecules in dead tissues and wastes into simpler molecules.

Energy FlowEnergy Flow

Energy PyramidsEnergy Pyramids

Energy Transfers within an Energy Transfers within an ecosystemecosystem