Chapter 3Chapter 3Ecosystem Ecology Ecosystem Ecology

EcologyEcology

o EcologyEcology• ““eco” house & “logy” study ofeco” house & “logy” study of• The study of interactions among and between The study of interactions among and between

organisms in their abiotic environmentorganisms in their abiotic environment• Broadest field in biologyBroadest field in biology

o Biotic- living environmentBiotic- living environment• Includes all organismsIncludes all organisms

o Abiotic- non living or physical environmentAbiotic- non living or physical environment• Includes living space, sunlight, soil, Includes living space, sunlight, soil,

precipitation, etc.precipitation, etc.

EnergyEnergy

o The ability or The ability or capacity to do workcapacity to do work• Chemical, radiant, Chemical, radiant,

thermal, thermal, mechanical, nuclear, mechanical, nuclear, electricalelectrical

o Energy exists as:Energy exists as:• PotentialPotential energy energy

(stored energy) (stored energy) • KineticKinetic energy energy

(energy of motion)(energy of motion)

ThermodynamicsThermodynamics

o Study of energy and its transformationsStudy of energy and its transformationso System- the object being studiedSystem- the object being studied

• Closed System Closed System does not exchange does not exchange energy with energy with surroundings (rare in surroundings (rare in nature)nature)

• Open System Open System exchanges energy exchanges energy with surroundingswith surroundings

Laws of ThermodynamicsLaws of Thermodynamics

o First Law of ThermodynamicsFirst Law of Thermodynamics• Energy cannot be created or destroyed; it Energy cannot be created or destroyed; it

can change from one form to anothercan change from one form to another• Ex: organisms cannot create energy they need to Ex: organisms cannot create energy they need to

survive- they must capture it from another sourcesurvive- they must capture it from another source• Focus is on quantityFocus is on quantity

o Second Law of ThermodynamicsSecond Law of Thermodynamics• When energy is converted from one form to When energy is converted from one form to

another, some of it is degraded to heatanother, some of it is degraded to heat• Heat is highly entropic (disorganized)Heat is highly entropic (disorganized)

• Focus is on qualityFocus is on quality

PhotosynthesisPhotosynthesis

o Biological process by which energy from Biological process by which energy from the sun (radiant energy) is transformed the sun (radiant energy) is transformed into chemical energy of sugar moleculesinto chemical energy of sugar molecules

o Energy captured by plants via Energy captured by plants via photosynthesis is transferred to the photosynthesis is transferred to the organisms that eat the plantsorganisms that eat the plants

6 CO6 CO2 2 + 12 H+ 12 H22O + radiant energyO + radiant energy

CC66HH1212OO66 + 6 H + 6 H22O + 6 OO + 6 O22

Cellular RespirationCellular Respiration

o The process where the chemical energy The process where the chemical energy captured in photosynthesis is released captured in photosynthesis is released within cells of plants and animalswithin cells of plants and animals

o This energy is then used for biological workThis energy is then used for biological work• Creating new cells, reproduction, movement, Creating new cells, reproduction, movement,

etc.etc.

CC66HH1212OO66 + 6 + 6 OO2 2 + 6 H+ 6 H22OO

6 CO6 CO22 + 12 H + 12 H22O + energyO + energy

Energy FlowEnergy Flow

o Passage of Passage of energy in a one-energy in a one-way direction way direction through an through an ecosystemecosystem• ProducersProducers• Primary Primary

consumersconsumers• Secondary Secondary

consumersconsumers• DecomposersDecomposers

Food Chains- The Path of Energy Food Chains- The Path of Energy FlowFlow

o Energy from food passes from one Energy from food passes from one organism to anotherorganism to another• Each “link” is called a Each “link” is called a trophic leveltrophic level

Food webs represent interlocking food Food webs represent interlocking food chains that connect all organisms in an chains that connect all organisms in an

ecosystemecosystem