ECOLOGYECOLOGY

Chapter 3 - The BiosphereChapter 3 - The Biosphere

What is Ecology?What is Ecology?

It is the scientific study of It is the scientific study of interaction among organisms interaction among organisms and between organisms and and between organisms and their environmenttheir environment

What is the Biosphere?What is the Biosphere?

The biosphere is the The biosphere is the combined portions of the combined portions of the entire planet where life entire planet where life exists.exists.

Levels of OrganizationLevels of Organization

To understand relationships To understand relationships within the biosphere ecologists within the biosphere ecologists ask questions abut events and ask questions abut events and organisms that range in organisms that range in complexity from a single complexity from a single individual to the entire individual to the entire biospherebiosphere

Levels, cont.Levels, cont.

SpeciesSpecies: a group of organisms so : a group of organisms so similar to one another that they can similar to one another that they can breed and produce fertile offspring.breed and produce fertile offspring.

PopulationsPopulations: a group of individuals : a group of individuals that belong to the same species and that belong to the same species and live in the same area.live in the same area.

CommunitiesCommunities: different populations : different populations that live together in a defined area.that live together in a defined area.

Levels, cont.Levels, cont.

Ecosystems:Ecosystems: all the organisms that all the organisms that live in a particular place, together live in a particular place, together with their nonliving or physical with their nonliving or physical environment.environment.

Biomes:Biomes: a group of ecosystems that a group of ecosystems that have the same climate and dominant have the same climate and dominant communities.communities.

Levels of OrganizationLevels of Organization

Ecological MethodsEcological Methods

Scientists use three basic approaches Scientists use three basic approaches to conduct ecological research. They to conduct ecological research. They are:are:

ObservingObserving ExperimentingExperimenting ModelingModeling

b)

c)

a)

Energy Flow in the Energy Flow in the EcosystemEcosystem

Living systems need a Living systems need a constant input of energy.constant input of energy.

Identify the main source of Identify the main source of energy for life on Earthenergy for life on Earth

Some types of organisms rely Some types of organisms rely on the energy stored in on the energy stored in inorganic chemical inorganic chemical compoundscompounds

Energy Flow, cont.Energy Flow, cont. AutotrophsAutotrophs

Organisms that Organisms that use energy from use energy from the environment the environment to make complex to make complex organic organic compoundscompounds

Also known as Also known as producersproducers

Two typesTwo types PhotosynthesisPhotosynthesis ChemosynthesisChemosynthesis

HeterotrophsHeterotrophs Rely on other Rely on other

organisms for organisms for their energy and their energy and food supply.food supply.

Also known as Also known as consumersconsumers Types:Types:

HerbivoresHerbivores CarnivoresCarnivores DetritivoresDetritivores DecomposersDecomposers

Feeding RelationshipsFeeding Relationships Energy flows through the Energy flows through the

ecosystem in one direction.ecosystem in one direction.

Food ChainFood Chain

Food WebFood Web

What is a trophic level?What is a trophic level?

Each step in a food Each step in a food chain or food web chain or food web is a trophic levelis a trophic level

Each trophic level Each trophic level depends on the depends on the level below it for level below it for energyenergy

Ecological PyramidsEcological Pyramids

Can be used to represent energy, Can be used to represent energy, matter or number of individuals at matter or number of individuals at each trophic leveleach trophic level

Energy Pyramid: only 10% of the Energy Pyramid: only 10% of the energy available at one trophic level energy available at one trophic level makes it to the next levelmakes it to the next level

Pyramids, cont.Pyramids, cont.

Biomass Pyramid: represents all the Biomass Pyramid: represents all the living tissue (food) at each trophic living tissue (food) at each trophic level. level.

Pyramid of Numbers: the number of Pyramid of Numbers: the number of individual organisms at each trophic individual organisms at each trophic level usually decrease as you go up level usually decrease as you go up the pyramid of numbers.the pyramid of numbers.

Cycles of MatterCycles of Matter

Unlike the one-way flow of energy, Unlike the one-way flow of energy, matter is recycled in the biospherematter is recycled in the biosphere

Elements , chemical compounds and Elements , chemical compounds and other forms of matter are passed other forms of matter are passed from one organism to another from one organism to another through biogeochemical cyclesthrough biogeochemical cycles

Water cycleWater cycle

Other biogeochemical Other biogeochemical cyclescycles

Carbon Cycle - carbon is especially Carbon Cycle - carbon is especially important because it is the key important because it is the key ingredient in all living organisms. ingredient in all living organisms. Carbon is found in oceans, the air, Carbon is found in oceans, the air, and certain types of rock and certain types of rock

Nitrogen Cycle - All organisms require Nitrogen Cycle - All organisms require nitrogen to make amino acids which nitrogen to make amino acids which are used to build proteinsare used to build proteins

Phosphorous Cycle- Unlike carbon Phosphorous Cycle- Unlike carbon nitrogen and oxygen, phosphorous nitrogen and oxygen, phosphorous does not enter the air, it remains does not enter the air, it remains mostly in rock, soil minerals, and mostly in rock, soil minerals, and ocean sedimentsocean sediments

Phosphorus is of great biological Phosphorus is of great biological importance for molecules like DNA importance for molecules like DNA and RNAand RNA

ProductivityProductivity

Primary Productivity: the rate at Primary Productivity: the rate at which organic matter is created by a which organic matter is created by a producer.producer. Controlled by the availability of Controlled by the availability of

nutrients in the environmentnutrients in the environment Limiting nutrient: the one nutrient that Limiting nutrient: the one nutrient that

when in short supply, will limit the when in short supply, will limit the primary productivity of the ecosystem.primary productivity of the ecosystem.

Algal BloomAlgal Bloom