Ecology, Ecosystems and Food Ecology, Ecosystems and Food WebsWebs

Biotic- Biotic- plants, animals, microbesplants, animals, microbes

Abiotic-Abiotic-

physiochemical physiochemical substances and substances and gradients including gradients including byproducts of biotic byproducts of biotic components (air, components (air, nutrients, minerals)nutrients, minerals)

populationpopulation- group of same species existing and - group of same species existing and interacting in a given areainteracting in a given areacommunitycommunity- groups of different species - groups of different species interacting in a given areainteracting in a given areaecologyecology- a community interacting with the abiotic - a community interacting with the abiotic componentscomponents

Structure of the EarthStructure of the Earth

core-core- innermost solid layer innermost solid layermantle-mantle- second layer containing the second layer containing the

plastic asthenosphere and a solid rock plastic asthenosphere and a solid rock layer comprising part of the lithospherelayer comprising part of the lithosphere

crust-crust- thinnest outermost layer, includes thinnest outermost layer, includes part of the lithospherepart of the lithosphere

atmosphere consists of:atmosphere consists of:

troposphere- first 11 troposphere- first 11 miles, 78% nitrogen, miles, 78% nitrogen, 21% oxygen21% oxygen

stratosphere- 11-30 stratosphere- 11-30 miles, contains ozonemiles, contains ozone

mesosphere and mesosphere and thermosphere- two thermosphere- two outermost layersoutermost layers

hydrosphere hydrosphere

surface and underground surface and underground water, polar ice caps, water, polar ice caps, icebergs, permafrost and icebergs, permafrost and water vapor water vapor

ecosphere/biosphereecosphere/biosphere

area where living area where living organisms are found, organisms are found, includes parts of includes parts of lithosphere, lithosphere, atmosphere and atmosphere and hydrosphere hydrosphere

ThermodynamicsThermodynamics

First Law: Energy First Law: Energy cannot be created or cannot be created or destroyed, just destroyed, just transferred from one transferred from one form to anotherform to another

Second Law: When Second Law: When ever energy is ever energy is transferred some transferred some energy is lost in the energy is lost in the form of heatform of heat

What sustains life?What sustains life?

one way energy flowone way energy flow

cycle of nutrients and cycle of nutrients and mattermatter

gravitygravity

Types of systems:Types of systems:

open- matter and nutrients can enter open- matter and nutrients can enter system from outside, such as runoff into a system from outside, such as runoff into a streamstream

closed- closed-

system contains all of the system contains all of the matter that it will be able to matter that it will be able to use, like a biosphere use, like a biosphere

Types of nutrients:Types of nutrients:

macronutrients- macronutrients- nutrients that nutrients that organisms need in organisms need in relatively large relatively large amountsamounts

role of macronutrients: role of macronutrients:

O- building block of protoplasm, biological O- building block of protoplasm, biological oxidationoxidation

C- building block of organic compoundsC- building block of organic compounds H- acceptor of oxygenH- acceptor of oxygen N- building block of protein, nucleoprotein, N- building block of protein, nucleoprotein,

enzymesenzymes

Macronutrients Con’t:Macronutrients Con’t:

P- photosynthesis P- photosynthesis component, builder of component, builder of protein and protein and nucleoproteinnucleoprotein

other macrconutrients other macrconutrients needed in lesser needed in lesser amounts include S, K, amounts include S, K, Ca, Mg, FeCa, Mg, Fe

micronutrients- micronutrients-

nutrients needed in nutrients needed in trace amounts such trace amounts such as Na, Cl, Cu, I, Zn as Na, Cl, Cu, I, Zn for such varied for such varied functions as cell functions as cell division, carbohydrate division, carbohydrate metabolism, and metabolism, and nitrogen fixationnitrogen fixation

Types of ecosystems:Types of ecosystems: terrestrial/biomesterrestrial/biomes

chaparralchaparral coniferous and deciduous coniferous and deciduous

forestforest desertdesert prairieprairie tundratundra tiagatiaga

AquaticAquatic freshwaterfreshwater marinemarine estuarineestuarine

EcotoneEcotone

boundary between boundary between ecosystems that has ecosystems that has characteristics of both characteristics of both

How organism survival is How organism survival is determined:determined:

limiting factors- factor that limits growth, limiting factors- factor that limits growth, too much too much oror too little can inhibit growth too little can inhibit growth

range of tolerance- variations in range of tolerance- variations in environmental conditions under which a environmental conditions under which a species can exist, species can exist,

In general, the greatest number of In general, the greatest number of organisms living in the mid or optimal organisms living in the mid or optimal rangerange

Abiotic Factors:Abiotic Factors:

Water Water

necessary for all life necessary for all life (as we know it) (as we know it)

special properties of water:special properties of water:

specific heat- specific heat- (energy required to raise 1 gm of water by 1(energy required to raise 1 gm of water by 1ooC)C) helps in climate moderationhelps in climate moderation

latent heat- energy required for phase change, latent heat- energy required for phase change, water has highest known value, keeps air near water has highest known value, keeps air near lakes and forests coolerlakes and forests cooler

density- density- reaches maximum at 4reaches maximum at 4ooC, allows ice to C, allows ice to float, causes water to turn over in bodies of water float, causes water to turn over in bodies of water in the fall and springin the fall and spring

Special Properties con’t:Special Properties con’t:

solvency- solvency- helps to cycle nutrientshelps to cycle nutrients

ionization- ionization- ability for electrolytic dissociation lends ability for electrolytic dissociation lends itself to natureitself to nature

surface tension- surface tension- lends itself to capillary action lends itself to capillary action and surface tension and surface tension (second only to Mercury)(second only to Mercury)

Albedo:Albedo:

Insolation- incoming solar radiationInsolation- incoming solar radiation

albedo- reflectivity of earth, how much light albedo- reflectivity of earth, how much light bounces offbounces off

solar flux varies diurnally and seasonally solar flux varies diurnally and seasonally infrared radiation- heats the lower air, water infrared radiation- heats the lower air, water

and landand land

Insolation Con’t: Insolation Con’t:

varies in deciduous forests with changes in canopyvaries in deciduous forests with changes in canopy degree of temperature change caused depends n degree of temperature change caused depends n

presence of waterpresence of water water quickly extinguishes all wavelengths but blue water quickly extinguishes all wavelengths but blue (ie: (ie:

color of oceans)color of oceans)

Precipitation- Precipitation-

Prevailing winds and topography affect Prevailing winds and topography affect amount of rainfall and therefore determines amount of rainfall and therefore determines ecosystem distribution.ecosystem distribution.

Water Facts:Water Facts:

only 5% of all water is in circulation, 99% of that only 5% of all water is in circulation, 99% of that 5% is in the ocean5% is in the ocean

fresh water is about 0.1% of total in circulation, fresh water is about 0.1% of total in circulation, of that 0.1%, 75%(0.075% of total) is tied up in of that 0.1%, 75%(0.075% of total) is tied up in polar ice capspolar ice caps

Turnover in the water cycle- Turnover in the water cycle-

precipitation divided precipitation divided by total water in the by total water in the atmosphere indicate a atmosphere indicate a turnover rate of every turnover rate of every 11 days (or 35 times 11 days (or 35 times a year).a year).

Temperature Temperature in very wet or very dry ecosystems, in very wet or very dry ecosystems,

temperaturetemperature is an important limiting is an important limiting factor.factor.

In very hot or very cold ecosystems, In very hot or very cold ecosystems, moisturemoisture is the more important limiting is the more important limiting factor factor

Energy Flow:Energy Flow:

Energy flows only in Energy flows only in one direction (unlike one direction (unlike nutrients) in an nutrients) in an ecosystemecosystem

substantial energy substantial energy loss occurrs at each loss occurrs at each trophic level.trophic level.

Trophic level Trophic level

level with equal level with equal number of energy number of energy transfers such as transfers such as primary consumers primary consumers and secondary and secondary consumers. consumers.

Trophic Pyramid

Autotrophs- organisms Autotrophs- organisms that produce their own that produce their own energy supply using solar energy supply using solar or chemical energy, or chemical energy, producersproducers

Heterotrophs- organisms Heterotrophs- organisms that rely on other that rely on other organisms for their organisms for their energy supply, energy supply, consumersconsumers

energy fixation by autotrophs energy fixation by autotrophs

sunlight plus chlorophyll sunlight plus chlorophyll (or other pigments)(or other pigments)

energy is stored as glucose with Oenergy is stored as glucose with O22 and and

water as byproductswater as byproducts

6CO6CO22 +12H +12H22O O

CC66HH1212OO6 6 + 6O+ 6O22 + 6H + 6H22OO

Measuring the productivity of an Measuring the productivity of an ecosystem:ecosystem:

Net Primary Productivity (NPP) = Net Primary Productivity (NPP) =

energy incorporated energy incorporated -- energy used in respiration energy used in respiration

This can be done by several This can be done by several methods methods

Biomass- harvesting and Biomass- harvesting and calculating the caloric content of calculating the caloric content of dry weightdry weight

COCO22 assimilation- measuring assimilation- measuring

how much COhow much CO22 is used by the is used by the

plant plant (using sensors or clear chambers)(using sensors or clear chambers)

OO22 production- used for aquatic production- used for aquatic

systemssystems

Illinois cornfield study- Illinois cornfield study-

biologists calculated biologists calculated a cornfield used only a cornfield used only 1.6% of the available 1.6% of the available solar energysolar energy

of the energy the corn of the energy the corn did capture, 23.4% did capture, 23.4% went towards went towards maintaining the plant maintaining the plant (mostly cellular respiration).(mostly cellular respiration).

Gross vs. Net Production:Gross vs. Net Production:

Gross is total, net is what Gross is total, net is what is left after plant is left after plant maintenance maintenance

in fields an average of in fields an average of 15-15-24%24% of absorbed energy of absorbed energy is used to self maintainis used to self maintain

this goes up to this goes up to 50-60%50-60% in in temperate foreststemperate forests

and and 70-75%70-75% in tropical in tropical forestsforests

Estuaries, swamps and marshes have Estuaries, swamps and marshes have highest NPPhighest NPP

Open ocean, tundra and desert have the Open ocean, tundra and desert have the lowest. lowest.

Food chains/webs:Food chains/webs:

Producers (autotroph) Producers (autotroph) primary consumers (heterotrophs)primary consumers (heterotrophs)

secondary consumersecondary consumer decomposersdecomposers

nutrient poolnutrient pool

Example of a food chain:Example of a food chain:

PlantsPlants rabbits (herbivore) rabbits (herbivore) (100%)(100%) (10%)(10%)

fox (carnivore) fox (carnivore) decomposers decomposers(1%) (1%)

nutrient pool (for use by nutrient pool (for use by plants)plants)

Energy flows along this same path, but Energy flows along this same path, but much (about 90%) is lost in the form of heat much (about 90%) is lost in the form of heat at each change in trophic level at each change in trophic level

When you get to a secondary consumer (3When you get to a secondary consumer (3rdrd level), you have only 1% of the initial energy level), you have only 1% of the initial energy found in the plants.found in the plants.

This is known as the ecological This is known as the ecological efficiency of the food chain or energy efficiency of the food chain or energy pyramid.pyramid.

Biomass* of the Biomass* of the different trophic levels different trophic levels is used to convey the is used to convey the total amount chemical total amount chemical energy available in a energy available in a given ecosystem.given ecosystem.

* * the dry mass of organic the dry mass of organic materialmaterial

The biomass in a given ecosystem can be The biomass in a given ecosystem can be shown in the form of a pyramidshown in the form of a pyramid

The changes in biomass from one level to the The changes in biomass from one level to the next indicate the amount of energy lost in each next indicate the amount of energy lost in each level for that systemlevel for that system

The pyramid for grassland has the expected The pyramid for grassland has the expected

shape, large on the bottom with shape, large on the bottom with successively smaller biomasses on top.successively smaller biomasses on top.

However, the biomass pyramid in the ocean However, the biomass pyramid in the ocean appears to have a very small base because appears to have a very small base because much of the first level lives symbiotically much of the first level lives symbiotically inside corals inside corals

Most systems in nature are more complex Most systems in nature are more complex than simple food chainsthan simple food chains

Attempts to show the full relationship are Attempts to show the full relationship are called food webscalled food webs

Example of a shoreline ecosystem:Example of a shoreline ecosystem:

What do healthy ecosystems do:What do healthy ecosystems do:

moderate climatemoderate climate renew air, water and soilrenew air, water and soilcycle nutrientscycle nutrientsprovide energy resourcesprovide energy resources

Ecosystems Con’t:Ecosystems Con’t:

provide food and shelterprovide food and shelter slow soil erosion, prevent slow soil erosion, prevent

floodingflooding natural population controlnatural population control provide biodiversityprovide biodiversity

How do ecosystems sustain How do ecosystems sustain themselves:themselves:

by using sun for main energy sourceby using sun for main energy source

by recycling materials needed to sustain by recycling materials needed to sustain organismsorganisms

Dung Beetles

The EndThe End