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Definition: study of the interactions among livingthings and their surroundings

Key Knowledge:

1.Matter cycles, energy flows

2.Abiotic factors cause changes in biotic factors in aecosystem

Chapters 13-16 in the textbook

Abiotic: Non-living parts of theenvironment

Soil Sunlight Climate Temperature Rainfall Nutrients

Biotic: living parts of theenvironment

Plant Animals Decomposers

(Bacteria and Fungus)

General Organization

Organism= any individual livingthing

Population= Individualorganisms of a single speciesin one area.

Community= more than onepopulation living in the samearea.

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Example of aCommunity

Differentspecies offish

Differentspecies ofcorals(animals)

Starfish(animal)

Algae

(microscopic plants)

General Organization Ecosystem= All the populations and

abiotic factors in an area. Habitat = the environment that a

particular species prefers within anecosystem

Niche= the role that an organism fills“job”

Biomes= Ecosystems with similarclimate and plants.

Characteristics of a Biome No distinct boundaries Defined by types of plants Similar climate conditions, but may be

located in a totally different part of theworld (Africa and Asia)

Classification of biomes:–land biomes–water biomes (marine or freshwater)

Can make their own food throughenergy from the sun or inorganicsubstances

AKA: Primary Producer

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Obtains energy by eating otherorganisms,

AKA: Consumers

Types of ConsumersPrimary consumers: eat producers

(herbivores)

Secondary consumers: eats bothproducers & consumers (omnivores)

Tertiary consumers: top predator(carnivore)

Trophic levels are a way of identifyingwhat kinds of food an organism uses.

1st trophic level= primary producers2nd trophic level= primary consumers3rd trophic level= secondary consumers4th trophic level= tertiary

consumer

Decomposers & Scavengers Decomposers feed on wastes & dead

material from all trophic levels Ex: bacteria, fungi

Scavengers are consumers that eatdead animals (like road kill)

Ex: vulture

Energy in an ecosystem istransferred (cycles) through

the trophic levels of thatecosystem

Biomass and Energy Transfer1 hawk

10 snakes100 mice feed

1000 plants feed

Rule of 10****-Only 10% of the energy istransferred to the nextorganism.

Biomass- amount of livingmatter, number oforganisms, or determinesthe amount of energy

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Very few animals feed on only one foodsource, food webs are a more accurate

picture of how animals feed.

Biological Magnification The build-up of toxins in living organisms

with movement up the trophic levels . Toxins collect in at the top of food web

because top consumers eat so much. Examples:

DDT: Dichlorodiphenyltrichloroethane Developed during WWII as a

pesticide Very high levels of DDT were

found in top consumers. DDT is stored in fat.

Organisms died or hadreproductive problems

Banned in US and Canada duringthe 70’s.

Still found in almost all living things Developing countries are still use DDT

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Invasive Species A species that is brought by HUMANS into

a new environment and outcompetes theones already there.

They have no competitors, no diseases sothey outgrow other populations

Example: Africanized honey bees,which will take over the hive of thehoney bees.

Example: Zebra mussels attach toboats and cover piers withinmonths

Keystone Species A species that plays a key role in the

ecosystem Increases biodiversity by keeping the

number of each species in balance– Examples

Sea otter in the kelp forests Beavers in rivers

BeaverSea Otter

HUMAN IMPACT

A Sad True Story

An Ecological Mystery Long term study of sea otter population along

the Alaskan and Aleutian Islands 1970: Sea Otters healthy and populations

growing 1990: Sea Otter #’s declining

– Maybe due to emigration, not deaths 1993: 800 km area in Aleutian Islands studied

– Sea Otter #’s reduced by 50%

Vanishing Sea Otters 1997: Study of area repeated Sea Otter pop. had declined by 90%

– 1970: > 53,000 Otters in the study area

– 2012: < 2800

Why?– Reproductive issues– Starvation, pollution, disease?

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Cause of the Decline 1991: one researcher observed an orca

whale (killer whale) eating a sea otter. Sea lions or seals are the normal prey of

orcas. Decline in usual prey led to feeding shift. Single orca could consume 1,825

otters/year. Clam Lagoon (CONTROL GROUP), which

was not accessible to orcas, had no declinein otter population

No Big Deal.. Right? Declines in ocean fish due to over fishing

and climatic changes led to a reduction infood for sea lions & seals, so their #’sdecreased

This forced the orcas to enter into thecoastal waters where they consumed seaotters.

Sea otters normally feed on sea urchins.As sea otters decreased, the urchinsnumbers increased.

Urchins eat kelp, and the large numbers ofurchins damaged kelp forests.

The decline in the kelp forests has had animpact on many others species because ofthe decrease of oxygen and an increase incarbon dioxide in the water.

Other Species AffectedBald EagleMusselSea StarsSeagulls

All matter essential for life moves incycles between living things & the

environment

Examples of cycles:carbon cyclewater cyclenitrogen cycle

Why is carbon important to us?1) Carbon is used to make hair,

muscle, & skin2) Carbon stores energy so living

things can think, move, etc3) Fossil fuels (gas, coal, oil) are

made from carbon

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Where is carbon found in the environment?

1. atmospheric gas (CO2)2. rocks (limestone, diamonds)3. fossil fuels (oil, coal, etc.)

How does carbon enter living things?

1) CO2 gas enters plants

2) Photosynthesis allows plants tochange CO2 into a sugar

3) Animals then get carbon by eatingthe sugar found in plants

How does carbon get backinto the environment?

1. Plants & animals release CO2 duringrespiration

2. Burning of wood & fossil fuels

3. Using electricity, (most power plants usefossil fuels)

4. Cow farts (seriously)

5. Decomposition when bacteria and fungusbreak down tissue of dead things

How are fossil fuels formed?1. When living things die & fall to

the bottom of water, they areburied & compressed

2. They eventually form coal,petroleum, or natural gas

So what’s the cycle?

the 2 main steps arephotosynthesis & respiration!

The Carbon CycleThe movement of carbon through the

environment

2 major driving forces1. Photosynthesis- plants and algae take up

CO2 from the air or water to make sugar

2. Cellular Respiration- consumers usesugar for energy and release CO2 into theair or water

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Future Predictions

Due to humans using more fossilfuels, more CO2 is released each

yearthis may result in global warming since

CO2 traps heat (remember thegreenhouse effect)

What is global warming?

Facts about Nitrogen

78% of air is nitrogen gas (N2)Living things can’t use nitrogen

when it’s a gas (N2)

Why do living things needNitrogen?

To make amino acids & proteins To make DNA

The Nitrogen CycleStep #1

Nitrogen gas (N2) is found in theatmosphere

Step #2”Nitrogen Fixation”: Bacteria

living at the roots changethe N2 gas into a usableform like ammonia ornitrates

Lightning also “fixes” nitrogen

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Step #3Plants then use the ammonia

or nitrates in the soil

Step #4Animals get nitrogen from

plants by eating them

Step #5When plants & animals die, the nitrogenin them is released back into theatmosphere as a gas (N2) This is done by denitrifying bacteria

Step #6Nitrogen gas is released back into the

atmosphere

What are the two processthat are responsible; forcycling Carbon in theenvironment?

What things add carbon?Which things take it away?Photosynthesis and Cellular RespirationPhotosynthesis : take it awayCellular Respiration, Fossil Fuels andDecaying organisms add it.

Other CyclesHydrologic (water) Cycle

Phosphorus Cycle

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Potassium Cycle Breaking the Water Cycle The only way for water to get back

to the atmosphere is throughtranspiration (plant sweating)

When we cut down trees they nolonger transpire

So water does not get into the airto become rain

The area becomes a desert in avery short time period– Really bad in rainforest regions,

because the soil is so shallow

Community InteractionsIn order to sustain an

environment, organisms andabiotic factors interact

EXAMPLES:–Symbiosis–Succession

Forms of Species Interaction

1. Parasitism: one benefits & one isharmed (humans and tape worm)

2. Commensalism: one benefits &other is neutral (anemone and clown fish)

Symbiosis: relationships between two species(3 types)

3. Mutualism: both organisms benefit(rhino and bird)

Forms of Species Interaction Continued

Competition: two species are fightingfor the same resources

Predation: one species hunts theother

Ecological succession: change in thetypes of species in a communityobserved over time

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Succession Why does successionhappen?

Communities & environmentschange over time

1) Primary Succession

When communities form in new areas–Ex: volcanoes, rocks, etc

Steps of Primary Succession1. Pioneer species appear lichens

(grow on rock & turn it into soil) Pioneer Species: the first organisms

to occupy an area

2. Grass & small plants appear3. Weeds & shrubs4. Shallow trees (ex: pine trees)5. Climax community stable & final

stage (ex: deciduous trees)

Climax Community

A community thathas achievedstability andspecies diversity

2) Secondary Succession Occurs in areas that were cleared by

disturbance (fire, tornado, floods, etc)– faster than primary (soil already formed)

Same as primary except pioneerspecies are grasses instead of lichens

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Successionleads to….. 1.Birth Rate

2.Death Rate

3.Immigration (movement into an area)

4.Emigration (Movement, exiting an area)

FACTORS THAT AFFECTPOPULATION GROWTH

Exponential Growth J-shaped curve on a graph Population doubles every generation Humans are reproducing this way!

Humans - Trouble ahead?

Logistic Growth S–shaped curve on graph How real growth looks Populations grow fast early, then slow

down, as we get closer to CARRYINGCAPACITY

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Biomassand

energy transferat the lowesttrophic leveldetermines the

carrying capacity ofthe ecosystem.

Carrying CapacityMaximum # of individuals a population

can support– Populations will increase to carrying

capacity, and they decrease again oncethey have reached it.

Limits to Pop. Growth1. Density-dependent limiting factors -

reduce population growth with thatdepends on current population size– Affect crowded populationsDiseaseCompetition (for shelter, food, water)Predation (predator eats prey)

How might thebubonic plague

have beendifferent if the

medievalpopulationsdidn’t live soclose to each

other?

2. Density-independent limiting factors– environmental factors affecting apopulation regardless of size– Affect all populations (crowded or not)WeatherNatural disasters (fire, etc)Human activities

Would thephysicaleffects ofhurricaneKatrina be

any differentin a town of

100, then in atown of

100,000?

New Orleans, LA

Gulf Port , MS