Ecology

how organisms interact with each other and the nonliving environment.

We share the Earth…

with a whole lot of other creatures…

We don’t share very well….

Ecology• Putting it all together…

– the study of interactions between creatures & their environment is important because…

Everything is connectedto everything else

Ecosystem• Living (Biotic) factors

– all plants, animals, and decomposers living in an area

• Physical (Abiotic) factors– soil, rock, temperature, moisture, sunlight

(NONLIVING FACTORS)

habitat = address (where you live)niche = job (the role you play)

THE INTERACTION OF THE LIVING AND NONLIVING IN A PART OF THE ENVIRONMENT

Name 3 Abiotic Factors and 3 Biotic Factors

ABIOTIC

clouds, atmosphere, water, carbon dioxide,

oxygen, dirt, sun

BIOTIC

deer, frog, ducks, fox, birds, grass, trees

many of the same organisms living

together

different populations living

together

a community and the abiotic environment

the “layer” of Earth where life exists

LEVELS OF ECOLOGICAL ORGANIZATION

a living thing

The BIOSPHERE

THE LAYER OF EARTH WHERE

LIFE EXISTS

Populations

MANY OF THE SAME ORGANISMS LIVING TOGETHER

A COMMUNITY

DIFFERENT POPULATIONS LIVING TOGETHER•LIONS

•ZEBRAS (well…maybe not!)•VULTURES

•GRASS

EARTH’S LAND ECOSYSTEMS (BIOMES) A COMMUNITY AND THE ABIOTIC (NONLIVING) ENVIRONMENT

What do ecosystems require in order to maintain stability?

• Constant Energy Source

• Producers to convert light energy into chemical energy (organic compounds - PHOTOSYNTHESIS)

• Nutrients to be recycled (C, N, H2O, P, S) (decomposers)

• Feeding relationships– all food chains

start with energy from the sun

– first level of all food chains is plants (producers)

– most food chainsusually go up only 4 or 5 levels

– all levels connect to decomposers

Food chains

Fungi

Level 4

Level 3

Level 2

Level 1

Decomposers

Producer

Primary consumer

Secondary consumer

Tertiary consumer

Topcarnivore

Carnivore

Herbivore

Sun

Bacteria

WHY IS EACH LEVEL OF THE ECOLOGICAL PYRAMID SMALLER THAN THE ONE BELOW IT?

MORE ORGANISMS CAN EXIST HERE

THAN HERE

AND HERE

?

There is there loss of energy at each level of the food chain.To where is the energy lost? The cost of living!

only this energymoves on to the next level in the food chain

17%Growth(biomass)

50%waste (feces)

33%cellularrespiration

energy lost todaily livingenergy lost todaily living

Feeding Levels• How much energy

can you get from food?– only the energy that is

stored in the organism– 80-90% energy lost

from one level to next– food chain can only

have 4 or 5 levels

Food Webs• Food chains are linked

together into food webs and overlap each other. Everything is connected!

• “Read” the arrow from the tail to the point as “is/are eaten by.” So, FISH SQUID is read as “fish are eaten by squid” and PHYTOPLANKTON KRILL is read as “phytoplankton are eaten by krill.”

• Would there be more fish or more phytoplankton in this ecological pyramid? PHYTOPLANKTON!

The SUN is the SOURCE!

sun

secondary consumers(carnivores)

primary consumers(herbivores)

producers (plants)

loss of energy

loss of energy

loss of energy

THE ECOLOGICAL PYRAMID

The amount of ENERGY AVAILABLE

at each level DECREASES as you go up, so…

There are fewer

organisms at each level

as you go up, or less

“BIOMASS”

Vegetarians or Meat-eaters??• How many people can Earth support?

– If we are meat eaters?– If we are vegetarian?

more people canlive on Earth

fewer people canlive on Earth

Example Grid-In Problem: A caterpillar consumes 100 kilocalories of energy. It uses 35 kilocalories for cellular respiration, and loses 50 kilocalories as waste (heat and in waste products). How much energy is allocated for growth (creation of new biomass)? Determine the trophic efficiency for its creation of new biomass.

But what about nutrients?• Energy flows through the

food chain and is LOST but NUTRIENTS CYCLE

– nutrients must be RECYCLED to be available for the next generation

– DECOMPOSERS return nutrients to the soil after creatures die• fungi

• bacteria

nutrients

decomposers

Nutrients cycle around… through decomposers

soil

producers

consumers

decomposers

potassium

nitrogen

iron

calcium

phosphorus

magnesium

carbon

loss of energy

loss of energy

sun

secondary consumers(carnivores)

primary consumers(herbivores)

loss of energy producers (plants)

decomposers

Nutrients cycleEnergy flows

soilsoil

biosphere

Ecosystem Inputs

constant inputof energy

nutrients cycle

nutrients can only

cycle

inputs energy nutrients

inputs energy nutrients

Don’t forgetthe laws of Physics!

Matter cannotbe created ordestroyed

energy flowsthrough and is LOST

Carbon • Abiotic Source: The atmosphere

(CO2)

• Biotic Processes: Photosynthesis and Cellular Respiration and Decomposition

Oxygen• Abiotic Source: The atmosphere

(O2)

• Biotic Processes: Used in cellular respiration. Released in photosynthesis

Nitrogen• Abiotic Source: Atmosphere (N2)

• Biotic Processes: Nitrogen-fixing bacteria enable plants to use N2; Released to environment by decomposition

Phosphorous• Abiotic Source: Rocks (lithosphere); Released in

weathering• Biotic Processes: incorporated into food chains in the

soil; Released by decomposition

Sulfur• Abiotic Source: Rocks - Lithosphere

• Biotic Processes: Incorporated into food chains in the soil; Released by decomposition

Hydrogen• Role: Major component of all biological molecules;

Does not exist freely in nature

• Abiotic Source: Rocks – Hydrosphere (H2O

• Biotic Processes: Incorporated into food chains along with water, Released through decomposition/water release

CARBON DIOXIDE CYCLE

INORGANIC COMPOUNDS CYCLE TOO!

WHAT LIMITS THE SIZE OF

POPULATIONS

?

WHAT LIMITS THE SIZE OF

POPULATIONS?LIMITING FACTORS

COMPETITION

CARRYING CAPACITY

PREDATOR-PREY RELATIONSHIPS

LIMITING FACTORS (RESOURCES)!-temperature-food sources-

-water supply-minerals-sunlight-

If the requirements for an organism’s survival are not present,

they cannot survive in that ecosystem.

COMPETITION•ORGANISMS THAT EAT THE SAME FOOD SOURCE COMPETE WITH EACH OTHER FOR THAT FOOD SOURCE.•Which organisms are competing with each other in this food web?•LION & WOLF•ELK, DEER & COW

• If the deer population decreases due to disease…• What will happen to the grass population?

• What will happen to the lion and wolf populations?

IN FOOD WEBS…AND ALL OF ECOLOGY…EVERYTHING IS CONNECTED TO EVERYTHING ELSE. A CHANGE IN ONE THING AFFECTS ALL!

• What will happen to the elk and cow populations?

INCREASES

DECREASE

COMPLICATED! Will they increase b/c they have more grass to eat or will they decrease b/c the lions will eat more elk and the wolves will eat more cows?

A CHANGE IN ONE POPULATION AFFECTED ALL OF THE POPULATIONS IN THE FOOD WEB!

CARRYING CAPACITY!

The BLUE LINE shows “carrying capacity” or the number of organisms that the ecosystem can support. It remains constant.

PREDATOR PREY RELATIONSHIPS

The PREDATORS then begin to die off because their food source is declining, at which point the PREY population increases because fewer of them are being eaten and more of them can reproduce…ANDTHE CYCLE STARTS ALL OVER AGAIN!

When the PREY population increases, the PREDATOR population also increases, but there is a LAG because it actually takes time for the PREDATOR population to make new organisms. As the PREDATORS increase, the PREY population decreases, because there are more PREDATORS eating them!

THE PREDATOR AND PREY ARE IN

DYNAMIC EQUILIBRIUM!

ECOLOGICAL SUCCESSION

VIEW THE VIDEO ON THE NEXT PAGE OR AT

http://www.youtube.com/watch?v=IuRWph5a1GE&feature=youtube_gdata

THE VIDEO GOES FAST, SO HIT THE PAUSE/PLAY BUTTON IF YOU NEED TO SLOW IT

DOWN…OR PLAY IT MORE THAN ONCE…

GO TO THE NEXT SLIDE TO SEE THE MOVIEMORE DETAILS ABOUT ECOLOGICAL

SUCCESSION CAN BE FOUND IN YOUR REVIEW BOOK!