ENERGY FLOW IN ECOSYSTEMS

TOPICS LISTENERGY FROM THE SUN

PERCENTAGES

ALBEDO EFFECT

PHOTOSYNTHESIS and CELLULAR RESPIRATION

THERMODYNAMICS

ROLES IN ECOSYSTEMS

• KEYSTONE SPECIES

• ECOLOGICAL NICHE

• INTRASPECIFIC VS.

INTERSPECIFIC

COMPETITION

• EXOTIC SPECIES

PYRAMIDS

•PYRAMID OF ENERGY

•PYRAMID OF BIOMASS

•PYRAMID OF NUMBERS

WHERE DOES OUR ENERGY COME FROM?

The SUN is the source of energy for the vast

majority of life on Earth.

ENERGY FROM THE SUN

What happens to

the majority of the

Sun’s energy?

It heats the atmosphere, earth’s surface, and water.

PERCENTAGES:__27___ % is reflected by Clouds and Earth’s Surface

__69___ % warms the atmosphere, land, and hydrosphere

___1___ % generates wind patterns

_0.023_ % is used in the process of photosynthesis

ALBEDO EFFECTA measure of the AMOUNT of sunlight

REFLECTED from an object.

Expressed as a decimal value

Example: 27 % reflection by clouds is 0.27

What are examples of objects that REFLECT

sunlight?

In general, LIGHT-COLOURED objects such

as:_______________________________________

These highly reflective objects have a HIGH

ALBEDO.

What are examples of objects that

ABSORB sunlight?

In general, DARK-COLOURED objects such as:

_________________________________________

These light-absorbing objects have a LOW

ALBEDO.

Also, GREENHOUSE GASES have a low albedo.

ALBEDO EFFECT

PHOTOSYNTHESIS

What is it?

A biochemical process

whereby PRODUCERS use

the Sun’s energy, carbon

dioxide, and water to

produce sugar and oxygen.

GENERAL CHEMICAL EQUATION:

6 CO2+ 6 H2O + Sun’s Energy C6H12O6 + 6 O2

CO2 is carbon dioxide C6H12O6 is

glucose (sugar)

H2O is water O2 is oxygen

Oxygen is necessary for CONSUMERS.

Sugars are necessary as a usable form of

energy for nearly ALL LIFE on EARTH.

CELLULAR RESPIRATIONWhat is it?

A biochemical process whereby CONSUMERS release the energy stored in the sugar they ingest.

By eating sugars and breathing in oxygen, consumers produce carbon dioxide, water, and energy for life processes.

GENERAL CHEMICAL EQUATION:

C6H12O6+ 6 O2 6 CO2+ 6 H2O + Energy

WHAT KINDS OF LIFE

PROCESSES?

THERMODYNAMICS

What is THERMODYNAMICS?

The study of ENERGY

TRANSFORMATIONS from one

form to another (ex: chemical

energy to heat energy)

There are two Thermodynamic LAWS that

apply to ecosystems

FIRST LAW OF THERMODYNAMICS

Energy CANNOT be CREATED NOR

DESTROYED, only TRANSFERRED FROM

ONE FORM TO ANOTHER.

SECOND LAW OF THERMODYNAMICS

During energy transfers, SOME ENERGY is

“LOST” as HEAT ENERGY and is not passed

on.

PYRAMIDS

PYRAMID OF ENERGY

Recall from an earlier lesson that we can

represent ENERGY TRANSFER in an

ecosystem with a pyramid of energy, and

that only about 10 %of energy is passed

from one trophic level to the next.

There are 2 other types of pyramids that

are USEFUL GRAPHICAL INDICATORS of

ecosystem patterns:

PYRAMID OF BIOMASS

PYRAMID OF NUMBERS

BIOMASS

The mass of an organism WITHOUT water;

its dry weight. Measured in kg.

A PYRAMID OF BIOMASS is a graphical representation of the TOTAL BIOMASS of all the members of each trophic level.

Often similar in shape to a Pyramid of Energy.

PYRAMID OF NUMBERS

A graphical

representation of the

TOTAL NUMBERS of all

members of each trophic

level in a food chain.

Sometimes, these are

shaped liked pyramids,

but there are exceptions!

AN EXCEPTION:

For example, if the following was a rough

sketch of our pyramid of energy, would

the pyramid of numbers look the same?

ANSWER:

No, of course not! There would be more caterpillars than any other organism, so our “pyramid of NUMBERS” would look like:

HOMEWORK

Page 39, # 3, 4, 5, 7, 14

Draw 3 pyramids (energy, biomass, and numbers) for the following food chain:

HAWK (1, 10 J, 5 kg)

WOODPECKER (10, 100 J, 10 kg)

WORM (1000, 1000J, 50 kg)

FIR TREE (1, 10000J, 150 kg)

ROLES IN ECOSYSTEMS

It is time to discuss some of the

interrelationships that take place in

ecosystems between species.

Some specific roles organisms can take

on include:

KEYSTONE SPECIES

ECOLOGICAL NICHE

INTRASPECIFIC VS. INTERSPECIFIC

COMPETITION

EXOTIC SPECIES

KEYSTONE SPECIES

A species that is considered so important to

ECOSYSTEM STABILITY, that if that species

declined, the ecosystem might collapse.

Why is it called “keystone”?

It is an analogy for a

keystone that holds together

an archway.

Example:

SEA OTTER is a keystone in the

CALIFORNIA KELP ecosystem

Without otters, kelp does not grow.

ECOLOGICAL NICHE

An organism’s NICHE is its “role” that it

plays in a particular ecosystem.

It includes everything an organism does

to survive and reproduce, including:

•Feeding relationships

•Habitat

•Breeding grounds/behaviours

•Activity times

•Competitive relationships

Organisms tend to have UNIQUE niches,

based on where and how they are best

adapted to survive.

EXAMPLE:

Galapagos Island Finches

Found on the Galapagos Islands,this little finch

evolved into many SUBSPECIES , all adapted to a

DIFFERENT NICHE.

http://www.youtube.com/watch?v=l25MBq8T77w

SPECIES COMPETITION

Sometimes in nature there is COMPETITION

for NICHES when two or more organisms

have similar requirements for SPACE, FOOD,

and/or WATER.

“Survival of the Fittest” usually prevails

2 MAIN TYPES:

INTRASPECIFIC COMPETITION

Between the SAME SPECIES

EX:___________________________________________________

INTERSPECIFIC COMPETITION

Between DIFFERENT SPECIES

EX:____________________________________________________

INTRASPECIFIC COMPETITION

SAME SPECIES COMPETING

INTERSPECIFIC COMPETITION

DIFFERENT SPECIES COMPETING

EXOTIC SPECIES

These are NON-NATIVE species that are

not natural parts of ecosystems.

Compete INTERSPECIFICALLY with native

species in the area.

Examples:

Moose in NL –4 in 1904

Green Crab in Atlantic Canada

Zebra Mussels (p. 42-44)

EXOTIC SPECIES –GREEN CRAB

HOMEWORK

READ P. 42-44

P. 44, # 2, 3, 4