Download File

Q/A
Places and things that create a high Albedo
effect are?
~ Pollution
~ Snow
~ Sand, rocks
Energy Flow in
Ecosystems
Section 1.1
Energy flows in ecosystems
Draper and Reed (2004). Our Environment: A Canadian Perspective, Third Edition
Food Chains and Food Webs
Energy is transferred from one organism
to another along food chains
 Food chains show the sequence of who
feeds on or decomposes whom in an
ecosystem
 Every organism has a feeding or trophic
level

Trophic Levels

1st Trophic Level


2nd Trophic Level


Primary Consumers; herbivores & omnivores
3rd Trophic Level


Basic provider of food, plants (producers)
Secondary Consumers; carnivores & omnivores
4th Trophic Level

Tertiary Consumers; Carnivores that eat other
carnivores & omnivores
Food Webs show all of the complex
feeding relationships between organisms
in an ecosystem
 Humans have claimed nearly 40% of the
terrestrial food supply, leaving only 60%
for the millions of other organisms


http://www.youtube.com/watch?v=TE6w
qG4nb3M&feature=related
Limits on Energy Transfer
Not all of the energy that a plant creates
can be transferred to the animal that eats
it
 The plant uses most of that energy to
stay alive and grow
 Once an animal eats a plant it doesn’t
store all of that energy
 Most of the energy is used to move its
limbs, pump blood, keep warm, etc.

Q/ A

While looking at an ecosystem, you observed this food
chain:
sun,
 algae,
 tadpole,
 fish,
 alligator.


What are the trophic levels being observed? What is
happening to the energy through this food chain?
The higher up the food chain you go, the
less energy is available
 In every ecosystem there is less energy
available to secondary consumers than
there is to primary consumers


http://www.brainpop.com/science/ecolog
yandbehavior/foodchains/
Thermodynamics

The study of energy transformations

The first law of thermodynamics – states
that although energy can be changed
from one form to another, it cannot be
created or destroyed
Thermodynamics
The second law of thermodynamics –
states that during any energy change,
some of the energy is changed into an
unusable form, usually thermal energy
(heat) that cannot be passed on
 Each time energy is changed some
energy is “lost”
 At each step in the chain less energy is
available

Q/A

What are the two laws of
Thermodynamics ? Explain in your own
words.
Energy Pyramids

Show the energy flow from one trophic
level to another
Roles in Ecosystems
Each organism has its own place within
an ecosystem
 Its place in the food web, its habitat,
breeding area and active times are
called its ecological niche.
 Each species in an ecosystem has a
different niche.
 Why?

Niches

Hawk vs. Owl
Hawk active during day, can soar above
open fields, but can’t fly through dense
bush. Eyes excellent in detecting colour.
 Owls have shorter wings, can hunt in
forests or dense areas, they also hunt at
night. Eyes excellent in detecting motion.

Zebra Mussel
Zebra mussels came into Lake Erie in
the late 1980’s from bilge water
discharged by ships.
 Natural habitat is the Caspian Sea in
western Asia.
 From Lake Erie, it migrated to Lake
Huron, Rideau Canal, Ohio River,
Mississippi, and Gulf of Mexico.

Video
Competition for Niches
When a new species enters an
ecosystem, this sparks a competition for
niches.
 New species= exotic species.
 However, this happens naturally. Think
seeds carried by the wind, or animals
who take root in a new area.
