Transcript Chapter 5:Energy Flow in Ecosystems

OUR PLANET
Energy in the Ecosystem
I Give Up. What’s black & white and read all over?
How Do Ecosystems Work?
The Sun - The source of all energy on Earth*
Without the sun, our planet would be cold and dark
without anything to eat and fresh water would be scarce!
Producers (Autotroph) – Make their own food; Ex: Plants
Photosynthesis changes solar energy into chemical energy
Without producers there wouldn’t be any food for the…
Consumers (Heterotrophs) – Obtain energy from other
organisms; Ex: Animals, Fungi and many bacteria
Which are these?
Consumer
Producers
???
Types of Consumers
There are four different types of consumers…
Types of
Consumers
Energy Source
Examples
Herbivore
producers
cow, pleco
Carnivore
Omnivore
Decomposer
other
consumers
producers &
consumers
decaying
matter
snake, vulture
people, bears
fungi &
bacteria
Why is a vegetarian still considered an omnivore?
Can Life Exist Without The Sun?
*Without the sun, life on earth could still exist due to…
Chemotrophs – These deep ocean bacteria get energy
from hydrogen sulfide that’s released from volcanic
vents
These bacteria support
entire ecosystems that
have never seen the sun!
Could life exist on Titan,
one of Saturn’s moons, that’s
almost 1 billion miles from
the sun?
Maybe… It would need a volcanic core
to keep it’s ocean from freezing.
Storing & Using Energy
What does a plant need to survive?
Photosynthesis uses Water, Carbon Dioxide and Sunlight
to create Sugar (energy stored as glucose) & Oxygen (waste)
H2O + CO2 + Energy  C6H12O6 + O2
While plants use photosynthesis to create food (stored
energy),
plants & animals have another process to use the energy…
Cellular Respiration – Plants and animals use Sugar and
Oxygen to get energy, releasing water & carbon dioxide
C6H12O6 + O2  H2O + CO2 + Energy
What do you notice about these equations?
Let’s Review…
What have you learned so far?
1. Describe how energy from the
sun can be used by a wolf.
2. Describe the four different
types of consumers.
3. Explain the similarities and
differences between photosynthesis
and cellular respiration.
How Energy Flows
Trophic Level – Each step in which energy and matter are
transferred within an ecosystem; Ex: Energy pyramid
Most of the energy taken in by
an organism at one trophic level
is used before that energy can
be passed to the next level.
Organisms use their energy
to complete life’s processes.
Which level has the highest
population? Which has
the lowest population?
An Analogy for Trophic Levels
• Think of our school
population in terms of size :
– Bottom = students – biggest
population
– Above the students are the
teachers
– Top of the pyramid is smallest
population: Administration (Mr.
Nichol and the Vice Principals)
How Energy Flows
The 10% Law – Only 10% of the energy at each trophic
level is passed on to the next and 90% is used or lost.
Carnivores are found at the top.
And just ~50 Calories from the
grass are passed on to the lion.
Next are the herbivores.
But only ~500 Calories are
passed on to the giraffes.
At the base of every
pyramid are producers.
.
Make ~5,000 Calories
of energy/m2 each year.
A Closer Look At Trophic Levels
Food Chain – A specific diagram that shows how energy
flows from one organism to another
Why did the bald eagle population
drop so much in the 1970s?
Thin eggs were being crushed by
the mom before they could hatch.
A look at the food chain showed
that DDT, a powerful pesticide,
became more concentrated as it
moved up each trophic level.
In part, due to the damage caused by DDT, bald eagles
were on the endangered species list from 1973-2007.
Seeing The Big Picture
Food Webs – Shows multiple, interconnected food chains;
A more accurate image of how
organisms survive in an ecosystem
Each year, 1-3 million people are
killed by a deadly disease known as…
Malaria! It is transmitted, person
to person, by the mosquito.
Wouldn’t it be great if we could
kill all the mosquitoes in the world?
How many other creatures would
be affected if mosquitoes vanished?
Let’s Review…
What have you learned in this unit?
1. What is a trophic level?
2. Why does an energy pyramid
typically only have 4-5 levels?
3. Which types of organisms are
found at each level of an energy
pyramid?
4. Give an example of when studying
a food chain would be important.
5. Give an example of when studying
a food web would be important.