OUR PLANETOUR PLANET

Energy in the Energy in the EcosystemEcosystem

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…

Why is a vegetarian still considered an omnivore?

Types ofConsumers

Energy Source

Examples

Herbivore producers cow, pleco

Carnivoreother

consumerssnake, vulture

Omnivoreproducers & consumers

people, bears

Decomposerdecaying matter

fungi & bacteria

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 supportentire ecosystems thathave never seen the sun!

Could life exist on Titan,one of Saturn’s moons, that’salmost 1 billion miles fromthe sun?

Maybe… It would need a volcanic coreto 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 andOxygen 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 thesun can be used by a wolf.

2. Describe the four differenttypes of consumers.

3. Explain the similarities anddifferences between photosynthesisand 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 byan organism at one trophic levelis used before that energy canbe passed to the next level.

Organisms use their energyto complete life’s processes.

Which level has the highestpopulation? Which hasthe 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 thegrass are passed on to the lion.

Next are the herbivores.But only ~500 Calories arepassed on to the giraffes.

At the base of everypyramid 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 populationdrop so much in the 1970s?

Thin eggs were being crushed bythe mom before they could hatch.

A look at the food chain showedthat DDT, a powerful pesticide,became more concentrated as itmoved 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 howorganisms survive in an ecosystem

Each year, 1-3 million people arekilled by a deadly disease known as…

Malaria! It is transmitted, personto person, by the mosquito.

Wouldn’t it be great if we couldkill all the mosquitoes in the world?

How many other creatures wouldbe 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 pyramidtypically only have 4-5 levels?

3. Which types of organisms arefound at each level of an energypyramid?

4. Give an example of when studyinga food chain would be important.

5. Give an example of when studyinga food web would be important.