Energy in EcosystemsMr. Chapman

Biology 20

All organisms must have a source of energy in order to survive. Like machines, bodies are things that need fuel to keep going.

The sun is the ultimate source of energy for all organisms on earth.

The Main Source of Energy: The Sun

Although the ultimate source of energy is the sun, not all organisms obtain their energy directly from the sun.

Producers are organisms that get their energy from nonliving resources, meaning they make their own food.

Producers are also called autotrophs, auto meaning “self” and troph meaning “nourishment.”

The “Chain” of Command:

We can see the distribution of producers across the planet using satellite imagery.

http://www.classzone.com/cz/books/bio_07/resources/htmls/animated_biology/unit5/bio_ch13_0406_ab_producer.html

Can you explain the trends in producer populations that are seen from year to year?

The “Chain” of Command

Consumers are organisms that get their energy by eating other living or once living resources, such as plants and animals.

Consumers are also called heterotrophs. Hetero is a prefix that means “different.”

The “Chain” of Command:

Although not all organisms directly consume producers, all organisms depend on producers.

Producers convert energy from the sun into sugars that consumers can use for energy. Without producers, all life on Earth would die due to starvation.

Everything Depends on Producers

Many people are surprised to see the word “almost” in the title of this heading.

Plants are the main producers found on the Earth, accounting for the majority of the energy needed by consumers to survive.

Plants produce this energy through a process known as photosynthesis.

There is, however, another type of producer that exists. Are you aware of its existence, or familiar with it?

Almost All Producers Obtain Energy From Sunlight

Scientists were stunned in 1977 when they first visited deep-sea vents on the bottom of the ocean.

Underneath the ocean, they found thriving ecosystems where super-heated water shoots up from the ocean floor.

Studies showed that very small prokaryotes were able to make their own food from the minerals in the water. They had no need for sunlight.

Shocking Discovery!

Chemosynthetic Bacteria

http://www.youtube.com/watch?v=4LoiInUoRMQ

Chemosynthesis – the process by which an organism forms carbohydrates using chemicals, rather than light, as an energy source.

A series of reactions changes the chemicals into a usable energy form.

Different reactions occur depending on which chemicals are present.

Chemosynthesis

ChemosynthesisAside from just these underwater super-heated vents, there are also chemosynthetic organisms in sulfur-rich marsh flats and in hydrothermal pools, such as those in Yellowstone National Park.

These chemosynthetic bacteria use the very same process in order to produce their food as well.

1. Few producers live deep below a lake’s surface. Suggest an explanation for this pattern.

2. Could producers survive without consumers? Explain why or why not.

Hypothesize and Infer...