Energy in Ecosystems

Chapter 13, Unit 13.3

Objectives

• To describe the roles of producers and consumers in ecosystems.

• To apply the concept of producers and consumers to your own life.

• To compare photosynthesis to chemosynthesis.

Main Ideas

• Producers provide energy for other organisms in an ecosystem.

• Almost all producers obtain their energy from sunlight.

Chlorophyll Abundance on Earth

Biodiversity

• One of the most important concepts in ecology and all of science!

• It is an expression of the energy and richness of an ecosystem.

• Note on the previous map, the ecosystem with the most biodiversity lie around the equator, where you find the greatest concentration of sunlight.

Biodiversity

• Biodiversity is the result of millions of years of evolution – new species are born as species adapt to their environment and are modified over time by natural selection. – Adaptation leads to, over time, speciation, which

means one species splits into two (becoming reproductively isolated) or more new species.

• Biodiversity – bio means life and diversity means variety. Literally it means the diversity of life.

Wild Canine Adaptations and Diversity

Biodiversity

• It is what supports food webs and ecosystem. – As an ecosystem loses its biodiversity, it becomes

impoverished and, if it loses its keystone species, it can collapse altogether (remember the coral, sea otters, and wolves).

• It is conservatively estimated that, worldwide, three species go extinct every hour – almost all due to human caused ecological changes.

Centinela – a Case in Point

• In the Andean foothills of Ecuador, there is a ridge called Centinela. – It is a symbol of the silent destruction of

biodiversity.– When the forest on Centinela was cut, many rare

species, only recently discovered by botanists, were reduced from healthy populations to extinction.

– Unfortunately, this is too common and dangerous for us – our world loses its living buffer.

Centinela

• Centinela burning

Important Vocabulary

• Producer• Autotroph• Consumer • Heterotroph• Chemosynthesis• Photosynthesis• You will have to know what these mean!

Photosynthesis

• An equation that is the key to life:– 6H2O + 6CO2

• What vital process does this formula denote?• Answer: Photosynthesis.• Why does life as you know it depend on this

formula? • Answer: Photosynthesis captures the sun’s energy

and transforms it to chemical energy, which can be used by other organisms (including us).

Sunlight C6H12O6 + 6O2

The Flow of Energy

• We learned about biotic and abiotic factors in our last unit (13.2). Another important part of an ecosystem is the flow of energy to fuel life processes in all organisms.– Breathing and growing.

• We are going to find out where the energy comes from and what role it plays within an ecosystem.

The Flow of Energy

• Producers – are organisms that get their energy from nonliving resources.– in other words THEY MAKE THEIR OWN FOOD– Producers are also called autotrophs.• -troph is a suffix that comes from the Greek word

meaning “nourishment.”• Auto- is a prefix and means “self”• Autotroph, put together means self-nourishing.

The Flow of Energy

• Consumers – organisms that get their energy by eating other living things (plants and animals).

• Consumers are also called Heterotrophs– Hetero- means “different,” so heterotroph literally

means different-nourishing (in other words, they get nourishment from other organisms).

Examples of Autotrophs

All ecosystems depend on producers. These photos are of producers: redwood trees in California, tropical rainforest trees in the Amazon, and phytoplankton which help to fuel aquatic fresh and salt water ecosystems.

Examples of Heterotrophs

All these animals are heterotrophs. In the upper left corner are our Yellowstone wolves, then a blue jay, a krill (a small marine shrimp), and a blue whale (the largest creature to have lived on Earth and a consumer of krill, which they filter from the sea through their baleen).

A Simple Food Chain

• We will talk more about life webs and pyramids in the next unit but a simple one is:

This is a very simple food chain from the very cold waters of Antarctica.

• The producer is the phytoplankton.

• Krill (small shrimp) eat the phytoplankton.

• The blue whale eats the krill.

Almost all producers use sunlight

• Almost all producers obtain their energy from sunlight – driving the photosynthesis.– Photosynthesis is a two step process in which

green plants, cyanobacteria, and some protists form carbohydrates from the reaction of carbon dioxide and water.

– Energy is stored by the producers as carbohydrates for powering their metabolism.

– Oxygen is the waste product of photosynthesis, which is very lucky for us!

Question in Transit

• Q: What would happen to a forest ecosystem if it is clear cut?

• A: Primary consumers would die out or have to migrate to a new location - that might not exist, or is not good habitat. Secondary consumers would have to migrate or die.

Not All Producers Use Light Energy

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

• Chemotrophs are were discovered at deep-sea vents on the bottom of the ocean (where there is no sunlight). – The vents are places where superheated water

shoots out of the ocean floor.

Chemotrophs

• Chemotrophs are tiny prokaryotes which, at those vents, were found capturing minerals from the water (replacing sunlight) and making their own food.

• We have discovered Chemotrophs living in sulfer-rich salt marsh flats in hydrothermal pools in Yellowstone National Park (and other places where there is hydrothermal activity).

Archea are Chemotrophs

• As we have already discussed in class, Archea are chemotrophs.

• The live in deep sea vents and hydrothermal pools (like geysers).

• They use minerals available in those hostile environments as an energy source.

• They date back to the beginning of life on Earth, before there was oxygen (3.5 billion years ago).

Review Questions

• Q: How does the stability of an ecosystem depend on its producers?

• A: Producers bring energy into an ecosystem.• Q: What are the two processes used by

producers to obtain energy? • A: Photosynthesis and chemosynthesis

Review Questions Continued

• Few producers live deep below a lake’s surface, create a hypothesis that explains this fact.

• A: Sunlight cannot penetrate the water to a great depth, so photosynthesizing organisms are more common near the water’s surface.

Review Questions Continued

• Q: Could producers survive without consumers? Explain why or why not.

• A: Producers do not require consumers to fill material needs as a food source. Therefore, in that sense, producers do not need consumers to survive. However, a lot of producers depend on consumers for reproduction and survival.

Review Questions Continued

• Q: How might chemosynthetic organisms help scientists to understand how life developed on Earth?

• A: Chemosynthetic organisms live in environments that may be similar to those that existed on Earth billions of years ago when life was beginning to develop. Studying these organisms enables us to create models of how life forms might have evolved on Earth.