Ecology and Succession

Ecological Succession

Succession: The gradual, sequential growth of a community in an area.

Pioneer species: The first species to colonize an area

Primary Succession: Succession in an area that has not supported life previously.

Primary Succession

In primary succession, the pioneer species tend to be simple species that need very little to survive.

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_______________ are a perfect example.

Primary Succession

Primary succession may take many thousands of years to reach climax community.

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Climax community: the final ​stage of succession that is characterized by a stable, balanced ecosystem.

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Primary Succession

​Pioneer species (lichens, mosses) help turn the bare rock into soil.

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Grasses and flowers help deepen the soil.

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Eventually the soil becomes deep and rich enough to support trees.

Examples of primary succession:

A glacier retreats and leaves bare rock behind.

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An underwater volcano erupts and forms a new island made of volcanic rock.

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A sand dune forms.

Secondary Succession

Succession that follows disruption of an existing community.

Secondary Succession

Secondary succession tends to be much quicker because the soil is already deep and capable of supporting complex plant life.

Secondary Succession

In secondary succession, the pioneer species are often more complex, such as grasses, weeds, and flowers.

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Note that plants always come before animals.

Examples of secondary succession:

The renewal of a forest after a fire.

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Regrowth in an area previously disturbed by human activity.

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Regrowth after a natural disaster (hurricane, flood, earthquake).

Lichens

Lichens make great pioneer species because:

They don't need soil. They can live on bare rock.

They break the rock down to soil.

They are producers. They make their own food from sunlight using photosynthesis.

Producer

Organisms that produce their own food through photosynthesis.

Also called autotrophs.

Photosynthesis: capture the energy from sunlight and convert it to food

Consumer

Organisms that consume other organisms for energy.

Also called heterotrophs.

Primary Consumer

Organisms that consume producers for energy.

Also called herbivores.

Secondary Consumer

Organisms that consume other consumers for energy.

Also called carnivores.

Tertiary Consumer

Consumers at the top of the food pyramid.

Also called top carnivores.

Multiple Choice

How would you classify most of the organisms shown eating in the previous video?

• Producers

• Primary Consumers

• Secondary Consumers

• Tertiary Consumers

Multiple Choice

How would you classify howler monkeys?

• Producers

• Primary Consumers

• Secondary Consumers

• Tertiary Consumers

Multiple Choice

How would you classify capuchins (the white monkey)?

• Producers

• Primary Consumers

• Secondary Consumers

• Tertiary Consumers

Multiple Choice

How would you classify the iguana? (Hint: iguanas are herbivores).

• Producer

• Primary Consumer

• Secondary Consumer

• Tertiary Consumer

Multiple Choice

How would you classify the snakes?

• Producers

• Primary Consumers

• Secondary Consumers

• Tertiary Consumers

Multiple Choice

How would you classify the hawk?

• Producer

• Primary Consumer

• Secondary Consumer

• Tertiary Consumer

Decomposers

Consumers that recycle dead organisms by breaking them down.

Flow of Energy

Energy for life on Earth begins with the sun.

Without sunlight, nearly all life on Earth would cease to exist.

Flow of Energy

From the sun it goes to producers (autotrophs).

Plants and other producers use sunlight to produce food through the process of photosynthesis.

Flow of Energy

Energy then goes to the organisms that eat the producers.

These are primary consumers, also known as herbivores.

Flow of Energy

And then to the organisms that eat the consumers that ate the producers. 

These are secondary consumers, also known as carnivores.

However, some are omnivores.

Flow of Energy

Energy finally goes to the organisms that eat the secondary consumers.

These are tertiary consumers, also known as top carnivores.

This is a food chain.

The arrows show the flow of energy.

Energy flows from the Sun to the producers.

Energy flows from the producers to the primary consumers.

Energy flows from the primary consumers to the secondary consumers.

And energy flows from the secondary consumers to the tertiary consumers.

Food Web

A food web is all the interlocking food chains within an ecosystem.

Food Web

The more organisms that are in the food web the more stable that ecosystem is.

If the food web is too small, one change in the ecosystem can be devastating.

Multiple Choice

Based on the food webs, which ecosystem would you expect to be more stable?

• Ecosystem A

• Ecosystem B

• They are equally stable

Ecosystem B is more stable because if one animal dies off, there are still many more food choices.

Energy Pyramid

Tertiary Consumers - top carnivores

Secondary Consumers - carnivores

Primary Consumers - herbivores

Producers - photosynthesis

Primary consumers are typically herbivores—animals that eat plants. They are called heterotrophs because they must eat other things to survive. This is different from producers, which are autotrophs and make their own food. Common examples of this type of consumer are insects, rodents, and deer.

These organisms are the first consumer, and the second link, in a food chain. They are the second trophic level from the bottom in an energy pyramid. A typical food chain can also have secondary, tertiary, and quaternary consumers. In real life, the primary consumer can have more than just one type of food source, and that can be represented in a food web.

Primary consumers are the second level in a food chain. They obtain energy from eating producers. Producers are usually plants that can synthesize energy from the sun. Therefore, we typically consider those first consumers to be herbivores, meaning they are not meat eaters.

Chemotroph

Chemotrophs: get their energy using chemicals from the earth and convert it into useable chemicals for energy. (usually extremophiles!)