Ecological Succession

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

V49IovRSJDs&list=PL7A7502811

06CD067&index=60&feature=plpp

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Ecological Succession

• Ecosystems are constantly changing in

response to natural and human

disturbances.

• As an ecosystem changes, older

inhabitants gradually die out and new

organisms move in, causing further

changes in the community.

• The organisms change the ecosystem

over time.

Ecological Succession • Ecological Succession = the series of

predictable changes that occur in a

community over time

• Succession can occur because of slow

changes in the physical environment or

sudden disturbances, like a natural

disaster or human activity.

Primary Succession

• Primary Succession – establishment

of plant communities on newly formed

habitats previously lacking plants

–Due to a disturbance that leaves no

soil behind: volcanic eruptions or

glaciers receding

–Begins with bare rock

–Rock lichen moss grass

shrub oak/hickory forest

What are lichen you say?

What Are Lichen? • It is not just one organism, but two

organisms living in a symbiotic

relationship (fungi and algae)

• Lichen is a PIONEER SPECIES, which

means it is the first species to populate

an area.

• Lichen can grow on bare rock. They

help break up the rock as they grow.

When they die, they help form the soil

so that plants can begin to grow.

Primary Succession

• Can take 1000 years

Secondary Succession

• Secondary Succession –

return of vegetation to its

former state following a

disturbance (fires, floods,

mudslides, tornadoes, etc.)

Grass shrub oak/hickory forest

Secondary Succession • Faster than

primary

succession

• May only take a

few hundred

years

Secondary Succession

• Begins with soil on which the

previous ecosystem has been

removed (by fire, agriculture,

flooding, etc.)

• First species are small plants

(grasses) instead of lichen, because

soil is already present and doesn’t

have to be formed before things can

grow.

Climax Community • A stable group of plants and animals that is the end result of the succession process – Deciduous Forest = many large deciduous trees, a few coniferous trees, and lots of biodiversity

• Does not always mean big trees

–Grasses in prairies

–Cacti in deserts

Article Analysis

• What did you learn or find interesting from

the article?

• How does it relate to Succession?

• Did it discuss Primary or Secondary

Succession?