Ecological Succession

Changes in Ecosystems:Ecological Succession1.5Changes by FireNaturally occurring catastrophic events can change the planet we live on. Earth is constantly changing.

Sometimes these changes take millions of years, but sometimes they happen in just minutes

MOST DEADLY AND DESTRUCTIVE VOLCANO IN THE UNITED STATES:MOUNT ST. HELENSDefinition of SuccessionNatural, gradual changes in the types of species that live in an area

The gradual replacement of one plant/animal community by another through natural processes over time

Can be primary or secondaryPrimary SuccessionBegins in a place without any soil Sides of volcanoesLand uncovered by retreating glacierAfter flooding when soil was washed awayStarts with the arrival of living things such as lichens that do not need soil to surviveCalled PIONEER SPECIES

Lichen: A combination of algae and fungus that can survive on bare rock, tree bark, and other surfaces.Lichen is a pioneer speciesOther early species include mosses and ferns. They begin the breakdown of rocks into soil

These rocks are slowly becoming the soil!Primary SuccessionSoil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces

When lichens die, they decompose, adding small amounts of organic matter to the rock to make tiny amounts of soil

Primary SuccessionSimple plants like mosses and ferns can grow in the new soil

Primary SuccessionThe simple plants die, adding more organic materialThe soil layer thickens, and grasses, wildflowers, and other plants begin to take over

Primary SuccessionThese plants die, and they add more nutrients to the soilShrubs and trees can survive now

Primary SuccessionInsects, small birds, and mammals have begun to move inWhat was once bare rock now supports a variety of life

Im cute!

Primary Succession: Starts on Bare Rock!

No SOIL yet.

Secondary SuccessionBegins in a place that already has soil & was once the home of living organisms

Occurs faster than primary succession

Examplesafter forest firesafter agriculture/cultivation

Secondary Succession:Soil already in placeClimax CommunityA stable group of plants and animals that is the end result of the succession processAFTER SUCCESSION THE POPULATION AND NUMBER OF SPECIES INCREASES!!Nature is all about a balance (equilibrium).

Todays Reading/Questions1. What is ecological succession?

A. The gradual change of an ecosystem over time; the gradual change of the types of species that live in an areaTodays Reading/Questions2. Explain the difference between primary and secondary succession.

A. Primary succession begins on bare rock/rocky surface with no existing soil, plants, etc. (new land)Secondary succession begins with soil already in place (nature takes over)Ecological SuccessionCreate a Venn Diagram comparing primary and secondary succession and underneath write a Notes Summary!Summary of the notes and information learned

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