Changes in Ecosystems: . Ecological Succession

Do all ecosystems stay the same all the time? What are some things that cause changes to ecosystems? Natural and unnatural (Quickly and slowly)

Ecological succession Natural, gradual changes in the types of species that live in an area; can be primary or secondary The gradual replacement of one plant community by another through natural processes over time

Ecological succession Series of predictable changes that occur in a community over time. Caused by: Physical environment Natural disturbance Human disturbance

Primary Succession Begins in a place without any soil Sides of volcanoes Landslides Glacier melting Starts with the arrival of living things such as lichens that do not need soil to survive, called PIONEER SPECIES.

Pioneer species Lichens

http://www.life.uiuc.edu

Primary Succession Pioneer species: Lichens, don’t need soil to grow They die and adding organic material. Simple plants like mosses and ferns can grow in the new soil The simple plants die, adding more organic material The soil layer thickens, and grasses, wildflowers and other plants begin take over. This plant die and add more nutrients to the soil Shrubs and trees can survive now Insects, small birds, and mammals have begun to move in What was once bare rock now supports a variety of life http://www.uncw.edu http://uisstc.georgetown.edu

Reaching a mature community can take CENTURIES.

Secondary Succession Begins in an area where the ecosystem has been disturbed, but where soil and organisms still exist. Occurs faster and has different pioneer species than primary succession

Succession following a disturbance that destroys a community without destroying the soil Fires - Forest clearing Natural Human disturbance Hurricane - Farming

Secondary succession Unlike primary succession, secondary succession occurs in a place where and ecosystem currently exists. And occurs more rapidly than primary succession.

http://www.geo.arizona.edu

http://www.ux1.eiu.edu

Climax Community A stable group of plants and animals that is the end result of the succession process Does not always mean big trees Grasses in prairies Cacti in deserts

Think-Pair-Share Shoulder Partners PAGE 408-410 PRIMARY SUCCESSION SECONDARY SUCCESSION

References: http://www.slideshare.net/radhakrishnan1962/ecological-succession-1 Science explorer Prentice Hall. Environmental Science

Succession in Marine Ecosystems Deep and dark Can succession happen? 1987 dead whale off of California Unique community of organisms living in remains Represents stage in succession in an otherwise stable, deep-sea ecosystem Whale-fall community

Whale-Fall Succession Begins when large whale dies Sinks to barren ocean floor Scavengers and decomposers flock to carcass , our first community Amphipods Hagfish sharks After a year, most tissues have been eaten Now, second small community of organisms live here Body is decomposing, releasing nutrients into the water Small fishes Crabs Snails worms Only skeleton remains… Third community moves in Heterotrophic bacteria Decompose oil in bones release of chemical compounds Who uses these chemical compounds? Chemoosynthetic autotrophs In come the crabs, clams, and worms that feed on this bacteria