Presentation on theme: "LG: How Do Ecosystems Recover from a Disturbance? January 2013 Regents food web question."— Presentation transcript:
LG: How Do Ecosystems Recover from a Disturbance? January 2013 Regents food web question
ECOLOGICAL SUCCESSION is the series of changes that occur in an ecosystem over time. It can occur on LAND or in AQUATIC ecosystems.
There are TWO types of succession on LAND. 1. PRIMARY 2. SECONDARY
PRIMARY SUCCESSION is the sequence of communities that form in an originally lifeless habitat. Primary succession occurs on BARE ROCK.
What could occur to give us bare rock in a place that had already had plants living?
Primary Succession The first organisms (pioneer organism) to appear are LICHENS. Lichen is a FUNGUS and ALGAE living in a MUTUALISTIC relationship.
The first living things to grow successfully on a newly formed sand dune are known as a. saprophytes b. pioneer organisms c. carnivorous plants d. heterotrophs
Lichens grow on bare rock and break down (weather) the rock to form a thin layer of soil.
Primary Succession The lichen make up a PIONEER COMMUNITY. A pioneer community is the first one in a new habitat.
Base your answer on the diagram below, which shows the sequence of plant communities that have occupied land that was left barren 300 years ago, and on your knowledge of biology. Which plant species represent pioneer organisms? a. broomsedge and pine seedlings b. ragweed and aster c. crabgrass and horseweed d. oak and hickory trees
Lichens & Mosses
2. Lichens & mosses (pioneer) 3. Grasses and shrubs 4. Trees (climax community) 1.Bare rock THE STAGES OF PRIMARY SUCCESSION
Base your answer on the diagrams below of four stages of a biological process and on your knowledge of biology. What would most likely be the predominant life form found in stage I? a. ferns b. tracheophytes c. mushrooms d. pioneer species
A Typical New York State Succession
A slab of bare rock is covered with lichens. In time, mosses cover the rock, followed by grasses, and finally by small shrubs and tree saplings. In this example, the lichens represent a. a climax community b. a dominant species c. secondary consumers d. pioneer organisms
A CLIMAX COMMUNITY is a diverse and mature community that does not go through more succession. should be able to withstand disruption better than earlier ecosystems, causing succession to stop
ECOSYSTEM STABILITY During succession, the stability of an ecosystem changes Stability is the ability of an ecosystem to remain constant in the face of disturbance
Which organism is one of the first autotrophs to appear in this succession? a. frog b. aquatic plant c. tree d. fish
As the diversity of an ecosystem increases, the stability increases A more diverse ecosystem contains a more complex food web o This means an organism is more likely to find an alternate food source if need be.
Changes in an ecosystem over a long period of time are shown in the diagram below. These changes will most likely lead to a a. stable ecosystem that can last for many years b. loss of heterotrophs that cannot be recovered c. long-term rise in environmental temperatures d. forest consisting of only producers and decomposers
Base your answer on the diagram below, which shows the sequence of plant communities that have occupied land that was left barren 300 years ago, and on your knowledge of biology. Dominant plant species in the climax community include a. pine trees b. hickory trees c. mosses d. lichens
The diagram below shows various ecological communities that occupied an area over a period of 300 years. Which statement best describes the diagram? a. Community A is the most stable community. b. Community B replaced community C after a period of 100 years. c. Community C developed into community A after a period of 75 years. d. Community D modified the environment, making it more suitable for community E
SECONDARY SUCCESSION occurs where an existing community has been cleared by some disturbance but the soil is not destroyed.
Secondary Succession DEFORESTATION and FIRE are disturbances that will clear the existing community but not destroy the soil.
Over a long period of time, the stages represented in the diagram below were each present in a particular ecosystem. After a forest fire, what is the most likely order in which these stages appeared? a. D C A B b. B D C A c. A B C D d. B C D A
Aquatic Succession Aquatic HABITATS are in WATER. Over long periods of time ponds fill in slowly with sediments and plants.
The ponds fill in over time to become a marsh, a meadow or eventually a forest.
Which statement best describes one of the stages represented in the diagram below? a. The mature forest will most likely be stable over a long period of time. b. If all the weeds and grasses are destroyed, the number of carnivores will increase. c. As the population of the shrubs increases, it will be held in check by the mature forest community. d. The young forest community will invade and take over the mature forest community.