Download Gateway Preparation Class: June 2, Thursday 1

Gateway Preparation Class: June 2, Thursday 1-4 pm Peachtree Ridge HS
Notes to study for Gateway:
Changes in Freeville:
ECOLOGICAL CHANGES
Bottom Line: Ecological changes refer to the growth or regrowth of species in an ecosystem over time. A common term associated with this
concept is ecological succession. In ecological succession, the trend is an ecosystem moves from early stages where only pioneer species,
such as small plants, mosses and lichen, towards its climax community, which is the stable, full grown variety of species characteristic for its
biome. There are two types of ecological succession – primary succession and secondary succession. In primary succession, an ecosystem
starts from nothing – even soil has to be made by pioneer species like moss and bacteria decomposing organic material. In secondary
succession, an ecosystem that has been establish is disrupted by a natural disaster or human activity and must regrow with any remaining
species and soil already present. In either type of succession, once plant life has been (re)established, animal life can be sustained through
the food chain.
Vocabulary:
ecosystem: all the biotic (living) and abiotic (non-living) factors interacting in an area; ex: trees, soil, moisture and squirrels in a field.
community: all the different living species (biotic factors) interacting in an area; ex: mice, coyote and humans interacting.
ecological succession: series of changes that occur in an ecosystem over time typically moving from pioneer stage to climax community
stage.
pioneer species: species that first inhabit an area in succession; typically small autotrophs that better conditions for species which later
inhabit the area; examples: lichen, mosses, small plants
climax community: fully grown, stable variety of species that is characteristic of the biome for an area; ex: hardwood deciduous forest in
Georgia
habitat disruption: an act that changes the number and type of species in an area; ex: forest fires, flood, pollution
primary succession: type of ecological change process in which an area starts with no life or soil and develops into a functioning
ecosystem; ex: volcanic lava cools in the ocean to form lifeless rock; eventually pioneer species like algae and mosses, carried by currents,
inhabit the rock; their breakdown eventually makes soil and more life can migrate or be carried to the rock habitat.
secondary succession: type of ecological change process in which an ecosystem that is already established is disrupted and must regrow
with the remaining species; ex: a forest fire burns many trees and grasses leaving some species to regrow; pioneer species include small
plants and grasses.
Video Notes: Ecological Succession Bozeman Science 6:30 http://www.youtube.com/watch?v=V49IovRSJDs\
Other videos:Animation: 1) http://wps.prenhall.com/wps/media/objects/2688/2752944/Web_Tutorials/23_A02.html
2) Stages of Primary Succession 3:30 https://www.youtube.com/watch?v=TLpc71YOtcE
3) Soil formation in primary succession v. secondary succession 2:38 http://www.tubechop.com/watch/7650196
Change:
Lack of rain
Snake dies
Too many locust
How would the change affect the food chain?
Chemistry of Ecological Changes
Primary succession‚ areas where rocks breaking down mix with organic material to make basic soil.
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Physical erosion - Freeze Thaw cycle - water gets into small cracks in the rocks, freezes, makes cracks larger, eventually breaks rocks and
Abrasion -Rock rubbing on rocks, Glaciers rubbing rocks together, water rubbing rocks together, Also Wind with sand blasting on the
surface of rocks.
Chemical erosion
a. Acid rain / acid water - breaking rocks down into other chemical compounds
b. Lichen –produce acids 1) breaks rocks and 2) that binds to minerals making them more useful for plants
Biological Erosion - Plants roots get into cracks, grow and expand, breaking rocks.
Eventually rocks break down into sand, plants and animals live/grow in sand, die and add nutrients. Eventually becomes soil
Pioneer community ‚ first community of organisms, plants and animals, to move into a new environment.
Secondary succession areas with soil developing from either primary successional area, or where plants removed (landslides, earthquakes,
bulldozers, forest fires) and they are now growing back. Many secondary pioneer communities are nitrogen fixers. Take atmospheric nitrogen in
root nodules and break it down to usuable nitrogen. When die/decompose release valuable nutrients (Nitrogen, Carbon, Potassium, Phosphorus
etc). Having Nitrogen is key as it is a limiting factor - without nitrogen organisms can't make DNA, thus no growth!
How plants and animals use chemicals
In order for a plant to grow and thrive, it needs a number of different chemical elements. The most important are:
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Carbon, hydrogen and oxygen - Available from air and water and therefore in plentiful supply
Nitrogen, phosphorus, potassium (a.k.a. potash) – fertilizers
1.
Every amino acid contains nitrogen.
2.
Every molecule making up every cell's membrane contains phosphorous (the membrane molecules are called phospholipids), and so
does every molecule of ATP (the main energy source of all cells).
3.
Potassium makes up 1 percent to 2 percent of the weight of any plant and, as an ion in cells, is essential to metabolism.
Without nitrogen, phosphorus and potassium, the plant simply cannot grow because it cannot make the pieces it needs. It's like a car factory
running out of steel or a road crew running out of asphalt. If missing or hard to obtain from the soil, this will limit the growth rate for the plant. In
nature, the nitrogen, phosphorous and potassium often come from the decay of plants that have died. In the case of nitrogen, the recycling of
nitrogen from dead to living plants is often the only source of nitrogen in the soil.