Biology by Bradford
8.7.A, 8.7.B, 8.7.C, 8.7.DPrimary succession
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8.7 Disruptions in Ecosystems: revision map
The subtopic in the middle and six tasks round it: label a diagram, complete a table, put a process in order and fill 8 gaps. Every box rests on a learning objective of the topic in the AP Biology course and exam description. Type into the blanks and check them, or print it on A4, Letter or A3 with an answer key.
Disruptions in Ecosystems
AP Biology · Unit 8 EcologyHover over a box to see it. Untick it to leave it off this sheet and its printout.
Name8.7.BSpecies from elsewhere
A species moved by people to a new place may have no predators or diseases there. If it spreads quickly and outcompetes native species, it is an species, and it can reduce biodiversity and change how the ecosystem works, as zebra mussels and cane toads have done. Native species that did not evolve with the invader often have no defense against it.
8.7.ADisruptions
| Kind | Examples |
|---|---|
| fire, flood, drought, volcanic eruption, hurricane | |
| Human | deforestation, pollution, damming rivers, overfishing, introduced species |
Many disruptions are sudden, but some, like climate change, build slowly. After a disruption, an ecosystem may recover, or change into something different if it was pushed far enough.
Topic 8.7Disruptions in Ecosystems
8.7.DRecovery
Where soil is left, as after a fire or flood, secondary succession is fast, because seeds and roots are still there. Primary succession starts on bare rock or new volcanic land: pioneer species such as break the rock down and add organic matter to start a soil, and shrubs and then trees follow. Each stage changes the conditions in ways that favor the next.
8.7.CClimate and chemistry
Burning fossil fuels raises the carbon dioxide in the atmosphere, which traps heat, so global temperatures rise, and ranges, breeding times and migrations shift. Some of the CO₂ dissolves in the oceans and lowers their pH, called ocean , which makes it harder for corals and shellfish to build their shells. Species that cannot move or adapt fast enough may go extinct.
8.7.CEutrophication
Number the steps in order.
- Fertilizer or sewage washes into a lake, adding nitrogen and phosphorus.
- Algae grow rapidly in an algal bloom.
- Decomposers feed on the dead material and use up the oxygen.
- Fish and other animals die from the lack of oxygen.
- The bloom blocks light and the plants below die.
Word bank acidificationbare rockclimax communityinvasivelichensNaturalpioneer speciesshrubs
Answer key
Every box on the sheet with its gaps filled in, as the subtopic reads in full.
LabelPrimary succession
- bare rock
- pioneer species
- shrubs
- climax community
TableDisruptions
Kind Examples Natural fire, flood, drought, volcanic eruption, hurricane Human deforestation, pollution, damming rivers, overfishing, introduced species Many disruptions are sudden, but some, like climate change, build slowly. After a disruption, an ecosystem may recover, or change into something different if it was pushed far enough.
GapsSpecies from elsewhere
A species moved by people to a new place may have no predators or diseases there. If it spreads quickly and outcompetes native species, it is an invasive species, and it can reduce biodiversity and change how the ecosystem works, as zebra mussels and cane toads have done. Native species that did not evolve with the invader often have no defense against it.
GapsClimate and chemistry
Burning fossil fuels raises the carbon dioxide in the atmosphere, which traps heat, so global temperatures rise, and ranges, breeding times and migrations shift. Some of the CO₂ dissolves in the oceans and lowers their pH, called ocean acidification, which makes it harder for corals and shellfish to build their shells. Species that cannot move or adapt fast enough may go extinct.
OrderEutrophication
- Fertilizer or sewage washes into a lake, adding nitrogen and phosphorus.
- Algae grow rapidly in an algal bloom.
- The bloom blocks light and the plants below die.
- Decomposers feed on the dead material and use up the oxygen.
- Fish and other animals die from the lack of oxygen.
GapsRecovery
Where soil is left, as after a fire or flood, secondary succession is fast, because seeds and roots are still there. Primary succession starts on bare rock or new volcanic land: pioneer species such as lichens break the rock down and add organic matter to start a soil, and shrubs and then trees follow. Each stage changes the conditions in ways that favor the next.