Biology by Bradford
8.5.A, 8.5.BA food web
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8.5 Community Ecology: revision map
The subtopic in the middle and four tasks round it: label a diagram, complete a table and fill 10 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.
Community Ecology
AP Biology · Unit 8 EcologyHover over a box to see it. Untick it to leave it off this sheet and its printout.
Name8.5.BA few species matter most
A has an effect on its community out of proportion to its numbers. When sea otters were removed from a kelp forest, sea urchins increased and cleared the kelp, which was home to many other species. A change at one level of a food web, such as the loss of a top predator, can pass through the web as a trophic cascade. Species that make up much of the biomass, and ones that build habitat, such as corals, also shape the whole community.
Topic 8.5Community Ecology
8.5.AInteractions between species
| Interaction | Effect (+ helps, − harms) | Example |
|---|---|---|
| − / − | two plants sharing the same light | |
| + / − | a lynx and a hare | |
| + / + | a flower and its pollinator; mycorrhizae | |
| Commensalism | + / 0 | an epiphyte growing on a tree |
| Parasitism | + / − | a tapeworm in a host gut |
8.5.ANiches and competition
The role of a species in its community, which includes where it lives, what it eats and when it is active, is its niche. Two species cannot share exactly the same niche for long, since the better competitor will exclude the other: this is the principle of . Species that share a resource avoid each other by using it in different ways, which is resource partitioning.
Word bank Competitioncompetitive exclusiondecomposerkeystone speciesMutualismPredationprimary consumerproducersecondary consumertop predator
Answer key
Every box on the sheet with its gaps filled in, as the subtopic reads in full.
LabelA food web
- producer
- primary consumer
- secondary consumer
- top predator
- decomposer
TableInteractions between species
Interaction Effect (+ helps, − harms) Example Competition − / − two plants sharing the same light Predation + / − a lynx and a hare Mutualism + / + a flower and its pollinator; mycorrhizae Commensalism + / 0 an epiphyte growing on a tree Parasitism + / − a tapeworm in a host gut GapsNiches and competition
The role of a species in its community, which includes where it lives, what it eats and when it is active, is its niche. Two species cannot share exactly the same niche for long, since the better competitor will exclude the other: this is the principle of competitive exclusion. Species that share a resource avoid each other by using it in different ways, which is resource partitioning.
GapsA few species matter most
A keystone species has an effect on its community out of proportion to its numbers. When sea otters were removed from a kelp forest, sea urchins increased and cleared the kelp, which was home to many other species. A change at one level of a food web, such as the loss of a top predator, can pass through the web as a trophic cascade. Species that make up much of the biomass, and ones that build habitat, such as corals, also shape the whole community.