Term
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Definition
| a group of species in a particular place and the interactions that bind them |
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Term
| What deterines community structure? |
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Definition
which species are present
species richness
species abundance
organization of feeding levels
most difficult and least understood question in ecology |
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Term
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Definition
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Term
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Definition
- collection of species that are capable of getting to and surviving the abiotic conditions in an environment
- represents potential member of a community
- species pool > than true member ship
- depends on:
ability to disperse into an area
physical/chemical tolerances |
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Term
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Definition
| Change in number and types of species following a disturbance or the creation of a new substrate |
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Term
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Definition
any discrete, punctuated killing, displacement or damaging or one or more individuals that creates an opportunity for new individuals to become established
- should create an opening in the community for another individual to colonize
- any event that has an impact on a community and by event affect the abunace of species |
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Term
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Definition
- changes in species composition on newly exposed substrates that have not been modifed by organism
- land scape or habitat that has been wiped clean
example: area where glacier has just retreated, no top soil, nothing less
follows catastrophic disturbance, |
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Term
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Definition
- changes in species composition where disturbance has modified a community but not destroyed the soil
- refers to all disturbances other than catastrophic. organic matter is still present
examples: fires, oil spills, strong wind storms, herbivory |
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Term
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Definition
examples: termites, beavers, elephants. affects the way the ecosystem functions probably keystone species
elephants trampling the ground, no trees growing |
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Term
| Who developed the monoclimax hypothesis? |
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Definition
| Frederic Clements (1916, 1936) |
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Term
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Definition
FACILITATION
1. disturbance occurs
2. sequence of changes in community structure(sere)
3. change is predicatable
4. Progresses to climax state
endpoint of succession
community structure at equilibrium
stable (always returns to same state)
5. climax state determined by:
species pool
climate
Community is highly integrated super organism |
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Term
| Monoclimax hypothesis and r-k selection |
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Definition
r- selected species: early stages of succession
high dispersal ability
high reproduction
short lifespan
low competitive ability
k selected species: late states of succession
poor dispersers
low reproduction
slow growing
highly competitive |
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Term
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Definition
an invading species makes habitat less suitable for itself and more suitable for future species
- key assumption for monoclimax model |
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Term
| what two factors determine the climax state? |
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Definition
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Term
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Definition
all organisms in community play a vital role in the function and operation of the community
- every species is a keystone species
- commnity very tightly linked |
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Term
| Example in support of monoclimax hypothesis |
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Definition
Glacial Moraine in Alaska
- lowers nutrients
- lowers pH |
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Term
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Definition
- any species can colonize area
- early occupans modify environment and make it less suitable for others
- competition drives succession
- established species inhibit invation by other species
- long lived, best competitior more likely to persisit
CLIMAX STATE UNPREDICTABLE |
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Term
| Examples of inhibition hypothesis |
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Definition
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Term
| example of inhibition and monoclimax interacting together |
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Definition
Mount St. Helen
- combination of processes occuring durning primary succession
Dean and Hurds
- bathroom tile and colonization of subtidal plates
Pastures in New York |
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Term
| what are the 3 problems with the climax state? |
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Definition
1. Identical habitats yield different climax states.
2. Succession might occur too slowly
3. climax depends more than species and climate change in environment can cause change in climax state |
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Term
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Definition
| the study of the relationship between geography and species distrubution and abundance |
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Term
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Definition
Mac Arthur and Wilson(1967)
Comprehensive Theory: predicts species richness when community at equillibrium
- based on s |
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Term
| What constitutes an island in the general sence of the term? |
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Definition
| discrete habitats separated by uninhabitable space |
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Term
| What four factors determine species richness? |
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Definition
immigration rate(I) - where there are no species living there, there is alot of potential for Immigration to occur there
extinction rates(E) - number of extinctions per unit time goes up as species richness goes up
island size
degree of isolation |
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Term
| Dynamic Stable Equilibrium |
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Definition
Equilibrium: richness remains constant over time
stable: returns to S following a disturbance
dynamic: kinds of species always changing at s |
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