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BIOL2010 L14-30
| Question | Answer |
|---|---|
| Population dynamics? | Change in abundance and distribution of a species over time |
| Allele effects? | Population growth rates that decrease below replacement level at low population density, potentially leading to extinction |
| Density dependent rate? | As population density rises, births or immigration decrease or deaths or emigration increase, and consequently a graph of population density vs the rate will have a positive or negative slope |
| Density independent rate? | As population density increases, the rate does not change so the graph of population density vs the rate will have a slope of 0 |
| Limiting factor? | A factor is defined as limiting if a change in the factor produces a change in average or equilibrium density |
| Regulating factor? | A factor is defined as potentially regulating if the % of mortality caused by the factor increases with population density or if the reproductive rate decreases with population density |
| Habitat? | The locality, site and particular type of local environment occupied by an organism and has conditions that determine the presence, survival and reproduction of a population |
| Transplant experiment? | Move individuals of a species to an unoccupied area and determine whether they can survive and reproduce successfully in the new enviro |
| What were the 5 major extinction events? | End of Ordovician, Late Devonian, end of Permian, end of Triassic and end of Cretaceous |
| What effect did the Permian extinction event have on communities? | More complex organisms evolved, species had higher metabolism. Caused dramatic changes in the type of community |
| Keystone species? | Key ecological role filled by one species. Removal of this species changes the abundance or diversity of other species |
| What are the 3 main hypotheses for species-area relationships? | 1. Habitat diversity- bigger habitat, greater chance of having more species 2. Equilibrium theory - rates of extinction are less in a larger area than smaller areas 3. Random replacement (null) - number of species and area is result of random colonizati |
| Services provided by ocean sediments? | Carbon geochemical cycling, nitrogen and sulphur cycling. |
| Four mechanisms of recolonisation of marine areas after disturbance | Vegetative regrowth, within patch recruitment, lateral movement of neighbouring vegetation, colonisation of dispersing propagules. |
| Transitive vs intransitive competition? | Transitive - linear hierarchy of competition resulting in a dominant species. Intransitive - circular competition, no dominant species. |
| How do you measure community stability? | Resilience to disturbances, variability in the species abundances over time, persistence of the community in time. |
| Competetive ability vs niche differences | Competetive ability - ability to limit other species more than themselves Niche difference - differences between species that mean they compete with themselves more than others |
| coexistence theory | niche differences greater than competitive ability. |
| Population dynamics? | Changes in abundance and distribution of a species over time. Growth rate determines how quickly a population changes. Affected by competition/predation. |
| Key factor analysis? | Assumes all mortality factors are additive and ignores compensatory mortality(vital limitation). A key factor is defined as the component of the life table that causes the major fluctuations in population size. Can be used to predict population trends. |
| Source, sinks and pseudosinks? | Source - B>D, I<E Sinks - B<D, I>E Pseudosink - B<D, I>E (B>D at lower density) |
| Facilitation model? | Succession proceeds via one species helping the next species in the sequence to establish |
| Inhibition model? | Succession proceeds via one species trying to stop the next species in the sequence from establishing |
| Monoclimax hypothesis? | All vegetation in a region converges ultimately to a single climax plant community |
| Primary succession? | Succession occurring on a landscape has had no biological legacy (ie occurs on a new vacant site) |
| Secondary succession? | Succession occurring on a landscape that has a biological legacy in the form of seeds, roots and some live plants (ie recovery of a disturbed site) |
| Climax state? | The final or stable community in a successional series. It's in equilibrium with the physical and biotic environment |
| Intermediate disturbance hypothesis? | The idea that biodiversity will be maximal in habitats that are subject to disturbances at a moderate level, rather than a low or high level |
| Sequential niche breakage theory? (for log distribution) | Assume community niche structure is hierarchical and niche space isn’t thought of as a single resource axis |
| Neutral theory assumptions? (for log distribution) | - All species are ecologically equivalent - No species is competitively superior to the other species - Species arrive at random evolutionarily - Communities are saturated (full) with species and in equilibrium |
| How species interact - describe the 2 models (web of life and individualistic) | Web of life - what happens to one species affects the others Individualistic model - species act in an individualistic way |
| Equilibrium model of community organization? | The view that ecological communities are relatively constant in composition and are resilient to disturbances |
| Nonequilibrium model of community organization? | The view that ecological communities are not constant in their composition because they are always recovering from biotic and abiotic disturbances, never reaching equilibrium |
| Resilience? | Capacity of a community to go through a disturbance and return to an original stable state |
| Global stability? | Occurs when a community can recover from any disturbance, large or small, and go back to its initial stable state |
| Local stability? | Occurs when communities recover from only small disturbances and return to their former configuration of species composition and abundances. In different habitats the equilibrium point may differ |
| Energetic hypothesis for food chains? | The length of food chains is limited by the inefficiency of energy transfer along the chain. Predicts that food chains will be longer in more productive systems |
| Dynamic stability hypothesis for food chains? | Population fluctuations at lower trophic levels due to disturbances are magnified at higher levels. The longer the chain, the harder it is for predators to recover |
| Gross primary production? | Energy or carbon fixed via photosynthesis per unit time |
| Net primary production? | Energy or carbon fixed in photosynthesis minus the energy or carbon lost via respiration per unit time |
| 3 main hypotheses for species-area relationships? | 1. Habitat diversity-bigger area, likely to have more microhabitats, more niches and species 2. Equil theory-big area, rates of extinctions likely to be less than small area 3. Random placement-Number of species and area is result of random colonisation |
| Priority effects? | The order of arrival among varying species may contribute to species richness. The resulting community depends on who colonizes it first. Has alternative stable states |
| Environmental filtering? | Abiotic factors that have a restricting effect upon species richness |
Created by:
cmw001001
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