BIO130H1 Lecture Notes - Lecture 8: The Strongest
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BIO130H1 Full Course Notes
Verified Note
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Document Summary
Model populations go extinct because of 1) strong density dependence (overshoot+crash) 2) unstable competition 3) unstable predator prey (disease-host) 4) allee effects at low density. Don"t go extinct because of 1) nonequilibrial conditions 2) habitat patchiness 3) rescue-by- migration 4) variation in life history strategy. Organismal/holistic hypothesis: certain species found together because they"re biologically integrated and depend on each other"s presence like tissues of an organism. Individualistic hypothesis: species are distributed independently of each other. Important limitations are dispersal and filtering by physical environment (abiotic factors/tolerance). Robert whittaker confirmed individualistic hypothesis is correct using direct gradient analysis. Sampled plant occurrence at many points through ranges (e. g. elevation or moisture). The strongest environmental filtering is driven by physical factors, not other species. However, species interactions e. g. herbivory do affect some distributions only secondarily.
