BIO SCI 94 Lecture Notes - Lecture 17: Habitat Fragmentation, Metapopulation, Logistic Function

• School: UC-Irvine
• Department: Biological Sciences
• Course: BIO SCI 94
• Professor: Nancy Burley

Document Summary

As n k (carrying capacity), population growth rate 0. What causes this (cid:1445)s(cid:1446) shaped curve of the logistic growth curve? limited resources, or biotic factors. Density independent factors (abiotic) -- climate, weather, catastrophic events. Abiotic factors are insensitive to the population size meaning no matter how big or small the population is, it will be impacted by abiotic factors. Density dependent factors (biotic) -- competition, predation, parasitism/disease. Biotic factors causes the population to level off at the carrying capacity. Metapopulations -- group of populations connected by migration. Humans cause a habitat fragmentation causing different species to be in different areas. Local populations -- can go extinct, but recolonization is possible if patches are still available (connect the populations back together) In genetic drift (small populations), we tend to lose genetic diversity. Human activity causes habitat fragmentation increased frequency of metapopulation structure. It causes species to live in separate areas and have them migrate between areas.