Week 5 Notes PDF

Preview

Summary

These notes cove material from week 5....

Description

EVR2001: 2/6: Geographic Isolation: • isolated populations can not interbreed, evolutionary trajectory is likely to deviate • Habitat is subdivided and organisms cannot travel within areas • Organisms start to deviate from original species • Ex: Mountain, river to lake • After Many generations the mutations can cause the species to no longer produce fertile offspring • Become separate species through allopatric speciation Biodiversity: • Variety and variability among living organisms and ecological complexes • Genetic diversity - Within-species diversity as measured by DNA • Species Diversity - species richness, evenness, dominance • Ecological Diversity - habitats, niches, ecological proccess Simpsons Index: • Various versions are based on the probability of any two sampled individuals belonging to the same species. The lower the probability, the more diverse • Ranges from 0-1 • The higher the index, more diversity Biomes: • warmer and wetter environments have higher biodiversity than colder and drier ones • more energy flowed in the more organisms it can support Endemism: • Endemic species- species that exist in a small area and no where else • common on tropical islands Biodiversity Hot Spots: • Conservation priorities • regions that contain a disproportionate share of biodiversity Mass Extinctions • Extinction intensity- percent of well preserved marine genera not present in subsequent interval • Permian-Triassic mass extinction • 57% of aquatic 83% of all genus 90-96% of all species went into extinction • Caused by global warming event by deposits of methane Current Threats: HIPPO • Habitat Destruction- degradation and fragmentation • Invasive Species- ecological release - species released that are unnatural to habitat - ball python, cats - Unlike native habitat, not competition or predators - Not all species will take off as invasive, needs appropriate climate - Zebra Mussels in the Great Lakes

EVR2001: • Pollution - can kill organisms outright, some kill slowly/delayed - some increase chance of cancer, other mutations, birth defects • Population - rapid population growth - human are improaching on habitats and displacing animals • Overharvesting - Poachers - Elephant tusks, rhino horns, furs all of status through black market - even fish and coral reefs Climate Change • Endangered Species Act (ESA, 1973) • Protects threatened and endangered species in the US by delineating critical habitat and prohibiting harming listed species and habitat • Does not allow individuals to develop land where an endangered species lives Convention on International Trade in Endangered Species (CITES, 1975) • bans international trade with products obtained from endangered species • does not directly address habitat loss, poverty, or conservation • smuggling still persists on the black market Tools for species-level biodiversity • sanctions to dissuade poachers • Providing alternative livelihoods • Captive breeding • !...