GEOS 130 Lecture Notes - Lecture 11: Least-Concern Species, Ordovician, Ecosystem Services
21 Sep 2017
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Ex: penicillin is a fungus, but also a largely used antibiotic worldwide. 5 major extinction events in earth"s history. Ex: late ordovician period swept by glaciation. About 10-100 million more species to be discovered. Of these 10-100 million, most are plants and invertebrates. We don"t know how many species go extinct each year, but an estimated 11,000-58,000 of the 5-9 million animals species go extinct every year. Some estimate 25% of all species will go extinct in next 50 years. For most species the greatest cause of decline and extinction is habitat loss. Most habitat loss is due to human impacts. Habitat fragmentation is the reduction of habitat into small, isolated patches. Some invasive species are accidentally introduced like aquatic species for example. 138 billion lost to invasive species in us. 40% threatened or endangered species due to invasives. Native or home range-where the species originated. Pollution-when toxic contaminants such as pesticides, heavy metals, acids, and oil spills.
