BIOL 112 Lecture Notes - Lecture 7: Desiccation, Continental Drift, Ocean Acidification
Document Summary
Large scale events in evolution; marked by speciation and extinction: high speciation + low extinction = high biodiversity, microevolution over a large amount of time. Adaptive radiation: many species rapidly emerging from a single species, two conditions conducive to speciation, specialization to an ecological niche (role, access to new environment, darwin"s finches; 13 species arose from an ancestral species. Extinctions: mass extinction: 50% or more of a species die, climatic extremes, continental drift, catastrophic events. Fossil record contains 5 mass extinctions in 540 million years. Current rate 1000 times the typical rate; climate change, habitat loss: extinctions are usually followed by adaptive radiations and diversifications. Geologic record: rock strata & fossil record; provide info about earth. Early prokaryotes: 3. 8-3. 5 bya; earth"s sole inhabitants 2. 5-2. 1 bya. Eukaryotes: first are single celled; formed via endosymbiosis; host cells engulfs bacteria; host cell and bacteria both provide each other with something. Multicellular eukaryotes move to land; fungi, plants and animals; adaptations to avoid dessication.
