BIOC58H3 Lecture 6: BIOC58 Lecture 6
Document Summary
Lecture 6 mass extinctions & the anthropocene. Clicker q1: review *exam question: a lake turns over once per year in the summer, and is typically stratified such that the warmest waters are found deeper in the lake the rest of the year. Part 1 mass extinctions of the past. Five major mass extinction events: mass extinctions at irregular intervals dating back almost billion years, may be more but have no evidence of them. If one factor, or all, contributed still debated: climate like involved, even if wasn"t direct cause, 4. Cretaceous-tertiary (k-t), 65 mya: most famous > extinction of most dinosaur lineages (avian clade remained. Silurian: 3: ~90% of all species went extinct during this one (end-permian, 4: this one was likely caused by the chicxulub asteroid impact in mexico (k-t, 5: possibly caused by land plants taking up co2 from atmosphere (end- Denovian: asteroid event applies to many extinction periods, leave this option for last in exam question.
