BIS 2B Lecture Notes - Lecture 33: Milankovitch Cycles, Paleocene, Transpiration

• School: UC-Davis
• Department: Biological Sciences
• Course: BIS 2B
• Professor: Schreiber, Sebastian

Document Summary

75% of species go extinct from kt asteroid impact. Followed by rapid evo radiation in early cenozoic. History of cenozoic life (div into tertiary and quarternary) Flowering plants (angiosperms) - most diverse group today. 240k species (most of the plants on earth today) Hydraulic innovations in stem vessels and leaf veins. Ecosystem engineering: angiosperms" higher transpiration rates incr tropical rainfall. Other instance: lineage evolves symbiosis w/ n-fixing bacteria housed in root nodules. Incr rates of biological n-fixation in ecosystem + biologically available n for plant growth. Take up nutrient vs. fix nitrogen from atmosphere. Diversified, spread to dominate most (plant) comms. Plant evolves new qualitative chem defense, adaptive radiation. Insect evolves counterdefense, adaptive radiation plant defense becomes attractants for specialized herbivores. ~25% of species on earth are plant-eating insects. Switch to angiosperms huge radiation in species compared to sister lineage that did not switch. Radiate rapidly into many eco niches (~10my) Brings the rise of grass, c4 grasslands, and grazers.