IUCN (International Union for the Conservation of Nature) Red List documents 844 extinctions since 1500, a loss of 2.2 % of all evaluated species and 0.04 % of all described species Certainly an underestimate because all species are not described Corrections made by using the best-known groups of species For example, 100 birds and mammals have gone extinct between 1900-2000 species of birds and mammals 0.65 % loss per century or 1 bird or •Hence, 15,333 – mammal species per year with the historical record for birds and mammals 0.0003 species per •Compared – year 333 times greater than background rate of extinction •Hence, Geological record of extinctions 99.9% of species that have ever lived have gone extinct Extinction has been an ever-present but dynamic process over the 3.5 billion year history of life on earth 5 major crashes Cause of 5 major ancient extinction waves? but the We basically still don’t know, meteor hypothesis isn’t very strong:
IUCN (International Union for the Conservation of Nature) Red List documents 844 extinctions since 1500, a loss of 2.2 % of all evaluated species and 0.04 % of all described species Certainly an underestimate because all species are not described Corrections made by using the best-known groups of species For example, 100 birds and mammals have gone extinct between 1900-2000 •Hence, 15,333 species of birds and mammals – 0.65 % loss per century or 1 bird or mammal species per year •Compared with the historical record for birds and mammals – 0.0003 species per year •Hence, 333 times greater than background rate of extinction Geological record of extinctions 99.9% of species that have ever lived have gone extinct Extinction has been an ever-present but dynamic process over the 3.5 billion year history of life on earth 5 major crashes Cause of 5 major ancient extinction waves? We basically still don’t know, but the meteor hypothesis isn’t very strong:
2016%20Lecture%2008%20-%20Extinction.docx