Destruction and creation

1. Destruction and creation Goals Learn about the K-T boundary Asteroid impacts and mass extinctions Hominid evolution Ethics of artificial life 1

2. The K-T boundary Where we left off on our discussion of evolution of life on Earth… Eukaryotes evolved with symbiont prokaryote-organelles (2.1 b.y.a.); Oxygen levels and other stresses had encouraged the Cambrian Explosion of multicellular life (545 m.y.a.);Biodiversity was extraordinary; the Burgess Creek Shale (post Cambrian Explosion) shows arthropods from about 25 subphyla, only 4 of which persist today; Life invaded land (475 m.y.a.); Organisms developed the resistance to desiccation, and invaded the land (400 m.y.a.); Dinosaurs and mammals (245 m.y.a.). 2

3. The K-T boundary Heavy losses: Microbes: significant losses Marine inverts: 60% losses (genera) Terrestrial inverts: major losses Terrestrial plants: huge losses Dinosaurs: extinct Ancestral birds: heavy losses Mammals: moderate losses Moderate losses: Fish: only 10-20% losses Fungi: benefits! Amphibians: minor losses Reptiles: minor losses 245 MYA, terrestrial biodiversity was high. 65 MYA, a major extinction event occurred on a global basis, at the end of the Cretaceous Period, and beginning of the Tertiary Period. Examples of effects: Summary: Plants and animals: 75% species loss Plant and animal kill: 99% by individual! What had happened? 3

4. K-T boundary characteristics Global in occurrence; High in iridium and other rare metals (osmium, gold, etc); Quartz in layer shows shock characteristics (high P, T); It contains rock droplets that were once molten; Its carbon layers suggest soot once occurred at a global scale. Evidence suggests a gigantic meteoric impact Impact site: Yucatán Peninsula (200 km Chicxulub crater); Object a comet or asteroid 10 km in diameter; 100,000,000 megaton bomb (most massive human bomb was 50 megatons); Glowing debris on global scale; Global tsunami events; Months of smoke and ash, resulting in global winter; Subsequent possible greenhouse phase; Possible oceanic poisoning by nitrites. 4

5. The big five mass extinctions Ordovician-Silurian periods 440-450 MYA: 2nd largest; claimed 27% (families), 57% (genera). Likely due to climate changes; not an impact. Late Devonian period 360-375 MYA: Part of a series, claimed 19% (families), 50% (genera), 70% (species). Instigated the arrival of amphibians. Permian-Triassic periods 251 MYA: Largest; 57% (families), 83% (genera). Opened the way for dinosaurs by removing amphibians and mammal-like reptiles. Triassic-Jurassic periods 205 MYA: 23% (families), 48% (genera). Cretaceous-Tertiary periods 65 MYA: 75% (species). Current times 1900s to 2100: 50% (species). Caused by humans. 5

6. The extinction that takes us out Causes: More asteroids/comets Magnetic field reversals Supernovae Gamma-ray bursts Ecological collapse Global volcanism What about the next impact event? Global kill rate: ???: ??% (families), ??% (genera). Our space and military programs would be unable to respond effectively. 6

7. Hominid evolution We now take the audacious step of applying the same techniques throughout the scientific process—the techniques that have created vaccines, ipods, and spacecraft—and study the evolution of our own species. Some basic misconceptions on (hominid) evolution “It’s just a theory;” There are no missing links; We did not evolve from monkeys, orangutans, gorillas, chimpanzees, or bonobos; Anthropologists are not in huge disagreement on the basic concepts of biological evolution (Project Steve). 7

8. Hominid evolution An extensive record now exists of the development of humans over the last several million years. There are many players, and new fossils are being discovered frequently. Most new fossils are simply repeat findings of previously known hominids. Some fossil Australopithecus and Homo species T1, A. africanus, 2.6 My T2, A. africanus, 2.5 My T3, H. habilis, 1.9 My T4, H. habilis, 1.8 My T5, H. rudolfensis, 1.8 My T6, H. erectus, 1.75 My B1, H. ergaster (early H. erectus), 1.75 My B2, H. heidelbergensis, 300,000 – 125,000 y B3, H. sapiens neanderthalensis, 70,000 y B4, H. sapiens neanderthalensis, 60,000 y B5, H. sapiens neanderthalensis, 45,000 y B6, H. sapiens sapiens, Cro-Magnon, 30,000 y 8

9. The prevailing (but not only theory) is that while the Earth has had a number of species of hominids, three entities were widespread until recently: We are all Africans H. sapiens neanderthalensis: Europe H. erectus: Asia H. sapiens: Africa It seems that Homo sapiens sapiens emigrated from Africa, and displaced the other species/subspecies. Note: we did not evolve from existing apes! 9

10. Cultural evolution modifies evolutionary processes • Rise of agriculture; • Rise of easy transportation modifies gene flow; • Rate of cultural evolution dwarfs biological evolution. • Technological evolution rules evolutionary processes • Genetic engineering of plants and lower organisms commonplace; • Creation of artificial life in progress (Craig Venter’s Mycoplasma mycoides); • 2014 insertion of dNaM-d5SICS (called “XY”) artificial base pair into E. coli; • Genetic engineering of humans is inevitable • IlyaIvanov inseminated female chimps with human sperm in 1927. • He prepared to inseminate five human females with orangutan sperm in 1929. • He was interrupted only by changes in Soviet politics. Critical future mileposts in our evolution 10

11. Impending crises approach (we shall see) • Resource exhaustion? • Technological singularity?Moore’s law—the # of transistors on a chip doubles every two years.When CAD-facilitated computer construction reaches a point comparable to human intelligence, machine evolution will exceed human evolution.And we all know what that means… Critical future mileposts in our evolution 11