1. HUMANS Homo sapiens

2. On a small branch of the tree of life, among the Mammals, a group emerged Visual, tree dwelling, grasping hands and feet, most similar to Prosimians of today

3. This group radiated from a common ancestor <60MYA 1758, Linnaeus named the group Primate - “chiefs of creation” Named 3 genera based on limited species - Lemur, Simia, Homo Good fit to current view – prosimians, monkeys, apes

4. In Homo, Linnaeus included Chimpanzees, Orangutan, and Humans. Gorillas and Gibbons were not yet known. Today all separate genera

5. Jane Goodall

6. Divergences (common ancestors) indicated by fossils and molecular data Apes and Old World monkeys < 30MYA Humans and Chimps <10 MYA

7. The human lineage (“Hominan”) contains many extinct species, exact relationships not certain due to lack of genetic data

8. Hominans have many distinctive traits Bipedal locomotion Precision grip Tool use Reduced sex size dimorphism Reduced jaw, Meat eating Large Brain Culture, Language 3.5 MYA

9. While very closely related to the great apes, humans are clearly significantly different. Recall the Cetacea Recall: Camels are more closely related to whales than to horses. Given sufficient “adaptive opportunity”, change can be rapid What is the key hominan adaptive “innovation”? Is this a contradiction?

10. Australopithecus sp. – 4-2 MYA Bipedal, brain 30% “Lucy” Homo erectus 1.7 MYA Brain 60% Migrated as far as Indonesia Extinct 200,000 YA Out of Africa

11. Possible exception – Homo floresiensis (discovered 2004) http://magma.nationalgeographic.com/ngm/0504/feature1/index.html Size of Australopithecus Skull of H. erectus Existed on Flores Island as late as 18,000 years ago Various hypotheses Island induced dwarfism?

12. Homo neanderthalensis – 200,000 years ago, Europe Brain 100% Extinct 30,000 years - DNA Replaced by Homo sapiens Used fire

13. Homo sapiens Oldest fossil - 160,000 years - Ethiopia Asia by 50,000 years New World, 15,000 years Global dispersal African origin – all genetic variation One species – could have been different

14. National Geographic March 2006

16. Adaptation (mainly cultural) to a wide variety of habitats - biomes Primary mode – “hunter-gatherer” for most of history Strong dependence on natural environment Omnivory – balance abundance and nutrition

17. Pastoralism: Evidence of plant and animal domestication <10,000 years Slash & Burn common Many groups mixed hunting- gathering with small scale cultivation

18. Agricultural civilizations <8,000 years 1-4/1-3

19. Hunter-Gatherer => Pastoralism => Agriculture Increasing control over resource species, less dependent on ecosystem controls, change in “knowledge” Ecosystem forces - primarily antagonistic, nature must be “dominated” rather than understood

20. Persistent exponential growth in humans suggests that we have not yet encountered significant environmental deterioration. Question: Do we want to?? Do we want to reach K Human ? No one knows what K Human is

21. Humans have become a dominant force in the biosphere

22. Ecological Footprint: In addition to total numbers, level of resource use (culturally variable) by individuals determine the total impact on the biosphere

23. 1.7/1.5 Can the earth support our footprint?

24. Recall – biosphere is thin Classifying human impacts – problem because of multiple effects and interactions. E.g., coal mining – impacts on land, water, air, energy future About 20 mi. thick “2-dimensional” Life has altered it greatly Humans might also

25. One classification scheme 1. Ecosystem replacement a. urban, suburban b. agriculture, rangeland & soil erosion c. mining 2. Alteration of existing systems a. over-harvesting b. fragmentation c. non-native species 3. Global impacts a. chemical pollution b. nutrient enrichment c. climate change Potential consequences – biodiversity loss, reduced “ecosystem services”, soil erosion, climate & sea level changes Human Impacts

26. Cities Urban areas 2% of land area 48% of population Often on productive land City expansion - population growth - urban sprawl Human Impacts –1a Urban population Ecosystem replacement

27. 19521967 19721995 Las Vegas, NV Human Impacts –1a

28. Urban support systems Where does food come from? Agriculture – 77% Rangeland – 16% Fisheries – 7% Over 30% of (non-polar) land area converted to agriculture – from forest and grassland 80% of food produced by industrialized agriculture – for people & animals Cities need resources from large areas - photosynthesis Human Impacts 1b 7-1/8-1 Ecosystem replacement

29. Rangeland Less productive grasslands used for grazing livestock 40% of land Replace native grazers eliminate predators overstocking non-native grasses Human Impacts 1b Ecosystem replacement

30. Tropical deforestation Logging of tropical forest One-time Weathered soils Nutrients in biomass main fate – grazed grassland Human Impacts 1b Ecosystem replacement

31. Soil Erosion Human Impacts 1b Recall – soil crucial, takes many 100s, 1000s of years to form Erosion – natural process – loss/movement of soil due to wind & water accelerated with plants removed (agriculture, rangeland, deforestation) 7-6/8-4 Major effort in soil conservation after dust bowl in US Ecosystem replacement

32. Mining Extraction of materials from rock - diverse Surface & Subsurface Not sure how much land surface involved. Water runoff affected - acidity, heavy metals Fossil fuels – burning releases CO 2 Human Impacts 1c Ecosystem replacement

33. Overharvesting We still directly harvest from native ecosystems – e.g., fisheries, forests Living populations are “renewable” – can be harvested in the long term Overharvesting - decreased sustainable harvest - risk of extinction - ecosystem alteration Human Impacts 2a Increasing “traditional” populations stress systems wood gathering, “bushmeat” Alteration of existing systems

34. 7-4/8-14 Human Impacts 2a Most fisheries are overharvested Alteration of existing systems

35. Short-rotation forestry6-1/6-4 Human Impacts 2a Most current forestry practices are not sustainable Alteration of existing systems

36. Fragmentation Remaining systems are reduced in size, isolated Viable populations often require large, continuous tracts Fragmentation invariably leads to reduced biodiversity – often delayed Fairfax Co., VA Human Impacts 2b Alteration of existing systems

37. Non-native species Human activities have increased spread of many species Some have become “invasive” – displacing native species 5-9/7-9 Argentine Fire Ant Purple Loosestrife Human Impacts 2c Alteration of existing systems

38. Chemical Pollution Thousands of chemicals are emitted by modern industry – products, byproducts, and breakdown products regulation difficult Human Impacts 3a Generally point sources, but diffuse in air & water Some bioaccumulate & biomagnify Classic case: DDT 5-12/7-12 Global impacts

39. Nutrient Enrichment We are increasing key plant nutrients, N, P and CO 2 N & P for agricultural production CO 2 is increasing due to fossil fuel burning & deforestation Phosphorus – rocks mined & ground into fertilizer Nitrogen – industrial N-fixation, planting of legumes - human N-fixation now exceeds all others annually All these inputs spread globally What’s the problem, isn’t it good to increase plant resources? Human Impacts 3b Global impacts

40. Eutrophication – effect of increased nutrients on ecosystems first studied in aquatic systems from runoff of agriculture - soil, fertilizer & animal waste now seen in terrestrial systems Increased NPP Reduced biodiversity Algal blooms Increased decomposition => reduced O 2 Anaerobic - Fish kills, methane production Human Impacts 3b 8-19/9-21 Global impacts

41. Climate Change Elevated CO 2, Methane and Nitrous Oxide from fossil fuel burning and other sources add greenhouse gases This can change patterns of weather and increase average global temperature Human Impacts 3c 12-8/12-19

42. 1979 2003 Ice in polar regions and at high altitudes declining - reduces reflection - rise of sea level Human Impacts 3c Global impacts

43. 20,000 YA 17 ft (5m) W. Antarctic sheet 170 ft (50m) E. Antarctic sheet NOAA Human Impacts 3c Global impacts

44. Snows of Kilamanjaro may be gone in 15 years Human Impacts 3c Global impacts

45. Major impact – species are adapted to prevailing levels of resources, NPP and climate. Changes in these levels - fundamentally alter the relative fitness of species - the range of essentially every species is predicted to shift. But can they move? Human Impacts 3b,c Global impacts

46. Consequences of human impacts – environmental “problems” Check out the “Millennium Ecosystem Assessment” http://www.millenniumassessment.org/en/index.aspx

47. Loss of Biodiversity - major consequence of many human impacts Extinction is fast & forever Many species threatened Biodiversity is a kind of knowledge, a “library” What will you tell your grandchildren if we let the gorilla go extinct? Speciation takes a while 5-6/7-6

48. We’ve gotten this far by learning to cooperate How much farther can we go?

49. What is your vision of Utopia?

50. The End End