Origins of Life and Sustaining Biodiversity

1. Origins of Life and Sustaining Biodiversity Chapters 8, 9 , and 4

2. Origins of life

3. Origins of Life • Chemical evolution (1 billion yrs): formation of organic molecules and cells • Biological evolution (3.7 billion years): evolve from cells to present diversity Considerable evidence suggests that life developed in 2 phases over the past 4.6-4.7 billion years.

4. Origins of Life • Chemical evolution • Biological evolution

5. Macroevolution vs Microevolution • Microevolution • Change in a populations gene pool over time • Selective Pressures exerted on population and individuals selected (do better under new pressures) and evolve polulation Macroevolution:long-term, large-scale evolutionary changes by which new species arise (speciation) from ancestral species & others are lost to extinction

6. Selective Pressures: A factor Affecting population growth. Acts on phenotype affecting genotype = Natural Selection • Directional Selection: Individual at one end of spectrum become more common. Become ‘new average’ • Stabilizing Selection: • Selects norm- • extremes eliminated

7. Disruptive Selection • Both extremes are selected – eliminating the norm! (Pays to be different!) • Adaptive Trait: a selected trait that enables an organism to survive through natural selection and reproduce better

8. Question #2:How does the formation of new species (speciation) and extinction of species affect biodiversity? Explain the mechanism of speciation and how this increases biodiversity.

9. Mechanism of Speciation • Geographic Isolation • 2 groups from same species become physically separated for long time period • Reproductive Isolation • Mutation & natural selection act on separated populations • Each group adapts to different environmental conditions • Over time, leads to formation of 2 new species Causing divergent evolution.

10. Geographic Isolation can Lead to Speciation Adapted to cold through heavier fur, short ears, short legs, short nose. White fur matches snow for camouflage. Arctic Fox Northern population Spreads northward and southward and separates Early fox population Different environmental conditions lead to different selective pressures and evolution into two different species. Gray Fox Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Southern population Fig. 4-7, p. 71

11. Question #3:Define ecological niche. Distinguish between fundamental niche and realized niche. List the factors that determine the realized niche.

12. Ecological Niches and Adaptation • Ecological Niche :Occupation Problem: Niches Overlap creating inter and intraspecific competition Fundamental Niche Realized Niche

13. Niche Fundamental Full potential range of physical, chemical, and biological conditions and resources an organism could theoretically use if there was no competition with other species. Realized In order for an organism to survive and avoid competition for resources it will use only part of its fundamental niche – this is the realized niche.

14. Which area is fundamental and which is realized?

15. Generalist Species (r-selected) • Broad Niches • can live in many places • can eat a variety of foods • can tolerate a wide range of environmental conditions

16. Specialist Species • Occupy narrow niches (may only have 1 possible habitat) • use few food types • can only tolerate a narrow range of environmental conditions • prone to extinction when environment changes • reduces competition & allows for sharing of limited resources

17. Specialized Feeding Niches for Birds If resources are limited, natural selection favors specialized adaptations on species, Herring gull is a tireless scavenger Brown pelican dives for fish, which it locates from the air Black skimmer seizes small fish at water surface Ruddy turnstone searches under shells and pebbles for small invertebrates Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation Knot (a sandpiper) picks up worms and small crustaceans left by receding tide Flamingo feeds on minute organisms in mud Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Piping plover feeds on insects and tiny crustaceans on sandy beaches Louisiana heron wades into water to seize small fish reducing competition by resource partitioning.

18. Summary of Broad and Narrow Niches • Generalist species • Better able to survive rapidly changing environmental conditions • Specialist species • Benefit under constant environmental conditions (reduces competition)

19. Niches of Specialist and Generalist Species Specialist species with a narrow niche Generalist species with a broad niche Niche separation Number of individuals Niche breadth Region of niche overlap Resource use Fig. 4-4, p. 68

20. Limits on Adaptations • A population’s ability to adapt is limited by it’s gene pool & the speed with which it can reproduce • Natural selection can only work on currently existing traits…. (beneficial adaptations are rare) • Rapid reproducers are able to adapt much more quickly to changes in environment

21. Sustaining Biodiversity

22. Sustaining Biodiversity

23. The Species Approach The Ecosystem Approach Goal Goal Protect populations of species in their natural habitats Protect species from premature extinction Strategy Strategy Preserve sufficient areas of habitats in different biomes and aquatic systems • Identify endangered species • Protect their critical habitats Tactics Tactics • Protect habitat areas through private purchase or government action • Eliminate or reduce populations of nonnative species from protected areas • Manage protected areas to sustain native species • Restore degraded ecosystems • Legally protect endangered species • Manage habitat • Propagate endangered species in captivity • Reintroduce species into suitable habitats Two Approaches to sustaining biodiversity Stepped Art Fig. 8-3, p. 156

24. The Species Approach can be supported at home by Reconciliation Ecology Affords wildlife refuge/compatible Protect areas/neighborhood contests Xeric Landscaping: fits climate Gene banks Gardens/share with nature Zoos/aquariums (limitations) Diversify Yard Plants Biologically diverse campuses, golf courses,cemetaries

25. The Species Approach can be supported at home by Reconciliation Ecology Reduce Invasive species:establish laws, thoroughly inspect imports, know your invasives – reduce native competition

26. INVASIVE SPECIES Prevention is the best way to reduce threats from invasive species, because once they arrive it is almost impossible to slow their spread. Figure 11-13

27. The Ecosystem Approach Support national Parks Support management of public lands Do not buy lumber from Deforested Regions Restore Ecology: Xeric landscaping

28. Types of US Public Lands • Multiple-use lands: National Forest System; Natural Resource Lands • Moderately restricted-use lands: Natural Wildlife Refuges • Restricted-use lands: Natural Park System; Natural Wilderness Preservation System

29. US Federal Public Lands National parks and preserves National forests (and Xs) National wildlife refuges Fig. 8-6b, p. 158

30. Reasons to preserve Biodiversity Extrinsic Value (what isn't intrinsic) The 5th Extinction : rate is increasing Natural Capital Degradation Natures Pharmacy Genetic Loss Recreational Intrinsic: shouldn’t need a reason

31. Reasons to preserve biodiversity Symbiosis Communities Specialized Niche Food Source Nutrient Cycling Biodiverse Hotspots have over 60% of Endemic Species of world and lost nearly 70% of it

32. Biodiversity Hot Spots in the US Top Six Hot Spots 1 Hawaii 2 San Francisco Bay area 3 Southern Appalachians 4 Death Valley 5 Southern California 6 Florida Panhandle 2 4 3 5 6 Concentration of rare species 1 Low Moderate High Fig. 9-17, p. 199

33. 3 Types of Species Extinction Local Extinction:No longer found in an area but is found elsewhere in the world Ecological Extinction:So few are left they can no longer perform their ecological role Biological Extinction:No longer found anywhere on earth

34. Which type of extinction is panda, the wolf,the Dodo?

35. Do you know the difference? • Endangered : so few left could become extinct • Threatened :I s still abundant but declining in numbers and may become endangered

36. May take nature 5 million years to replace the species that may be lost in the 21st century Extinction is accelerated by greenhouse effect, pesticide,herbicide, threats, poaching, invasive species, habitat fragmentation… GONE:

37. What are the root causes of ? Population growth economic policies that do not support the environment high per capita resource use leading to degradation of the environment poverty extinction

38. What are the direct causes of ? Habitat loss and fragmentation Hunting and poaching Overfishing Predator and pest control Capture and sale of exotic plants and animals Climate change and pollution Introduction of nonnative species extinction

39. Characteristics of Extinction-prone Species Characteristic Examples Low reproductive rate (K-strategist) Blue whale, giant panda, rhinoceros Specialized niche Blue whale, giant panda, Everglades kite Narrow distribution Many island species, elephant seal, desert pupfish Bengal tiger, bald eagle, grizzly bear Feeds at high trophic level Fixed migratory patterns Blue whale, whooping crane, sea turtles Rare Many island species, African violet, some orchids Commercially valuable Snow leopard, tiger, elephant, rhinoceros, rare plants and birds California condor, grizzly bear, Florida panther Large territories Fig. 9-4, p. 188

40. Human Impacts on Extinction Rates • Humans have greatly accelerated extinction rates • Conservative estimates of 0.1% to 1% per year. • Due to human population increases • Extinction rates higher in biodiversity “hot spots” • Speciation crisis • Inadequate estimations of extinction rates • Precautionary strategy

41. Human Impacts on Biodiversity Changes in water supply and temperature Deforestation Changes in water supply and temperature Deforestation Water use and pollution and soil nutrient loss Freshwater supply and demand Food supply and demand Water availability Changes in precipitation and temperature Erosion, pollution, and changes in water flow CO2, CH4, N2O emissions Habitat change and fragmentation of habitat Forest product supply and demand Loss and fragmentation of habitat Loss and fragmentation of habitat Climate change CO2 emission Changes in transpiration and albedo Loss and fragmentation of habitat Loss of crop genetic diversity Habitat change Reduced resistance to change Biodiversity loss Fig. 22.2, p. 551

42. Human Impacts on Biodiversity • Human “footprint” • Disturbing the land • Destruction of wetlands • Deforestation • Aquatic biodiversity • Premature extinctions Fig. 8-2, p. 155

43. Causes of Premature Extinction Habitat loss Pollution Overfishing Habitat degradation and fragmentation Commercial hunting and poaching Climate change Sale of exotic pets and decorative plants Introducing nonnative species Predator and pest control Secondary Causes • Population growth • Rising resource use • No environmental • accounting • Poverty Basic Causes Fig. 9-7, p. 190

44. Percentages of Various Types of Organisms Threatened with Extinction by Human Activities 34% (51% offreshwater species) Fish 24% Mammals 20% Reptiles 14% Plants Birds 12% Fig. 9-5, p. 188

45. THE HIPPO: Causes of Premature Extinction • “HIPPO” • Habitat destruction and fragmentation: Reduced Ranges • Invasive (alien) species • Population growth (humans)-Industrialism • Pollution • Overharvesting

46. Extinction Rates Geological Periods Carboniferous Cretaceous Devonian Jurassic Silurian Triassic Tertiary Ordovician Permian Quaternary Cambrian Mass extinctions 800 600 ? 400 200 0 570 505 438 360 286 208 144 65 0 408 245 2 Millions of years ago • Background (natural) rate of extinction • Massextinction • Mass • Depletion Number of families of marine animals Fig. 22.10, p. 558

47. Extinction Types • Background Extinction: Natural rate of extinction • Mass Extinction: Significant rate above background caused by catastrophy. 5 so far during past 500 MY • Mass Depletion: higher than normal but not as high as mass extinction • Humans effect extinction: • speciation - extinction = biodiversity: Premature extinction

49. Solutions: Protecting Wild Species from Depletion and Extinction • Bioinformatics: Data used to promote ecological wellness • International Treaties: CITES • National Laws: Lacey Act of 1900Endangered Species Act • Habitat conservation plans: limits projects that may destroy endangered/threatened • Zoos, botanical gardens, and gene banks

50. Regulations - International CITES - Convention on the International Trade of Endangered Species signed by 169 countries to date prohibits the trade of live specimens or products of 900 species on list