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Global Biodiversity

Global Biodiversity. Global Biodiversity Patterns and Processes. Global Biodiversity Patterns and Processes. What is Biodiversity? Biological diversity is the sum of all living things It can be considered at many levels (e.g. genetic, regional, evolutionary lineage, number of ecosystems)

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Global Biodiversity

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  1. Global Biodiversity

  2. Global BiodiversityPatterns and Processes

  3. Global BiodiversityPatterns and Processes • What is Biodiversity? • Biological diversity is the sum of all living things • It can be considered at many levels (e.g. genetic, regional, evolutionary lineage, number of ecosystems) • Hierarchical perspective: genes, pop(s), species, communities, ecosystems, landscapes

  4. Global BiodiversityPatterns and Processes • Genetic Diversity • Genetic diversity is the ultimate source of biodiversity at all levels • Recent advancements now allow us to measure (and quantify) genetic diversity • Important in establishing breeding programs • May allow species to broaden tolerances

  5. Global BiodiversityPatterns and Processes • Genetic Diversity • Consider the use of genes in crops and livestock…can be either incorporating genes or just preserving existing breadth • Consider Bt cotton: Bacillus thuringiensis (Bt) is a spore forming bacterium that produces crystals proteins, which are toxic to many species of insects.

  6. Global BiodiversityPatterns and Processes

  7. Global BiodiversityPatterns and Processes • There are trade-offs

  8. Global BiodiversityPatterns and Processes • Population-level Diversity • The variation within members of a species or population is extremely important (represents evolutionary history and is the source of potential future adaptations) • Also provides a great deal of information about the amount and rate of gene flow between and among populations (more later)

  9. Global BiodiversityPatterns and Processes • It is the local populations where environmental challenges occur and genetic diversity is maintained • Consider a species/population of corn that evolved in soil with high mineral (e.g. metals or salt) levels • That population maybe become an invaluable crop species in some locations

  10. Global BiodiversityPatterns and Processes • Guppies in Trinidad streams have evolved without fish predators • Consequently, they have very different life-history characteristics than species/populations exposed to predators • If a reintroduction or population supplementation is needed, knowledge of genetics and plasticity important

  11. Global BiodiversityPatterns and Processes • Populations may also serve a functional role, which may be independent of other populations • E.g. pollinators

  12. Global BiodiversityPatterns and Processes • Human Cultural Diversity • Consider human cultural diversity and the reservoir of knowledge, skills, and traditions throughout the world • E.g. 6,526 distinct languages

  13. Global BiodiversityPatterns and Processes

  14. Global BiodiversityPatterns and Processes • Non-random distribution of habitats

  15. Global BiodiversityPatterns and Processes • Diversity of Species • Despite many references to ‘biodiversity’ and others at the species level (e.g. ESA, CITES) it is the populations that are as or more important (but not as easily comprehended by the public or politicians)

  16. Global BiodiversityPatterns and Processes • What is the difference between a species and population? • Can be somewhat difficult to determine if they are one species or two… • Why? • Problems: fossils, asexual organisms, lack of knowledge It is really a gradient

  17. Global BiodiversityPatterns and Processes • For many ‘bioinventories” or rapid assements, may use concept of ‘morphospecies’ • As species (and populations) evolve, they continue to accumulate genetic differences • To determine relatedness among these species (or pop(s)), biologists attempt to reconstruct phylogenies (more later)

  18. Global BiodiversityPatterns and Processes • Biological classification system based upon the idea of hierarchical organization and relatedness • King Phillip Came Over For Golf Saturday • Should always be a bifurcating tree

  19. Global BiodiversityPatterns and Processes

  20. Global BiodiversityPatterns and Processes • How many species are there? • Approximately 1.75M named with another 300K fossil sp • On average, 300 sp named each day • Two new phyla have been named in past 25 yrs • Range is 10M-50M

  21. Global BiodiversityPatterns and Processes

  22. Global BiodiversityPatterns and Processes • For starters, the immense richness of viruses, bacteria, archaea (singled-cell organisms in extreme environs), protists and other unicellular organisms • Only 80,000 fungi described • In Britain, 6x fungi vs. vascular plants • Extrapolate worldwide, 1.6M fungi • Nematodes >200 sp in a few cm3

  23. Global BiodiversityPatterns and Processes • Mites: 30,000 sp described (but probably >1M) • Insects: almost 1M described, but consider canopy fogging • 4 sites <70km proximity, 1% common 55%

  24. Global BiodiversityPatterns and Processes • Diversity of higher taxa • Until recently, 5 kingdoms recognized Plantae Animalia Fungi Monera (bacteria) Protista

  25. Global BiodiversityPatterns and Processes • Today, there is a recognized division among the prokaryotes and we have the Archaea and Bacteria • Genetic diversity is as great as that across Eukaryotes • Many new kingdoms ascribed to Archaea, Bacteria, and Protists • Why care?

  26. Global BiodiversityPatterns and Processes • They evolutionary lineage of each species is important for several reasons • 1) evolutionary potential relies on the diversity of life (many differences, albeit small) • 2) lineages are storehouses of info on the history of life • 3)functioning ecosystems depend upon the variety of life • 4) aesthetic benefits correlated with diversity

  27. Global BiodiversityPatterns and Processes • Diversity of biological communities • The composition of communities changes over time and space • Membership within a community is probabilistic • 3 common metrics • Sp richness, evenness, abundance • Frequently compare metrics across habitats or sites (or genes) • Could also use weighted measures…

  28. Global BiodiversityPatterns and Processes • Are there limitations to using a metric like diversity? • Species identity…lose valuable information on functional role, exotic vs. native, life-history characteristics • Biological communities are of conservation interest because the relative abundances, combinations, +/- can all provide valuable information

  29. Global BiodiversityPatterns and Processes • Ecosystem and Biome Diversity • Typically terrestrial systems typically classified by shape and life-forms of the plants that dominate them • Holdridge’s widely used life zone system is entirely based upon climatic variables • Although communities grade into one another, major divisions are useful for analyses and descriptions

  30. Global BiodiversityPatterns and Processes

  31. Global BiodiversityPatterns and Processes

  32. Global BiodiversityPatterns and Processes

  33. Global BiodiversityPatterns and Processes • Things also change at relatively large scales based upon: latitude, altitude, and precipitation gradients • At a finer scale, things change with soil type, slope, and species composition • Recently the WWF reclassified the Earth’s biomes into 867 terrestrial biomes (thought to represent distinct assemblages)

  34. Global BiodiversityPatterns and Processes • Ecosystem approach • Managing at the ecosystem allows for common goals across multiple owners and allows for ‘large scale’ planning that is likely appropriate for even relatively large organisms

  35. Global BiodiversityPatterns and Processes • Species Richness over Geologic Time • The number of species at any given moment represents the balance between extinction and speciation rates • That number will vary according to the frequency and intensity of extinction and/or speciation events

  36. Global BiodiversityPatterns and Processes • The fossil record shows a rough estimate of trends in species richness during the history of life on Earth • Cellular life began about 3.8 bya (bacteria) and eukaryotics probably about 2 bya • Things were relatively quiet until the ‘Cambrian explosion’

  37. Global BiodiversityPatterns and Processes • Fig 2.5 Diversity of marine families from Cambrian to present

  38. Global BiodiversityPatterns and Processes • Terrestrial plant appeared early in the Silurian and their richness increased rapidly during the Devonian • Then during the Cretaceous, another important event occurred, the appearance of ‘angiosperms’ • Had ‘cascading effects’

  39. Global BiodiversityPatterns and Processes • Fig 2.6 • Each group, ferns, gymnosperms and angiosperms, have all dominated at one time

  40. Global BiodiversityPatterns and Processes

  41. Global BiodiversityPatterns and Processes

  42. Global BiodiversityPatterns and Processes • Rates of species formation • Speciation rates are not consistent • When do you think it accelerates?

  43. Global BiodiversityPatterns and Processes • Rates of species formation • The first was the Cambrian (500mya) • Second Paleozoic (440mya) • The third set diversity way back in Permian (250mya), followed by Triassic explosion

  44. Global BiodiversityPatterns and Processes • Cambrian: all major groups of living organisms appeared during this time (and some that did not make it) • Paleozoic and Triassic greatly increased families, genera and species, but no new phyla emerged

  45. Global BiodiversityPatterns and Processes • Factors impacting rates of speciation • Any guesses? • Mass extinctions • Increasing separation of landmasses • New species and species interactions

  46. Global BiodiversityPatterns and Processes • Diversity explosions throughout the ages

  47. Break-up of Pangea in Laurasia ad Gondwanaland followed by more isolation

  48. Global BiodiversityPatterns and Processes

  49. Global BiodiversityPatterns and Processes • Rates of Extinction • Similarly, rates vary throughout time • 6 major events 60% 75% 95% 65% 75% **

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