Conservation Biology Exam #2

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Conservation Biology Exam #2
2011-10-13 12:31:56
Conservation Biology Exam

Conservation Biology Exam # 2
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  1. How do we assess global diversity? What is the ultimate source of biodiversity?
    • Changes or mutations (alternations)in the genetic code (DNA/RNA)
    • In both coding and non-coding regions
    • Accumulation of mutations of non-coding regions also tells us the evolutionary relationship of organisms
  2. What are the 3-levels that we measure genetic variations within a species?
    • 1.) At an individual level (some individuals in a population maybe fixed for two dominate alleles that have no variation at the gene locus)
    • 2.) Within population variations (One individual might have a genotype of AA, but there might be several individuals within the population with a little "a" allele
    • 3.) Between population variations (Different populations become adapted locally and have genetic divergence)
  3. Why is variation important in populations?
    Populations that tend to be more genetically diverse, on average, are considered to be a healthier population
  4. Coding regions
  5. Non-coding regions
  6. Heterosis (Heterozygous advantage or hybrid vigor)
    Heterozygous offspring have a higher survival and fitness compared to homozygous parents
  7. Fitness (biological fitness)
    relative reproductive output of an individual in a population compared to everyone else
  8. In conservation programs, biodiversity and heterosis suggests:
    that we try to maintain or maximize genetic diversity within a population and with individuals
  9. Why is DNA a more sensitive tool compared to using proteins?
    • DNA codes for the same amino acids
    • DNA is a more sensitive tool because a lot of silent mutations don't affect proteins that are produced from the genetic code or sequence
    • Change in genetic sequence which increases the genetic variation at the DNA level, but wouldn't result in an increase variation at the protein level
  10. When a population get bigger in size, What happens to the amount of heterzygousity or genetic variation in a population?
    It increases
  11. Rates of genetic variation
    • Tends to increase with bigger population size, but at different rate for different organisms
    • Some taxa evolve at different rates than other taxa
  12. Correlation Co-efficient (r)
    tells the strength of a linear relationship
  13. If two variables are plotted
    X= population size
    If X increases and Y increases, what is the range of (r)
    • r= 0 to +1 (positive correlation)
    • 0 means no correlation and +1 means perfect correclation
  14. If two variables are plotted
    X=population size
    If X increases and Y decreases, what is the range for (r)
    • r= -1 to +1
    • +1 means all the points fall in a perfect straight line on a positive slope
    • -1 means all the points fall in a perfect straight line on a negative slope
  15. What % of the relationship of y is explained by the variation of x?
    (If the co-efficient is squared and multiplied by 100, it turns it into a %)
    • Example: r= .94
    • (.94)2(100) = 88%
    • **12% is something else than population size
  16. Cheetahs are an exception to the rule
    • Cheetahs are highly inbreed
    • Very little genetic diversity between individuals (inbreeding and inbreeding depression can occur)
    • Have a high infant mortality rate (doesn't matter if inbred or outbred)
    • Genetically weak species
    • Probably went through a genetic bottleneck at some point in their history
  17. Inbreeding
    mating between close relatives
  18. Inbreeding depression
    loss in vigor and fitness due to an increase in homozygousity
  19. Organisms that are highly inbred do not have a lot of genetic variation because they have a very limited gene pool
  20. Why does inbreeding depression occur when close relatives reproduce?
    • Heterosis = less genetic variation (reduces survival and fitness)
    • Genetic mutations (higher in our family line than in the general public)
    • Recessive alleles as pairs
  21. What causes populations to vary genetically?
    • 1.) Natural selection (some genotypes/phenotypes are favored in some environments over other enviroments; different selective pressures)
    • Example of frog: webbing on feet
    • 2.) Neutral evolution mechanisms
    • (genetic drift, founder's effect, and bottlenecks)
    • Only effects neutral alleles, which does not directly affect the survival or fitness of an organism
    • Genetic drift is usually for in small populations
  22. Neutral alleles
    are alleles that do not directly affect the survival or fitness of an organism
  23. What two factors do modern biologists believe drive the evolution of populations?
    Natural selection and neutral evolution mechanisms
  24. Genetic drift
    random loss/fixation of alleles in populations (has nothing to do with selective advantages)
  25. What are some possible explainations of why two populations would not be genetically divergent from one another?
    • Gene flow (1st answer you should think of)
    • Same environment (where the same genotypes/phenotypes are favored)
    • Separated recently (suggests that the two populations were recently separated and have not had the time to accumulate genetic differences)
  26. How do we assess biodiversity of a community or habitat?
    • Simplest measure is species richness (S)
    • ** it is not a very useful metric because it does not utilize/report the relative abundance of individuals in each species
  27. Species richness (S)
    # of species trait that occur in a given community, habitat, or ecosystem
  28. How do we measure abundance?
    • 1.) Count individuals and convert our counts into proportions
    • Example: 90 out of 100= .9
    • 2.) Use fractional amount of area that each species covers or occupies
    • Proportion of area covered by the species (like plants)
    • Example: Plant "A" occupied 50% of the area covered = .5
  29. Better measures for biodiversity
    Diversity indices take into account the relative abundance of each species besides just counting to see if one species is available/present or not
  30. 2-types of diversity indices
    • 1.) Dominance indices
    • Example: Simpson's dominant index
    • 2.) Indices for sensitive to rare species
    • Example: Shannon index
  31. Dominance indices
    • They give much more influence to the index to common (= dominant) species
    • Good when you have a lot of dominant individuals in a community
  32. Simpson's dominant index
    • delta with subscript S = the sum of 1/pi squared
    • where pi is the proportion of individual species i
  33. Indices for sensitive to rare species
    • Good for conservation programs because we are dealing with rare species
    • Gives some influence to rare species when you calculate the index
  34. Shannon Index
    H'=-sum of (pi(lnpi))
  35. Indicator species
    usually animals or plants; organisms that are used as a surrogate to assess the conditions (health) of an ecosystem
  36. How do you chose an indicator species?
    • Depends on the environment
    • Examples:
    • 1.) Amphibians (frogs and salamanders) = fresh water habitat
    • They are tied to water for cutaneous respiration and reproduction
    • 2.) Lichens (obligate mutualism between fungus and algae) = air quality
    • 3.) Spotted owl = old growth forests
    • (they are monitored because they are endangered and because they are used as indicator species)
  37. 2- ways to use indicator species
    • 1.) Use endemic species and monitor for changes in their distribution and abundance (also health)
    • Looking for population declines
    • 2.) Use invasive species as an indicator of environmental change
    • Do not naturally occur in they community, but have showed up in the community due to enviromental changes
  38. Endemic species
    species found in a community naturally and nowhere else
  39. Invasive species
    species that are not naturally occuring in a community
  40. Halophytes
    organisms that like to live in salty conditions
  41. Problems with indicator species
    • 1.) Don't know the effect of the indicator species on the other organisms in ecosystem
    • 2.) Extrapolation to other species may be invalid because each has its own requirements
    • 3.) Invalid monitoring schedule (don't follow the species long enough)
    • 4.) Biased choice of indicator species; often verts and relatively large (Higher in trophic levels and are not sensitive to early changes in the environment)
  42. Keystone species
    • European Honeybees
    • Gopher tortoises
    • African elephants
    • Sea otters
  43. 50/500 rule (maintain population)
    • n= 50 (prevent inbreeding depression)
    • n= 500 (prevent genetic drift)

    • Less than 50= populations are endanger of both inbreeding depression and genetic drift
    • Less than 500= population protected from inbreeding depression, but loose alleles due to genetic drift
  44. Problems when establishing a conservation reserve
    • 1.) Species list (gives a list, but not the abundance)
    • 2.) Do not know the species diversity
    • 3.) Many organisms live in ecosystems with poorly defined boundaries (How do we know where to set-up boundaries)
  45. Biome
    • Large-scale community that can be indentified based on the dominant vegetational types
    • Plants are important and define a biome and what kind of biome in a given area
  46. 2- most important factors that determine a biome
    • 1.) annual average temp
    • 2.) annual average ppt

    • Temp in. and ppt de. = desert
    • Temp de. and ppt de. = tundra (cold des.)
    • Temp. in. and ppt in. = t.r.f
    • Temp intermed. and ppt in. = temp. rainforest
  47. Biodiversity
    • 1.5 to 2.0 million extant species been described by science
    • 300,000 extinct species
    • Estimated 10 to 50 extant species
  48. Why are estimates so variable?
    • Depends on species concept used
    • Biased; based on species that affect humans
    • Tend to describe larger species
  49. Some groups underrepresented
    • bacteria
    • viruses
    • fungi
  50. 1975 Strong and Levin
    • Fungal species went from 80,000 to 1.5 million species
    • Stated that there are 6 unique fungal species per plant species (6X 250,000)
  51. Earth 4.2 to 4.5 billion years old
    1st 100 million years too hot to support life
  52. Oldest fossils approx. 3.8 to 4.0 billion years old
    • Prokaryotes
    • No membrane bound organelles
    • Non-membrane bound nucleus
    • DNA floats around freely in the nucleod
    • Few organelles (mitochondria)
  53. Organisms in higher cells that were swallowed up that were free-living
    • Mitochondria
    • Cholorplasts
    • Centrials
  54. Evidence for free-living organisms
    • Double membrane
    • Own DNA
    • The divide independently of nucleus
  55. Endosymbiotic theory
    some of our complex eur. cells which have organelles became part of cell because larger cells swallowed up and did not digest.... reached an agreement
  56. Riapaian
    a long banks of fresh flowing water