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					Topic 5: On the
   wild side
   Biodiversity
Prep
 Snab website. Topic resources topic 5
  topic introduction.
 Plus read pp 2-3



   Video: Life on Earth 1
Biodiversity
 Abbreviation for BIOLOGICAL DIVERSITY

 What is BIODIVERSITY?

 http://flood.nhm.ac.uk/eb/homepage.shtml
 http://www.beep.ac.uk/content/174.0.html

 As you can see, there is no one specific
  definition! But all the definitions have
  three major components
Biodiversity has 3
components

  Species diversity

  this refers to
  the number of different species
  (the more species present the greater the
   diversity)
 Genetic diversity

 this refers to the genetic variation
  between members of a species
 Ecosystem diversity

 this refers to the variety of different
  habitats in an ecosystem:
 the more different habitats there are the
  greater the species diversity
 The principal working definition to use is:


 Biodiversity is the number
   and variety of species.
How much biodiversity is
there?
    See Fig 5.5 on p4




Total number of species = 1.66 million
How much biodiversity is
there?
 See Fig 5.5 on p4

 What is the estimate of the total number of species?

 1.66 million
 Approximately how many more animals (Kingdom Animalia) are there than plants?

 963000 + 270000/270000 = x 4.6
 What is the proportion of insects in relation to the estimated number of all organisms
   currently known?

 963000/1660000 = 0.58
 (i.e. more than half of all the organisms known are insects! Or, there
     are more insects than there are all the other types of organisms
     put together!)
It is thought that these figures are probably a serious
    underestimate (estimate of the total number of species
    vary from 5 – 30 million. Why?

 Differences between some species may be very subtle
  and very similar species may be classified together as
  just one

 Not all organisms have been found yet – many parts of
  the biosphere are still inaccessible e.g. the deep oceans,
  tropical rainforests (especially the tree canopy)

 Tiny inconspicuous organisms are difficult to study, e.g.
  fungi, bacteria, protoctists, so fewer people are likely to
  research them in detail
Where do the estimates of
species numbers come from?
 Read the ‘Did you know’ box on page 7.

 Answer qu 5.2.

 Suggest why these two methods of estimating species
  number may not give accurate values for total species
  numbers?
 The assumptions made may be incorrect:
    The ratio of butterfly species to total insect species may vary
     widely in different parts of the world
    Each tree species may not be host to the same number of
     species, e.g. 284 species of insect are found on oak trees but
     only 64 on beech trees)
Activity 5.4

  Qu 1. Why an ‘unrecorded species’?
  A species that has not previously been named
   and formerly described
  Qu 2. How many beetle species?
  450 000 named; all have the characteristics
   that distinguish them from other species
  Qu 3. % of estimated beetle species
   described so far?
  450000/1000000 = 45%
 Qu 4. Characteristics of all beetles?
 Exoskeleton, biting mandibles, six legs,
  hard wing covers, 4 distinct life stages
 Qu 5. How many scientific names?
 One, in two parts. e.g. Blaps gigantean.
  Pogonus rodolphi
 Qu 6. Who devised naming system?
 Carolus Linnaeus (Carl von Linne);
  Swedish; 1758
 Qu 7. What are holotypes?
 The original specimens that were used to
  describe the species and against which other
  potential members of the same species are
  compared.
 Qu 8. Why is naming a constraint on
  cataloguing biodiversity?
 Detailed drawings/observations needed; also
  need to ensure nobody else has already
  identified and named the organism; time-
  consuming.
So, what is a species?
  A species is a group similar of organisms,
  with similar morphology, physiology and behaviour
  which can interbreed to produce fertile
   offspring
  and are reproductively isolated (in place, time or
   behaviour) from other species


  Learn this!
  Use the words highlighted in red as a working
   definition.
  See Key biological principle on page 5
Q5.1
Decide whether the groups are the same species
or different species

   A. Gp A has 98% of its genes (i.e. genetic
    material) in common with gp B.
   Different species.
   2% is a lot of difference (humans and chimps
    differ by 1.4%!)
   B. Gp C can interbreed with group A to
    produce fertile offspring (i.e.. which can
    produce offspring themselves)
   Same species
   – produce fertile offspring
 C. Gp D physically v similar to gp B but
  different colour. Matings between B and D
  produce offspring of intermediate colour but
  male offspring are sterile
 B and D are closely related (i.e. can breed) but
  distinct species
 since male offspring infertile.
 D. Gp E looks very similar to group F but has
  darker feathers. Genetic fingerprints of gps E
  and F are identical.
 Same species
 – no genetic difference (so share a common
  gene pool)
So, how good is the
definition?
  How do tigons, ligers, mules, zeedonks,
   wholphins and cama fit in with the
   species definition?

  Do your own research to find out what
   these animals are and how they fit in with
   the species concept.
Species concept/ligers &
tigons
  http://www.pbs.org/wgbh/evolution/library
   /05/2/l_052_02.html
So what about mules?
  Mules are hybrids of horses and donkeys;




Mules share features in common with both parents but also look
different, but they are not a separate species
 They are infertile i.e. cannot produce offspring
  themselves.
 Reason:
 the chromosomes don’t work
 Horses have 64 chromosomes, donkeys have
  62
 so the mule has 63 chromosomes
 (i.e. 31.5 pairs so chromosome pairing cannot
  happen in gamete formation by meiosis)
zeedonks
  Hybrid between a zebra (44 chromosomes) and a
   donkey (62 chromosomes)
When a female Lion
and a male Tiger have            When a female Tiger and a
a cub it is called a              male Lion have a cub it is
Tigon (smaller than               called a Liger (larger than
Lions and Tigers)                         Lions and Tigers).




                        tigons      liger
                                       Mother - Liger.




The Ti-Liger is a compound hybrid
and is the result of breeding a male
  Tiger to a female Liger (hybrid).



                                           Father - tiger
             Naming organisms
Each species has its own individual and unique
name which is internationally recognised.

All organisms have common names, but they
can vary in different parts of a country or the
world e.g. hedge sparrow and dunnock are
actually the same species.

To get round this all organisms have a specific
biological name which all scientists use to
avoid confusion; they are named using a
universal scientific system known as the
Binomial system, i.e. the name consists of two
parts.
                       Example
           Greater horseshoe bat = common name

 Rhinolophus ferrumequinum

Genus name           Species name
(shared by closely         Specific
related species)       Lower case
Capital letter

   Written in italics in print
 Underlined when hand-written
              i.e.
 Rhinolophus ferrumequinum
 Lesser horseshoe bat
Rhinolophus hipposideros




 Same genus name but different species name
      Willow tit
                    Very similar but slightly different!
   Parus montanus

                               Marsh tit
                            Parus palustris




 Great tit
Parus major
      Gorilla         Chimpanzee
                     Pan troglodytes
   Gorilla gorilla




   Clearly           Dr Anthony Seldon;
different, so              human
  different            Homo sapiens
   names
                       Qu 5.3 p9

 Common name                 Scientific name

 Creeping buttercup          Ranunculus repens
 Meadowsweet                 Filpendula ulmaria
 Lady’s mantle               Alchemilla vulgaris
 Dropwort                    Filipendula vulgaris
a: State to which genus creeping buttercup belongs
Ranunculus

b: Decide whether meadowsweet and dropwort or lady’s
mantle and dropwort are more closely related; why?
Meadowsweet and dropwort more closely related; same
genus name
Biological classification.
Why are organisms classified?
        To produce a universal 'filing system' to put groups
    of similar organisms together (like a library classification
    system); if a new organism is discovered it may be
    possible to fit it into an existing group, in which case a lot
    can be predicted about it, or it may require the
    generation of a new group if it does not fit. Allows us to
    catalogue biodiversity (i.e. recognise and count the
    numbers of different species)

       To construct groups about which generalisations can
    be made, e.g. all bats fly, are viviparous etc.

      To allow predictions to be made about individual
    members of a group, e.g. if a particular plant produces
    medicinal chemicals it is likely that other members of the
    same group will also do so.
How are organisms classified?
 Natural Classification.

   Classification puts organisms into groups (or sets) where all the
    members of one group resemble each other (share more common
    features) more than they do members of other groups.

   Organisms are grouped together to reflect evolutionary relationships
    because they share common ancestors. So all the organisms in one
    group are more closely related to each other than to members of other
    groups.

   Groups/sub-groups formed by consideration of homologous anatomical and
    morphological structures (structures based on a common pattern,
    genetically determined, little affected by effect of environment) e.g. the
    vertebrates all have a common pattern of bones in their limbs suggesting
    that they are all derived from a common ancestor.

   Analogous structures (structures with the same function but different
    origins) which do not reflect evolutionary relationships are of no use in a
    natural classification, e.g. wings.
The Classification system
 Groups of different sizes can be generated, depending on the number
 and refinement of the common characteristics used to produce a
 taxonomic hierarchy.

 largest group   Kingdom fewest criteria, fewest groups     Animalia
                  Phylum                                    Chordata
                   Class                                    Mammalia
                   Order                                    Primate
                   Family                                   Hominidae
                   Genus                                    Homo
smallest group Species most criteria most groups            Homo sapiens
                      *                                     Human being
                          Each level is called a taxon
         i.e. a group of organisms showing the same basic features
                    Hence classification is called taxonomy

                   *Mnemonic to remember this:
             King Prawn Curry Order For Gassy Smiles
See pp 9 - 12
           Look at Fig 5.12A
    Determine whether the common
       characteristic features for
       butterfly fish of the genus
         Chaetodon are valid.
           Look at Fig 5.13.
What features do the bannerfish have in
      common with butterfly fish?

    Thin body, small mouth at end of
 extended snout, dark band across eye.

     What distinctive features do the
bannerfish of the genus Heniochus seem
  to have in common (which sets them
        apart from butterfly fish)?
  Long extended part to their dorsal fin
Classification of butterfly fish
                           all heterotrophic, no cell
                           walls, motile, nervous
                           system

                          all have dorsal spinal cord


                          all fish with bony skeletons


                          all have thoracic pelvic gills


                         all have thin body, small mouth at
                         end of
                         extended snout, dark band across
                         eye
Biological identification

  To be able to estimate biodiversity we need to
   be able to recognise and name individual
   species accurately.
  One way of doing this is to use a branching or
   dichotomous key.
  This uses pairs of particular characteristic
   features in a step-wise sequence which
   ultimately leads to the name of the particular
   species.
Dichotomous key to identify butterfly fish
of genus Chaetodon.
                         Identify the fish
                            in Fig 5.11




                           Chaetodon auriga
Why might identification
keys not work?
 Particular features required in the key may
   be absent because:
  damage to specimen
  wrong stage of development (e.g. very
   young)
  previously unknown species
Computerised
Identification Keys
 http://www-
  saps.plantsci.cam.ac.uk/trees/index.htm

 http://web.aces.uiuc.edu/weedid/
Advantages

  Easy to use
  Can start at a variety of access
   points
  Easily updated
  Can include diagrams, photos,
   glossaries
  Accessible via Internet
Disadvantages

  Needs computer facilities which are
   not always available e.g. in field
  Limited by species used to construct
   the key; rare species may omitted.
Biodiversity
The Five Kingdoms
  See Biodiversity 5 Kingdoms ppt
How is diversity
measured?
     Extension work
Example of the problem
[Table 5.2 p15]
   Number of species      Site 1                 Site 2
   Plants                 80                     50
   Beetles                20                     0
   Other insects          0                      20
   Birds                  0                      15
   Spiders                0                      5
   Molluscs               0                      5
   Mammals                0                      5
   TOTAL NUMBER           100                    100

Both sites contain 100 species. But which has the higher
biodiversity?
Site 2? Wider range of different taxonomic groups?
But how could we quantify this?
How is diversity
measured?
 Diversity is the variety of different
   species present in a community in a
   particular habitat.
 In a community the diversity of organisms
   depends on
  the number of different species present
  the number of organisms of each species
   present
  the total number of organisms
 Species richness is a measure of the
  number of species in a community in a
  particular habitat but it provides no
  information about how many organisms
  there are.
 Species diversity reflects not only how
  many species are present but also the
  abundance (i.e. how many) of each of
  those species present.
To illustrate:
 A field of wheat is a community with several
  species in it (e.g. wheat plus a few weeds) but
  is dominated by only one (the wheat), in which
  case it is said to have a
 low species diversity
 However a tropical rainforest is a community
  with significant numbers of many different
  species in it so it has a
 high species diversity.
Diversity can be quantified by using the Simpson’s Diversity Index.

                                    N(N – 1)

           Index of diversity D =   _______

                                    S n(n-1)

      N = total number of organisms of all species present
      n = total number of organisms of each individual species
      S = sum of …
        Example
        The table below shows the number of dolphins of different species
        seen during a two-hour boat trip in the Atlantic Ocean off the Azores.
            Species                                   Number
            Common dolphin                            28
            Risso’s dolphin                           17
            Striped dolphin                           4
            Bottlenose dolphin                        12
Calculation of the Index of Diversity
             Species                    n         (n - 1    n(n – 1)
             Common dolphin             28        27        756
             Risso’s dolphin            17        16        272
             Striped dolphin            4         3         12
             Bottlenose dolphin         12        11        132
             Totals                     N = 61              S n(n-1)
                                                            = 1172
                D = N (N – 1)/S n(n – 1) = 61 x 60/1172 = 3.12.
 Use the data you obtained from the pond
  study to calculate the diversity index for
  Swan Lake. [NB: Ignore the data for the
  planktonic crustacea]




 (Word. Pond data sheet 2)
On its own the index of diversity tells us very little.

  However it is useful because it allows
comparisons to be made:

•between different communities e.g. the diversity
index for the dolphins in the waters off the Azores
or in the Bahamas is much higher than it would be
in the English Channel.

•within the same community at different times e.g.
the diversity index for the plants in the field layer in
a beechwood is higher in spring than it is in
summer.
Exploring biodiversity

 http://flood.nhm.ac.uk/eb/hotspots.shtml

 Extension 5.1. Part 1.
World biodiversity

  http://www.unep-wcmc.org/

				
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