1.1 Biodiversity

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1.1 Biodiversity
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Biodiversity
There are 3 levels of diversity
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Genetic diversity

• The sum of alleles present in a particular
  species represents their genetic diversity
• Genetic diversity allows populations to adapt to
  changing environmental conditions
• This makes the species as a whole more likely to
  survive and/or evolve over time

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Genetic diversity

• Some modern practices, such as growing
  monocultures, put species success at risk because
  it decreases genetic diversity
• This practice makes a species more susceptible to
  disease and pests
• Scientists often look for genes in wild
  populations of the same species to boost immunity
  or resistance and increase genetic diversity in
  genetically uniform crops

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Species Diversity

• The variety and relative abundance (biomass) of
  species in a given area
• Generally ecosystems with lots of species
  diversity are more productive and have a higher
  tolerance for stress and changes than those with
  lower diversity

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Ecosystem Diversity

• A wide range of habitats, a wide variety of
  organisms and the relationships that connect them
  determine how successful an ecosystem will be
• Changes to one part of an ecosystem can vary from
  some effect to a profound effect on the health
  and sustainability of the system as a whole (e.g.
  keystone species)

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Valuing Biodiversity

• Biodiversity provides ecosystem services that
  benefits all organisms including humans
• Medicines, agriculture, decomposition of toxic
  substances etc. benefit humans
• Pollinator services for plants
• Nutrients cycle through the different spheres
• Modification and maintenance of the enviroment

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Honeybee crisis

• Why are honeybees important?
• Before humans imported the European honeybee to
  North America (1800s) there were over 4000
  different pollinators. Now there are very few.
• What happened?
• Consider the three levels of diversity in your
  answer.

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1.2 The Science of Classification
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Renaissance

• Era of rebirth, exploration from Europe begins
• Interest shifted from the Divine to the human
  form
• Interest in human physiology and function,
  disease
• Era of experimentation, observation and analysis
  begins

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William Harvey

• 1578-1658
• Discovered the circulation of the blood
• Part of the trend to looking for natural causes
  and cures for diseases

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• The beginning of modern medical practice
• Doctors
• replaced village wise women so they needed to
  make medicines
• Required a reliable way of identifying medically
  important plants
• Beginning of the study of Botany

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Herbals

• Related species of plants do not look the same in
  all habitats
• Within the same related group some can be
  beneficial, others poisonous
• Invention of the printing press allowed mass
  publication of accurate diagrams and descriptions

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Modern Taxonomy

• Factors that contributed to modern taxonomy
• Global European exploration brought many new
  species to Europe
• No system for naming new or existing organisms
  was in place
• The same plant or animal could have different
  names even in the same language

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Linneaus (1707-1778)

• Born Carl von Linné (Swedish)
• Father of modern taxonomy
• Greatly influenced by Aristotles concepts of
  fixed genus and species
• Major work Systema Naturae

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Systema Naturae

• Hierarchical levels beginning with Kingdom
  (Plantae and Animalae)
• Each kingdom divided into Classes, each Class
  into Orders, Genera, and Species
• Not classes in the modern sense created by God
• Binomial nomenclature
• Each organism has a unique genus and species

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Systema Naturae

• Plants were classified according their method of
  reproduction
• A brilliant guess!
• Used Latin (and Greek) so that the method was
  international

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Systema Naturae

• Limitations
• Only physical features (morphology) could be
  used for classification
• Function or behaviour could not be used for
  classification purposes

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Modern Taxonomy

• Linneaus system is still the basis for modern
  taxonomy
• Added Phylum between Kingdom and Class, and
  Family between Order and Genus
• Still use Latin although many new species use
  words with other language roots

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Modern Taxonomy

• Genus is always capitalized, species in lower
  case
• Genus and species are written in italics (print)
  or underlined (handwritten)
• When used for the second time in a document the
  genus name is often abbreviated to the first
  letter
• E.g. Homo sapiens becomes H. sapiens

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Two Kingdoms
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Three Kingdoms
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Five Kingdoms
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Six Kingdoms 3 Domains
Eukaryotic cells
Prokaryotic cells
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Domains

• Domains are the broadest taxon in use
• There are currently three domains
• Archaea
• The oldest forms of life, prokaryotic, many were
  anaerobic and contain extremophiles
• Bacteria
• Also prokaryotic
• Eukarya
• All eukaryotic organisms

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Modern taxonomy

• Linneaus grouped species according to morphology
  appearance
• Now scientists have access to DNA analysis and
  phylogeny to help with classification
• Phylogenetic trees are useful in showing
  relationships over time and divergence from a
  common ancestor

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Cladistics

• A particular method of hypothesizing
  relationships among organisms. Like other
  methods, it has its own set of assumptions,
  procedures, and limitations.
• The best method available for phylogenetic
  analysis, it provides an explicit and testable
  hypothesis of organism relationships.

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Cladistics

• There are three basic assumptions in cladistics
• 1. Any group of organisms are related by descent
  from a common ancestor.
• 2. There is a bifurcating pattern of
  cladogenesis.
• 3. Change in characteristics occurs in lineages
  over time.

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Phylogenetic tree(s)
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Each node represents a point where a major
divergence in characteristicsoccurred
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Tree of Life
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Levels of Classification

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

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Mnemonic

• King
• Phyllips
• Class
• Orders
• Family
• Geni to
• Speak

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Binomial Nomenclature

• Or a two part naming system
• Commonly referred to as the scientific name of
  an organism
• Each species is unique (review definition!)
• Related species are grouped together into the
  same genus
• Related genera (plural of genus) form families

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Binomial Nomenclature

• Related families are grouped into orders
• Orders are grouped into classes
• Different classes form a phylum
• Different phyla (plural of phylum) form a kingdom

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Panthera pardus
The genus and species names are always written in
italics (or underlined if hand written) and the
genus name is capitalized.
The first time the genus name is used it is
written out in full, afterwards it can be
abbreviated to a capital letter, for example P.
pardus or P. leo.
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pardus
Panthera
Felidae
Carnivora
Mammalia
Chordata
Animalia
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Binomial Nomenclature

• The term taxon (plural is taxa) refers to a level
  in the hierarchy
• The Insecta are such a large group that
  superfamillies and suborders are used as well

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Dichotomous Keys

• Method used to create identification keys based
  on pairs of characteristics
• Only morphology (observable characteristics) can
  be used no behviour or function can be used
• Structured format to the keys
• Two types spider and standard formats

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Spider Key
2a
yes
1a
3a
Large claws present
yes
yes
no
Has five or more distinct appendages
Shaped like a star
2b
no
no
3b
1b
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Standard format key

• 1a. Has five or more distinct appendages 2
• 2a. Has large claws . lobster
• 2b. Does not have claws . 3
• 3a. Shaped like a star .. starfish
• 3b. Not star shaped . octopus
• 1b. Has less than five distinct appendages
  whale

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Notes on Keys

• Use an a and b for each level
• Start at the margin and indent for each new level
• Keep levels even no matter what the number is, it
  is the number of criteria that matter
• Split numbers as needed so that each
  identification can follow through without
  changing branches
• Use dots to fill the space to the right margin
  where either a number or item appear

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Standard format key

• 1a. Has five or more distinct appendages 2
• 1b. Has less than five distinct appendages..
  whale
• 2a. Has large claws .... lobster
• 2b. Does not have claws . 3
• 3a. Shaped like a star . starfish
• 3b. Not star shaped . octopus

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Notes to key

• Pairs of related criteria appear together
• Single space between each number
• Use dots to fill the space between the criteria
  and the right margin where either a number or
  item appear

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Dichotomous Key
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The prefix di means 2 so there are two
characteristics to consider in each choice or
step of the key. Each characteristic must be
chosen so that there is a yes or no answer.
There cannot be ambiguity or a possible 3rd
choice.
The answer will determine which step is next in
the process
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