Classification of Organisms

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• Unit 13
• Classification of Organisms

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• I. Isnt everything living thing either a plant
  or an animal?
• A. Aristotle is credited with the first true
  classification system. He grouped all living
  things into two basic groups plant and animal.

OR
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• B Linnaeus further classified plants and animals
  by dividing them into related groups. He used
  the Latin language, because Latin was not longer
  spoken conversationally and thus was less likely
  to change.
• 1. He first grouped related organisms. He called
  this a genus. For example, all of the dog-like
  creatures were grouped as the genus Canis.

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• 2. He next gave every different type of organism
  in the group a specific name, which he called
  specie. For example, the dog became
• Canis familiaris and the wolf
• Canis lupus. Notice the genus is capitalized
  but the specie begins with a lower case letter!
• Both are italicized or underlined.

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Loxosceles reclusa (Brown Recluse)

• 3. Thus, every organism was given a two-word
  name, the genus and specie. This practice of
  binomial nomenclature continues today, giving
  each organism a scientific name.
• 4. The benefit of binomial nomenclature includes
  eliminating confusion due to common names (ex.
  cottonmouth and water moccasin are actually the
  same animal) and allows scientists around the
  world to more easily communicate.

What name do you use for this organism?
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• C. Even after the microbial world was discovered,
  the two kingdom system continued. (Yes,
  science can be very slow to change.)
• D. As knowledge of the diversity of organisms
  increased, Whittaker (in 1969) expanded
  classification to include five kingdoms.

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• E. The science of classification, taxonomy, now
  allowed scientists to assign seven levels of taxa
  to living organisms

Kings Play Cards On Fat Green Stools
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• 1. The kingdom is the most general of these seven
  taxa, thus the kingdom would contain the greatest
  number of organisms.
• 2. Specie is the most specific of these seven
  taxa, thus the specie would contain only one type
  of organism. A specie is defined as a group of
  organisms which can interbreed and produce
  fertile offspring.

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• F. Today, we use three domains, which are divided
  into six kingdoms. These domains are based on
  new information about possible evolutionary
  relationships.

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• II. What happens when you find an organism and
  you are stymied?
• A. Dichotomous keys are tools that use a series
  of paired statements and the visible
  characteristics of the organism. Of course, a
  dichotomous key is only useful if the organism
  has already been classified and given a
  scientific name.

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• 1. Always start at statement 1 (or the beginning
  point)
• 2. Decide which path best describes the organism
  (Statement A or Statement B)
• 3. Follow that path to find the next choice (Go
  to )
• 4. When you can go no further, you will find the
  name!

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• B. If the organism has NOT been classified,
  taxonomists must begin the process of
  classification. In order to correctly classify
  an organism, scientists use many modern tools
• 1. Morphology describes the physical
  characteristics of an organism. Typically, this
  is enough information to place the organism
  within a domain and kingdom.
• Example Presence of a nucleus places the
  organism in Domain Eukarya

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• 2. DNA and biochemical analysis allow scientists
  to test less visible, but distinguishing,
  characteristics.
• Example Gram staining a bacteria cell allows
  scientists to distinguish between archaea and
  prokarya.

Gram-positive anthrax bacteria (purple rods) in
cerebrospinal fluid sample. If present, a
gram-negative bacterial species would appear
pink. (The other cells are white blood cells)
Gram-negative E. Coli bacteria.
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• 3. Comparing embryology allows scientists to
  group organisms that share common fetal
  development.
• Example The diagram below would suggest the
  last four organisms are most closely related.

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• 4. Evolutionary phylogeny describes the
  evolutionary relationships between organisms.
  These relationships are deduced based on shared
  traits that may have been passed from ancestor to
  new species. Traits may include physical traits
  (ex. presence of jaws), or may be genetic traits
  (shared genes). These relationships can be
  illustrated in a phylogenetic tree or cladogram

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1) German Shepherd, Great Dane, parrot, Irish
setter, canary, husky, robin, pigeon

• Title_________________
• _____________________ _____________________
• _____________________ _____________________

• Title_________________
• _____________________ _____________________
• _____________________ _____________________

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2) apples, peas, orange, banana, carrot, lettuce,
turnip, pear, grape, potato

• Title_________________
• _____________________ _____________________
• _____________________ _____________________
• _____________________

• Title_________________
• _____________________ _____________________
• _____________________ _____________________
• _____________________

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• Review Questions
• 1. Who first officially classified organisms?
• Aristotle, then Linnaeus created our current
  system
• 2. What was the contribution of Linneaus to
  taxonomy?
• He grouped related organisms and created
  binomial nomenclature (every organism has a two
  word name- genus and species)
• 3. What are the two parts of a scientific name?
• Genus and species
• 4. What are the domains used in the current
  classification system?
• Prokarya, Archae, Eukarya

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• Review Questions
• 5. How many kingdoms are used in the current
  classification system?
• Six
• 6. What is a dichotomous key?
• A key that uses paired statements and visible
  characteristics to identify a known organism.
• 7. What 4 modern tools are used to classify a
  newly discovered organism?
• Morphology, biochemical similarities,
  embryology, and phylogeny (evolutionary
  relationships)

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• III. Why am I not a fungus?
• A. Kingdom Bacteria
• 1. Cellular Structure Prokaryotic with cell
  wall, unicellular
• 2. Metabolism
• a. Food getting Very diverse some are
  photosynthetic, some are chemosynthetic and
  some are heterotrophic, taking in food by
  active transport.
• b. Cellular energy Some are aerobic for
  the production of ATP, some are anaerobic.

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WARNING- X-Rated Image of Bacteria Sexually
Reproducing

• 3. Reproduction Mostly asexual through binary
  fission may exchange DNA using a process called
  conjugation.
• 4. Ecological/Economic Importance Bacteria are
  important to the environment because they drive
  the nitrogen cycle and are decomposers. Bacteria
  can be beneficial to humans (ex. useful in making
  foods such as yogurt) or harmful (ex. some may
  cause disease such as syphilis)

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• B. Kingdom Archaea (Extreme bacteria!)
• 1. Cellular Structure Prokaryotic with cell
  wall, unicellular (different chemicals in cell
  wall than Kingdom Bacteria)
• 2. Metabolism
• a.Food getting Very diverse some are
  photosynthetic, some are chemosynthetic and
  some are heterotrophic, taking in food by active
  transport.
• b. Cellular energy Some are aerobic for the
  production of ATP, some are anaerobic.

Aerobic Oxygen used Anaerobic No oxygen used
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• 3. Reproduction Mostly asexual through binary
  fission may exchange DNA using a process called
  conjugation.
• 4. Distinguishing habitats They are all
  classified as extremophiles they live in
  extreme environments such as thermal vents,
  swamps, guts of animals, and areas of high
  salinity.

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• C. Kingdom Protista
• 1. Cellular Structure Eukaryotic (some with
  cell wall and some without), some are unicellular
  (amoeba) and some are multicellular (seaweed)
• 2. Metabolism
• a. Food getting Very diverse some are
  photosynthetic (plant-like), and some are
  heterotrophic (animal-like), taking in food by
  active transport.
• b. Cellular energy All utilize aerobic
  respiration for the production of ATP.

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• 3. Reproduction Asexual through binary fission
  (in animal-like protists) and fragmentation (in
  plant-like protists). Some may exchange DNA
  though conjugation (sexual).
• 4. Ecological/Economic Importance
• a. Plant-like protists (commonly called algae)
  are the primary producers of oxygen used for
  cellular respiration. They are also the
  producers that form the base of all aquatic food
  webs.

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• b. Animal-like protists (commonly called
  protozoans) are important primary consumers in
  aquatic food webs. Many protozoans also cause
  diseases such as malaria.
• c. A specialized group of protists called slime
  molds are important decomposers.

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• D. Kingdom Plantae
• 1. Cellular Structure Eukaryotic with cell
  wall, all multicellular
• 2. Metabolism
• a. Food getting All are photosynthetic
  (autotrophic).
• b. Cellular energy All utilize aerobic
  respiration for the production of ATP.
• 3. Reproduction All reproduce sexually (using
  sperm and egg or spores) may reproduce asexually
  (using vegetative propagation or spores)

Each one of these buds can develop into a new
plant next year. In fact a whole row of potato
plants can be started from just one good tuber.
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• 4. Ecological/Economic Importance Plants are
  exponentially more complex as compared to algae,
  but perform many of the same ecological roles
  (oxygen production, base of food web). Plants
  are also used for numerous products such as
  clothing (cotton), paper, medicine (aspirin), and
  lumber.

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• E. Kingdom Fungi
• 1. Cellular Structure Eukaryotic with cell
  wall, mostly multicellular (mushroom) with some
  unicellular (yeast)
• 2. Metabolism
• a. Food getting Heterotrophic with
  extracellular digestion (fungi secrete
  digestive enzymes and absorb nutrients across
  the cell wall)
• b. Cellular energy Some utilize aerobic
  respiration for the production of ATP
  (mushrooms), some are anaerobic (yeast).

Birds Nest Fungi
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• 3. Reproduction May be asexual (budding in
  yeast and spore production in other fungi), or
  sexual (spores).
• 4. Ecological/Economic Importance Fungi are
  important decomposers. Fungi can be beneficial
  to humans (ex. used to make food and alcohol), or
  harmful (cause diseases such as ring worm and
  athletes foot)

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• F. Kingdom Animalia
• 1. Cellular Structure Eukaryotic with no cell
  wall, all are multicellular
• 2. Metabolism
• a. Food getting All are heterotrophic and
  have diverse methods for acquiring food.
• b. Cellular energy All utilize aerobic
  respiration for the production of ATP but some
  specialized cells can convert to anaerobic
  respiration when oxygen is scarce

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• 3. Reproduction All animals reproduce sexually
  (egg and sperm), but some simple animals may also
  reproduce asexually (fragmentation in sponges,
  regeneration in worms)
• 4. Ecological/Economic Importance Animals are
  important consumers in food webs. Animals may be
  beneficial to humans (ex. foods) or harmful (ex.
  worms may cause disease)

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• Review Questions
• 1. Which 2 kingdoms contain bacteria?
• Archaebacteria and Eubactera
• 2. Which 2 kingdoms are prokaryotic?
• Kingdom Bacteria and Kingdom Archae
• 3. The organisms of which kingdom do not have
  cell walls?
• Kingdom animalia
• 4. Name the kingdoms that contain important
  decomposers.
• Bacteria and Fungi
• 5. Name the kingdoms that contain producers.
• Plantae and Protista
• 6. Why are you not a fungus?
• I am not a decomposer, do not get my food
  through extracellular digestion, and do not
  reproduce asexually!