Classification of Living Things

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Classification of Living Things
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Definitions

• Taxonomy the science of classifying organisms
  based on biological similarities
• Carolus Linnaeus the father of taxonomy
• Binomial nomenclature the way that organisms
  are named using two word Latin descriptions
• Kingdom the most general description of living
  things (6)
• Phylum the second level of classification

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Definitions cont

1. Class the third level of classification
2. Order the fourth level of classification
3. Family the fifth level of classification
4. Genus a Latin name that describes a specific
   organism
5. Species the most specific level of
   classification

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Definitions cont..

1. Eubacteria a unicellular kingdom of bacteria
   that have a cell wall and a cell membrane made of
   carbohydrates
2. Archaebacteria a unicellular kingdom of
   bacteria that are way different than the
   eubacterias
3. Plantae - multicellular kingdom of organisms that
   include flowering plants, mosses, and ferns
4. Animalia a multicellular kingdom of organisms
   that includes an incredible diversity of animals
5. Fungi a multicellular kingdom of organisms that
   can not move to get their food

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Definitions cont.

1. Protista unicellular kingdom of organisms that
   contain organelles and a nucleus
2. Dichotomous Key a tool used by scientists to
   determine the scientific name of an organism
3. Scientific name - the name given to an organism
   using the genus and species name
4. Common name a nickname given to an organism
5. classification placing organisms into similar
   groups

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The "Nuts and Bolts" of Taxonomy and
Classification
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Why Classify?

• There are more than 2.5 million different living
  things on earth.
• Millions more have not yet been discovered.
• Life is diverse and needs to be organized.
• It is organized so that scientists all over the
  world have a universal method of classifying.
• Organisms are placed into groups with biological
  similarities.

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History of Classification

• Aristotle - 2000 years ago
• Plant or Animal
• Stem differences Land dweller
• Water dweller
• Air dweller

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Problems with this early system

• Some plants and animals could not be classified
  using this system.
• People also used common names.
• Common names - dont describe things accurately
• Example
• Jellyfish is not a fish

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Same common name for different species

• Maple Trees Silver Maple, Sugar Maple, Red
  Maple are each different species

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Cougar, Mountain Lion, Puma

• By the 1700s scientists realized that common
  names were too confusing.
• They vary among languages and even
• regions.

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Carolus Linnaeus

• Binomial Nomenclature
• two names
• All organisms are called by their Genus and
  species

1707 - 1778
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Canis lupus
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Canis latrans

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Canis domesticus
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How are organisms classified?

• Kingdom (6)
• Phylum
• Class
• Order
• Family
• Genus
• Species

The least specific
The most specific
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The Six Kingdoms
Archaebacteria
Eubacteria
Protists
Fungi
Animalia
Plantae
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Eubacteria
Kingdom of bacteria that have no nucleus
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Eubacteria

• Larger of the two prokaryote kingdoms.
• Surrounded by a cell wall made of carbohydrates.
• Wide range of organisms simple to elaborate
• Range from living in soil to infectious bacteria.
• Such a large range number of phyla is debated.

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Examples of Eubacteria

• Cyanobacteria (blue-green bacteria)
• Photosynthetic
• Found throughout the world salt water to
  freshwater
• Some species survive in hot springs, or in the
  arctic
• Usually a pioneer species colonization after
  volcanoes

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Archaebacteria
Kingdom of bacteria that are more developed than
the eubacteria
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Archaebacteria

• Lack an important carbohydrate found in the cell
  walls of eubacteria.
• Differ in lipids, ribosomes, and gene sequences.
• Organisms that live in extremely harsh
  environments- thick mud, digestive tracts, salty
  environments, and thermal vents.

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Protista
Kingdom of unicellular organisms
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Protista

• Single-celled eukaryotic organisms
• Divided into three groups
• Animal-like protists
• Plant-like protists
• Fungus-like protists
• Examples amoeba, paramecium, euglena, slime mold

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Fungi
The mushrooms and molds
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Fungi

• Build cell walls that do not contain cellulose.
• Heterotrophic- DO NOT CARRY OUT PHOTOSYNTHESIS
• Examples yeast, molds, mushrooms

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Plantae
Kingdom of plants
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Plantae

• Multicellular
• Cell walls contain cellulose
• Autotrophic- can carry out photosynthesis using
  chlorophyll
• Examples flowering plants, mosses, ferns,
  multicellular algae

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Animalia
Kingdom of animals
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Animalia

• Multicellular
• Heterotrophic
• Cell membranes/ no cell walls
• Includes incredible diversity

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• Memorize the levels of classification in order.
• A good way to remember them is
• King Pete Caught Over Five Green Snakes
• Kids Playing Catch On Freeways Get Squished
• You can also come up with your own sentence to
  help you remember them in order.
• Memorize all 6 kingdoms

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Carolus Linnaeus
1707 - 1778
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The Father of Taxonomy

• His system for naming, ranking, and classifying
  organisms is still in wide use today (with many
  changes).
• His ideas on classification have influenced
  generations of biologists during and after his
  own lifetime, even those opposed to the
  philosophical and theological roots of his work.

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Classification

• Carolus Linnaeus developed the classification
  system
• His system was called binomial nomenclature
• Organisms were named using the Latin genus and
  species names
• An international committee keeps track of all new
  names
• A Dichotomous Key is used by scientists to
  research new organisms and to figure out
  scientific names

Let's take a look at how it works..
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KingdomAnimalia
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Phylum Chordata
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Class Mammalia
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Order Carnivora
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Family Ursidae
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Genus Ursus or Ursus
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Species arctos or arctos
Scientific Name
Ursus arctos
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Ursus arctos
Scientific Name
or
Ursus arctos
Species
Genus
Common name
Grizzly Bear
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Writing a scientific name

• The scientific name is equal to binomial
  nomenclature
• The genus and species name are always used
• The genus name is always written first
• It always begins with a capital letter
• The species name is written right after the genus
  name
• It always begins with a lower case letter
• Both words must be underlined or written in
  italics

Studentia lazyrentus
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Name each Kingdom
Number your paper from 1 to 6
1
2
3
5
4
6
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Check your answers

• Animalia
• Fungi
• Archaebacteria
• Protista
• Plantae
• Eubacteria

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Dichotomous Key

• A dichotomous key is a tool that allows the user
  to determine the identity of items in the natural
  world, such as trees, wildflowers, mammals,
  reptiles, rocks, and fish.
• Keys consist of a series of choices that lead the
  user to the correct name of a given item.
• "Dichotomous" means "divided into two parts".

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Rules when reading a dichotomous key

• Always read both choices, even if the first seems
  to be the logical one at first.
• Be sure you understand the meaning of the terms
  involved. Do Not Guess.
• When measurements are given, use a calibrated
  scale. Do Not Guess.
• Since living things are always somewhat variable,
  do not base your conclusion on a single
  observation. Study several specimens to be sure
  your specimen is typical.
• If the choice is not clear, for whatever reason,
  try both divisions. If you end up with two
  possible answers, read descriptions of the two
  choices to help you decide

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Dichotomous Key Example

• 1. a. wings covered by an exoskeleton go to
  step 2
• b. wings not covered by an exoskeleton ..go
  to step 3
• 2. a. body has a round shape .ladybug
• b. body has an elongated shape
  .grasshopper
• 3. a. wings point out from the side of the body
  .dragonfly
• b. wings point to the posterior of the body
  .housefly

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• Notice that there were four organisms to be
  identified and it only took three steps. There
  should be one less step than the total number of
  organisms to be identified in your dichotomous
  key.

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Constructing a dichotomous key

• Use constant characteristics rather than variable
  ones.
• Use measurements rather than terms like "large"
  and "small".
• Use characteristics that are generally available
  to the user of the key rather than seasonal
  characteristics or those seen only in the field.
• Make the choice a positive one - something "is"
  instead of "is not".
• If possible, start both choices of a pair with
  the same word.
• If possible, start different pairs of choices
  with different words.
• Precede the descriptive terms with the name of
  the part to which they apply.