Classification

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Classification

• Chapter 17-Pg. 502-523

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Finding Order in Diversity

• Why Classify Organisms??
• Biologists use classification systems to name
  organisms and group them in a logical order
• Taxonomy Scientists classify organisms and
  assign each organism a universally accepted name

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The History of Organization

Aristotle 384-322 BC Interested in biological
classification. Patterns in nature.
Carl Linnaeus 1707-1778 ACE Father ofBiological
Classification!
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Aristotle

• Developed the first system of classification.
• He classified all living things into plants and
  animals.
• Animals were grouped depending on where they
  lived. (On land, in air or in water)
• Later scientist became convinced that his system
  did not work because of organisms living in
  multiple habitats.

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Carolus Linnaeus

• Developed the system of classification that is
  still used today.
• He selected physical characteristics that led to
  classification based on close relationships of
  organisms.
• He used characteristics such as bats having hair
  and feeding their young milk to classify the
  organisms.
• The system devised by Linnaeus gives each
  organism two names called Binomial Nomenclature.

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WHY DO WE CLASSIFY ORGANISMS?

• We classify organisms in order to study the
  diversity of life.
• Biologist use a classification system to name the
  organism and group them into a logical manner.

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In order to make their job easier, scientists
classify living things into groups, based on how
they are the same, and how they are different.
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What is Classification?
Classification arranges objects, ideas, or
information into groups by finding common
traits or characteristics.
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Assigning Scientific Names

• For many species, there are often regional
  differences in their common names
• EX Buzzard in the UK refers to a hawk, Buzzard
  in the US refers to a vulture
• To eliminate such confusion, scientists agreed to
  use a single name for each species

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Assigning Scientific Names

• Binomial Nomenclature Scientists assign each
  kind of organism a universally accepted name in
  the system
• Two word system using the Genus and Species
• Words are always written in italics
• First word (Genus) is capitalized and second word
  (Species) is lowercase
• Second word is a Latinized description of a
  particular trait
• Developed by an 18th C. Swedish botanist named
  Carolus Linnaeus
• EX Grizzly Bear Ursus arctos

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Assigning Scientific Names

• Differences in Binomial Nomenclature
• 1st part of scientific name is genus to which the
  organism belongs
• A genus is composed of a number of closely
  related species
• 2nd part of scientific name is unique to the
  species within the genus
• EX Ursus arctos Grizzly Bear, Ursus maritimus
  Polar Bear
• EX Papio annubis and Papio cynocephalus do NOT
  belong to the same species since the species part
  of the name is different. However, they do
  belong to the same genus

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Common name Robin

• Erithacus rubicula
• Turdus migratorus

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Common name Black and Polar Bear

• Ursus americanus
• Ursus maritimus

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There are six basic characteristics of life. All
living things have the following traits.

• 1. Show an orderly structure, or organization,
  of tiny units called cells.
• Reproduce to make more living things.
• Change during their lives through growth and
  development.
• Adjust to their surroundings.
• Obtain and use energy to run the processes of
  life.
• Pass on traits to their offspring.

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2 types of Reproduction

• ASEXUAL (binary fission) a single parent passes
  exact copies of its DNA to its offspring.
  Occurs in bacteria and single celled organisms
  such as the amoeba.
• The single-celled amoeba demonstrates
• a simple method of asexual reproduction
• it divides in half by a process called fission,
• producing two smaller daughter cells. After
• a period of feeding and growth, these two
• daughter cells will themselves divide in half.

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2 types of Reproduction

• 2. SEXUAL - organisms having genetic
  characteristics derived from two parents are
  produced.
• Male and female reproductive cells (gametes)
  unite to form a single cell, known as a zygote,
  which later undergoes successive divisions to
  form a new organism.

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Adjust HOMEOSTASIS

• Organisms respond to their external environment
  and then process the internal demands
  accordingly.
• The maintenance of stable internal conditions in
  spite of changes in the external environment.
• Example temperature of a human is always
  around 98.6 regardless of the temperature
  outside.

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Groups are also arranged in hierarchical order.
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Assigning Scientific Names

• Linnaeuss System of Classification
• Based on Taxonomy naming system
• Taxonomy is the branch of biology concerned with
  the grouping and naming of organisms.
• a group at any level of an organization is
  referred to as a taxon.
• Is hierarchical and consists of 7 taxonomic
  categories
• From largest to smallest
• Kingdom (King) Made up of phylums
• Phylum (Phillip) Made up of several different
  classes
• Class (Came) Made up of several different
  orders
• Order (Over) Made up of several different
  families
• Family (For) Made up of several different
  genuses
• Genus (Grape) Made up of several different
  species
• Species (Soda)

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SPECIES

• A GROUP OF SIMILAR LOOKING ORGANISMS THAT SHARE
  SIMILAR CHARACTERISTICS AND CAN INTERBREED WITH
  ONE ANOTHER TO PRODUCE FERTILE OFFSPRING.
• horse donkey mule (non-fertile offspring)
• species species non-species

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Assigning Scientific Names

• Examples of Taxonomic Levels
• The most general and largest of Linnaeuss system
  is the Kingdom
• Linnaeus recognized the kingdoms of plants
  (Plantae) and animals (Animalia)
• The class of Mammalia includes mammals which are
  organisms that have
• Are warm-blooded
• Have body hair
• Produce milk for their young

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Modern Evolutionary Classification

• Traditional classifications like Linnaeuss
  tended to take into account primarily general
  similarities in appearance
• However, some organisms that ARE NOT closely
  related look alike because of convergent
  evolution!
• Evolutionary Classification The procedure of
  grouping organisms based on their evolutionary
  history
• Species within one genus should be more closely
  related to each other than a species in another
  genus
• All genera within a family share a common
  ancestor. Similar genes

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Modern Evolutionary Classification

• Derived Characters An evolutionary innovation
• EX Free swimming larva, segmented body
• Cladistic Analysis Analysis that focuses on the
  order in which derived characters appear in an
  organism
• Looks only at derived characters, or those
  characteristics that are evolutionary innovations
  (EX body structures, adaptations)
• New characteristics emerge as lineages evolve
  over time
• Cladogram a table analyzing derived characters
  that shows the evolutionary relationship between
  organisms
• Helps scientists understand how lineages branched
  from one another in the course of evolution
• Shows the order in which derived characters
  evolved

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Modern Evolutionary Classification

• Similarities in RNA and DNA
• Similar genes are evidence of common ancestry
• Similarities in DNA can help determine
  classification and evolutionary relationships
• EX A cow and a yeasts degree of relationship
  can be determined from their genes
• EX Scientists have found that humans and yeast
  have similar genes for the assembly of certain
  proteins (Myosin)
• All organisms use DNA and RNA to pass on
  information

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Modern Evolutionary Classification

• Similarities in RNA and DNA Cont
• DNA evidence can help show the evolutionary
  relationship between organisms and how species
  have changed
• EX Presence of similar genes in very dissimilar
  organisms implies that the organisms share a
  common ancestor like vultures and storks!

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Kingdoms and Domains

• In the 1800s scientists used a 3 kingdom
  classification system
• Animals, Plants, Protista
• Scientists grouped organisms according to how
  long they have been evolving independently
• Biologists knowledge of diversity of life
  continued to grow
• We now know there are 6 Kingdoms
• Archaebacteria (used to be grouped as the Monera
  category)
• Eubacteria (used to be grouped as the Monera
  category)
• Protista (used to be grouped with Plants)
• Fungi
• Plantae
• Animalia

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Kingdoms and Domains

• The Three Domain System
• Modern analysis of evolutionary trees have given
  rise to a new taxonomic category Domain
• A domain is more inclusive and larger than a
  kingdom
• There are 3 Domains
• Eukarya includes kingdoms protist, fungi,
  plants, animals
• Archaea includes kingdom Archaebacteria
• Bacteria Includes kingdom Eubacteria
• The 3 domains are thought to have diverged from a
  common ancestor before the evolution of the main
  groups of eukaryotes
• Recognizes fundamental differences between 2
  groups of prokaryotes- Bacteria Archaea

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Kingdoms and Domains

• Domain Archaea
• Kingdom Archaebacteria ancient bacteria
• Unicellular Prokaryotes (do not have a true
  nucleus)
• Found in extreme environments salt lakes, swamps
  and VERY deep within the ocean. Deep sea
  bacteria, make their own food (autotroph) using
  energy derived from minerals coming form without
  oxygen. Also heterotrophs
• Cell wall do not contain unusual lipids
  (peptidoglycan)
• Subdivided into 3 groups based on their habitat
  --- methanogens, thermoacidophiles, extreme
  halophiles

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Halophiles (like salt)
Thermophiles (like heat)
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• Kingdoms and Domains

• Domain Bacteria
• Kingdom Eubacteria- true bacteria
• Prokaryotes
• Unicellular
• Heterotroph or autotroph
• Can be aerobic (require oxygen) or anaerobic
  (dont need oxygen)
• Cell walls are thick rigid contain lipid
  (peptidoglycan)
• Found in practically every environment on Earth.
• Can be identified by Gram staining (gram positive
  or gram negative)
• Come in 3 basic shapes --- cocci (spheres),
  bacilli (rod shaped), spirilla (corkscrew shape)
• Some need oxygen to survive others do not

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Eubacteria

• Staphylococcus aureus 
• Bacillus anthracis
• E. coli

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Kingdoms and Domains

• Domain Eukarya
• Eukaryotes
• Consists of the 4 kingdoms
• Protista
• organisms that cannot be classified as plants,
  animals, or fungi
• Usually unicellular but some multicellular
• Have chloroplasts (autotroph) or Heterotroph
• Membrane-bound organelles
• Cell wall of cellulose
• Classified by the way they move- flagellum,
  cilia, or pseudopods
• EX Algae, Ameobas, Parameciums and kelp

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Amoeba
Rotifer
Euglena
Algae
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Kingdoms and Domains

• Kingdom Fungi
• Eukaryotes
• Heterotrophs that feed on dead or decaying matter
  (saprobes). Decomposers obtain energy by
  breaking down organic material that they absorb
  from the environment.
• Do not contain chlorophyll
• Store food energy as glycogen.
• decomposers recyclers
• Can be single or multicelled
• Cell walls contain chitin (tough outer covering)
• Non-motile (cannot move)
• Lack true roots, stems, leaves
• EX Mushrooms yeast

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Mold
Mushrooms
Ringworm
Yeast
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Kingdoms and Domains

• Kingdom Plantae
• -Eukaryotes
• Photosynthetic autotrophs or producers
• Non-motile
• Multicellular
• Contain chlorophyll inside of chloroplasts
• Undergo photosynthesis
• Cell walls contain cellulose
• All plants that reproduce sexually
• EX mosses, ferns, flowering plants, cone-bearing
  plants, etc

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Kingdoms and Domains

• Animalia
• Eukaryotes
• Multicellular heterotrophic
• Cells contain a nucleus and membrane bound
  organelles
• Show levels of organization including cell,
  tissue, organ, system
• Cells are specialized for particular functions
• No cell walls or chloroplast
• Motile- can move about
• EX animals

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Animalia

• 99 of the organisms in Kingdom Animalia are
  invertebrates meaning they lack a backbone.
• Organisms that have a backbone are called
  verterbrates.

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1. Which Kingdom do I belong to?
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2. Which Kingdom do I belong to?
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3. Which Kingdom do I belong to?
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4. Which Kingdom do I belong to?
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5. Which Kingdom do I belong to?
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6. Which Kingdom do I belong to?
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7. Which Kingdom do I belong to?
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8. Which Kingdom do I belong to?
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9. Which Kingdom do I belong to?
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10. Which Kingdom do I belong to?
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1. Sponges and Cnidarians

• The only animals that
• do not have tissues.
• Mostly marine.
• Ex. Jellyfish, corals

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2. Mollusks

• Have something called a coulomb (sac-like
  structure) that encloses their internal organs.
• Most have a hard external skeleton (shell).
• Ex. Snails, oysters, clams, octopuses

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2. Mollusks
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3. Worms

• Cylinder shaped bodies.
• Live on both land and water.

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4. Arthropods

• Most diverse of all animals.
• Have an external skeleton.
• Have jointed appendages, such as antennae and
  jaws.
• High rate of reproduction.
• 2/3 of all animals.

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4. Arthropods
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5. Echinoderms

• Ability to regenerate a lost limb.
• Ex. Sea stars, sea urchins

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6. Verterbrates

• Internal skeleton made of bone.
• Includes mammals, fish, birds, reptiles and
  amphibians.

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What are Dichotomous Keys?

• a method for determining the identity of
  something (like the name of a butterfly, a plant,
  a lichen, or a rock) by going through a series of
  contrasting choices that leads the user to the
  correct name of the item.
• Dichotomous means "divided in two parts".

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Using a dichotomous key

• At each step of the process of using the key, the
  user is given two choices each alternative leads
  to another question until the item is identified.
  
• 1a. If the leaves are flat.go to question 4.
• 1b. If the leaves are needle-like.go to
  question 2.
• 2a. Are the needles in a bunch? Go to question
  5
• 2b. Are they spread along the branch?pine tree
• Eventually, when enough questions have been
  answered, the identity of the tree is revealed.

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• 1a Butterfly exhibits only one color.
  Boring butterfly
• 1b Butterfly has two or more colors. Go to
  2.
• 2a. Butterfly has a red body.
• 2b Butterfly has a black body. Go to 3.
• 3a. Butterfly contains the color red.
  Inachis io
• 3b. Butterfly contains the color orange.
  Danaus plexippus

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Why is Taxonomy Important?
New Discoveries
Unknown species discovered.
Questions
New fossil Uncovered.
How can you answer these questions?