Classification:

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Classification

• Georgia Performance Standards
• SB3. Students will derive the relationship
  between single-celled and multi-celled organisms
  and the increasing complexity of systems.
• b. Compare how structures and function vary
  between the six kingdoms (archaebacteria,eubacteri
  a, protists, fungi, plants, and animals).
• c. Examine the evolutionary basis of modern
  classification systems.
• d. Compare and contrast viruses with living
  organisms.
• SB5. Students will evaluate the role of natural
  selection in the development of the theory of
  evolution.
• e. Recognize the role of evolution to biological
  resistance (pesticide and antibiotic resistance).

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Essential Questions

1. How does the evidence of evolution contribute to
   modern classification systems?
2. Why classify?
3. On what criteria do Taxonomists base their
   classification of organisms?
4. Are viruses alive?
5. What is the role of evolution in antibiotic and
   pesticide resistance?

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Why Classify?

• To study the diversity of life, biologists use a
  classification system to name organisms and group
  them in a logical manner.
• In taxonomy, scientists classify organisms and
  assign each organism a universally accepted name.
  
• By using a scientific name, biologists can be
  certain that everyone is discussing the same
  organism.

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Early Efforts at Naming Organisms

• The first attempts at standard scientific names
  often described the physical characteristics of a
  species in great detail.
• Results in long names
• Difficult to standardize the names of organisms
• Different scientists described different
  characteristics.

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Binomial Nomenclature

•  Carolus Linnaeus developed a two-word naming
  system called binomial nomenclature.
• In binomial nomenclature, each species is
  assigned a two-part scientific name.
• First word is the genus
• Second word is the species

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Organizing Lifes Diversity
Chapter 17
17.1 The History of Classification

• When writing a scientific name, scientists use
  these rules

• The first letter of the genus name always is
  capitalized, but the rest of the genus name and
  all letters of the specific epithet are lowercase.

• If a scientific name is written in a printed book
  or magazine, it should be italicized.

• When a scientific name is written by hand, both
  parts of the name should be underlined.

• After the scientific name has been written
  completely, the genus name will be abbreviated to
  the first letter in later appearances (e.g., C.
  cardinalis).

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Linnaeus's System of Classification

• A group or level of organization is called a
  taxonomic category, or taxon
• King Phillip Came Over From Genoa Spain

• The are 7 taxonomic categories. (from smallest to
  largest)
• species
• genus
• family
• order
• class
• Phylum
• kingdom.
• Domain

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The 7 taxonomic categories

• Species - a group of organisms that breed with
  one another and produce fertile offspring.
• Genus - a group of closely related species.
• Family - genera that share many characteristics.
• Order - is a broad taxonomic category composed
  of similar families.
• Class - is composed of similar orders.
• Phylum- several different classes that share
  important characteristics.
• Kingdom - largest taxonomic group, consisting of
  closely related phyla

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Classification Pop Quiz

• 1.  How are living things organized for study?
• 2. Describe the system for naming species that
  Linnaeus developed.
• 3. What are the seven taxonomic categories of
  Linnaeuss classification system from largest to
  smallest?
• 4. Why do scientists avoid using common names
  when discussing organisms?
• 5. Based on their names, you know that the
  baboons Papio annubis and Papio cynocephalus do
  NOT belong to the same
• a. Class b. family
• c. Genus d. species

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Modern Evolutionary Classification 

• Organisms are grouped into categories that
  represent lines of evolutionary descent, not just
  physical similarities
• This strategy of grouping organisms together
  based on their evolutionary history is called
  evolutionary classification.
• Modern classification systems are based upon
  biochemical and genetic evidence that indicates
  evolutionary relationships

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How do we determine evolutionary relationships?

• 1. Look for structural similarities.
• 2. Look at breeding behavior.
• 3. Look at geographic distribution and find
  where organism are located and their range.
• 4. Look at Chromosomes for similar structure and
  number.
• 5. Look at biochemistry Look for similar DNA
  sequences and therefore similar proteins

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Phylogenetic Classification

• Phylogeny the evolutionary history of a
  species.
• Phylogenetic classification is a classification
  system that shows the evolutionary history of a
  species.
• Cladistics It is assumed that a group of
  organisms diverged and evolved from a common
  ancestral group.
• Derived traits Characteristics of the original
  group that are retained.

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Classification Using Cladograms

• Cladistic analysis identifies and considers only
  the characteristics that arise as lineages evolve
  over time.
• Characteristics that appear in recent parts of a
  lineage but not in its older members are called
  derived characters.
• Derived characters can be used to construct a
  cladogram, a diagram that shows the evolutionary
  relationships among a group of organisms.

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Traditional Classification Versus Cladogram
Section 18-2
Appendages
Conical Shells
Crustaceans
Gastropod
Crab
Crab
Limpet
Limpet
Barnacle
Barnacle
Molted exoskeleton
Segmentation
Tiny free-swimming larva
TRADITIONAL CLASSIFICATION
CLADOGRAM
Go to Section
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• Cladogram a branching diagram using cladistics.
• Image taken fromhttp//evolution.berkeley.edu/evo
  library/article//evo_03

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Organizing Lifes Diversity
Chapter 17
17.2 Modern Classification
Cladograms

• The greater the number of derived characters
  shared by groups, the more recently the groups
  share a common ancestor.

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Modern Evolutionary Classification

• Molecular Clocks
• Comparisons of DNA can also be used to mark the
  passage of evolutionary time.
• A model known as a molecular clock uses DNA
  comparisons to estimate the length of time that
  two species have been evolving independently.

• Comparison reveal how dissimilar the genes are.
• Degree of dissimilarity is an indication of how
  long ago the two species shared a common
  ancestor.

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Checkpoint Questions

• How is information about evolutionary
  relationships useful in classification?
• How are genes used to help scientists classify
  organisms?
• 3. What is the principle behind cladistic
  analysis?
• 4. Describe the relationship between
  evolutionary time and the similarity of genes in
  two species.
• 5. How have new discoveries in molecular biology
  affected the way in which we classify organisms
  compared with the system used by Linnaeus?
  Constructing a Chart  

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Kingdoms and Domains 

• The six-kingdom system of classification includes
  the following kingdoms
• Eubacteria
• Archaebacteria
• Protista
• Fungi
• Plantae
• Animalia.

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The Three-Domain System

• The domain is the most inclusive taxonomic
  category larger than a kingdom   
• The three domains are
• Bacteria kingdom Eubacteria
• Archaea, kingdom Archaebacteria
• Eukarya Kingdom protists, fungi, plants, and
  animals.

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Key Characteristics of Kingdoms and Domains
Classification of Living Things
Eukarya
Bacteria Eubacteria Prokaryote Cell walls
with peptidoglycan Unicellular Autotroph
or heterotroph Streptococcus, Escherichia coli
Archaea Archaebacteria Prokaryote Cell walls
without peptidoglycan Unicellular Autotroph
or heterotroph Methanogens, halophiles
Protista Eukaryote Cell walls of cellulose in
some some have chloroplasts Most unicellular
some colonial some multicellular Autotroph or
heterotroph Amoeba, Paramecium, slime molds,
giant kelp
DOMAIN KINGDOM CELL TYPE CELL
STRUCTURES NUMBER OF CELLS MODE OF
NUTRITION EXAMPLES
Plantae Eukaryote Cell walls of cellulose
chloroplasts Multicellular Autotroph Mos
ses, ferns, flowering plants
Fungi Eukaryote Cell walls of chitin Most
multicellular some unicellular Heterotroph Mu
shrooms, yeasts
Animalia Eukaryote No cell walls or
chloroplasts Multicellular Heterotroph Sp
onges, worms, insects, fishes, mammals
Go to Section
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Section 18-3
Living Things
are characterized by
Important characteristics
which place them in
and differing
Domain Eukarya
Cell wall structures
such as
which is subdivided into
which place them in
which coincides with
which coincides with
Go to Section
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The Six Kingdoms

• Kingdom Archaebacteria Bacteria that live in
  extreme environments void of oxygen. Cell
  membrane lipids, RNA, and cell wall structures
  are different than other bacteria.
• Kingdom Eubacteria all other bacteria. Strong
  cell walls and less complicated genetic makeup.
  Live in many habitats
• Kingdom Protista Eukaryote that lacks complex
  organ systems and lives in moist environments.
  Can be unicellular or multicellular

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The Six Kingdoms Continued

• Kingdom Fungi Heterotrophs that do not move from
  place to place. Uni or multicellular eukaryotes
  that absorb nutrients from organic material.
• Kingdom Plantae Multicellular photosynthetic
  eukaryotes. Can not move from place to place.
  Cells organized into tissues, tissues organized
  into organs.
• Kingdom Animalia Animals multicellular
  heterotrophs. Able to move from place to place.
  No cell walls. Cells form tissues that form
  organs that form organ systems.

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Organizing Lifes Diversity
Chapter 17
17.3 Domains and Kingdoms
Domain Archaea

• Archaea are thought to be more ancient than
  bacteria and yet more closely related to our
  eukaryote ancestors.

• Archaea are diverse in shape and nutrition
  requirements.

• They are called extremophiles because they can
  live in extreme environments.

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Organizing Lifes Diversity
Chapter 17
17.3 Domains and Kingdoms
Domain Bacteria

• Eubacteria are prokaryotes whose cell walls
  contain peptidoglycan.

• Eubacteria are a diverse
  group that can survive in
  many different environments.

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Bacteria and Viruses
Chapter 18
18.1 Bacteria
Mutations

• Bacteria reproduce quickly and their population
  grows rapidly.

• Mutations lead to new forms of genes, new gene
  combinations, new characteristics, and genetic
  diversity.
• Rapid mutations cause bacteria to become
  resistant to many antibiotics and pesticides.

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Organizing Lifes Diversity
Chapter 17
17.3 Domains and Kingdoms
Domain Eukarya

• All eukaryotes are classified in Domain Eukarya.

• Domain Eukarya contains Kingdom Protista, Kingdom
  Fungi, Kingdom Plantae, and Kingdom Animalia.

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Organizing Lifes Diversity
Chapter 17
17.3 Domains and Kingdoms
Kingdom Protista

• Protists are classified into three different
  groupsplantlike, animal-like, and funguslike.

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Organizing Lifes Diversity
Chapter 17
17.3 Domains and Kingdoms
Kingdom Fungi
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Organizing Lifes Diversity
Chapter 17
17.3 Domains and Kingdoms
Kingdom Plantae

• Members of Kingdom Plantae form the base of all
  terrestrial habitats.

• All plants are multicellular and have cell walls
  composed of cellulose.

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Organizing Lifes Diversity
Chapter 17
17.3 Domains and Kingdoms
Kingdom Animalia

• All animals are heterotrophic, multicellular
  eukaryotes.

• Animal organs often are organized into complex
  organ systems.

• They live in the water, on land, and in the air.

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Organizing Lifes Diversity
Chapter 17
17.3 Domains and Kingdoms
VirusesAn Exception

• A virus is a nucleic acid surrounded by a protein
  coat.

• Viruses do not possess cells, nor are they cells,
  and are not considered to be living.

• Because they are nonliving, they usually are not
  placed in the biological classification system.

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Characteristics of Viruses

• Viruses are not cells
• Viruses are not alive
• Viruses do not use energy
• Viruses can reproduce only when inside living
  cells
• Viruses do contain genetic info. can evolve
  over time.

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Defenses Against Viruses

• Why cant we treat viral diseases with
  antibiotics?
• Vaccinations also protect against some viral
  diseases.
• Harmless viruses stimulate the immune system to
  create defenses against the harmful form of the
  virus.
• Vaccines only work on viruses whose surface
  proteins do not change (mutate). (Small pox,
  measles, polio)
• HIV, cold viruses, and flu viruses (genes mutate
  too often for vaccines to become effective)

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Checkpoint Questions

• What are the six kingdoms of life as they are now
  identified?
•  What are the three domains of life?
• 3. Why was the kingdom Monera divided into two
  separate kingdoms?
• 4. Why might kingdom Protista be thought of as
  the odds and ends kingdom?
• 5. Which kingdoms include only prokaryotes? Which
  kingdoms include only heterotrophs?

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Dichotomous Keys

• A tool used to identify organisms is a
  dichotomous key.
• A dichotomous key is a series of paired
  statements that describe physical characteristics
  of different organisms.
• In this activity, you will use a dichotomous key
  to identify tree leaves.

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