ap biology lecture #44 classification organisms classified from most general group, domain, down to...
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AP Biology
Lecture #44Classification
• Organisms classified from most general group, domain, down to most specific, species– domain, kingdom,
phylum, class, order, family, genus, species
Finding commonality in variety
use the mnemonic!
Solar System
Earth
No. America
U. S.
WI
So. WI
Green Co.
New Glarus
Devil Cat
Ghost Cat
Mountain Lion
Screaming Cat
Puma
Florida Panther
•There are at least 50 common names for the animal shown on the previous 7 slides.
•Common names vary according to region.
•Soooo……why use a scientific name?
• Why are some kinds similar and others NOT similar?
• Question to be answered later?
• How can we make sense of (explain) this diversity?
• How can we organize what we know about these organisms?
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.
Answer: CLASSIFY!
• Similar “types” (species) grouped together, separated from other species.
• Then, group similar groups together, etc.
•The science of classifying organisms is called taxonomy.
•The “father of modern taxonomy” was Carolus Linnaeus (Carl von Linné).
Why Do We Classify Organisms?• Biologists group organisms to
represent similarities and proposed relationships.
• Classification systems change with expanding knowledge about new and well-known organisms.
Tacitus bellus
• Classification system organizes biological knowledge.
• Classification itself is HYPOTHESIS about relationships, similarity because of common ancestry.
Leucaena leucocephala Lead tree
Classification• Binomial Nomenclature
– Two part name (Genus, species)
• Hierarchical Classification– Seven Taxonomic Catagroies
• Systematics– Study of the evolution of biological
diversity
CLASSIFICATION
Archaebacteria&Bacteria
Classification• Old 5 Kingdom system
• Monera, Protists, Plants, Fungi, Animals
• New 3 Domain system– reflects a greater
understanding of evolution & molecular evidence• Prokaryote: Bacteria• Prokaryote: Archaebacteria• Eukaryotes
– Protists– Plants– Fungi– Animals
Prokaryote
Eukaryote
KingdomProtist
KingdomFungi
KingdomPlant
KingdomAnimal
KingdomArchaebacteria
KingdomBacteria
Kingdoms
Single-celled ancestor
prokaryotes
eukaryotes
Eubacteria
Archaebacteria
Protista
multicellular
uni- tomulticellular
autotrophs
heterotrophs
Plantae
Fungi
Animalia
absorptivenutrition
ingestivenutrition
Hierarchical Classification• Taxonomic categories
– Kingdom King– Phylum Philip– Class Came– Order Over– Family For– Genus Green– Species Soup
CLASSIFICATION = Sequence of levels. Linnaean system, from Carolus Linnaeus, 1740's
Kingdom Phylum Class Order Family Genus Species
King Phil called old fat George stupid.
CLASSIFICATION = Linnaean system
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
CLASSIFICATIONWhittaker’s Five Kingdoms, 1965
• Kingdom Monera (Bacteria)
• Kingdom Protista• Kingdom Fungi• Kingdom Plantae• Kingdom Animalia
Woese, 1985• Prokaryotic organisms are far more
diverse than thought previously.• Domain Eubacteria (prokaryotic “true bacteria”)
• Domain Archaea (prokaryotic “archaeans”)
• Domain Eukarya (eukaryotic organisms)
Bacteria Archaea Eukarya
Bacteria Archaea Protista Plantae Fungi Animalia
Monera Protista Plantae Fungi Animalia
The three-domain system
The six-kingdom system
The traditional five-kingdom system
• Prokaryotic organisms are far more diverse than thought previously.
• Domain Eubacteria (prokaryotic “true bacteria”)
– Kingdom Gram-positive bacteria– Kingdom Gram-negative bacteria– Kingdom Mycoplasmas– Kingdom Rickettsias– Kingdom purple-sulfur bacteria– and more
• Domain Archaea (prokaryotic “archaeans”)
• Domain Eukarya (eukaryotic organisms)
Domain Eubacteria
• Prokaryotic organisms are far more diverse than thought previously.
• Domain Eubacteria (prokaryotic “true bacteria”)• Domain Archaea (prokaryotic “archaeans”)– Kingdom Thermophiles– Kingdom Halophiles– Kingdom Methanogens– Kingdom ARMANS
• (“Archeal Richmond Mine Acidophilic Nanoorganism” Science vol 314, 22 Dec. 2006.)
• Domain Eukarya (eukaryotic organisms)
Domain Archaea
• Prokaryotic organisms are far more diverse than thought previously.
• Domain Eubacteria (prokaryotic “true bacteria”)• Domain Archaea (prokaryotic “archaeans”)• Domain Eukarya (eukaryotic organisms)– Kingdom Protista– Kingdom Fungi– Kingdom Plantae– Kingdom Animalia
Domain Eukarya
Kingdom Protista
Amoeba Paramecium Giardia
Water Mold Slime Mold
Euglena DinoflagellatesDiatomBrown AlgaeGreen Algae
Kingdom Fungi
Kingdom Plantae
Bryophyte (Moss)
Pteridophyte(Fern)
Pteridophyte(Fern)
Coniferophytes (Pine Trees) Angiosperm;
DicotAngiosperm;
Monocot
Kingdom Animalia
DOMAIN
KINGDOM
CELL TYPE
CELL STRUCTURES
NUMBER OF CELLS
MODE OF NUTRITION
EXAMPLES
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
Fungi
Eukaryote
Cell walls of chitin
Most multicellular; some unicellular
Heterotroph
Mushrooms, yeasts
Plantae
Eukaryote
Cell walls of cellulose; chloroplasts
Multicellular
Autotroph
Mosses, ferns, flowering plants
Animalia
Eukaryote
No cell walls or chloroplasts
Multicellular
Heterotroph
Sponges, worms, insects, fishes, mammals
EukaryaClassification of Living Things
Key Characteristics of Kingdoms and Domains
Go to Section:
Section 18-3
are characterized by
such as
and differing which place them in
which coincides withwhich coincides with
which place them in which is subdivided into
Living Things
Kingdom Eubacteria
Kingdom Archaebacteria
Eukaryotic cellsProkaryotic cells
Important characteristics
Cell wall structures
Domain Eukarya
Domain Bacteria
Domain Archaea
Kingdom Plantae
Kingdom Protista
Kingdom Fungi
Kingdom Animalia
Go to Section:
EubacteriaArchaebacteriaProtistaPlantaeFungiAnimalia
Kingdoms
Domain Kingdom Phylum Class Order Family Genus SpeciesDid King Phil call old fat George stupid ?
Carolus von Linnaeus(1707-1778)
Swedish scientist who laid the foundation for
modern taxonomy
Binomial Nomenclature• Carolus von Linnaeus • Two-word naming system
– Genus• Noun, Capitalized,
Underlined or Italicized– Species
• Descriptive, Lower Case, Underlined or Italicized
Ursus americanus
American Black Bear
Binomial Nomenclature: “a two-name system”
First part of name: genus first letter always capitalized
Second part of name: species first letter always lowercase
Entire name is underlined and italicized
Names must be submitted for acceptance by original discoverer, and are generally Latin or Latinized
Canis domesticus Canis lupus
Names are generally closely related organisms are often in the same genus, also giving clues about their names.
Some names are given for the discoverer, or the discovery location, or even a Latinized descriptive term in English.
Often Latin names contain clues about the type of organism being described.
Systematics:Evolutionary Classification of
Organisms
• Systematics is the study of the evolution of biological diversity, and combines data from the following areas.– Fossil record– Comparative homologies– Cladistics– Comparative sequencing of DNA/RNA among
organisms– Molecular clocks
Mammals Turtles Lizards and Snakes
Crocodiles Birds Mammals Turtles Lizards and Snakes
Crocodiles Birds
CladogramPhylogeneticTree
Taxonomic Diagrams
A phylogenetic tree is a family tree that shows a hypothesis about the evolutionary relationships thought to exist among groups of organisms. It does not show the actual evolutionary history of organisms.
Why a hypothesis?
Phylogenetic trees are usually based on a combination of these lines of evidence:
Fossil record
Morphology
Embryological patterns of development
Chromosomes and DNA
Taxa show unique combinations of characteristics.
For example, birds have feathers, beaks, and wings, and lay eggs, while mammals have hair, teeth, and give live birth.
Cladistics - is a relatively new system of phylogenetics classification that uses shared derived characters to establish evolutionary relationships. A derived character is a feature that apparently evolved only within the group under consideration.
Diagrams called cladograms are used to represent the phylogeny of organisms.
A phylogenetic tree based on a cladistic analysis is called a cladogram.
What derived character is shared by all the animals on the cladogram on the next slide?
There are three basic assumptions in cladistics:
1.Organisms within a group are descended from a common ancestor.
2.There is a bifurcating pattern of cladogenesis.
3.Change in characteristics occurs in lineages over time.
Cats are more similar to dogs than they are to frogs, because they share a more recent common ancestor with dogs
TRADITIONAL CLASSIFICATION
CLADOGRAM
Appendages Conical Shells
Crab Barnacle Limpet Crab Barnacle Limpet
Crustaceans Gastropod
Molted exoskeleton
Segmentation
Tiny free-swimming larva
Traditional Classification Versus Cladogram
Birds MammalsReptile
AmphibianFish
Four LimbsAmniotic Egg
EndothermicFur
Feathers
Vertebrae
Fish
Amphibians
Reptiles
Birds Mammals
Possible evolution of the Kingdom Animalia
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 reveals more DNA in common, the more recent the common ancestor
Dichotomous Keys Identify Organisms • Dichotomous keys versus evolutionary classification• Dichotomous keys contain pairs of contrasting
descriptions.• After each description, the key directs the user to another
pair of descriptions or identifies the organism.
Example: 1. a) Is the leaf simple? Go to 2
b) Is the leaf compound? Go to 3
2. a) Are margins of the leaf jagged? Go to 4b) Are margins of the leaf smooth? Go to 5