Download of Cells - StangBio

Chapter 18: Classification
Section 18-1:
Finding Order
in Diversity
Linnaeus's System of Classification
• Uses taxonomic categories that are based on
shared morphological (physical), behavioral, and
biochemical characteristics:
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
largest classification group
smallest classification group
Linnaeus's System of Classification
• Species together in a smaller taxon
automatically also share all their
larger taxa.
– If they’re in the same phylum, they’re
also in the same kingdom and domain.
– Same order? Also same phylum,
kingdom, and domain.
– Same family? Also same order, class,
phylum, kingdom, and domain.
– Same species? Same everything else!
Domain
Linnaeus's System of Classification
• Here is the classification
for a leopard.
– Cats are also in the family
Felidae. What phylum are
cats in?
– Dogs are in the order
Carnivora. What class are
dogs in?
– Chimps are in the class
Mammalia. Does that mean
chimps are in the genus
Panthera?
Linnaeus's System of Classification
• Classification mirrors
relatedness. The more
taxa (classification groups)
two species share, the
more closely related they
are.
Assigning Scientific Names
Binomial nomenclature – 2 part naming
system
• Typed in italics or underlined when hand
written
• 1st word is capitalized and it refers to the
organism’s genus
• 2nd word is lower case and it refers to the
organism’s species
• Example: polar bear – Ursus maritimus
Dichotomous Keys
• Dichotomous Key –
tool used to help identify
unfamiliar organisms
Section 18-2:
Modern Evolutionary Classification
Cladograms
• Cladogram – diagram that shows evolutionary
relationships among a group of organisms / Shows
order of divergence
• Derived characteristics –
characteristics that
appear in recent parts
of a lineage but not in
its older members
Circle the location of the most recent common ancestor of pigeons and lizards.
Here! To find a common ancestor, trace their lineages BACK towards the origin
until the nearest place that the two lineages meet.
LCA with Lizards
LCA with Perch
Which species is more closely related to salamanders, lizards or perch?
Lizards! The more recent the last common ancestor (LCA), the more related.
Which species is more closely related to mice, chimps or pigeons?
Chimps!
(Tricky) Which species are perch most closely related to?
All but hagfish: Salamanders, Lizards, Pigeons, Mice, and Chimps! The LCA is
equally recent for all of them.
Which species is more closely related to salamanders, perch or hagfish?
Perch!
How to construct a cladogram
1. Construct a table of characteristics that have
have been derived by the evolutionary process
(a.k.a. have evolved).
2. Compare the organisms to see if they
share derived characteristics.
•
For example, all but the amoeba share the
common derived trait of being multicellular,
but only the cat and the kangaroo share the
derived trait of hair.
3. Using the patterns of shared derived
characteristics, construct a cladogram as a
series of Y’s or branches.
• At every Y, the organism that does not share a
common characteristic with the rest of the
group should be "branched off".
• Also, indicate the derived characteristics on
the branches using dots.
Section 18-3:
Domains and Kingdoms
The Domains
• Organisms are classified into one of 3
different domains (archaea, bacteria, and
eukarya).
Archaea
Eukarya
Domain: Bacteria
(Old Kingdom: Eubacteria)
Cell Type: Prokaryotic
# of Cells: Unicellular
Cell Characteristics:
no membrane-bound organelles
cell walls with peptidoglycan (thick,
rigid carbohydrates)
Nutrition: Autotrophic or Heterotrophic
What makes them unique: can live
anywhere from free-living in soil or
deadly parasites
Examples: E.coli, Streptococcus
Domain: Archea
(Old Kingdom: Archeabacteria)
Cell Type: Prokaryotic
# of Cells: Unicellular
Cell Characteristics:
no membrane-bound organelles
cell walls WITHOUT peptidoglycan
unusual lipids in cell membranes
Nutrition: Autotrophic or
Heterotrophic
What makes them unique: live in
extreme environments (most will
die if there is oxygen)
Examples: methanogens, halophiles
Domain: Eukarya
Kingdom: Protista
Cell Type: Eukaryotic
# of Cells: unicellular or colonial
Cell Characteristics:
nucleus and membrane-bound
organelles
Most don’t have cell walls
Some have chloroplasts
Nutrition: Autotrophic or Heterotrophic
What makes them unique: # of cells
Examples: Paramecium, Ameoba,
Volvox, Slime molds, Giant Kelp
(seaweed), algae
Domain: Eukarya
Kingdom: Fungi
Cell Type: Eukaryotic
# of Cells: Mostly Multicellular
Cell Characteristics:
nucleus and membrane-bound
organelles
cell walls made of chitin
(carbohydrate)
Nutrition: Heterotroph
What makes them unique: Involved
with breaking down and recycling
dead and decaying matter. Digest
externally by secreting enzymes
Examples: Mushrooms, Molds,
Yeasts
Domain: Eukarya
Kingdom: Plantae
Cell Type: Eukaryotic
# of Cells: Mostly Multicellular
Cell Characteristics:
nucleus and membrane-bound
organelle
cell walls made of cellulose
(carbohydrate)
Nutrition: Autotroph
(photosynthesis)
What makes them unique: nonmotile
Examples: Mosses, ferns,
flowering plants, trees
Domain: Eukarya
Kingdom: Animalia
Cell Type: Eukaryotic
# of Cells: Multicellular
Cell Characteristics:
nucleus and membranebound organelles
NO cell walls
Nutrition: Heterotrophic
What makes them unique: All
motile
Examples: sponges,
cnidarians, worms, insects,
mollusks, fish, amphibians,
reptiles, birds, mammals
Summary of the Kingdoms