Transcript Chapter 18: Classification

Chapter 18:
Classification
You are required to put on clothes each day
before coming to school.
How do you go about this in the most efficient
manner to get you out of the house on time for
school each day?
• There are 1.5 million different identified
species (alive and extinct)
• How can we keep all these organisms
in order?
• Classification
– is the method of logically grouping
organisms based on some common
characteristics
• Taxonomy
– does the actually grouping into the groups
called TAXON (s – TAXA) with some kind of
biological significance.
– Ie. Things that fly, swim, walk, have
feathers, etc.
How many different terms can you think of for trying to
tell someone something is really good?
Do these terms have meanings that may confuse
someone else?
• There is a need for a common term to
describe an individual organism so that
all people understand when the term is
used.
• Carolus Linnaeus (mid 1700’s) came up
with the system of Binomial
Nomenclature.
Carolus Linnaeus
• He assigned two Latin names to each
different species of organisms.
• This is their Scientific name.
• Homo sapiens (human) Homo sapiens
Ursus maritimus (polar bear) Ursus maritimus
Acer rubrum (red maple)
Ursus arctos (grizzly bear)
Cur Latin?
• Scientific names will always be in Latin.
• Latin is a dead language that will not
evolve unlike other languages.
• Little chance of change through time.
• Universally understood in the science
community
The Taxonomic order:
• From the largest, most inclusive group to the
smallest, most exclusive, specific taxa.
Taxa
Human
Kingdom
Phylum
Class
Order
Family
Genus
Species
Animalia
Chordata
Mammalia
Primate
Hominoidae
Homo
sapiens
Grizzly
Animalia
Chordata
Mammalia
Carnivora
Ursidae
Ursus
arctos
Chimp
Animalia
Chordata
Mammalia
Primate
Hominoidae
Pan
troglodyte
Which two organisms are more closely related and why?
• Modern methods of classification rely
on evolutionary relationships in place
of homologous structures.
• Birds, bats and insects should not be
classified together because they all
have wings and fly.
• Evolutionary classification classifies
organisms in taxa based on lines of common
descent, not physical similarities
– Uses proteins, DNA and genes to determine
classification and relatedness
• Human Genome project that decoded our
DNA helped to show evolutionary
relationships with other species, even totally
unrelated species. Think back to your Amino
Acid lab
– The more closely related organisms are, the more
Amino acids they will have in common and the
more recently they evolved from some kind of
common ancestry.
Kingdoms and Domains
• 1700’s – Plants and Animals only
• 1800’s – Protists, Plants and Animals
• 1950’s – 5 Kingdom system, including
Fungus and Monera
• Now – 6 Kingdoms divided into 3
Domains
Domains:
1. Bacteria – Unicellular, prokaryotic (no
nuclear membrane) with cell walls made up
of peptidoglycan.
–
Kingdoms: Eubacteria – true bacteria. “Normal “
bacteria
2. Archaea – Unicellular, prokaryotic but do not
have cell walls containing peptidoglycan.
These are primitive organisms that could
withstand very harsh environments and a
lack of oxygen.
–
Kingdom: Archaebacteria – methanogens in the
digestive tract of animals and halophiles that live
in the Dead Sea.
3.
Eukarya – Eukaryotic organisms. May be uni or
multi cellular. All have nuclear membranes
– Kingdom: Protista – basically unicellular. Have
plant-like, animal – like or fungus- like
representatives.
•
***Most difficult kingdom to classify. No clear cut
boundaries.
Ie.Amoeba, paramecium, slime mold, Volvox
–
–
–
Kingdom Fungi – Absorptive heterotrophs,
basically multicellular organisms with cell walls
made up of chitin. Ie. Yeast, mushroom, molds
Kingdom Plantae – Multicellular, photosynthetic
organisms. All are autotrophic. Nonmotile with
cell walls containing cellulose. Ie. Mosses,
ferns, conifers, flowering plants and some
algae.
Kingdom Animalia – Multicellular, ingestive
heterotrophs. All lack cell walls. Motile for some
time in their life cycle. Ie. Sponges, jelly fish,
worms, insects, octopus, fish, birds,
reptiles, you
The New and Improved Six Kingdom System
Kingdom
Cell Type
# of Cells
Nutrition
Representative
organism
Archaebacteria
Prokaryotic
Unicellular
Autotrophic or
Heterotrophic
Blue-green bacteria,
Methanogens
Eubacteria
Protista
Fungi
Plantae
Animalia
Prokaryotic
Unicellular
Autotrophic or
Heterotrophic
E.coli,
Staphylococcus,
Streptococcus,
Spirochetes
Eukaryotic
Uni, multi or
colonial
Autotrophic or
Heterotrophic
Amoeba, Paramecium,
Euglena,
Plasmodium,
Diatoms
Eukaryotic
Uni or
Multicellular
Absorptive
Heterotroph
Yeast, Mushrooms,
Molds, smuts,
rusts
Multicellular
Autotrophic
(some
heterotrophic)
Eukaryotic
Eukaryotic
Multicellular
Ingestive
Heterotroph
Mosses, ferns,
Horsetails,
Conifers,
Flowering plants
Sponges, Coral, Sea
stars, EW,
Insects, Fish,
Amphibians,
Reptiles, Birds,
Mammals