Transcript biology_chapter_18

Chapter 18
Classification
Section 18-1
• Why Classify?
• Because of the diversity and number of
organisms on planet Earth.
• Each organism need a name, and it needs to
be organized into groups that biological
meaning.
• Taxonomy-scientists classify organisms and
assign each one a universally accepted name.
• Carolus Linnaeus developed a two-word
naming system called binomial nomenclature.
We still use this system today.
• Each species is assigned a two-part scientific
name. It is always written in italics. The first
word is capitalized, and the second word is
lowercase.
• The name for a grizzly bear, Ursus arctos, is
one example.
• The first name, Ursus, is the genus name.
Genus is a group of closely related species.
The genus Ursus contains 5 other types of
bears, including polar bears.
• The second part of the name, arctos, is the
species name.
• Linnaeus’s classification system is hierarchical,
which means it consists of levels.
• There are 7 levels, and the list is from largest
to smallest:
• Kingdom, Phylum, Class, Order, Family,
Genus, Species.
• Each of the 7 is known as a taxon, which is a
taxonomic category.
• Family-A group of genera that share many
characteristics. Example: Bears are in the
family Ursidae.
• The bears, along with 6 other families of
animals, such as dogs (Canidae) and cats
(Felidae) are grouped together in the Order
Carnivora. An Order is a broad taxonomic
category made of similar families.
• Class is the next larger category. It is made up
of similar Orders.
• Example: The order Carnivora is placed in the
class Mammalia, which includes animals that
are warm blooded, have body hair, and
produce milk for their young.
• Several different classes make up a Phylum
(plural Phyla). It includes many different
organisms that share important
characteristics.
• The largest group is Kingdom. All animals are
placed in the kingdom Animalia.
Flowchart
Section 18-1
Linnaeus’s System of Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Figure 18-5 Classification of Ursus arctos
Section 18-1
Grizzly bear Black bear
Giant
panda
Red fox
Coral Sea star
Abert
squirrel snake
KINGDOM Animalia
PHYLUM Chordata
CLASS Mammalia
ORDER Carnivora
FAMILY Ursidae
GENUS Ursus
SPECIES Ursus arctos
• Phylogeny: the study of evolutionary
relationships among organisms.
• Biologists now group organisms into
categories that represent lines of evolutionary
descent, or phylogeny, not just physical
similarities. This is known as evolutionary
classification.
• This studies how long ago organisms have had
a common ancestor.
• The assumption in evolutionary classification
is that new and better traits arise over long
periods of time.
• Derived Characteristics are those that appear
in recent parts of a lineage or line but are not
present in older more distant times.
• A Cladogram is a diagram that shows the
evolutionary relationships in a group of
organisms.
Traditional Classification Versus Cladogram
Section 18-2
Appendages
Crab
Conical Shells
Barnacle
Limpet
Crustaceans
Crab
Gastropod
Barnacle
Limpet
Molted
exoskeleton
Segmentation
Tiny free-swimming larva
CLASSIFICATION
BASED ON VISIBLE
SIMILARITIES
CLADOGRAM
Traditional Classification Versus Cladogram
Section 18-2
Appendages
Crab
Conical Shells
Barnacle
Limpet
Crustaceans
Crab
Gastropod
Barnacle
Limpet
Molted
exoskeleton
Segmentation
Tiny free-swimming larva
CLASSIFICATION
BASED ON VISIBLE
SIMILARITIES
CLADOGRAM
The Kingdoms
• Before the 1990’s, there were only thought to
be 5 kingdoms: Monera, Protista, Fungi,
Plantae, and Animalia.
• During the 1990’s, a sixth kingdom was added
as Monera was split into 2 new kingdoms:
• Eubacteria, Achaebacteria, Protista, Fungi,
Plantae, and Animalia.
Figure 18-12 Key Characteristics of
Kingdoms and Domains
Section 18-3
Classification of Living Things
DOMAIN
Bacteria
Archaea
KINGDOM
Eubacteria
Archaebacteria
CELL TYPE
Eukarya
Protista
Fungi
Plantae
Animalia
Prokaryote
Prokaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Cell walls with
peptidoglycan
Cell walls
without
peptidoglycan
Cell walls of
cellulose in
some; some
have
chloroplasts
Cell walls of
chitin
Cell walls of
cellulose;
chloroplasts
No cell walls
or chloroplasts
Unicellular
Unicellular
Most unicellular;
some colonial;
some
multicellular
Most
multicellular;
some
unicellular
Multicellular
Multicellular
MODE OF
NUTRITION
Autotroph or
heterotroph
Autotroph or
heterotroph
Autotroph or
heterotroph
Heterotroph
Autotroph
Heterotroph
EXAMPLES
Streptococcus,
Escherichia coli
Methanogens,
halophiles
Amoeba,
Paramecium,
slime molds,
giant kelp
Mushrooms,
yeasts
Mosses, ferns,
flowering
plants
Sponges,
worms,
insects, fishes,
mammals
CELL
STRUCTURES
NUMBER OF
CELLS
Domains
• The Domain category is more inclusive and is
larger than a Kingdom.
• At this point in time there are 3 Domains:
Eukarya, Bacteria, and Archaea.
Figure 18-13 Cladogram of Six Kingdoms
and Three Domains
Section 18-3
DOMAIN
ARCHAEA
DOMAIN
EUKARYA
Kingdoms
DOMAIN
BACTERIA
Eubacteria
Archaebacteria
Protista
Plantae
Fungi
Animalia