Transcript Classification - Nutley Schools

Reference Text:
Modern Biology
Chapter 18 – Classification
• All Organisms on earth
are said to have descended
from an ancient common
ancestor – the classification
of all species reflects their
relationship with many
related species…
WHAT THINGS DO WE CLASSIFY?
WHY DO WE CLASSIFY THEM?
Every Year, thousands of new species
are discovered.
To study so many life-forms, biologists organize
or classify them into numerous groups based on
their similar characteristics (structures).
Classification: to group things according to
similar/different structures that they share.
Classification is very useful in Biology…
• Indicates relationships between species
• Accurately & uniformly names organisms; star
fish and jelly fish aren't’ really fish
TAXONOMY:
The branch of biology that classifies organisms
according to their characteristics and
evolutionary history
TAXONOMISTS
Taxonomists are scientists that identify & name
organisms.
Taxonomists name things in
a way that reflects their
classification.
They use the same language
(Latin or some Greek) for
all names.
Panthera tigris
Panthera onca
The first classification
system was developed
2000 years ago by Greek
Philosopher Aristotle. He
was the first taxonomist.
Aristotle divided
organisms into plants &
animals
•
•He then subdivided them by
their habitat - land, sea, or air
dwellers
As more & more organisms
began to be discovered,
Aristotle’s system was no
longer adequate for naming &
organizing all life on earth.
Sea”horse”??
Linnaeus’s System
In response to the need
for better organization,
an 18th century Swedish
botanist named Carolus
Linnaeus offered a
solution to the confusion
of classifying and naming
organisms.
Carolus Linnaeus
1707 – 1778
• Created
a hierarchical
system for classifying
•
organisms
Developed naming
system still used today
The “Father of
Taxonomy”
Linnaeus’s System
• Linnaeus classified organisms based on
similarities in morphology (form &
structure), rather than by location.
For example, although
Bats can fly, he classified
them as mammals, not
birds, because they share
common traits with other
mammals; they have hair,
have live births and nurse
their offspring with milk.
Linnaeus’s System
• The Linnaeus System
•
of Taxonomy uses a
hierarchical system
for classifying
organisms from
broadest to most
specific..
Called Levels of
Classification!
Linnaeus’s System
Linnaeus’s Seven-Level Classification
System:
Kingdom, Phylum, Class, Order, Family,
Genus, species
Each category is called taxa, hence the
name
taxonomy!
Linnaeus’s System
Linnaeus’s Seven-Level
Classification System:
BROADEST TAXON
Kingdom
Phylum
Class
Order
Family
Genus
MOST SPECIFIC
Species







Levels of Classification
Keep
Plates
Clean
Or
Family
Gets
Sick
Which two animals would be more closely
related, two from the same phylum or two
from the same genus?
Linnaeus’s System
Linnaeus also developed
the modern system of
naming organisms
known as:
Binomial
nomenclature
Oops! Common names can vary!
Example:
mountain lion
______________
puma
______________
catamou
______________
cougar
______________
. . . are all names for the same animal
Also, some early scientific names were often
long and difficult to remember…
The European bee, for example, carried the
name Apis pubescens, thorace subgriseo,
abdomine fusco, pedibus posticis glabris
utrinque margine ciliatis.
Linnaeus’s System
Binomial nomenclature is a
two-part naming system
that identifies a species
with 2 names:
Uses Genus & species
Either Latin or Greek
Italicized in print
Capitalize Genus, but
NOT species
Underline when writing





Turdus migratorius
American Robin
Binomial Nomenclature
Which TWO are more closely related?
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Taxonomic Classification
Taxonomic Group:
Kingdom:
Phylum:
Class:
Order:
Family:
Genus:
Species:
Name: Genus &
species
tiger
Animal
Chordates
Mammals
Carnivores
Felines
Panthera
tigris
grey wolf
Animal
Chordates
Mammals
Carnivores
Canines
Canis
lupus
REMEMBER:
Organisms are classified together because
they are similar; they are similar because
they stem from a common ancestor.
Woodchuck
Squirrel
Linnaeus focused on morphology or features of
an organism when classifying it.
Today we know that those features are largely
influenced by genes, which are inherited, or
passed down from our ancestors.
Modern taxonomists classify the
tremendous diversity of organisms based on
how close their evolutionary relationships
are with other living and once-living things.
They all agree that the classification of an
organisms should reflect their
PHYLOGENEY
•
Phylogeney: The evolutionary relationships
between all groups of organisms based on
ancestor/descendant relationships.
The morphology Linnaeus followed holds
true to phylogeny or evolutionary
relationships in most cases….
Modern taxonomists construct a Phylogenetic
tree, or family tree to show these
relationships.
The phylogenetic
tree shows the
evolutionary
relationships
between
different groups
of organisms.
Pangolin
Armadillo
Modern Taxonomist consider several lines
of evidence when classifying organisms
according to their evolutionary history:
Four Types of evidence include:
• Morphology (homologous structures)
• Embryological development
• DNA, RNA, Amino acid sequences
• Fossil records
Homologous Structures (BONES in the FORELIMBS) shows
Similarities in the morphology of mammals.
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Similarities in Vertebrate
Embryos
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Similarities in DNA
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Evidence found in the Fossil Record
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A relatively new system of
phylogenetic classification is called
cladistics.
•
Based on Derived characteristics:
•
Certain features that evolved only within
the group being studied
• Example: if the group being studied is
birds, having feathers is the derived
character.
In this approach, ancestry diagrams are made
through derived characters analysis.
These diagrams called CLADOGRAMS
Primate
Cladogram
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Aristotle classified organisms as
either plants or animals..
Linnaeus took it a step further
and classified organisms into
more specific groups such as
class, order, family, genus and species.
http://science.discovery.com/videos/100-greatest-discoveriesshorts-classification-of-species.html
…some organisms don't quite fit into the plant
or animal group.
As a result, several other kingdoms of
organisms are now used.
Today's scientists look at cell structure, how
the organism moves, gets food, and
reproduces to place it in the correct kingdom.
Two Current Classification Systems
•Six Kingdom System
•Three Domain System
Old Five Kingdom System:
Monera include all prokaryotic
organisms, which are all unicellular
life forms that lack a true nucleus.
Protista, Fungi, Plantae,Animalia
include all eukaryotic organisms,
which are all life forms that do
contain a true nucleus and various
organelles.
The NEW Six Kingdom System:
Archaebacteria & Eubacteria include
all prokaryotic organisms, which are
all unicellular life forms that lack a
true nucleus.
Protista, Fungi, Plantae,Animalia
include all eukaryotic organisms,
which are all life forms that do
contain a true nucleus and various
organelles.
FUNGI
ANIMALIA
PLANTAE
PROTISTS
EUBACTERIA
ARCHAEBACTERIA
Broadest, most inclusive taxons
are the Three Domains
Archaea, Bacteria, and Eukaryota
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Six-Kingdom System
Three-Domain System
The main criteria of grouping here is Eukaryotic vs. Prokaryotic
REMEMBER: These systems are not etched in stone!
They have been revised over the years, and will continue
to be revised when new evidence is discovered.
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Domain – Archaea
Kingdom - ARCHAEBACTERIA
• Probably the 1 cells to evolve
• Live in HARSH environments
• Found in:
– Sewage Treatment Plants (Methanogens)
– Thermal or Volcanic Vents (Thermophiles)
– Hot Springs or Geysers that are acid
– Very salty water (Dead Sea; Great Salt
Lake) – Halophiles
• Chemosynthesis: use inorganic compounds to
st
make food.
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Kingdom - ARCHAEBACTERIA
Hot Springs
Acid mine drainage
The Dead Sea
Sulfur Springs
Domain - Bacteria
Kingdom - EUBACTERIA
• Some may cause DISEASE
• Found in ALL HABITATS except harsh
ones
• Important decomposers for environment
• Commercially important in making
cottage cheese, yogurt, buttermilk, etc.
(Acidophilus).
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Kingdom - EUBACTERIA
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Live in the intestines of animals
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Domain Eukarya is Divided into 4
Kingdoms:
Protista (protozoans, algae…)
Fungi (mushrooms, yeasts …)
Plantae (multicellular plants)
Animalia (multicellular animals)
•
•
•
•
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Domain: Eukarya
Kingdom: Protista
•Most are unicellular
•Some are multicellular
•Some are
autotrophic, while
others are
heterotrophic
Aquatic
•
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Domain: Eukarya
Kingdom: Protista
Fungus Like –
made of threadlike
fibers
Animal Like –
move around and
eat other
organisms
Plant Like – contain
chlorophyll for
photosynthesis
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Domain: Eukarya
Kingdom: Fungi
• Multicellular, except
yeast
• Absorptive heterotrophs
•
(digest food outside
their body & then
absorb it)
Cell walls made of chitin
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Domain: Eukarya
Kingdom: Plantae
•Multicellular
•Autotrophic (except
for carnivorous plants)
•Absorb sunlight to
make glucose –
Photosynthesis
Cell walls made of
cellulose
•
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Mosses
Liverworts
Angiosperms
Gymnosperms
Ferns
Domain: Eukarya
Kingdom: Animalia
•Multicellular
•Ingestive
heterotrophs
(consume food &
digest it inside their
bodies)
Feed on plants or
animals
•
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Domain
Kingdom
Cell Type
Cell Type
Nutrition
Archaea
Archaebacteria
Prokaryote
Unicellular
Both
autotroph and
heterotroph
Bacteria
Eubacteria
Prokaryote
Unicellular
Both
Eukarya
Protists
Eukaryote
Both
Both
Eukarya
Fungi
Eukaryote
Both
Heterotroph
Eukarya
Plantae
Eukaryote
Multicellular
Autotrophic
(mostly)
Eukarya
Animalia
Eukaryote
Multicellular
Heterotroph
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Methanogens,
Thermophiles,
Acidophilles
Characteristics
Cell
Virus
Growth
yes
No
Homeostasis
Yes
No
Metabolism
Yes
No
Mutation
Yes
Yes; necessary for its survival
Genetic Material
Yes
DNA, RNA
Reproduction
Yes by mitosis
*Yes; but only possible when inside
a host cell
Structure
Cytoplasm, membrane bound
organelles, nucleus
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Biologists have developed a precise method to
help them classify and identify unknown
organisms.
The classification tool called a dichotomous key
•Used to identify
organisms
•Characteristics given in
pairs
•Read both characteristics
and either go to another
set of characteristics OR
identify the organism
1a
1b
2a
2b
3a
3b
4a
4b
Tentacles present – Go to 2
Tentacles absent – Go to 3
Eight Tentacles – Octopus
More than 8 tentacles – 3
Tentacles hang down – go to 4
Tentacles upright–Sea Anemone
Balloon-shaped body–Jellyfish
Body NOT balloon-shaped - 5
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