Diversity of Living Things
• Introduction to
Taxonomy, Diversity
and the Six Kingdoms
of Life.
Classification
• Everything classifies into one category or
another. When you go to the movies you are put
into a category for payment. When you use a
bank machine you are classified as English
speaking or French Speaking…
• The categories that are made and the groups
that belong in them reflect patterns in the world
around us.
• A particularly important challenge to biologists, is
finding a way to classify Earth’s millions of
species.
Where to Begin…
• Aristotle classified
living things into two
large groups. He
believed everything
was either in the
Kingdom Animalia or
the Kingdom Plantae,
terms we still use
today.
Aristotle’s Animals
•
Aristotle said that
animals were
anything that:
1) Moved
And
2) Ingested food
Aristotle’s Plants
•
Aristotle said plants
were anything that:
1) Stayed put
And
2) Obtained food
through the Sun
(photosynthesis)
Exceptions to Aristotle’s ‘Rule’
The move from Aristotle
• Aristotle’s thoughts were believed by
the majority of the populace right up
until the 17th century… when a
fantastic invention made the job of
classification a whole lot harder…
That invention was the microscope
Not Confirmed… yet…
Classifying becomes harder…
• The Microscope made
classification a whole lot
harder because now a
world of previously
unseen microscopic
organisms could be seen.
Some behaved like
animals and others like
plants, but some did both
animal and plant things
such as the Euglena
(pictured).
Leave it to the Germans to make
life easier…
• In 1866, Ernst
Haeckel, a German
biologist, proposed
classifying all microorganisms that are
neither plant nor
animal into a third
Kingdom, the
Kingdom Protista.
The Unwritten Rule
• ‘If you cannot classify it,
make a new Kingdom.’
• Mushrooms and
moulds were placed in
the animal kingdom
because they did not
perform
photosynthesis… now
they are in a 4th
Kingdom, the Kingdom
Fungi
Kingdom #5
• Bacterial cells differ
from the cells of the
other four kingdoms.
• Therefore they were
placed into a 5th
Kingdom, originally
called the Kingdom
Monera, but now
called Kingdom
Bacteria.
The 6th and Final Kingdom
• In the 1990s there was
increased interest in bacteria
that grew in extreme
environments. Detailed
studies showed that these
organisms were not in fact
bacteria, but differed in
protein and RNA structure,
thereby splitting the Kingdom
Monera into the previously
mentioned Kingdom Bacteria
and now, the Kingdom
Archaea, featuring these
extreme environment
prokaryotic organisms.
Natural Division amongst the
Kingdoms
• The 6 Kingdoms have a natural division
amongst them. The Kingdoms Bacteria and
Archaea are both made up of prokaryotes while
the other four Kingdoms are made up of
eukaryotes.
The Organization of the Kingdoms
• Detailed studies have shown that Archaea are
as different from Bacteria as they are with the
eukaryotes, therefore the 6 Kingdoms are put
into 3 Domains.
• The Domain Archaea has the Kingdom Archaea.
• The Domain Bacteria has the Kingdom Bacteria
• The Domain Eukarya has the other 4 Kingdoms
(Protista, Fungi, Plantae and Animalia)
Taxonomy
• The purpose of a
classification system
is to allow the
accurate identification
of a particular
organism, no matter
where it exists.
• Taxonomy is the
practice of classifying
organisms
The Linnean Classification System
• Today’s system of
Taxonomy was
constructed 300 years
ago by Swedish
botanist, Carolus
Linneaus.
• He used physical
characteristics to
identify different
species and separate
them into groups.
The Linnean classification system
• During the colonization of
the new world, European
explorers were able to
identify new species
using his system… it was
so easy to use.
• Today it has been
adapted to use DNA,
protein and mating
behaviours to help in
classifying organisms.
The Taxonomic Hierarchy
•
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•
•
•
•
•
•
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Eukarya
Animalia
Chordata
Mammalia
Carnivora
Felidae
Lynx
Rufus
Taxonomic Hierarchy
• We do not use the whole
taxonomic hierarchy
when naming. We use
the two smallest groups,
the Genus and the
Species.
• This is called binomial
nomenclature.
• Lynx rufus or Lynx rufus
are the acceptable written
names for this animal.