Transcript Classification Power Point Presentation

The Diversity of Life
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Biologists have
identified about 1.5
million organisms.
Thousands more
remain to be found.
Great variation in
organisms exists.
Diversity continued
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Some organisms
are clearly plant or
animal.
Other organisms are
more difficult to
classify.
Thus we need a
classification
system!
Plant and Animal Characteristics
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As previously discussed, it is relatively
simple to distinguish plants from
animals.
See handout.
Classification Categories
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The categories used
by biologists to
classify an organism
are: Kingdom,
Phylum,Class,
Order, Family,
Genus, and
Species.
See Table 6.1 on
page 95.
Nomenclature
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Nomenclature is a
system for naming
organisms.
Linnaeus developed
the binomial
system of
nomenclature.
Nomenclature continued
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Binomial means two
names.
The names must be in
Latin.
The first name is the
Genus and the second
name is the Species.
For example for a human
it is Homo sapiens and
for the frog Rana pipiens.
Modern Taxonomy
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In the mid 1800’s the common belief
was that species did not change.
Biologists collected single specimens
that were used to represent all species
of that one organism.
They called these type specimens.
Variations were ignored.
Later in 1859 it was noted that over long
periods of time a species will change in
response to the environment.
Species
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The term species refers to a similar
population of organisms that can
interbreed in nature.
Over time, species may interbreed,
evolve and form new species.
This phenomenon further supports the
need for a classification system.
Classification of Living
Organisms Handout
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This handout, shows
us that we have two
broad categories of
living things:
Prokaryotes and
Eukaryotes
The Prokaryotes
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Cells are called prokaryotic.
Lack a nucleus.
Lack membrane bound
organelles.
Ribosomes are smaller
than those in eukaryotic
cells.
DNA lacks histones
(Special protein)
Flagella are twisted strands
of protein.
Ex. Bacteria
Eukaryotes
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Cells are called eukaryotic
Cells have a well defined
nucleus, with DNA containing
histones.
Membrane bound organelles
are present(mitochondria, etc.)
Flagella have microtubules in
the 9+2 pattern.
Three Domain System
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Latest system to classify living things.
Developed in the last 20 years by
microbiologists who believe that
microbes dominate the diversity of life
on Earth.
This system is based on gene studies
and in particular on rRNA, which is
found in all living things.
Three Domain System continued
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The three domains include 2 groups for
bacteria and 1 for the rest of the living
things.
1. Archaea Bacteria: includes ancient
bacteria that can be found in very harsh
environments.
Ex. Methane producers, salt lovers,and
heat lovers.
Three Domain System continued
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2. Eubacteria: This domain includes
the true bacteria that are found in
various environments such as E.coli
that is found in the intestines of warm
blooded animals. Blue - green algae
are also included in this group.
3. Eucharya: All remaining organisms.
Cells have distinct nuclei and
organelles.