Transcript Classification power point

Classification
Biology 11
Citadel High School
2010
What is classification and why
do we classify?
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Classification is the action of grouping
objects in useful units.
Scientists are always discovering new species
of organisms.
We classify organisms in order to better
understand them and how they relate to
other organisms.
What is the science of
classifying?
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Taxonomy is the science of classifying
organisms. It consists in classifying
organisms according to similar and
different characteristics. The
characteristics used in classification can
vary.
The history of classification
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Aristotle (384-322 BC) was one of the
first taxonomists. He classified the
plants into grasses, bushes, and trees.
He classified the animals depending on
whether they lived on the earth, in
water, or in air. (It didn't explain the
fact that some birds were in water and
air.)
Natural Classification
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One of the objectives of the modern
taxonomy is to establish a natural
classification founded on evolution.
Related organisms have more features in
common than the distantly related
organisms.
Carolus Linnaeus
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A Swedish botanist who
elaborated a
classification that is
used again today.
Linnaeus established
binomial nomenclature.
Binomial Nomenclature
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The binomial nomenclature is a set of
scientific names formed of two words. The
first name designates the Genus (a group of
similar species), and the second designates the
species.
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Ex. sugar maple  Acer saccharum
Binomial Nomenclature
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Ex. sugar maple  Acer saccharum
The Genus is written with a capital and the
species with a lower-case letter and the two
names are in italic or underlined.
As binomial nomenclature is in Latin, scientists
all over the world can understand it, whatever
their maternal language.
Why dont we use common
names?
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Common names are not used
because they are not precise.
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Ex: cougar, puma and mountain lion
are all the same animal!
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Merle: is a different bird in different
Canada and in France.
The groups …
Categories
Example
English
kingdom
Animalia
Animal
phylum
Chordata
Chordates
sub-phylum
Vertebrata
Vertebrates
class
Mammalia
Mammalian
order
Primates
Primates
family
Pongidae
Pongidae (big monkeys)
genus
Gorilla
Gorilla
species
Gorilla Gorilla
Gorilla
subspecies
Gorilla Gorrilla
beringei
mountain Gorilla
Phylogeny
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Phylogeny is the history of the evolution
of the species. Scientists compared some
modern shapes to fossils of similar shapes.
According to the biologists, new species
appeared as the organisms adjusted
(evolved) and the populations changed.
Phylogenetic Trees (pg
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The representation of this classification
looks like a tree, the modern species
are indicated at the end of the
branches.
The groups closer in the tree have a lot
of common features ; the distant groups
are very different and they are
probably not closely related.
To determine the relations
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Taxonomists compare the
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appearance,
the internal structures,
the stages of development,
the chemical composition, etc.
All organisms are related either closely or
quite distantly.
http://4e.plantphys.net/images/ch01/wt0101a_s
.png
http://ionetics.blogspot.com/2006_05_01_a
rchive.html
Ernst Haeckel
middle of the 19th century
One of the first to describe the
evolutionary relationships
between living organisms.