Classification
of Living Things :
aka "taxonomy"
There are lots and lots and lots and lots and lots of different types of organisms out there. Taxonomy attempts to organize all of these organisms into increasingly smaller & smaller groups until you are left with a group of all the same type of organism (namely, a species).
Today's classification is based mostly on similarities in structure and evolutionary relationships.
Which of these brainy scientists is to blame (responsible) for our current classification system :
Charles Darwin, Robert Hooke, Carolus Linnaeus, or Rudolph Virchow ?
Do you know, do you know, do you know ? The answer is ...
Now before we get to classifying
anything, we have to make sure we know some ...(can you guess ?)
......VOCABULARY !!!!
See if you
know these terms. If you don't, everything else is just gonna look like
gobbaldy-gook.
So learn these 1st !!!
|
autotrophic |
multicellular
|
1.
capable of locomotion (can move from place to place --- walk, fly, swim)
2. not capable of
locomotion (movement)
3. composed of
more than one cell
4. composed of
only one cell
5. a cell that
does not have a membrane-bound nucleus
6. a cell that
does have a nucleus
7. a number of
individual cells that exist as a closely associating group
8. can synthesize
(make) organic compounds (food) from inorganic materials
9. must ingest
(eat) pre-formed organic materials (food) from its environment
Organisms first get classified into
a KINGDOM. Each kingdom has
certain defining characteristics. The kingdoms, which are a large & varied
group of organisms, then get divided up into smaller subgroups (called phyla),
which in tern get subdivided, and so on ...
The different kingdoms & their
characteristics is a pretty good chunk of info so I've placed it on a separate
page. To get to it click here. You could finish
working with this page first, or check out the kingdoms & come back, the
order doesn't really matter. The bad news is that eventually you're
responsible for understanding ALL of this ....
(it's OK, take it a little at a time).
A kingdom then, is the largest
group. Within a kingdom you have organisms that share certain characteristics. At the same
time, organisms in the same kingdom can be very different from one another. For
example humans, frogs, eagles, salmon, hydra, earthworms, grasshoppers, and
clams are all animals, and yet they are all quite different from each other.
So we take the wide variety of organisms in a kingdom and subdivide them into other groups. The subgroups (from largest to smallest) are :
KINGDOM, PHYLUM, CLASS, ORDER, FAMILY, GENUS, SPECIES
These groups can be remembered using this sentence :
King Phyl Came Over
For Good Spaghetti.
(The first letter of each word in
the sentence is the first letter of each
classification group & they're
listed in the correct order.)
In order to illustrate these
groups, let's look at the classification of a few animals.
|
GROUP NAME |
ORGANISM |
||||
|
HUMAN |
CHIMPANZEE |
HOUSE CAT |
LION |
HOUSEFLY |
|
|
KINGDOM |
Animalia |
Animalia |
Animalia |
Animalia |
Animalia |
|
PHYLUM |
Chordate |
Chordate |
Chordate |
Chordate |
Arthropoda |
|
CLASS |
Mammal |
Mammal |
Mammal |
Mammal |
Insect |
|
ORDER |
Primates |
Primates |
Carnivora |
Carnivora |
Diptera |
|
FAMILY |
Hominidae |
Pongidae |
Felidae |
Felidae |
Muscidae |
|
GENUS |
Homo |
Pan |
Felis |
Felis |
Musca |
|
SPECIES |
sapiens |
troglodytes |
domestica |
leo |
domestica |
|
Scientific Name |
Homo sapiens |
Pan troglodytes |
Felis domestica |
Felis leo |
Musca domestica |
NOTES :
1) all 5 of the
organisms are classified as animals because they are multicellular, have
eukaryotic cells, are heterotrophic, & capable of moving (motile)
2) the human,
chimp, cat & lion have enough similar characteristics that they are put in
the same phylum & in the same class too
3) the defining
characteristics of each subgroup (as you go down a column) become more &
more specific. the shared characteristics of the members of a kingdom are
broad, the shared characteristics of members of a species are very specific.
4) in order for
two organisms to be in the same "small" group, they must also be in
all the same "big" groups above it. for example : if two organisms
are in the same ORDER, they must be in the same class, phylum &
kingdom. even though the cat & the housefly have the same species group
name (domestica), they CAN'T BE the same species because they are not in the
same genus, family, order, etc. In fact, that last group name (species)
doesn't really mean anything all by itself. The correct, full species
name is the organism's two-part scientific name (see #5).
5) REALLY IMPORTANT : every organism is given a
scientific name which consists of its genus name (1st) & species name
(2nd). This is called binomial nomenclature (bi-nomial = 2-names) & is
attributed to Carolus Linnaeus (remember him ?). so a human's scientific name
is Homo sapiens, a lion's is Felis leo, a house cat's is Felis
domesticas, etc. In a SCIENTIFIC NAME, the genus name should be
capitalized & the species name lowercase, & both should be either italicized
or underlined.
6) the closer the
evolutionary relationship between two organisms, the more groups they have in
common. so of the 5 in this chart, the cat & lion are most closely related
(they are classified together in the first 6 groups). A human is more related
to a chimp (4 groups in common) than to a lion (only 3 common groups).
TIME FOR SOME QUESTIONS ABOUT SUBGROUPS !
1) Which choice lists the groups in order of decreasing variety ?
A. species, genus, family, phylum
B.
genus, species, kingdom, phylum
C.
kingdom, phylum, genus, species
2) Which choice is most closely related to Acer rubrum ?
A. Rubrum acer
B. Acer
saccharum
C. Quercus
acer
D. Quercus
rubrum
3) Which is an acceptable way to write the scientific name for humans ?
A. Homo Sapiens
B. Homo
Sapiens
C. homo
sapiens
D. Homo
sapiens
4) Which is true of two plants that belong in the same genus ?
A. they must be in the same family
B.
they must be the same species
C.
they must be the same color
D. they
can't be in the same phylum
5) Who originated the system of binomial nomenclature ?
A. Darwin
B.
Linnaeus
C.
Hooke
D.
Aristotle
REMEMBER TO CHECK
OUT THE "KINGDOMS" PAGE
(IF YOU HAVEN'T
ALREADY).
|
Back
to Biology Topics Outline |
Please e-mail questions,
comments, or site problems to mr.lubey |
Lubey's |
Classification
of Living Things : ANSWER PAGE
|
Carolus Linnaeus is the "father of modern taxonomy". |
|
ANSWERS
TO CLASSIFICATION VOCABULARY (<back)
|
|
ANSWERS TO "QUESTIONS ABOUT SUBGROUPS" 1) C ---> "decreasing variety" means the groups are getting smaller. Remember : kingdom big & varied, species small & specific. 2)
B ---> first of all the fact that you may have no idea what Acer rubrum
is actually doesn't matter. The question is about your understanding of
scientific names & the groups they represent. The most closely related to
Acer rubrum would be another Acer rubrum (the same species) but
that is not a choice. The next closest relation would be to members of the
same genus (Acer), so the answer is "B". Even though choice
"D" has "rubrum" as a species group name, it is a
different genus (Quercus), & therefor not as closely related to Acer
rubrum as "B" (Acer saccharum). 3) D ---> the acceptable formats are either Genus species or Genus species 4) A ---> if two organisms are in the same genus they are also in all the same subgroups that are larger than the genus group (family, order, class, phylum, kingdom) 5) B---> Linnaeus, it's a fact to memorize. |