CLASSIFICATION
Chapter 18 – pages 420-437
►2
- 4.5 million species (maybe 4x more)
► Taxonomy – the science of classifying
organisms. (identification, study of and
placing in appropriate groups.)
► Taxonomists – scientists who study and
carry out classification
► 2 purposes
 Identify organisms and naming them
 Basis for recognizing natural groups and putting
order in nature
Carolus Linnaeus
► Swedish
botanist that developed
the system we use today.
► Binomial Nomenclature - a
method of naming organisms by
using 2 names
► Every organism has a 2 part
Latin name – Genus, Species
► Examples – Homo sapiens
►
Latin was chosen because:
1. Well known language
2. Unchanging
3. Descriptive
►
Common names are not used because:
1. Confusing and misleading
2. Vary from region to region
3. May refer to several species
►
Seven major groups, called taxons or taxa
as plural, that all living things are placed
in.
Example
1.
2.
3.
4.
5.
6.
7.
Kingdom
Phylum
Class
Order
Family
Genus
Species
Animalia
Chordata
Mammalia
Primates
Hominidae
Homo
sapiens
Taxonomy
Address
► Kingdom
► Country
► Phylum
► Province
► Class
► Town
► Order
► Street
► Family
► Number
► Genus
► Last
► Species
name
► First Name
►
Taxonomists use several methods to classify
living things.
1. Structural similarities and differences
2. Genetic makeup
►
The more features in common, the closer the
relationship.
►
Species – structurally similar and have a close
genetic makeup. Are able to interbreed and
produce fertile offspring.
►
We use a 6 kingdom system
1.
2.
3.
4.
5.
Eubacteria – “true” bacteria
Archaebacteria - bacteria
Protista – algae, protozoa
Fungi – mushrooms, yeast, mold
Plantae – moss, ferns, conifers, flowering
plants
6. Animalia – sponges, worms, starfish, insects,
humans, etc.
► Dichotomous
keys are 2-part keys used to identify
living things.
► Choices are made about the organism and will
lead you to the proper identification.
Example:
►
►
►
►
1a. Fruit is a group of akenes.......................go to 2
1b. Fruit is a group of follicles.......................go to 4
2a. Petals none............................................go to 3
2b. Petals present.........................................Ranunculus
3a. Sepals usually 4......................................Clematis
3b. Sepals usually 5......................................Anemone
4a. Flowers regular........................................Aquilegia
4b. Flowers irregular......................................Delphinium
Spider key
► Scientists
today accept that organisms have
changed over time.
► The
study of evolutionary history of living
things is called phylogeny.
►A
diagram of these relationships among
organisms is called a phylogenetic tree.
► At
the base of the tree is the most ancestral
form and the branches are the descendants.