Chapter 18 Classification
Notes
Chapter 18-1 Classification
Classification -to organize living things into groups that have biological
meaning
Taxonomy - is the science of classifying organisms.
Assigning Scientific Names
The naming system was developed by a Swedish botanist named Carolus
Linnaeus. He developed a system of assigning names to organism’s called
Binomial nomenclature.
Binomial nomenclature uses a two word system based on physical and
structure features of the organism. The first part of the name is the
genus and the second part of the name is the species. The scientific
name is always italics. The first name is capitalized and the second name
is lowercased.
Example: earthworm
Lumbricus terrestris
Genus name
species name
There are two main advantages to binomial nomenclature:
1. It provides a common language for all scientists regardless of their
language.
2. It indicates similarities in anatomy and embryology. For example,
binomial nomenclature indicates that the American black bear
(Ursus americanus) and the grizzly bear (Ursus horribilus) are
closely related.
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Chapter 18 Classification
Notes
Linnaeus’s System of Classification
Linnaeus hierarchical system of classification includes seven levels.
They are arranged from the smallest to the largest. Each level is called
a taxon
Levels of Classification (7 taxa- level
KINGS
PLAY
CHESS
ON
FINE
GRAIN
SAND
A species is a group of organisms that look alike; are capable of
breeding; can produce viable (living) offspring that are fertile (capable
of breeding).
Let’s classify some animals!
Category
Kingdom
Phylum
Class
Order
Family
Genus
Species
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Human
Animalia
Chordata
Mammalia
Primates
Hominidae
Homo
sapiens
Housefly
Animalia
Arthropoda
Insecta
Diptera
Musidae
Musca
domestica
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Chapter 18 Classification
Notes
Scientific name of a human according to Linnaeus: Homo sapiens
Scientific name of a housefly according to Linnaeus: Musca domestica
18-2 Modern Evolutionary Classification
Darwin’s ideas about descent with mofification (evolution) has given rise
to the study of phylogeny. Phylogeny is the study of evolutionary
relationships among organism.
Biologists use a diagram called a phylogenic tree to represent lines of
evolution. This tree begins with the most ancestral (oldest) forms and
includes the branching leading to all of its descendants.
Phylogenic tree (Three domains)
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Chapter 18 Classification
Notes
Cladograms –A refined approach to classification that uses only
characteristics that are considered to evolutionary innovative
18-3 Kingdoms and Domains
Five kingdom system
1. Monera
2. Protista
3. Fungi
4. Plantae
5. Animalia
The Three-Domain System
Molecular analyses have given rise to a new taxonomic category called
Domain.
Three Domains
1. Eukarya- includes protista, fungi, plants and animals
2. Bacteria
3. Archaea
Summary of the 5(6) Kingdoms (see table on page 459)
Classification of organisms is based on:





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Cell type - Prokaryotic (no nucleus) vs Eukaryotic (nucleus)
Cell structure - cell wall and specialized organelles
Number of Cell- Unicellular vs Multicellular
Reproduction – Sexual vs Asexual
Mode of Nutrition (energy) – Autotrophic vs Heterotrophic
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Chapter 18 Classification
Notes
Kingdom Animalia
 most are capable of locomotion
 heterotrophic (must consume food)
 the majority reproduce sexually
 multicellular
 eukaryotic cells
Kingdom Plantae
 sessile –do not move
 autotrophic (photosynthesis)
 reproduce sexually (most of the time)
 can reproduce asexually
 multicellular
 eukaryotic cells
Kingdom Fungi
 sessile
 heterotrophic (suck nutrients mainly from dead or decaying organic
matter)
 reproduce both sexually and asexually
 most are multicellular
 eukaryotic cells
Kingdom Protista
 “junk kingdom” both heterotrophic and autotrophic
 all unicellular
 eukaryotic cells
 there are plant-like, animal-like and fungus-like protests
Kingdom Monera (split into Eubacteria and Archaebacteria)
 all unicellular
 prokaryotic cells (no nucleus)
 ex. bacteria
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