1. Chapter 18 - Classification
Lesson Overview
Chapter 18 - Classification

2. Assigning Scientific Names
The first step in understanding and studying diversity is to describe and name each species.
By using a scientific name, biologists can be sure that they are discussing the same organism. Common names can be confusing because they vary among languages and from place to place.

3. Binomial Nomenclature
In the 1730s, Swedish botanist Carolus Linnaeus developed a two-word naming system called binomial nomenclature.
The scientific name usually is Latin. It is written in italics. The first word begins with a capital letter, and the second word is lowercased.
ex. Homo sapiens

4. Binomial Nomenclature
The polar bear, for example, is called Ursus maritimus.
The first part of the name—Ursus—is the genus to which the organism belongs. A genus is a group of similar species. The genus Ursus contains five other species of bears, including Ursus arctos, the brown bear or grizzly bear.
The second part of a scientific name—maritimus for polar bears—is unique to each species and is often a description of the organism’s habitat or of an important trait. The Latin word maritimus refers to the sea: polar bears often live on pack ice that floats in the sea.

5. Linnaean Classification System
Linnaeus also developed a classification system that organized species into a hierarchy, or ranking.
In deciding how to place organisms into larger groups, Linnaeus grouped species according to anatomical similarities and differences(morphology).

6. Seven Levels
1. Kingdom: the largest and most inclusive of Linnaeus’s taxonomic categories
2. Phylum: classes are grouped includes organisms that are different but that share important characteristics
3. Class: closely related orders are grouped into the next larger rank
4. Order: closely related families are grouped into the next larger rank
5. Family: genera that share many similarities are grouped into a larger category
6. Genus: is a group of similar species
7. Species: individual organism

7. Camel Classification Species: Camelus bactrianus Genus: Camelus
Family: Camelidae
Order: Artiodactyla
Class: Mammalia
Phylum: Chordata
Kingdom: Animalia

8. Evolutionary Classification
The concept of descent with modification led to phylogeny—the study of how living and extinct organisms are related to one another.
A clade is a group of species that includes a single common ancestor and all descendants of that ancestor—living and extinct.
Cladograms
This information is used to link clades together into a cladogram, which illustrates how groups of organisms are related to one another by showing how evolutionary lines, or lineages, branched off from common ancestors.
Clades

9. Building Cladograms
This cladogram represents current hypotheses about evolutionary relationships among vertebrates.
Note that in terms of ancestry, amphibians are more closely related to mammals than they are to ray-finned fish!

10. Constructing a Cladogram
1 Identify the organism in the table that is least
closely related to the others.
2 Use the information in the table to construct a
cladogram of these animals.
Analyze and Conclude
1. Interpret Tables What trait separates the least
closely related animal from the other animals?
2. Apply Concepts Do you have enough
information to determine where a frog should be
placed on the cladogram? Explain your answer.
3. Draw Conclusions Does your cladogram
indicate that lizards and humans share a more
recent common ancestor than either does
with an earthworm? Explain your answer.
Devised Characters in Organisms
Organism
Devised Character
Backbone
Legs
Hair
Earthworm
Absent
Trout
Present
Lizard
Human

11. Three Domains
Domain is a larger, more inclusive category than a kingdom.
Under this system, there are three domains—
1. Domain Bacteria
2. Domain Archaea
3. Domain Eukarya

12. The Tree of All Life

13. Classification Flip Book
You Need:
3 pieces of construction paper
Glue stick
Marker for labels

14. Eubacteria Domain: Bacteria Cell type: prokaryotic
Cell structure: Cell walls with peptidoglycan.
Number of cells: Unicellular
Mode or Nutrition: Autotroph or heterotroph
Examples: Streptococcus, Escherichia coli

15. Archeabacteria Domain: Archaea Cell type: prokaryotic
Cell structure: Cell walls without peptidoglycan.
Number of cells: Unicellular
Mode or Nutrition: Autotroph or heterotroph
Examples: Methanogens, halophiles

16. Protista Domain: Eukarya Cell type: eukaryotic
Cell structure: Cell walls of cellulose in some; some have chloroplasts.
Number of cells: most unicellular; some colonial; some multicellular
Mode or Nutrition: Autotroph or heterotroph
Examples: Amoeba, Paramecium, slime molds, giant kelp

17. Fungi Domain: Eukarya Cell type: eukaryotic
Cell structure: Cell walls of chitin
Number of cells: most multicellular; some unicellular
Mode or Nutrition: Heterotroph
Examples: Mushrooms, yeasts

18. Plantae Domain: Eukarya Cell type: eukaryotic
Cell structure: Cell walls of cellulose; chloroplasts.
Number of cells: most multicellular: some green algae unicellular
Mode or Nutrition: Autotroph
Examples: Mosses, ferns, flowering plants

19. Animalia Domain: Eukarya Cell type: eukaryotic
Cell structure: No cell walls or chloroplasts.
Number of cells: multicellular
Mode or Nutrition: Heterotroph
Examples: Sponges, worms, insects, fishes, mammals