1. Chapter 18 Classification

2. Section 18-1 Why Classify? Because of the diversity and number of organisms on planet Earth. Each organism need a name, and it needs to be organized into groups that biological meaning. Taxonomy-scientists classify organisms and assign each one a universally accepted name.

3. Carolus Linnaeus developed a two-word naming system called binomial nomenclature. We still use this system today. Each species is assigned a two-part scientific name. It is always written in italics. The first word is capitalized, and the second word is lowercase.

4. The name for a grizzly bear, Ursus arctos, is one example. The first name, Ursus, is the genus name. Genus is a group of closely related species. The genus Ursus contains 5 other types of bears, including polar bears. The second part of the name, arctos, is the species name.

5. Linnaeus’s classification system is hierarchical, which means it consists of levels. There are 7 levels, and the list is from largest to smallest: Kingdom, Phylum, Class, Order, Family, Genus, Species. Each of the 7 is known as a taxon, which is a taxonomic category.

6. Family-A group of genera that share many characteristics. Example: Bears are in the family Ursidae. The bears, along with 6 other families of animals, such as dogs (Canidae) and cats (Felidae) are grouped together in the Order Carnivora. An Order is a broad taxonomic category made of similar families.

7. Class is the next larger category. It is made up of similar Orders. Example: The order Carnivora is placed in the class Mammalia, which includes animals that are warm blooded, have body hair, and produce milk for their young.

8. Several different classes make up a Phylum (plural Phyla). It includes many different organisms that share important characteristics. The largest group is Kingdom. All animals are placed in the kingdom Animalia.

9. Section 18-1 Flowchart Linnaeus’s System of Classification Kingdom Phylum Class Order Family Genus Species

10. Grizzly bearBlack bearGiant panda Red fox Abert squirrel Coral snake Sea star KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER Carnivora FAMILY Ursidae GENUS Ursus SPECIES Ursus arctos Section 18-1 Figure 18-5 Classification of Ursus arctos

11. Phylogeny: the study of evolutionary relationships among organisms. Biologists now group organisms into categories that represent lines of evolutionary descent, or phylogeny, not just physical similarities. This is known as evolutionary classification.

12. This studies how long ago organisms have had a common ancestor. The assumption in evolutionary classification is that new and better traits arise over long periods of time.

13. Derived Characteristics are those that appear in recent parts of a lineage or line but are not present in older more distant times. A Cladogram is a diagram that shows the evolutionary relationships in a group of organisms.

14. CLADOGRAM AppendagesConical Shells Crab Barnacle Limpet Crab Barnacle Limpet CrustaceansGastropod Molted exoskeleton Segmentation Tiny free-swimming larva Section 18-2 Traditional Classification Versus Cladogram CLASSIFICATION BASED ON VISIBLE SIMILARITIES

15. CLADOGRAM AppendagesConical Shells Crab Barnacle Limpet Crab Barnacle Limpet CrustaceansGastropod Molted exoskeleton Segmentation Tiny free-swimming larva Section 18-2 Traditional Classification Versus Cladogram

16. The Kingdoms Before the 1990’s, there were only thought to be 5 kingdoms: Monera, Protista, Fungi, Plantae, and Animalia. During the 1990’s, a sixth kingdom was added as Monera was split into 2 new kingdoms: Eubacteria, Achaebacteria, Protista, Fungi, Plantae, and Animalia.

17. DOMAIN KINGDOM CELL TYPE CELL STRUCTURES NUMBER OF CELLS MODE OF NUTRITION EXAMPLES Bacteria Eubacteria Prokaryote Cell walls with peptidoglycan Unicellular Autotroph or heterotroph Streptococcus, Escherichia coli Archaea Archaebacteria Prokaryote Cell walls without peptidoglycan Unicellular Autotroph or heterotroph Methanogens, halophiles Protista Eukaryote Cell walls of cellulose in some; some have chloroplasts Most unicellular; some colonial; some multicellular Autotroph or heterotroph Amoeba, Paramecium, slime molds, giant kelp Fungi Eukaryote Cell walls of chitin Most multicellular; some unicellular Heterotroph Mushrooms, yeasts Plantae Eukaryote Cell walls of cellulose; chloroplasts Multicellular Autotroph Mosses, ferns, flowering plants Animalia Eukaryote No cell walls or chloroplasts Multicellular Heterotroph Sponges, worms, insects, fishes, mammals Eukarya Classification of Living Things Section 18-3 Figure 18-12 Key Characteristics of Kingdoms and Domains

18. Domains The Domain category is more inclusive and is larger than a Kingdom. At this point in time there are 3 Domains: Eukarya, Bacteria, and Archaea.

19. Kingdoms Eubacteria Archaebacteria Protista Plantae Fungi Animalia DOMAIN EUKARYA DOMAIN ARCHAEA DOMAIN BACTERIA Section 18-3 Figure 18-13 Cladogram of Six Kingdoms and Three Domains