Classification/Taxonomy Chapter 18 1

Why Classify? To study the diversity of life, biologists use a classification system to name organisms & group them in a logical manner. 2

In other words, naming things. Taxonomy Defined: Discipline of classifying organisms and assigning each organism a universally accepted name. In other words, naming things. 3

Why common names don’t work Common names vary among languages. Example: United Kingdom – Buzzard refers to a hawk United States – Buzzard refers to a vulture Red-tailed Hawk Honey Buzzard Turkey Vulture 4

Early Taxonomists 2000 years ago, Aristotle (384 BC-322 BC) was the first taxonomist Aristotle divided organisms into plants & animals He subdivided them by their habitat ---land, sea, or air dwellers

Carolus Linnaeus (1707 – 1778) Classified organisms by their structure Created the system of naming we use today. His classification system includes 7 levels. In taxonomy, a group or level of organization is called a taxonomic category or taxon. 6

Binomial Nomenclature “Bi” means 2 “nomial” means naming Nomenclature means “the system of naming” Defined: In binomial nomenclature, each species is assigned a two-part scientific name. 7

Example of Binomial Nomenclature Polar Bear is Ursus maritimus Ursus: genus Ursus contains 5 other kinds of bears maritimus: species The Latin word, maritimus, refers to the sea. Polar bears often live on pack ice that floats in the sea. 8

Definitions to know Genus: is a group of closely related species Species: Group of similar organisms that can breed and produce fertile offspring 9

Kingdom: Largest taxonomic group, consisting of closely related phyla. Phylum: Group of closely related classes Class: Group of similar orders Order: Group of similar families Family: Group of genera (genus) that share many characteristics 10

What do these mean?...lets see Here We Go… Polar Bear Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Ursidae Genus: Ursus Species: maritimus What do these mean?...lets see 11

What they mean Species: maritimus (lives in marine environment) Genus: Ursus (kind of bear) Family: Ursidae (larger category of bears) Order: Carnivora (meat-eating animals) Class: Mammalia (warm-blooded, hair, & milk) Phylum: Chordata (vertebrates) Kingdom: Animalia (there are 6 kingdoms) 12

How to remember: King Phillip Came Over For Green Salad Kingdom Phylum Class Order Family Genus Species 13

Rules of the Game Uniqueness: Every name has to be unique. Universality: Zoologists have adopted, by international agreement, a single language to be used on a worldwide basis. All animals are given a generic (common name) and specific name in Latin (scientific name). These names are in italics or are underlined (i.e. Homo sapiens or Homo sapiens). 14

Phylum Chordata Class Mammalia Order Carnivora Family Ursidae Genus Ursus Species maritimus

Felis Genus species domestica leo margarita If these three species belong to the same genus, they are descended from a common ancestor. Felis domestica domestica Domestic Cat Felis Felis leo leo Lion Felis margarita margarita Sand cat`

Which TWO are more closely related?

A Problem with Traditional Classification Traditional classification systems relied on body structure comparisons only Due to convergent evolution, organisms that are quite different from each other evolve similar body structures. Convergent Evolution: Process by which unrelated organisms independently evolve similarities when adapting to similar environments. 18

A Problem with Traditional Classification Example: The Crab, The barnacle, & The limpet The barnacle and the limpet have similarly shaped shells & look alike The crab has a very different body form Based on anatomy, the barnacle & limpet could be classified together and the crab in a different group. 19

This is incorrect because crabs and barnacles are actually related

Segmentation Free swimming Larva Crustaceans Gastropods Molted Exoskeleton Even though they do not look a like, crabs & barnacles are actually related Segmentation Free swimming Larva 21

Evolutionary Classification Biologists now group organisms into categories that represent lines of evolutionary descent, not just physical similarities Evolutionary Classification: Is the strategy of grouping organisms together based on their evolutionary history.

Classification Using Cladograms Cladogram: A diagram that shows the evolutionary relationships among a group of organisms. 23

Segmentation Free swimming Larva Molted Exoskeleton Crustaceans Gastropods Molted Exoskeleton Using Cladograms, you can see that crabs and barnacles share similar characteristics because they both molt & are segmented Segmentation Free swimming Larva 24

You can also see that ALL have a free swimming larva stage Crustaceans Gastropods Molted Exoskeleton You can also see that ALL have a free swimming larva stage Segmentation Free swimming Larva 25

Classification Using Cladograms Cladogram: A diagram that shows the evolutionary relationships among a group of organisms. 26

Draw Your Own Cladogram Complete Quick lab on p. 453 in text. Answer the questions in your notes!

Classification History 1700s Plantae Animalia 1800s Protista Plantae Animalia 1950s Monera Protista Fungi Plantae Animalia 1990s Eubacteria Archaebacteria Protista Fungi Plantae Animalia 29

The Three-Domain System Recently, as evidence about microorganisms continue to accumulate, biologists came to realize that the Kingdom Monera were composed of 2 distinct groups. The 6-Kingdom system of classification includes kingdoms: 1. Eubacteria 2. Archaebacteria 3. Protista 4. Fungi 5. Plantae 6. Animalia 30

6 Kingdoms Eubacteria Archaebacteria Protista Fungi Plantae Animalia Prokaryote Prokaryote Eukaryote Eukaryote Eukaryote Eukaryote Autotroph or heterotroph Autotroph or heterotroph Autotroph/ heterotroph Heterotroph Autotroph Heterotroph Includes Algae Don’t belong in other euk No cell wall No chloroplasts Multicellular “Ancient Bacteria” Release enzymes to digest food Most common bacteria Cell walls & Chloroplasts Live in very hot places E. ecoli Pyrococcus furiosus Paramecium H. coccinea Fern frod Homo sapiens 31

These are T4 Bacteriophage Where do viruses go? Viruses: Are particles of nucleic acid, protein, and in some cases lipids that can reproduce ONLY by infecting living cells. Viruses are made of a core of either DNA or RNA surrounded by a protein coat. These are T4 Bacteriophage A bacteriophage is a virus which infects bacteria 32

Where do viruses go? (continued) Viruses are not considered alive because they don’t have ALL the characteristics of life. Example: They can’t reproduce independently These are the Influenza Viruses Influenza or "flu" is an infection of the respiratory tract that can affect millions of people every year. 33

The End.

Honors Biology EOC Review Complete the following pages in your Bio EOC Booklet: pages 10, 11, 28, 29

Visuals 36

Taxonomy Video 37