Classification/Taxonomy Chapter 18

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

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

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 HawkHoney BuzzardTurkey Vulture

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

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

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

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

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

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

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

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)

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

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).

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

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

Which TWO are more closely related?

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

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

Related This incorrect because crabs and barnacles are actually related

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

Evolutionary Classification Biologists now group organisms into categories that represent lines of evolutionary descent, not just physical similarities 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.

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

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

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

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. 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: The 6-Kingdom system of classification includes kingdoms: 1. Eubacteria 2. Archaebacteria 3. Protista 4. Fungi 5. Plantae 6. Animalia

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

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

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.

The End.

Visuals

Taxonomy Video