Page 12 Brainpop: Classification

Classification/Taxonomy UNIT 3

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

In other words, naming things. 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 different languages. Cat Arabic: quttah Czech: kocka French: chat German: katze Japanese: neko Russian: kotchka Spanish: gato

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

Why common names don’t work Many species have several common names. Sand tiger shark Sand shark Gray nurse shark

Why common names don’t work Same common name used for different species Dolphin Dolphin Mahi mahi Turciops truncatus

First Attempt to Classify Aristole (Greek Philosopher) * About 300 BC * Classified based on method of reproduction * Used the words like “genera” and “species” * Grouped animals between those with blood and those without blood * He had many errors in his classification system, but it was used until the 1700s

Carolus Linnaeus (1707 – 1778) Created the system of naming we use today. In taxonomy, a group or level of organization is called a taxonomic category or taxon.

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

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.

What do these mean?...lets see Here We Go… Polar Bear *Do NOT have to write* Species: maritimus Genus: Ursus Family: Ursidae Order: Carnivora Class: Mammalia Phylum: Chordata Kingdom: Animilia What do these mean?...lets see

What they mean *Do NOT have to write* 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: Animilia (there are 6 kingdoms)

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

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

Uniqueness: Every name has to be unique. Rules of the Game Uniqueness: Every name has to be unique. Universality: Zoologists have adopted, by International Code of Zoological Nomenclature, a set of rules for naming animals. A single language is to be used on a worldwide basis. All animals are given a generic name (common name) and specific name in Latin &/or Greek (scientific name). These names are in italics when TYPED or are underlined when HAND WRITTEN. Human: Homo sapiens Lion: Panthera leo

Taxonomy Video

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

A Problem with Traditional Classification Traditional classification systems relied on body structure comparisons only (not DNA) 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. Sugar Glider… Live in Australia Look similar, but totally unrelated! Flying Squirrel… Live in the US (GA)

Another 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.

This incorrect because crabs and barnacles are actually related

Modern Principles of Classification Modern classification system has its roots in the system of Linnaeus Modern classification has been revised to reflect Darwinian Principle of common descent Most recently, molecular systematics (DNA) has driven the most recent revisions in classification

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

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

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

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

The Three-Domain System In 1990, a new taxonomic level called Domain was introduced and changed how bacteria were classified. Domain Archaea Domain Bacteria Domain Eukarya There are 6 Kingdoms total: 1. Eubacteria 2. Archaebacteria 3. Protista 4. Fungi 5. Plantae 6. Animalia Both are Bacteria Everything else (Except viruses)

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

Phyla To Know Porifera: Sponges Cnidaria: Jellyfish, Sea Anemones, Corals Echinodermata: Sea Urchin, Starfish, Sand Dollars Mollusca: Snails, Clams, Octopus Arthropoda: Insects, Crustaceans, Spiders Chordata: Vertebrates

The End.