17.1 The Linnaean System of Classification KEY CONCEPT Organisms can be classified based on physical similarities. How would you classify this animal? This is a pangolin. Pangolins are native to Africa and Asia. They can be found under the Kingdom Mammalia. Although they do not have fur, they do produce milk for young.

17.1 The Linnaean System of Classification Why classify? Common names can be confusing: Firefly Spider monkey Mud puppy Black bear Horned toad Sea horse jellyfish crayfish ringworm Sea monkey

17.1 The Linnaean System of Classification Why Classify continued…. Only about 1.5 million species have been named on Earth million species are yet to be named on Earth.

17.1 The Linnaean System of Classification Taxonomy is the science of naming and classifying organisms. Taxonomy began with the ancient Greeks and Romans –Aristotle classified organisms into two groups: plants and animals. John Ray (1627–1705) –Believed that each organism should have a set name. –Otherwise, “men…cannot see and record accurately.” Gives scientists a standard way to refer to species and organize the diversity of living things. Linnaean taxonomy classifies organisms based on their physical and structural similarities. Organisms are placed into different levels in a hierarchy— a multilevel scale in which each level is “nested” (included) in the next-higher level.

17.1 The Linnaean System of Classification Linnaeus developed the scientific naming system still used today. A taxon is a group of organisms in a classification system. (Plural = taxa) Under taxon system, species are most commonly defined as a group of organisms that can breed and produce offspring that can reproduce. Linnaeus’ system gives each species a scientific name. White oak: Quercus alba

17.1 The Linnaean System of Classification Binomial nomenclature is a two-part scientific naming system that gives each species a two-part scientific name –uses Latin words –scientific names always written in italics –two parts are the genus name and species descriptor

17.1 The Linnaean System of Classification A genus includes one or more physically similar species. –Species in the same genus are thought to be closely related. –Genus name is always capitalized. A species descriptor is the second part of a scientific name. –can be in italics or underlined, but always lowercase –always follows genus name; never written alone (same word can be used in other genera: alba means white and is used in naming the white oak tree) –It can refer to a trait of the species (white) Tyto alba

17.1 The Linnaean System of Classification Scientific names help scientists to communicate world-wide. –Some species have very similar common names. –Some species have many common names.

17.1 The Linnaean System of Classification Linnaeus’ classification system has seven levels (taxa). Each level is “nested” or included in the level above it. From the most general to the most specific, these levels are kingdom, phylum (the term division is often used instead of phylum for plants and fungi), class, order, family, genus, and species. A kingdom contains one or more phyla, a phylum contains one or more classes, and so forth. The classification of the gray wolf, Canis lupis, is shown in FIGURE Moving down, the levels represent taxa that become more and more specific, until you reach the species level at the bottom.

17.1 The Linnaean System of Classification Getting familiar with the system What animals are dropped as we move from kingdom to phylum? Invertebrates What well-known Australian animal is excluded from the Carnivora order, which includes all true bears? Koala bear How can this be? Sharing a common name or having a similar name means very little in terms of actualrelatedness. An animal called a bear may not be a true bear. From what you can infer from the figure, what are characteristics of animals in the order Carnivora? terrestrial, toothed, four- legged, meat-eating mammals

17.1 The Linnaean System of Classification Members of a Species

17.1 The Linnaean System of Classification The Linnaean classification system has limitations. Linnaeus taxonomy doesn’t account for molecular evidence. –The technology didn’t exist during Linneaus’ time. –Linnaean system based only on physical similarities. –DNA and RNA is similar across all life forms –Genes of many organisms show important similarities at the molecular level

17.1 The Linnaean System of Classification Apply what we just learned! If two species belong to the same order, what other levels in the Linnaean system must they have in common? class, phylum, kingdom

17.1 The Linnaean System of Classification Physical similarities are not always the result of close relationships. The giant panda and the raccoon have similar ears and snouts. Because of these similarities, they have been placed in the same family in the Linnaean system. Molecular biologists have found that the giant panda is more closely related to members of the bear family than it is to raccoons. The red panda, shown in FIGURE 17.4, is more closely related to the raccoon than to the giant panda. He’s cute, huh????

17.1 The Linnaean System of Classification What do you think? What do you think bats are more closely related to? Birds or rodents and primates?

17.1 The Linnaean System of Classification Dichotomous Keys A written set of choices that leads to the name of an organism Scientists use them to identify unknown organisms

17.1 The Linnaean System of Classification Consider the following animals, Biologous Piglitus. They are all related, but each is a separate species. Use the dichotomous key below to determine the species of each Has aqua colored body......go to 2 Has blue colored body..... go to Has 4 legs.....go to 3 Has 8 legs Deerus octagis 3.3. Has a tail Deerus pestis Does not have a tail..... Deerus magnus 4.4. Has a pointy hump Deerus humpis Does not have a pointy hump.....go to Has ears Deerus purplinis Does not have ears......Deerus deafus

17.1 The Linnaean System of Classification Exploring the Kingdoms Have you ever swum in a pond? Every drop of pond water is teeming with single-celled organisms. At one time, scientists classified these organisms as either plants or animals. Who said that? Classification schemes change. Single-celled eukaryotes such as these pond dwellers now have a kingdom of their own.

17.1 The Linnaean System of Classification Classification is always a work in progress. The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae Animalia Plantae

17.1 The Linnaean System of Classification Classification is always a work in progress. The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae –1866: all single-celled organisms moved to kingdom Protista Animalia Protista Plantae

17.1 The Linnaean System of Classification Classification is always a work in progress. The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae –1938: prokaryotes moved to kingdom Monera –1866: all single-celled organisms moved to kingdom Protista Animalia Protista Plantae Monera

17.1 The Linnaean System of Classification The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae Classification is always a work in progress. –1938: prokaryotes moved to kingdom Monera –1866: all single-celled organisms moved to kingdom Protista Monera –1959: fungi moved to own kingdom Fungi Protista Plantae Animalia

17.1 The Linnaean System of Classification The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae Classification is always a work in progress. –1938: prokaryotes moved to kingdom Monera –1866: all single-celled organisms moved to kingdom Protista –1959: fungi moved to own kingdom –1977: kingdom Monera split into kingdoms Bacteria and Archaea Animalia Protista Fungi Plantae Archea Bacteria

17.1 The Linnaean System of Classification The three domains in the tree of life are Bacteria, Archaea, and Eukarya. Domains are above the kingdom level. –proposed by Carl Woese based on rRNA studies of prokaryotes –domain model more clearly shows prokaryotic diversity

17.1 The Linnaean System of Classification

Activity: Draw the Domains with Kingdoms

17.1 The Linnaean System of Classification Welcome Back! Today in Biology we will Continue Classification notes! Georgia Aquarium “Creature Presentations” for thirty minutes.

17.1 The Linnaean System of Classification Words to Know! Producer – organism that gets it’s energy from nonliving organisms (Example: plants making their own food from the energy provided by solar energy). Producers are also called autotrophs. Auto means self (Greek); troph means nourishment. Consumer – organism that gets it’s energy by eating (consuming) other living things or things that were once living (plants and animals). Consumers are also called heterotrophs. Hetero means what? Troph means what?

17.1 The Linnaean System of Classification A look into the Three Domains and Six Kingdoms! Domain Archaea includes Kingdom Archaebacteria (also called Kingdom Archae – depends on the textbook) contains single-celled (unicellular) prokaryotes cell walls are diverse but chemically different from bacteria produce asexually differences discovered by studying RNA known for living in extreme environments (methanogens in anaerobic swamps, helophiles in salt lakes, thermacidophiles in hot acidic environments) These guys to the right live without oxygen in undersea hot vents or in sand around volcanoes. They are called Pyrococcus furiosus and grow in temps higher than boiling water.

17.1 The Linnaean System of Classification Domain Eukarya Domain Eukarya includes all eukaryotes. Contains both unicellular and multicellular organisms Cells with a membrane-bound nucleus Sexual reproduction common Contains four kingdoms 1. Kingdom Protista This is a Zooflagellate. Why the name? Did you know that there are over 2000 species of Zooflagellates? Go tell a friend!

17.1 The Linnaean System of Classification Domain Eukarya includes all eukaryotes. 2. Kingdom Plantae

17.1 The Linnaean System of Classification Domain Eukarya includes all eukaryotes. 3. Kingdom Fungi

17.1 The Linnaean System of Classification Domain Eukarya includes all eukaryotes. 4. Kingdom Animalia

17.1 The Linnaean System of Classification Domain Bacteria Includes Kingdom Bacteria includes single-celled prokaryotes One of the largest groups of organisms on Earth Beneficial or harmful There are more bacteria in your mouth right now than have ever lived on Earth. Really! Classified by many traits: shape, need for oxygen, disease causing Guess where these guys live?

17.1 The Linnaean System of Classification Humans ARE the environment! Huh? Yes, not only do we share the environment, we ARE home sweet home to many prokaryotes. Say ahhhhhhhhhhhh and hello to 500 types of prokaryotes of which 25 types can be living in your mouth right now! One milliliter of your saliva (spit) can have up to 40 million bacterial cells.

17.1 The Linnaean System of Classification Prokaryotes are most abundant and widespread organisms on Earth. Prokaryotes can be grouped by their need for oxygen. –obligate anaerobes are poisoned by oxygen (can’t live with it) Example: archae that produce methane gas (live in intestines in cows) –obligate aerobes need oxygen (can’t live without it) Example: pathogens that cause tubercolosis and leprosy. –facultative aerobes can live with or without oxygen DOMAINS Bacteria and Archae Bacteria and archaea are both single-celled prokaryotes. These are beneficial intestinal bacteria. (Mutualism)

17.1 The Linnaean System of Classification Bacteria and archaea are structurally similar but have different molecular characteristics. Bacteria commonly come in three forms. –rod-shaped, called bacilli Lactobacilli: rod-shapedSpirochaeta: spiralEnterococci: spherical Archaea have many shapes. – spiral, called spirilla or spirochetes – spherical, called cocci

17.1 The Linnaean System of Classification Bacteria and archaea have similar structures. flagellum pili plasmid cell wall chromosome plasma membrance This diagram shows the typical structure of a prokaryote. Archaea and bacteria look very similar, although they have important molecular differences. –plasmid (small piece of genetic material that can replicate separately) –flagellum (used for movement) –pili (help them stick to other surfaces)

17.1 The Linnaean System of Classification Bacteria and archaea have molecular differences. –Bacteria have a polymer called peptidoglycan in their cell walls; archae do not. Peptidoglycan is an important defining characteristic for Bacteria. –The amount of peptidoglycan within the cell wall can differ between bacteria –Archae have lipids (fats) in their membranes that no other organism on Earth has. GRAM NEGATIVEGRAM POSITIVE

17.1 The Linnaean System of Classification Gram staining identifies bacteria into two types. Gram-negative bacteria have a thin layer of peptidoglycan and stain red. Gram-positive bacteria have a thicker peptidoglycan layer and stain purple. »Gram stain stains the polymer peptidoglycan in bacteria »Used to diagnose infectious bacterial diseases –gram-positive stains purple, more peptidoglycan –gram-negative stains pink, less peptidoglycan