Classification Chapter 18

Taxonomy: Life's Filing System - Crash Course Biology #19 - YouTube Taxonomy: Life's Filing System - Crash Course Biology #19 - YouTube

Strawberry, peach, apple, banana, watermelon How can you classify fruits? Construct a table with five rows and four columns. Label each row with the name of a different fruit. Observe each fruit and choose four characteristics by which you can tell the fruits apart. Label the columns in your table with these four characteristics. Record a description of each fruit in your table. Think About It Observing What characteristics did you use to describe the fruits? Classifying Based on your table, which fruits are most closely related? Explain.

Finding order in diversity – scientists named 2.5 million species – estimated 4-30 million additional species yet to be discovered Why classify – To avoid confusion caused by common names, biologists assign each species a scientific name – To study the diversity of life, biologist use a classification system to name organisms and group them in a logical manner – Taxonomy – discipline of assigning each organism a universally accepted name * have students stand up – 1) over 5 feet tall stay standing – 2) brown eyes stay standing – 3) female stay standing – 4) left handed stay standing

Assigning scientific names – Binonomial nomenclature » Each species is assigned a two- part scientific name » Written in italics, first word is capitalized, second is lower case Ex. Grizzly bear Ursus arctos Ursus – genus arctos – species there are 5 other types of bears in the same genus Ursus

Linnaeus’s systen of classification – Taxon – group into which organisms are classified – Linnaeus’s system of classification uses seven taxonomic categories. They are –from smallest to largest – species, genus, family, order, class, phylum and kingdom » Family – group of genera and share many characteristics » Order- group of similar families » Class – group of closely related orders » Phylum – group of closely related classes » Kingdom – group of closel related phyla Two videos on website prentice hall Biology book

Key Concept How are living things organized for study? Using a classification system to name organisms with a universally accepted name. Grouped in logical manner, more similar to one another than they are to organisms in other groups Key Concept Describe the system for naming species that Linnaeus developed. Each species is assigned a two part scientific name Key Concept What are the seven taxonomic categories of Linnaeus’s classification system? Species, genus, family, order, class, phylum, and kingdom King Philip came over for green spaghetti Why do scientists avoid using common names when discussing organisms? Common names vary among languages and even among regions within a single country Critical Thinking Applying Concepts Which category has more biological meaning—all brown birds or all hawk like birds? Why? All hawk like birds, because that category is based on a combination of significant structures, not just color

Cell Type Prokaryote – Organisms that DO NOT HAVE a membrane bound NUCLEUS Eukaryote – Organisms that HAVE a membrane bound NUCLEUS

Body Type Unicellular – Uni- means ONE – Organism made up of ONE CELL Multicellular – Multi- means MANY – Organism made up of MANY CELLS

Nutrition Autotrophic – Create their own energy from sun or chemicals – Producers Heterotrophic – Rely on other organisms for energy – Consumers

Cell Wall Cell structure that surrounds a cell Provides support and protection Can be made up of: chitin, cellulose, peptidoglycan, silica, proteins

MODERN EVOLUTIONARY CLASSIFICATION Problems with traditional classification – vultures american, african and asian » american habit of urinating on legs to cool themselves, same as storks. African and asian vultures do not. Evolutionary classification Overhead of humans and apes – guided by evolutionary theory, biologists new group organisms into categories that represent lines of evolutionary descent, not just physical similarities – evolutionary classification – method of grouping organisms according to how recently descended they are from a common ancestor. – traditional classification – figure 18-7 – Classification using cladograms » Cladistic analysis identifies and considers only characteristics that are evolutionary innovations, new characteristics that arise as lineages evolve over time » Derived characters – unique features that appear in some organisms but not others » Cladograms – branching diagram used to show the diverging sequence in which key evolutionary changes occurred

Limpet Barnacle crab

Cladograms A cladogram is a diagram used to show ancestral relationships between organisms Evolutionary tree of life

QUICK LAB PG. 453 How is a cladogram constructed? Procedure Identify the organism in the table that is least closely related to the others. Use the information in the table to construct a cladogram of these animals. Analyze and Conclude Analyzing Data What trait separates the least closely related organism from the other animals? Classifying List the animals in your cladogram in order of distance from the least closely related organism. Drawing Conclusions Does your cladogram indicate that lizards and humans share a more recent common ancestor than either does with an earthworm? Explain. Inferring Where would you insert a frog if you added it to the cladogram? Explain your answer.

18 Cladogram Earthworm Trout Lizard Human Backbone Legs Hair Frog Amniotic Egg

Tools for Classifying Dichotomous Keys

Similarities in RNA and DNA – all living organisms use RNA and DNA the same way – Common ancestry evident in genes » The genes of many dissimilar organisms show important similarities at the molecular level. These similarities can be used as criteria for classification » Common gene structure indicator of common ancestory Similar common feature of all living cells – the ribosome – the cellular “protein factor”. Gene that codes for myosin found in muscles in humans intercellular parts to move in yeast

Molecular clocks – molecular clock – model used to estimate the length of time that 2 species have been evolving independently based on mutations in an organisms DNA

Section assessment 1-5 pg. 455 Key Concept How is information about evolutionary relationships useful in classification? Organisms are placed in various taxonomic groups based on evolutionary descent. Key Concept How are genes used to help scientists classify organisms? Scientists compare DNA of different organisms to establish similarities between them and reconstruct possible evolutionary relationships What is the principle behind cladistic analysis? traces the process of evolution in a group of organisms by focusing on unique features that appear in some organisms but not in others Describe the relationship between evolutionary time and the similarity of genes in two species. The longer it ahs been since two species descended from a common ancestor, the more different their genes are likely to be. Critical Thinking Applying Concepts How have new discoveries in molecular biology affected the way in which we classify organisms compared with the system used by Linnaeus? New ways of classifying organisms reflect evolutionary relationships based on genetic similarities, whereas Linnaeus’s system of classifying organisms was based on physical similarities between organisms

Constructing a Chart Draw a cladogram of a manufactured item Automobiles Candy Video games Computers ????

Kingdoms and Domains The tree of life evolves – in the beginning…… then……. The six kingdom system of classification includes the kingdoms ANIMALIA, PLANTAE, FUNGI, PROTISTA, AND 2 BACTERIAL KINGDOMS EUBACTERIA AND ARCHAEBACTERIA. The 3 domain system – Domain – is a more inclusive category than any other – larger than a kingdom. – The three domains are: the domain of bacteria, which corresponds to the kingdom Eubacteria; the domain archae, which corresponds to the kingdom archaebacteria; and the domain eukarya, which is composed of animals, plants, fungi, and protists.

– Bacteria » Domain of unicellular prokaryotes that have cell walls containing peptidoglycans – Archaea » Domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycans – Eukarya » Domain of all organisms whose cells have nuclei, including protists, plants, fungi and animals Protistsa – kingdom composed mainly of single – celled eukaryotes: includes all eukaryotes that are not classified as plants, animals or fungi Plantae – kingdom of multicellular photosynthetic autotrophs that have cell walls containing cellulose Fungi – kingdom composed mainly of saprophytes, which obtain energy and nutrients from dead and organic matter Animalia – kingdom of multicellular eukaryotic heterotrophs whose cells do not have cell walls

CLASSIFICATION OF LIVING THINGS DOMAIN KINGDOM CELL TYPE NUMBER OF CELLS MODE OF NUTRITION EXAMPLES

Domains and Kingdoms Archaebacteria Eukarya Bacteria Archaebacteria Eubacteria Protista Fungi Plantae Animalia

Kingdom Archaebacteria Cell Type: prokaryote Cell Wall: not composed of peptidoglycan Body Type: unicellular Nutrition: autotrophic vs. heterotrophic Examples: Ancient bacteria--Extremophiles methanococcus; halophiles

Kingdom Bacteria Cell Type: prokaryote Cell Wall: composed of peptidoglycan Body Type: unicellular Nutrition: autotrophic & heterotrophic Examples: Common bacteria E. coli, streptococcus, staphylococcus

Kingdom Protista Cell Type: Eukaryotic Cell Wall: silica, calcium carbonate, proteins Body Type: unicellular & multicellular Nutrition: autotrophic & heterotrophic Examples: Misfits like--paramecium, euglena, amoeba

Kingdom Fungi Cell Type: eukaryotic Cell Wall: chitin Body Type: unicellular & multicellular Nutrition: heterotrophic (not a plant!) Examples: yeast, morel, puffball, Rhizopus stolonifer (bread mold)

Kingdom Fungi

Kingdom Plantae Cell Type: eukaryotic Cell Wall: composed of cellulose Body Type: multicellular Nutrition: autotrophic Examples: corn; ferns; roses; pine tree

Kingdom Animalia Cell Type: eukaryotic Cell Wall: no cell wall Body Type: multicellular Nutrition: heterotrophic Examples: manatee, shark, snakes, worms, coral, hummingbird, insects….