Classification & Diversity Chapter 18 Biology 112

Importance of Classification To study the vast number of living and fossil organisms (est. up to 40 million different species) To study the vast number of living and fossil organisms (est. up to 40 million different species) Provide natural groupings of living things Provide natural groupings of living things Taxonomy – the study of naming organisms Taxonomy – the study of naming organisms Problems with “common” names ex: June Bug refers to over a dozen different beetles Problems with “common” names ex: June Bug refers to over a dozen different beetles Early scholars tried to standardize the system by giving organisms a Latin name, “the universal language of science” Early scholars tried to standardize the system by giving organisms a Latin name, “the universal language of science” Problem with Latin names – difficult to use, changed regularly, and some had 15 names Problem with Latin names – difficult to use, changed regularly, and some had 15 names

Latin Names One carnation like flower had the name: One carnation like flower had the name: “Dianthus floribus solitariis squamis calycinis subovatis brevissimus corollis crenatis” Biologists needed a single, stable concise way of naming things Biologists needed a single, stable concise way of naming things

Binomial Nomenclature Swedish Botanist Carolus Linnaeus ( ) devised a shorthand method of naming organisms called the system of binomial nomenclature Swedish Botanist Carolus Linnaeus ( ) devised a shorthand method of naming organisms called the system of binomial nomenclature Used worldwide Used worldwide Gives each species a unique two part Latin name known as the scientific name Gives each species a unique two part Latin name known as the scientific name Carnation type plant: Dianthus caryophyllus Carnation type plant: Dianthus caryophyllus

Binomial Nomenclature – Scientific Naming Examples: Examples: Homo sapiens, Castor canadensis, Acer rubrum First word = genus and it’s first letter is always capitalized and word italicized First word = genus and it’s first letter is always capitalized and word italicized Genus is usually a proper noun or common name used by the Romans; ex: similar cats were in the genus Felis, dogs in the genus Canis Second word = species Second word = species Species is usually a Greek or Latin adjective that describes a significant characteristic of the species

Naming cont…. Example: Example: Campanula rotundifolia (campana means “bell”; rotund means “round”; folia means “leaves” A bell flower with rounded leaves

Classifying in Biology

Linneaus’s Classification System: HumanCougarTigerPintail Duck KingdomAnimalia Phylum/Divis ion Chordata ClassMammalia Aves OrderPrimateCarnivora Anseriformes FamilyHomindaeFelidae Anatidae GenusHomoFelisPantheraAnas Speciessapiensconcolortigrisacuta

Dichotomous Keys Classification manuals to conduct identification work Classification manuals to conduct identification work Constructed so that a series of choices must be made Constructed so that a series of choices must be made If choices are made correctly, the taxonomist is led to the name of the organism being identified. If choices are made correctly, the taxonomist is led to the name of the organism being identified.

HWK Time!! 112 Hwk: guided reading HWK Hwk: guided reading HWK 18-1

More Classifying Using Dichotomoous Keys 3 Keys – Go in lab Duotang!! 3 Keys – Go in lab Duotang!!

Classification Section 18.2 & 18.3

Phylogeny: Evolutionary relationships among organisms Evolutionary relationships among organisms Biologists group organisms into categories that represent lines of evolutionary descent, not just physical similarities. Biologists group organisms into categories that represent lines of evolutionary descent, not just physical similarities. The strategy of grouping organisms together based on their evolutionary history is called evolutionary classification The strategy of grouping organisms together based on their evolutionary history is called evolutionary classification

Evidence for Evolution – Homologous Structures?

Evidence for Evolution – Vestigial Structures?

Evidence for Evolution – Embryonic Development?

Evidence for Evolution – Physiology/Biochemistry?

Linnaean System vs. Evolutionary System of Classification KPCOFGS came way before scientists understood that organisms evolved. KPCOFGS came way before scientists understood that organisms evolved. The Phylogenic (Evolutionary) System names only clades The Phylogenic (Evolutionary) System names only clades Clades are groups of organisms that are all descended from a common ancestor Clades are groups of organisms that are all descended from a common ancestor

Cladogram

Tree of Life

Five Kingdoms of Classification Linnaeus – 2 Kingdoms (Animals and Plants Linnaeus – 2 Kingdoms (Animals and Plants LED TO: 1. Protista 2. Fungi 3. Monera 4. Plantae 5. Animalia

Recent Years: Six Kingdoms: 1. Eubacteria 2. Archaebacteria 3. Protista 4. Fungi 5. Plantae 6. Animalia

TODAY = 3 Domain System Domains: 1. Eukarya (protists, fungi, plants, animals) (uni and multicellular/eukaryotic) 2. Bacteria (unicellular/prokaryotic) 3. Archae (unicellular/prokaryotic) So what is the difference between 2 &3?

Guided Reading Assignment 18-2/18-3 – HWk check on Thursday!! 18-2/18-3 – HWk check on Thursday!!

Bio 111 Assignment 1. Read pages Copy Page 459 on ONE FULL page for your notes*** 3. Answer questions 1-6 on page Answer MC 1-10 on page 464

CLASSIFICATION REVIEW BIOLOGY 112

1. Why do Biologists assign each organism a universally accepted name? To provide consistency and avoid confusion To provide consistency and avoid confusion

What criteria are used to classify an organism? Evolutionary relationships as well as structural similarities of the organism

What features of Binomial Nomenclature make it useful for scientists? Each name is unique. Each scientific name (genus, species) is assigned to only 1 species, so different species are not confused Each name is unique. Each scientific name (genus, species) is assigned to only 1 species, so different species are not confused

Sequence Linnaeus’s seven taxonomic categories from smallest to largest: Species, genus, family, order, class, phylum and Kingdom Species, genus, family, order, class, phylum and Kingdom

Explain the goal of evolutionary classification: Group organisms based on their evolutionary history instead of grouping only according to physical similarities Group organisms based on their evolutionary history instead of grouping only according to physical similarities

How is a Cladogram used in classification? It is an attempt to trace the process of evolution in a group of organisms by focusing on unique shared derived features that appear in some organisms but not others It is an attempt to trace the process of evolution in a group of organisms by focusing on unique shared derived features that appear in some organisms but not others

How Do Biologists use DNA and RNA to Classify Organisms? They choose segments that are similar in all or many organisms and compare sequences within those molecules. The more similar between species, the closer the evolutionary relationships. They choose segments that are similar in all or many organisms and compare sequences within those molecules. The more similar between species, the closer the evolutionary relationships.

What is Phylogeny? Study of evolutionary relationships among organisms Study of evolutionary relationships among organisms

Describe how a Molecular Clock is used to Estimate the Length of Tie that Two Related Species Have Been Evolving Independently: Relies on a repeating process or MUTATION, and a comparison of DNA sequences in two species to see how alike or dissimilar the genes are. Relies on a repeating process or MUTATION, and a comparison of DNA sequences in two species to see how alike or dissimilar the genes are. The degree of dissimilarity is, in turn, an indication of how long ago the species shared a common ancestor The degree of dissimilarity is, in turn, an indication of how long ago the species shared a common ancestor

How do Domains and Kingdoms Differ? A domain is more inclusive and larger than a kingdom A domain is more inclusive and larger than a kingdom

What characteristics are used to place an organism in the domain Bacteria? Unicellular and Prokaryotic Unicellular and Prokaryotic Cell walls contain peptidoglycan Cell walls contain peptidoglycan

Which domain consists of prokaryotes whose cell walls lack peptidoglycan? Kingdom Archaea Kingdom Archaea

Describe the 4 Kingdoms that comprise the Domain Eukarya: Protists, Fungi, Plantae, Animalia Protists, Fungi, Plantae, Animalia

What characteristic(s) differentiate the kingdom Animalia from Plantae? Unlike members of the Plantae kingdom, members of the Animalia kingdom are heterotrophic, do not have cell walls, and are motile. Unlike members of the Plantae kingdom, members of the Animalia kingdom are heterotrophic, do not have cell walls, and are motile.