Classification Go to Section:

The Challenge Biologists have identified and named approximately 1.5 million species so far. They estimate that between 2 and 100 million species have yet to be identified.

Finding Order in Diversity 1. Why Classify? To study the diversity of life To organize and name organisms 2. Why give scientific names? Common names are misleading jellyfish silverfish star fish None of these animals are fish! Go to Section:

Why Scientists Assign Scientific Names to Organisms Some organisms have several common names This cat is commonly known as: Florida panther Mountain lion Puma Cougar Scientific name: Felis concolor Scientific name means “coat of one color” Go to Section:

Origin of Scientific Names By the 18th century, scientists realized that naming organisms with common names was confusing. Scientists during this time agreed to use a single name for each species. They used Latin and Greek languages for scientific names.

Linnaeus: The Father of Modern Taxonomy 1732: Carolus Linnaeus developed system of classification – binomial nomenclature Two name naming system Gave organisms 2 names Genus (noun) and species (adjective) Rules for naming organisms 1. Written is Latin (unchanging) 2. Genus capitalized, species lowercase 3. Both names are italicized or underlined EX: Homo sapiens: wise / thinking man Carolus Linnaeus Go to Section:

Binomial nomenclature is a two-part scientific naming system. uses Latin words scientific names always written in italics two parts are the genus name and species descriptor

Linnaeus’s System of Hierarchy Least specific Kingdom Which of the following contains all of the others? Family c. Class Species d. Order Based on their names, you know that the baboons Papio annubis and Papio cynocephalus do not belong to the same: Family c. Order Genus d. Species Phylum Class Order Family Genus Most specific Species Go to Section:

Modern classification is based on evolutionary relationships.

Modern Classification Linnaeus grouped species into larger taxa, such as genus and family, based on visible similarities. Darwin’s ideas about descent with modification evolved into the study of phylogeny, or evolutionary relationships among organisms.

How do we classify? Structural (anatomy and physiology) Biochemical (enzymes, proteins, DNA) Cytological (cell structure) Embryological (development) Behavioral (patterns of actions) Fossil (common ancestor)

Modern Classification Modern biologists group organisms into categories representing lines of evolutionary descent. Species within a genus are more closely related to each other than to species in another genus. Genus: Felis Genus: Canis

Similarities in DNA and RNA Scientists use similarities and differences in DNA to determine classification and evolutionary relationships. They can sequence or “read” the information coded in DNA to compare organisms.

Cladistics is classification based on common ancestry. Phylogeny is the evolutionary history for a group of species. evidence from living species, fossil record, and molecular data shown with branching tree diagrams

Cladistics is a method to make evolutionary trees. classification based on common ancestry species placed in order that they descended from common ancestor

A cladogram is an evolutionary tree made using cladistics. A clade is a group of species that shares a common ancestor. Each species in a clade shares some traits with the ancestor. Each species in a clade has traits that have changed.

basis of arranging species in cladogram Derived characters are traits shared in different degrees by clade members. FOUR LIMBS WITH DIGITS Tetrapoda clade 1 Amniota clade 2 Reptilia clade 3 Diapsida clade 4 Archosauria clade 5 EMBRYO PROTECTED BY AMNIOTIC FLUID OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW FEATHERS & TOOTHLESS BEAKS. SKULL OPENINGS BEHIND THE EYE DERIVED CHARACTER basis of arranging species in cladogram more closely related species share more derived characters represented on cladogram as hash marks

Nodes represent the most recent common ancestor of a clade. FOUR LIMBS WITH DIGITS CLADE Tetrapoda clade 1 Amniota clade 2 Nodes represent the most recent common ancestor of a clade. Reptilia clade 3 Diapsida clade 4 Archosauria clade 5 FEATHERS AND TOOTHLESS BEAKS. SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW Clades can be identified by snipping a branch under a node. OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS BEHIND THE EYE EMBRYO PROTECTED BY AMNIOTIC FLUID DERIVED CHARACTER NODE

Molecular evidence reveals species’ relatedness. Molecular data may confirm classification based on physical similarities. Molecular data may lead scientists to propose a new classification. DNA is usually given the last word by scientists.

Molecular clocks provide clues to evolutionary history.

Molecular clocks use mutations to estimate evolutionary time. Mutations add up at a constant rate in related species. This rate is the ticking of the molecular clock. As more time passes, there will be more mutations. Mutations add up at a fairly constant rate in the DNA of species that evolved from a common ancestor. Ten million years later— one mutation in each lineage Another ten million years later— one more mutation in each lineage The DNA sequences from two descendant species show mutations that have accumulated (black). The mutation rate of this sequence equals one mutation per ten million years. DNA sequence from a hypothetical ancestor

Scientists estimate mutation rates by linking molecular data and real time. an event known to separate species the first appearance of a species in fossil record

Ribosomal RNA is used to study distantly related species Mitochondrial DNA and ribosomal RNA provide two types of molecular clocks. Different molecules have different mutation rates. higher rate, better for studying closely related species lower rate, better for studying distantly related species Ribosomal RNA is used to study distantly related species many conservative regions lower mutation rate than most DNA

Mitochondrial DNA is used to study closely related species. mutation rate ten times faster than nuclear DNA passed down unshuffled from mother to offspring grandparents parents child Nuclear DNA is inherited from both parents, making it more difficult to trace back through generations. Mitochondrial DNA is passed down only from the mother of each generation,so it is not subject to recombination. mitochondrial DNA nuclear DNA

Kingdoms and Domains In the 18th century, Linnaeus originally proposed two kingdoms: Animalia and Plantae. By the 1950s, scientists expanded the kingdom system to include five kingdoms.

The Five Kingdom System

The Six Kingdom System In recent years, biologists have recognized that the Monera are composed of two distinct groups. As a result, the kingdom Monera has now been separated into two kingdoms: Eubacteria and Archaebacteria, resulting in a six-kingdom system of classification.

The Three-Domain System Scientists can group modern organisms by comparing ribosomal RNA to determine how long they have been evolving independently. This type of molecular analysis has resulted in a new taxonomic category—the domain.

The Three Domains The three domains, which are larger than the kingdoms, are the following: Eukarya – protists, fungi, plants and animals Bacteria – which corresponds to the kingdom Eubacteria. Archaea – which corresponds to the kingdom Archaebacteria.

The three domains in the tree of life Domains are above the kingdom level. proposed by Carl Woese based on rRNA studies of prokaryotes domain model more clearly shows prokaryotic diversity

Classification of Living Things The three-domain system Bacteria Archaea Eukarya The six-kingdom system Eubacteria Archae- bacteria Protista Plantae Fungi Animalia

Each level is more specific. Hierarchical Ordering of Classification Grizzly bear Black bear Giant panda Red fox Abert squirrel Coral snake Sea star KINGDOM Animalia PHYLUM Chordata CLASS Mammalia As we move from the kingdom level to the species level, more and more members are removed. Each level is more specific. ORDER Carnivora FAMILY Ursidae GENUS Ursus SPECIES Ursus arctos Go to Section:

Kingdom Archaebacteria Cell Type Prokaryote Number of Cells Unicellular Nutrition Autotroph or Heterotroph Location Extreme Environments Volcanoes, Deep Sea Vents, Yellowstone Hot Springs Examples Methanogens Thermophiles Go to Section:

Kingdom Eubacteria Cell Type Prokaryote Number of Cells Unicellular Nutrition Autotroph or Heterotroph Examples Streptococcus, Escherichia coli (E. coli) E. coli Streptococcus Go to Section:

The “Junk-Drawer” Kingdom Kingdom Protista Cell Type Eukaryote Number of Cells Most Unicellular, some multicellular Nutrition Autotroph or Heterotroph Examples Amoeba, Paramecium, Euglena, Paramecium Green algae The “Junk-Drawer” Kingdom Amoeba Go to Section:

Most Fungi are DECOMPOSERS Kingdom Fungi Cell Type Eukaryote Number of Cells Most multicelluar, some unicelluar Nutrition Heterotroph Example Mushroom, yeast, mildew, mold Mildew on Leaf Most Fungi are DECOMPOSERS Mushroom Go to Section:

Kingdom Plantae Cell Type Eukaryote Number of Cells Multicellular Ferns : seedless vascular Cell Type Eukaryote Number of Cells Multicellular Nutrition Autotroph Examples Mosses, ferns, conifers, flowering plants Douglas fir: seeds in cones Sunflowers: seeds in flowers Mosses growing on trees Go to Section:

Kingdom Animalia Cell Type Eukaryote Number of Cells Multicellular Nutrition Heterotroph Examples Sponges, worms, insects, fish, mammals Bumble bee Jellyfish Sage grouse Hydra Poison dart frog Sponge Go to Section:

Dichotomous Key Tool used by biologists to identify an unknown organism Series of paired statements of anatomical description that leads to an identification.

What bird am I ?

Key for Vertebrate Identification What am I ??? 1. a) animal has a spine…………………..go to 2 b) animal has no spine………..…invertebrate 2. a) animal has no gills and fins……..…. go to 3 b) animal has gills and fins…………….. Fish 3. a) animal has no scales…………..........go to 4 b) animal has scales………………..….reptile 4. a) animal has feathers …………………..bird b) animal has no feathers ……………..go to 5 5. a) animal has hair…………………….mammal b) animal has no hair………………..amphibian