Classification

Vocabulary Prokaryote – unicellular organisms without a nucleus Prokaryote – unicellular organisms without a nucleus Eukaryote – unicellular or multicellular organisms with a nucleus Eukaryote – unicellular or multicellular organisms with a nucleus

Vocabulary Autotrophs – “self feeder” organisms that can make their own food through photosynthesis Autotrophs – “self feeder” organisms that can make their own food through photosynthesis Heterotrophs – “other feeder” organisms that must ingest (eat) their food Heterotrophs – “other feeder” organisms that must ingest (eat) their food

Why Do We Classify Things? Placing items in categories is natural for humans. Placing items in categories is natural for humans. Wild animals: domesticated animals Wild animals: domesticated animals Edible plants: poisonous plants Edible plants: poisonous plants Fresh water fish:salt water fish Fresh water fish:salt water fish There are numerous examples of classification systems. There are numerous examples of classification systems.

The First Classification System The first classification system developed 2,500 years ago by Aristotle. The first classification system developed 2,500 years ago by Aristotle. Organisms were separated into two groups, Plants and Animals. Organisms were separated into two groups, Plants and Animals. A statue of Aristotle, 384 – 322 BC

Aristotle He further placed animals into three groups, those that fly, those that walk, and those that swim. He further placed animals into three groups, those that fly, those that walk, and those that swim.

Aristotle Plants were classified as trees, shrubs or herbs depending on size and structure. Plants were classified as trees, shrubs or herbs depending on size and structure.

Linnaeus But, more divisions were needed, and scientists would name organisms whatever they wanted. But, more divisions were needed, and scientists would name organisms whatever they wanted. A better system was needed that everyone could use. A better system was needed that everyone could use. In 1760 Carolus von Linnaeus published his book on classification. In 1760 Carolus von Linnaeus published his book on classification.

Carolus von Linnaeus ( ) Swedish scientist who laid the foundation for modern taxonomy Binomial Nomenclature Binomial “two names” Binomial “two names” Nomenclature is a system of naming Nomenclature is a system of naming Carolus von Linnaeus Carolus von Linnaeus Carolus von Linnaeus Carolus von Linnaeus Two-word naming system Two-word naming system –Genus Noun, Capitalized, Underlined or Italicized Noun, Capitalized, Underlined or Italicized –Species Descriptive, Lower Case, Underlined or Italicized Descriptive, Lower Case, Underlined or Italicized

Why Do We Classify Organisms? Biologists group organisms to represent similarities and proposed relationships. Biologists group organisms to represent similarities and proposed relationships. Classification systems change with expanding knowledge about new and well-known organisms. Classification systems change with expanding knowledge about new and well-known organisms. Tacitus bellus

Why a Scientific Classification System? Ambiguity of terms – –All scientists use the same system. Latin “dead language” – –The Latin terms will not change over time Categorization of relationships: – –Evolutionary – –Structural – –Biochemical

Classification Classification starts at the largest division that includes the most organisms. Classification starts at the largest division that includes the most organisms. Classification consists of three domains and six kingdoms. Classification consists of three domains and six kingdoms. BacteriaArchaeaEukarya The Three Domains

The Six Kingdoms How are organisms placed in kingdoms? How are organisms placed in kingdoms? –Cell type, prokaryotic or eukaryotic –The number of cells in their body, unicellular or multicellular –Their ability to make food, autotrophs or heterotrophs EubacteriaaArchaea ProtistaPlantae Fungi Animalia The six-kingdom system

Classification Kingdom Kingdom Phylum Phylum Class Class Order Order Family Family Genus Genus Species Species King King Phillip Phillip Came Came Over Over For For Good Good Soup Soup

The farther you go down the classification system the more specific the name becomes for that particular organism. The farther you go down the classification system the more specific the name becomes for that particular organism. What is classification based on? What is classification based on?

Classification Criteria Biochemistry Biochemistry Genetic System, DNA and RNA Genetic System, DNA and RNA Evolutionary History Evolutionary History Nutrition Nutrition Molecular Make-up Molecular Make-up A Dichotomous Key is used to classify organisms A Dichotomous Key is used to classify organisms

Classification System for Lynx and Bobcat Kingdom: Animalia Kingdom: Animalia Phylum: Chordata Phylum: Chordata Class: Mammalia Class: Mammalia Order: Carnivora Order: Carnivora Family: Felidae Family: Felidae Genus: Lynx Genus: Lynx Species: Lynx canadensis Lynx rufus Species: Lynx canadensis Lynx rufus lynx bobcat lynx bobcat The same to this point, the animals share the same characteristics

Family or Genus Relations? Family: Less closely related Less closely related Larger group Larger groupGenus: More closely related More closely related Precedes species= Precedes species=interbreeding Family:Felidae Lions, tigers, leopards Lions, tigers, leopards house cats,cheetahs, ocelots house cats,cheetahs, ocelots Genus: Panthera Leopards (pardus) Leopards (pardus) Lion (leo) Lion (leo) Tigers (tigris) Tigers (tigris)

Feline Family Members:

Genus: Panthera Lions and Tigers

The First Cat Most authorities agree that the domestic cat descended from the Caffre cat, a small breed of African wildcat. The Caffre cat was domesticated in ancient Egypt, possibly as early as 2500 BC.

Evolutionary History The evolutionary history of a species is called its phylogeny. The evolutionary history of a species is called its phylogeny. Cladistics is a system of taxonomy that reconstructs phylogenies by inferring relationships based on similarities. Cladistics is a system of taxonomy that reconstructs phylogenies by inferring relationships based on similarities.

Taxonomic Diagrams Biologists group organisms into categories that represent common ancestries, not just physical similarities. Biologists group organisms into categories that represent common ancestries, not just physical similarities. Early naturalists used physical characteristics and later, fossil data, attempting to represent evolutionary relationships among organisms. Early naturalists used physical characteristics and later, fossil data, attempting to represent evolutionary relationships among organisms.

Taxonomic Diagrams Today, modern classification systems use fossil data, physical characteristics and DNA/RNA information to draw increasingly more accurate branching diagrams. Today, modern classification systems use fossil data, physical characteristics and DNA/RNA information to draw increasingly more accurate branching diagrams. Two types of diagrams are Cladistic and Phylogenic diagrams Two types of diagrams are Cladistic and Phylogenic diagrams

Cladistics Cladograms are based only on characteristics observable in existing species. Cladograms are based only on characteristics observable in existing species. The branching patterns in a cladogram are defined by the presence of unique, characteristics shared by all members of the group. The branching patterns in a cladogram are defined by the presence of unique, characteristics shared by all members of the group.

Cladistics A branching diagram to show an evolutionary family tree is known as a cladogram. A branching diagram to show an evolutionary family tree is known as a cladogram. Cladistics hypothesize that every phylum originated from a single group of organisms that has branched into today’s species. Cladistics hypothesize that every phylum originated from a single group of organisms that has branched into today’s species.

Cladograms Each branch point or fork in the cladogram, shows a point in evolution where a unique characteristic developed to separate one group from another. Each branch point or fork in the cladogram, shows a point in evolution where a unique characteristic developed to separate one group from another. Cladograms are concerned with the order structural differences happened. Cladograms are concerned with the order structural differences happened.

Cladogram

Cladogram

Cladogram

Taxonomic Diagrams Phylogenetic trees, or phylogenies, represent hypothesized evolutionary relationships among organisms and may include extinct as well as modern species. Phylogenetic trees, or phylogenies, represent hypothesized evolutionary relationships among organisms and may include extinct as well as modern species.

A Phylogenic Tree