Classification

Species of Organisms There are 13 billion known species of organisms There are 13 billion known species of organisms This is only 5% of all organisms that ever lived!!!!! This is only 5% of all organisms that ever lived!!!!! New organisms are still being found and identified New organisms are still being found and identified 2

What is Classification? Classification is the arrangement of organisms into orderly groups based on their similarities Classification is the arrangement of organisms into orderly groups based on their similarities Classification is also known as taxonomy Classification is also known as taxonomy Taxonomists are scientists that identify & name organisms Taxonomists are scientists that identify & name organisms 3

Taxonomy Taxonomy is the field of Biology that deals with classifying organisms – Organisms are placed into categories based on shared characteristics – Organisms that are more closely related are placed in the same or similar categories

Taxonomy Carolus Linneaus devised a system for classifying organisms in the mid 1700’s – He created taxa that were based on similar or homologous structures – The broadest and largest taxon is called a Kingdom, while the smallest is called a species – Every organism was given a scientific name using the genus and species Ex: Homo sapiens or Canus lupus

Why not use common names? Common names differ from place to place – Ex: Crayfish, Crawdaddy, & Crawfish Common names do not always accurately describe the specimen – Ex: A jellyfish is not a fish Common names are to general – Ex: “Oak Tree” – there are many different species of oak trees

Other Benefits of Classifying Accurately & uniformly names organisms Accurately & uniformly names organisms Prevents misnomers such as starfish & jellyfish that aren't really fish Prevents misnomers such as starfish & jellyfish that aren't really fish Uses same language (Latin or some Greek) for all names Uses same language (Latin or some Greek) for all names 7 Sea”horse”??

Confusion in Using Different Languages for Names 8

Latin Names are Understood by all Taxonomists 9

Early Taxonomists 2000 years ago, Aristotle was the first taxonomist 2000 years ago, Aristotle was the first taxonomist Aristotle divided organisms into plants & animals Aristotle divided organisms into plants & animals He subdivided them by their habitat ---land, sea, or air dwellers He subdivided them by their habitat ---land, sea, or air dwellers 10

Early Taxonomists John Ray, a botanist, was the first to use Latin for naming John Ray, a botanist, was the first to use Latin for naming His names were very long descriptions telling everything about the plant His names were very long descriptions telling everything about the plant 11

Carolus Linnaeus 1707 – th century taxonomist Classified organisms by their structure Developed naming system still used today 12

Carolus Linnaeus “Father of Taxonomy” “Father of Taxonomy” Developed a 2 word naming system called binomial nomenclature Developed a 2 word naming system called binomial nomenclature Genus & species Genus & species 13

The Modern Classification System Identifying organisms by their genus and species name (Scientific Name) is called Binomial Nomenclature. – Scientific names are used to create a Universal Language

Modern Evolutionary Classification Biologists now group organisms into categories that represent lines of evolutionary descent or phylogeny not just physical similarities Phylogeny= evolutionary relationships among organisms 15

Standardized Naming Rules Italicized when typed Italicized when typed Capitalize genus, but NOT species Capitalize genus, but NOT species Underline when writing Underline when writing 16 Turdus migratorius American Robin

Binomial Nomenclature 17

The Modern Classification System All organisms are classified in a hierarchical system of groups that increase in inclusiveness There are seven taxa or groups into which organisms are place: – Kingdom, Phylum, Class, Order, Family, Genus, and Species

Kids Kids Pick Pick Candy Candy Over Over Fancy Fancy Green Green Salads! Salads! 19

The Modern Classification System You may use a pneumonic to remember the taxa – Ex: King Phillip Came Over For Good Spaghetti – Ex: Kings Play Cards On Flat, Green Stools – Ex: Kids Pick Candy Over Fancy Green Salads

The Modern Classification System The Species is the basic biological unit in the modern classification system Species are organisms that can interbreed and produce fertile offspring – Ex: Killer Whales – There are always exceptions: Female Horse x Male Donkey = Mule Male Horse x Female Donkey = Hinny

Domains *Broadest taxon *3 domains: -Bacteria -Archaea -Eukarya 22

Domains Archaea and Eubacteria are unicellular prokaryotes (no nucleus or membrane- Archaea and Eubacteria are unicellular prokaryotes (no nucleus or membrane- bound organelles) bound organelles) Eukarya are Eukaryotes more complex and have a nucleus and membrane-bound organelles Eukarya are Eukaryotes more complex and have a nucleus and membrane-bound organelles 23

The 3 Domains are divided into 6 Kingdoms DomainKingdom BacteriaEubacteria ArchaeaArchaebacteria EukaryaProtista Fungi Plantae Animalia 24

25 Archaea live in harsh environments and may represent the first cells to have evolved. Sewage treatment plants, thermal vents, etc.

26 Eubacteria, some of which cause human diseases, are present in almost all habitats on earth. Many bacteria are important environmentally and commercially. Live in the intestines of animals

The Six Kingdom System Protista – Singled-Celled & Multi- Celled – Heterotrophs & a few Autotrophs – Eukaryotic – Ex: Paramecium & Algae

Protista Most are unicellular Most are unicellular Some are multicellular Some are multicellular Some are autotrophic, while others are heterotrophic Some are autotrophic, while others are heterotrophic 28

The Six Kingdom System Fungi – Multi-Celled – Heterotrophs – Eukaryotic – Ex: Mushrooms & Yeast

Fungi Multicellular, except yeast Multicellular, except yeast Absorptive heterotrophs (digest food outside their body & then absorb it) Absorptive heterotrophs (digest food outside their body & then absorb it) Cell walls made of chitin Cell walls made of chitin 30

The Six Kingdom System Plantae – Multi-Celled – Autotrophs – Eukaryotic – Ex: Trees, Plants, Flowers

Plantae Multicellular Multicellular Autotrophic Autotrophic Absorb sunlight to make glucose – Photosynthesis Absorb sunlight to make glucose – Photosynthesis Cell walls made of cellulose Cell walls made of cellulose 32

The Six Kingdom System Animalia – Multi-Celled – Heterotrophs – Eukaryotic – Ex: Mammals, Insects

Animalia Multicellular Multicellular Ingestive heterotrophs (consume food & digest it inside their bodies) Ingestive heterotrophs (consume food & digest it inside their bodies) Feed on plants or animals Feed on plants or animals 34

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The Six Kingdom System The Six Kingdoms of Living Things 1. Animals 2. Plants 3. Fungi 4. Protists 5. Archaebacteria (Monera) 6. Eubacteria (Monera)

Classification The basis for classification is very similar to the basis for evolutionary relationships Physical traits of organisms, such as homologous structures, are used to determine evolutionary relationships – Ex: a Human’s Arm, a Bat’s Wing, & a Whale’s Flipper A more exact method is Biochemical Analysis – DNA – Cytochrome C – ancient protein, changed very little of millions of years, but there are many variations

38 Homologous Structures show Similarities in mammals.

Similarities in Vertebrate Embryos 39

Phylogenetic Tree A family, or phylogenetic tree, shows relationships among organisms – The organisms at the tip of the branches are more recently evolved – The organisms at the base of the tree are the oldest – Each time a branch divides, a new species has emerged

Phylogenetic Tree

Cladogram A cladogram is a branching structure that shows shared traits of organisms A cladogram can show differences in anatomy, physiology, or behavior among organisms

Cladogram

Primate Cladogram 45

Dichotomous Key A dichotomous key is a type of classification key – It is a tool for identifying unfamiliar organisms It is a list of observable traits that will lead you to the identity of the organism – The common name, as well as, the scientific name of the organism is usually obtained

Example of Dichotomous Key 1a Tentacles present – Go to 2 1a Tentacles present – Go to 2 1b Tentacles absent – Go to 3 1b Tentacles absent – Go to 3 2a Eight Tentacles – Octopus 2a Eight Tentacles – Octopus 2b More than 8 tentacles – 3 2b More than 8 tentacles – 3 3a Tentacles hang down – go to 4 3a Tentacles hang down – go to 4 3b Tentacles upright–Sea Anemone 3b Tentacles upright–Sea Anemone 4a Balloon-shaped body–Jellyfish 4a Balloon-shaped body–Jellyfish 4b Body NOT balloon-shaped - 5 4b Body NOT balloon-shaped

Dichotomous Key 1a. The organism has wings…go to 2 1b. The organism doesn’t have wings…go to 8 2a. The organism has 2 wings…go to 3 2b. The organism has 4 wings…go to 4 3a. The organism has feathers…go to 5 3b. The organism doe not have feathers…go to 7 4a. The wings are of equal size…go to 5 4b. The wings are of unequal size…go to 6

Dichotomous Key Heron Mosquito Mayfly