Classification of Living Things

Why do we classify things? Supermarket aisles Libraries Classes Teams/sports Members of a family Roads Cities Money

What is classification? Classification: putting things into orderly groups based on similar characteristics Taxonomy: the science of describing, naming, and classifying organisms

Early classification Aristotle grouped everything into simple groups such as animals or plants He then grouped animals according to if they had blood or didn’t have blood, and if they had live young or laid eggs, and so on…

Binomial Nomenclature Developed by Carolus Linnaeus Swedish Biologist 1700’s Two-name system Genus and species named using Latin or Greek words

Rules used to write scientific names Homo sapiens An organism’s genus is always written first; the organism’s species is always written second The genus is Capitalized; the species is written in lower case Scientific names of organisms are always italicized or underlined

Modern Taxonomy The Evidence used to classify into taxon groups   1) Embryology   2) Chromosomes / DNA   3) Biochemistry   4) Physiology   5) Evolution   6) Behavior

The modern system of classification has 8 levels: Order Family Genus Species Domain Kingdom Phylum Class

Helpful way to remember the 8 levels Dumb kids playing catch on freeways get squashed Or…make up your own… D K P C O F G S

Why do we need to classify? Imagine a store…..how do you know where to find the milk or the cereal? Are they in the same aisle? How is the store “organized”? Are all stores similar? Imagine your computer or mp3 player…..are all of your songs and files in a single folder or do you have them grouped in some way?

….this is why we CLASSIFY When you have a lot of information, it is best to organize and group items so that you can find them easier or easily see their relationship to other items ….this is why we CLASSIFY Even websites must  organize their products

Scientists also need a way to *NAME* organisms The “common names” used by people  can sometimes be misleading or confusing In order to communicate effectively, biologists need a CONSISTENT naming protocol. *Check out these slides of confusing names…..

Sea Lion? Antlion? Lion? Photo Credits Sea Lion: Bill Lim Ant Lion: Amphioxus Lion: law_keven Sea Lion? Antlion? Lion?

Which one of these is NOT actually a bear? Photo Credits Panda: Chi King Koala: Belgianchocolate Black Bear: SparkyLeigh

What kind of organism is it What kind of organism is it?(invertebrate, mammal, insect, fish, reptile..) Sea Monkey Firefly Ringworm Jellyfish Spider monkey Crayfish Sea Horse Photo Credit: Audringje; flickr

Consider this……….. Are all “Grey Wolves” grey? Are all “Black Bears” black? Which is more venomous – a water moccasin or a cottonmouth? Grey wolves can be white, black and any shade of gray. Black bears can also be brown or gray A cottonmouth and a water moccasin are the same animal – the names vary by region.

Humans The scientific name is always the genus + species Kingdom Animalia Phylum Chordata Class Mammalia Order Primate Family Hominidae Genus Homo Species sapiens The scientific name is always the genus + species Humans = Homo sapiens Photo by atomicshark

What are the scientific names of each of these organisms? Lion Tiger Pintail Duck Kingdom Animalia Phylum Chordata Class Mammalia Aves Order Carnivora Anseriformes Family Felidae Anatidae Genus Panthera Anas Species Leo Tigris acouta What are the scientific names of each of these organisms?

More on Naming.. The system of naming is called BINOMIAL NOMENCLATURE - which means it is a 2-name system. Scientific names must either be underlined or italicized The genus is always capitalized, the species is lowercase Can be abbreviated. Ex. F. leo and F. tigris

What is a species? Defined as organisms that can interbreed with one another, and produce fertile offspring

When two organisms of different species interbreed, the offspring is called a HYBRID Example:  ligers and mules

Check for Understanding 1.  Fill in the blanks:   ______________, Kingdom,  _____________,  Class, Order,  ________________,  Genus,  _______________ 2.  Which two groups are used for an organism's scientific name?  3.  Which of the following pairs is MOST closely related?               Acer rubrum  &  Acer  saccharum             Acer rubrum  &  Chenopodium rubrum 4. The system we use for naming is called  ____________ nomenclature. 5.  The science of classification is called ________________

The Kingdoms There are currently 6 kingdoms

Classification into a kingdom is based on certain criteria -Number of cells (unicellular or multicellular) -How it obtains energy (heterotroph or autotroph) -Type of cell (eukaryote or prokaryote)

Quick Vocabulary Lesson 1. Heterotroph _______________________________ 2. Autotroph ________________________________ 3. Unicellular ________________________________ 4. Multicellular ________________________________ Prokaryote ________________________________ Eukaryote _________________________________ Eukaryotes are organisms, including humans, whose cells have a well defined membrane bound nucleus (containing chromosomal DNA) and organelles. The division between prokaryotes and eukaryotes reflects the existence of two discrete levels of cellular organization.

1. Heterotroph: Organism that is unable to make its own food and must consume other organisms 2. Autotroph: Organism that is capable of making its own food through photosynthesis 3. Unicellular: single-celled organism 4. Multicellular: organism made of two or more cells 5. Prokaryote ________________________________ 6. Eukaryote _________________________________ Eukaryotes are organisms, including humans, whose cells have a well defined membrane bound nucleus (containing chromosomal DNA) and organelles. The division between prokaryotes and eukaryotes reflects the existence of two discrete levels of cellular organization.

Kingdom Animalia Multicellular Heterotrophic Eukaryotes Most can move Photo by Tambako the Jaguar Multicellular Heterotrophic Eukaryotes Most can move Examples: birds, insects, worms, mammals, reptiles, humans, anemones Photo by Eduardo Amorim

Kingdom Plantae Multicellular Autotrophic Eukaryotes Cannot move (due to cell walls) Examples: flowers, trees, ferns,mosses

Kingdom Fungae Multicellular (most) Heterotrophic (mainly decomposers) Eukaryotic Examples: mushrooms, yeast, molds Photos by nutmeg66

Kingdom Protista Most are unicellular Can be heterotrophic or autotrophic Eukaryotes (all have nucleus) Examples: Ameba, paramecium, euglena, algae Most live in water Photo of Ameba by PROYECTO AGUA **/** WATER PROJECT

Kingdom Eubacteria & Kingdom Archaebacteria Unicellular Can be autotrophic or heterotrophic Prokaryotes (do not have a nucleus) Eubacteria = common bacteria (E. coli, Salmonella) Archaebacteria = “ancient bacteria”, exist in extreme environments

Three Domain System     Recently, scientists have added a group above Kingdom.  Three groups, called DOMAINS, contain each of the six kingdoms. Domain Eukarya - includes organisms composed of eukaryotic cells (plants, animals, fungi, protists) Domain Bacteria - includes all prokaryotic cells, Kingdom Eubacteria Domain Archaea - includes only "ancient" bacteria, Archaebacteria

The Three Domains

Using the Classification System Field guides help identify organisms. -they highlight differences between similar organisms (like trees) Taxonomic Key (Dichotomous Key) -paired statements that describe the physical characteristics of different organisms

What steps would you use to identify an apple? Taxonomic Key 1a Fruits occur singly ................................................. Go to 3 1b Fruits occur in clusters of two or more ................ Go to 2 2a Fruits are round ................................................... Grapes 2b Fruits are elongate ............................................... Bananas 3a Thick skin that separates easily from flesh .........Oranges 3b Thin skin that adheres to flesh .............................. Go to 4 4a More than one seed per fruit ............................ Apples 4b One seed per fruit ............................................ Go to 5 5a Skin covered with fuzz.................... Peaches 5b Skin smooth, without fuzz........................... Plums What steps would you use to identify an apple?