Scientists do this in order to make it easier to study living things. Classification There are around 1.2 million species that have been described and some scientists believe there are approx. 8.7 million species on this planet (some estimates are close to 100 million…maybe even a trillion). How do we figure this out? Mathematical models! Bottom line…we’re not sure but there are a lot! Classification is…the process of grouping things together based upon their similarities. Scientists do this in order to make it easier to study living things.

Taxonomy is…the study of how living things are classified Taxonomy is…the study of how living things are classified. Taxonomists are the scientists that do this. How Did this all Start? Dude #1 Aristotle was a Greek philosopher and scientist who lived in the 300B.C.’s; he took a shot at classifying critters. He observed animals and grouped them into…swimming, walking, and flying things. Nice try…but we don’t use these groups…they’re too general.

More About Aristotle…for inquiring minds Aristotle also grouped animals into: those with blood and those without blood. That’s sorta close to our vertebrate (backbone) and invertebrate (no backbone) thing. Even though we have made some changes, We still DO use his basic approach.

Dude #2 Carolus Linnaeus was a Swedish scientist (mid-1700’s) who followed up on Aristotle’s work. He developed the system of using two names, so that scientists could communicate regardless of the language they spoke. We call this: BINOMIAL NOMENCLATURE. The first word is the genus and the second is usually an adjective that describes the organism (or where its from or who discovered it). More on this in a few slides.

Kingdoms are the broadest category and species the most…ummm…specific. Eight Levels of Classification (and one way to remember them) Domain…Dumb Kingdom…Kings *Phylum…Play Class…Chess Order…On Family…Fancy Genus…Glass Species…Stools Kingdoms are the broadest category and species the most…ummm…specific. *In plants…we call these DIVISIONS…sorry!

Domains Domains were added to the taxonomic system to take evolutionary differences and differences in DNA. This level is the broadest in scope. There are three DOMAINS: 1-Archaea 2-Bacteria 3-Eukarya

Bacteria (formerly Eubacteria) Protists Fungi Plants Animals The Six Kingdoms We’ll look at each in more detail later. Archaebacteria Bacteria (formerly Eubacteria) Protists Fungi Plants Animals

In this system of naming living things using two names, we use the genus and species names. Genus (capitalize this word): a grouping that contains several similar organisms. species (this will be lower case): an even smaller group within which organisms can mate and produce fertile offspring. Example: Crocodylus porosus (salt water crocodile), Crocodylus niloticus (Nile crocodile)…same genus; different species. Notice that the genus name is upper case and the species name…lower case.

Dichotomous Keys AKA: Taxonomic Key A bunch of paired statements that describe the physical characteristics of living things. You make observations; follow the key; and BINGO! Instant identification  Turn to page 226 and figure out what organisms are pictured by using the dichotomous (taxonomic) key.

Checkpoint Question #1!?!?!? What were the three main groups of animals in Aristotle’s system of classification? Large animals, small animals, and medium-sized animals Mammals, fish, and reptiles Those that fly, those that swim, and those that can walk, crawl, or run

Checkpoint Question #2!?!?!?!? In a scientific name, the genus name is similar to Your species name. Your family name. Your nickname.

Checkpoint Question #3!?!?!?!? What are the seven levels of classification from the broadest to the most specific? Domain, kingdom, phylum, class, order, family, genus, species Kingdom, phylum, order, class, family, genus, species Kingdom, phylum, family, order, genus, species

Checkpoint Question #4!?!?!?!? Who developed one of the earliest classification system for organisms? Aristotle Linnaeus Darwin

Checkpoint Question #5!?!?!?!? In the scientific name of a house cat, Felis domesticus, “felis” is the name of the animal’s Species Family Genus

Checkpoint Question #6!?!?!?!? A taxonomic key is a book with illustrations that highlights differences between similar-looking organisms. a process for determining the evolutionary history of an organism. a series of paired statements that describe the physical characteristics of different organisms.

Answers!!! 1-C 2-B 3-A 4-A 5-C 6-C