Classification There are around 2 million species that have been described and scientists believe there are anywhere from 4 million to over 100 million different kinds of life forms on this planet. How do we figure this out? Mathematical models! 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. Taxonomists are the scientists that do this. 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. 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. 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. 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. 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: 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. 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.

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

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

The Six Kingdoms We’ll look at each in more detail later. 1. Archaebacteria 2. Bacteria (formerly Eubacteria) 3. Protists 4. Fungi 5. Plants 6. Animals

In this system of naming living things using two names, we use the genus and species names. In this system of naming living things using two names, we use the genus and species names. Genus: a grouping that contains several similar organisms. Genus: a grouping that contains several similar organisms. Species: an even smaller group within which organisms can mate and produce fertile offspring. Species: 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. 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. 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. A bunch of paired statements that describe the physical characteristics of living things. You make observations; follow the key; and BINGO! Instant identification 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. 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? A) Large animals, small animals, and medium-sized animals B) Mammals, fish, and reptiles C) 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 A) Your species name. B) Your family name. C) Your nickname.

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

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

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

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

Answers!!! 1-C2-B3-A4-A5-C6-C