Classification of Earth’s Diversity

Biodiversity Biodiversity – the variety of organisms on earth is the result of 3.5 billion years of evolution Approx 8 million species on earth! To make sense of all of them, they are organized into meaningful groups Species are becoming extinct at an increasing rate, so there is a rush to catalog them

Common vs Scientific Names Common names are convenient, but there are problems: - same names are used for different species (robin here, robin Europe) - can be more than one name for same species (mt lion, cougar, puma) - very ambiguous (not very descriptive)

Common vs. Scientific Names Advantages of scientific names: –Provide a consistent naming system for all –Show evolutionary relationships –Systematics – the science of naming and grouping organisms according to biological meaning –Groups are called taxa (singular: taxon)

Binomial Nomenclature Bi = two, nomial = name Scientific names have two parts Always typed in italics (or underlined) First word is capitalized, second is not First word - genus – a group of similar species Second word - species – unique to ONLY that species

Ursus arctos Ursus americanus Ursus maritimus Ursus thibetanus Brown bear Black bear Polar bear Asian black bear Use Latin language

Linnaean Classification Carolus Linnaeus developed 1 st system Four levels of hierarchy, or ranks Today there are 7: Kingdom, Phylum, Class, Order, Family, Genus, Species Bears belong in the Family Ursidae Pandas are also in this Family, but have a different genus (Ailuropoda)

Mnemonic for remembering King Phyl Came Over For Good Spaghetti

Kingdom- Ex: p.514 Largest and most inclusive taxon All multicellular animals are in the kingdom Animalia

Phylum Contains groups of organisms that are different but share important characteristics Phylum Chordata features organisms with a nerve cord along the back Within the phylum, are groups called Classes…

Class Classes are groups that narrow down the differences even further Class Mammalia includes all animals that are warm-blooded, have body hair, and produce milk for their young Within a class are groups called orders…

Order Order Artiodactyla contains hoofed animals with an even number of toes Within an order are groups called Families Family Family – a group of several genera (plural of genus) that share similarities Bactrian camel and dromedary more closely related than the llama (Family Camelidae)

Genus species Camelus bactrianus – two humps Camelus dromedarius – one hump The genus Camelus includes both of these species

Identifying Organisms Dichotomous keys Used to VISUALLY identify organisms Has series of “couplets” or paired statements that describe visual traits (color, size, unique features, etc.) Each statement describes the presence or absence of a visible trait Each set of choices helps to narrow down the identity of the organism NOT like these

The most useful tool for such identifications is the dichotomous key, which contains information useful in identifying similar kinds of organisms, but is arranged in a way that allows the information to be used quickly. A dichotomous key is a list of paired statements (each statement is called a lead) that guides you to the identification of a specimen. The paired leads (the pair of leads together is called a couplet) are contrasting descriptions of certain characteristics. In a good key, couplets are written so that you must choose one or the other of the leads as being true for your specimen. Couplet leads should always be mutually exclusive In addition, the leads in a couplet should be parallel; that is, both should ask questions about the same character(s). DIRECTIONS:

Can you figure out the key? Help! Scientists have discovered quite a few new creatures on planet Pamishan. They need your help to identify and classify them. Use the dichotomous key on the next page to identify these creatures. ALWAYS start with step 1, and go to whichever step the key tells you