Classifying Living Things

Classification Classification is the process of grouping things based on their shared traits. Classification is the process of grouping things based on their shared traits. Biologists use classification to organize living things into groups, so that the organisms are easier to study Biologists use classification to organize living things into groups, so that the organisms are easier to study The scientific study of how living things are classified is called taxonomy. The scientific study of how living things are classified is called taxonomy.

Classification System Carolus Linnaeus is the Swedish scientist who developed a classification system based on the organisms’ observable features. Carolus Linnaeus is the Swedish scientist who developed a classification system based on the organisms’ observable features. Linnaeus’s naming system is called binomial nomenclature because each organism is given a two part name. Linnaeus’s naming system is called binomial nomenclature because each organism is given a two part name.

Funny Common Names Red Rat Snake / Corn Snake Red Rat Snake / Corn Snake Elaphe guttata Horny Toad Horny Toad Phrynosoma platyrhinos Phrynosoma platyrhinos Red-eared Slider Turtles Red-eared Slider Turtles Chrysemys scripta Chrysemys scripta

Binomial Nomenclature The first part of the organism’s name is its genus. This is a classification grouping that contains similar, closely related organisms. The first part of the organism’s name is its genus. This is a classification grouping that contains similar, closely related organisms. The second part of the organism’s name is its species. A species is a group of similar organisms that can mate and produce fertile offspring. The second part of the organism’s name is its species. A species is a group of similar organisms that can mate and produce fertile offspring.

How animals are given their scientific names Haliaeetus leucocephalus Haliaeetus leucocephalus Genus = Haliaeetus Genus = Haliaeetus Species = leucocephalus Species = leucocephalus Notice that scientific names are always italicized Notice that scientific names are always italicized The first word is always capitalized The first word is always capitalized The second word is always lower case The second word is always lower case

Seven Levels of Classification Today’s classification system uses several levels to classify organisms. The more characteristics that organisms have in common, the more level they share. Today’s classification system uses several levels to classify organisms. The more characteristics that organisms have in common, the more level they share. Kingdom Kingdom Phylum Phylum Class Class Order Order Family Family Genus Genus Species Species

5 (some Scientists say 6) Kingdoms of Organisms Bacteria (Monera) Bacteria (Monera) Archaebacteria Archaebacteria Eubacteria Eubacteria Protists Protists Fungi Fungi Plants Plants Animals Animals

Dichotomous Keys Taxonomist have developed special guides known as dichotomous keys to aid in identifying unknown organisms. Taxonomist have developed special guides known as dichotomous keys to aid in identifying unknown organisms. A dichotomous key consists of several pairs of descriptive statements that have only two responses. A dichotomous key consists of several pairs of descriptive statements that have only two responses.

Dichotomous Keys 1a. Organism has 4 legsGo to # 2 1b. Organism has more than 4 legsGo to # 20 2a. Organism has a tailGo to # 3 2b. Organism has no tailGo to # 35 3a. Organism has stripesBengal Tiger 3b. Organism has no stripesAfrican Lion

Dichotomous Key Try this one: Try this one: 1a. Organism walks on all 4 legs (quadruped)2 1b. Organism walks on 2 legs (biped)8 2a. Organism has visible fur3 2b. Organism has no visible fur20 3a. Organism lives in warm climates7 3b. Organism lives in cold climates4 4a. Organism has brown or black furUrsus americanus 4b. Organism has white furUrsus maritimus