Taxonomy

taxonomy…

• the classification of an organism (anything that is alive) based on structure, behavior, development, genetic makeup (DNA), nutritional needs and methods of obtaining food.

• divides organisms into several categories that start out broadly but become more specific.

• Kingdom, Phylum, Class, Order, Family, Genus, and Species.

The Six Kingdoms

• Until the discovery of chemosynthesizers, there were five kingdoms – monera, protista, fungi, plantae, and animalia.

• Today there are six recognized kingdoms that encompass every living thing known to man – archaebacteria, monera, protista, fungi, plantae, and animalia.

• Which kingdom are human part of?

…levels of classification…

• Kingdom – based on general characteristics.• Phylum – does it have a backbone?• Class – is it a mammal or an insect?• Order – even more specific than class.• Family – usually ends in “idae” or “idea”.• Genus – very specific; members of same genus can

often breed but offspring are infertile.• Species – most specific; organisms of the same species

are grouped base on the ability to breed and produce fertile offspring.

kingdom → phylum → class → order → family → genus → species

“King Phillip Came Over From Greece Sneezing”

Carl Linnaeus (1707 – 1778)

• Animalia• Chordata• Mammalia• Primate• Homindae• Homo• sapiens

Swedish botanist that devised current classification system.Used binomial nomenclature, a system for naming organisms using a two-part name to label the species.Written in Latin.Consists of genus and species.The entire scientific name is italicized or underlined, and genus name is capitalized. Ex) Homo sapiens

Why use Latin names?• Latin is one of the oldest languages on Earth.• Many other languages are derived from Latin.• No matter what country a person lives in, or

what language they speak, they will always know what organism is being referenced by its’ Genus species Latin name.

Limitations of hierarchical classification…

• Doesn’t take evolution into consideration.• Doesn’t take into account the variation that

exists among individuals within a species.Ex) all domestic dogs are called Canis lupus familiaris, but much variation exists among different breeds of dogs and even among individual dogs of the same breed.

The “True Test”?

• Organisms of the same species can breed successfully, producing “fertile” offspring.

• Fertile – the ability to breed/reproduce.• However, sometimes closely related species

can interbreed, such as the mating of a horse and donkey to produce a mule; a lion and a tiger to produce a liger; a dolphin and whale to produce a wolphin. In these situations, the offspring are sterile, or unable to reproduce.

Species crosses…

What if you encounter a species, and you don’t know what it is?

• Create a dichotomous key using the following list of specimens: pine tree, clam, rock,

• robin, tin can, deer, oak tree, mouse, dandelion, Paramecium, bicycle, ant

• Here's an example in written form using these items:• 1. a. Organism is living........................................................go to 4.• 1. b. Organism is nonliving..................................................go to 2.• 2. a. Object is metallic........................................................go to 3.• 2. b. Object is nonmetallic..................................................ROCK.• 3. a. Object has wheels......................................................BICYCLE.• 3. b. Object does not have wheels......................................TIN CAN.• 4. a. Organism is microscopic...................................PARAMECIUM.• 4. b. Organism is macroscopic............................................go to 5.• 5. a. Organism is a plant.....................................................go to 6.• 5. b. Organism is an animal.................................................go to 8.• 6. a. Plant has a woody stem..............................................go to 7.• 6. b. Plant has a herbaceous stem.................................DANDELION.• 7. a. Tree has needle like leaves.....................................PINE TREE.• 7. b. Tree has broad leaves............................................OAK TREE.• 8. a. Organism lives on land................................................go to 9.• 8. b. Organism lives in water...............................................CLAM.• 9. a. Organism has 4 legs or fewer......................................go to 10.• 9. b. Organism has more than 4 legs...................................ANT.• 10 a. Organism has fur........................................................go to 11.• 10 b. Organism has feathers................................................ROBIN.• 11 a. Organism has hooves.................................................DEER.• 11 b. Organism has no hooves............................................MOUSE.

•Identifying biological organisms can be performed using a dichotomous key.•A dichotomous key is an organized set of questions, each with yes or no answers. •Each question addresses a characteristic of the organism. How you answer determines which question you answer next.•The key starts with general questions and becomes progressively specific.•By following the key and making the correct choices, you should be able to ID your specimen to the indicated taxonomic level.•Works for ALL known organisms.

Review…• Taxonomy is the classification of organisms based on

common and differing characteristics.• The levels of classification are kingdom, phylum, class, order,

family, genus, and species.• The modern classification system is based on work done by

Carl Linnaeus.• Organisms that are the same species can reproduce and

have fertile offspring.• Some organisms of the same family can breed; however,

their offspring will be infertile, or sterile.• A dichotomous key is used to identify unknown organisms

by answering a series of “yes/no” questions.• Latin is the language used in classification because it is

common in the scientific community.