CHAPTER 18 NOTES

Classification

 

Systematics: the science of naming and grouping organisms.

 

The goal of systematics is to organize living things into taxa (groups) that have biological meaning. 

 

One of the most widely used classification systems is the Linnaean Classification System:

 

http://upload.wikimedia.org/wikipedia/commons/f/f7/Carolus_Linnaeus_(cleaned_up_version).jpg

Carolus Linnaeus

 

·     Linnaeus classified organisms into seven hierarchical taxa (groups).

·     Traditional Linnaean classification is based on easily observable visible characteristics.

 

 

Taxa

Example

Observable characteristics

Kingdom

Animalia

eukaryotic, multicellular,  heterotrophic

Phylum

Chordata

has a nerve cord along the back

Class

Mammalia

warm-blooded, has hair and produces milk

Order

Artiodactyla

Hoofed with even number of toes

Family

Camelidae (camels, llamas and alpacas)

wide pad of connective tissue on the base of the feet provides support on soft, sandy soils.

Genus

Camelus

Camels

Species

Camelus bactrianus

Ancient country in Asia

 

Systematics also includes naming organisms. Linnaeus developed a two word naming system called Binomial Nomenclature  (2-part name).

1.The first part of the name is the Genus. The Genus is always capitalized. This is similar to our last name and shows relatedness.

2. The second part of the name is the species. The species is always lower case. The entire name is in italics. The species is unique to that particular group of organisms.

 

NOTE: Scientific names are usually written in Latin because it is no longer spoken and therefore not subject to slang.

Example:

Scientific name: Ursus maritimus

Common name: polar bear

http://3.bp.blogspot.com/_cfNB9BdzID0/TURrvFLic4I/AAAAAAAAJbI/l6JpUlJ_YFU/s1600/polar-bear-rule-coal-plant.jpg

 

Ursus (latin for bear) refers to the genus which also includes five other species of bear including the brown bear or Ursus arctos

http://upload.wikimedia.org/wikipedia/commons/thumb/e/e2/Grizzlybear55.jpg/250px-Grizzlybear55.jpg

 

maritimus and arctos are unique to each species and are descriptive of an important trait or the organism’s habitat.

maritimus (Latin for sea)

arctos (Greek for bear)

·     Which organism is the least related to the others? 

 The Blue Whale

·      Which two organisms are the most closely related? 

 The coyote and the grey wolf

·      Which are more closely related, organisms in the same family or organisms in the same phylum?

 The same family

·     Which organism(s) is/are the most closely related to Canis domesticus?

 The coyote (Canis latrans) and the grey wolf (Canis lupus)

·      What is the scientific name of the common house cat belong?

      Felis domesticus

·      Which organism is more closely related to  Canis rufus:   Canis lupus  or  Quercus rufus? 

       Canis lupus

Why are scientific names important?

·     Common names can be confusing because they vary between languages and from place to place.

Example: What is this animal?

http://www.billsbearrugs.com/lion/mountain-lion-taxidermy-mounts.jpg

 

Answer: puma, mountain lion, cougar, panther

Scientific name: Felis concolor

 

What is the problem with traditional classification?

 

     Not all characteristics that are in common, such as color, mean that something is related.

     Sometimes structures have the same function but they are unrelated.  The similarities were caused by selective pressures not by ancestry.

Ex.  Streamlined Body Shape of sharks and dolphins

 

http://www.thedorsalfin.com/wp-content/uploads/2011/05/male-great-white-shark-at-surface.jpg  http://www.dolphinear.com/kids/bottlenose.jpg

 

 

 

 

Name:_____________________ Period:______

 

Dichotomous key: used to identify organisms using paired statements or questions that describe alternative possible characteristics or an organism.

Norns belong to the genus Norus and can be divided into eight species that are generally located in specific regions of the world. Use the dichotomous key to identify the norns below. Write their complete scientific name (genus + species) in the blank.

norn

Dichotomous Key on Norns

1. Has pointed ears .................................... go to 3
....Has rounded ears ....................................go to 2

2. Has no tail ............................................. Nornus kentuckyus
....Has tail .................................................. Nornus dakotus

3. Ears point upward .................................... go to 5
....Ears point downward ..............go to 4

4. Does not have hairy tufts on ears ............................. Nornus dallus
....Has hairy tufts on ears .......................................... Nornus californius

5. Engages in waving behavior ............................. Nornus walawala
....Does not engage in waving behavior....................go to 6

6. Has hair on head ............................................. Nornus beverlus
....Has no hair on head (may have ear tufts) .......go to 7

7. Has a tail ............................................. Nornus yorkio
....Has no tail, aggressive ............................ Nornus rajus

norn1

norn2

norn 3

A Nornus beverlus

B Nornus dallus

C Nornus rajus

norn 4

norn 5

norn 7

D Nornus kentuckyus

E Nornus californius

F Nornus walawala

norn 8

norn 6

 

G Nornus dakotus

H Nornus yorkio