Clas­si­fi­ca­tion of or­gan­isms

Jamaica Gleaner - - YL - MONACIA WIL­LIAMS Con­trib­u­tor

“If you are not will­ing to learn, no one can HELP you! If you are de­ter­mined to learn, no one can STOP you!” – Un­known

HELLO MY fel­low learn­ers, how are you this week? I hope ev­ery­thing is now fall­ing into place for you and you are well on your way to achiev­ing that oh-so-elu­sive grade one.

This week, we will be re­vis­ing one of the top­ics that you did in your first year of high school. We will be re­vis­ing be­cause, as you and I know, mem­o­ries are not what they used to be! What is this topic? It is the clas­si­fi­ca­tion of or­gan­isms.

Clas­si­fi­ca­tion is a part of ev­ery­body’s life. Book stores clas­sify books ac­cord­ing to their genre, fic­tion, non- fic­tion, science fic­tion, ro­mance, mys­ter­ies, etc, while mu­sic stores may have their mu­sic clas­si­fied as clas­si­cal, jazz, pop­u­lar, reg­gae, dance­hall, etc. Su­per­mar­kets also have a sys­tem of clas­si­fi­ca­tion. Apart from the ob­vi­ous group­ing, they also group items in such a way that their plac­ing will ap­peal to our sub­con­scious and, with­out re­al­is­ing it, we buy! A clas­si­fi­ca­tion sys­tem helps both the owner and the shop­per to find/iden­tify items eas­ily. In science, a clas­si­fi­ca­tion sys­tem is needed to pro­vide or­der and method in the study of liv­ing or­gan­isms.

We have been talk­ing about clas­si­fi­ca­tion sys­tems, but what ex­actly is clas­si­fi­ca­tion? A sim­ple def­i­ni­tion is as fol­lows:

‘Clas­si­fi­ca­tion is the group­ing of things on the ba­sis of fea­tures that they have in com­mon’.

THERE ARE TWO MAIN TYPES OF BI­O­LOG­I­CAL CLAS­SI­FI­CA­TION SYS­TEMS

Ar­ti­fi­cial – Or­gan­isms are placed in groups for con­ve­nience. The plac­ing in groups does not have any bear­ing on true re­la­tion­ships or evo­lu­tion­ary pat­terns.

Nat­u­ral – Or­gan­isms are placed into groups based on their nat­u­ral re­la­tion­ships. Both in­ter­nal and ex­ter­nal fea­tures are used to place the or­gan­isms into groups.

We will be con­cen­trat­ing on the nat­u­ral sys­tem of clas­si­fi­ca­tion. First, here are the def­i­ni­tions of some words that you may en­counter while read­ing up on this topic: Sys­tem­at­ics – The study of bi­o­log­i­cal di­ver­sity. Tax­on­omy – The study of the prin­ci­ples and meth­ods used in bi­o­log­i­cal clas­si­fi­ca­tion.

Nomen­cla­ture – The nam­ing of bi­o­log­i­cal groups.

Taxa (sin­gu­lar taxon) – A se­ries of groups ar­ranged in a hi­er­ar­chy.

Bi­ol­o­gists use what is known as the five king­dom clas­si­fi­ca­tion. In this, all or­gan­isms are di­vided into five large groups that are called king­doms. These are Prokary­otae (bac­te­ria and blue-green al­gae), Pro­toc­tista (pro­to­zoa and al­gae), Fungi (yeasts, moulds and mush­rooms), An­i­malia (an­i­mals) and Plan­tae (plants). Each king­dom is di­vided into seven main groups. These are, in de­scend­ing or­der: King­dom, Phy­lum, Class, Or­der, Fam­ily, Genus and Species. In the clas­si­fi­ca­tion of plants, Phy­lum is re­placed by Di­vi­sion. The group com­pris­ing the largest num­ber of or­gan­isms is King­dom and the one with the small­est group is the species. It means that the or­gan­isms in­cluded in the species are more closely re­lated to each other than to the rest of those in­cluded in the King­dom.

Ev­ery or­gan­ism is given a sci­en­tific name of two words. The first be­gins with an up­per-case let­ter and is the generic name (from the genus) and the sec­ond be­gins with a lower-case let­ter and is the spe­cific name (from the species). In your text, you will no­tice that all sci­en­tific names are writ­ten in ital­ics, e.g., Homo

sapi­ens; if you are writ­ing them, they must be un­der­lined, for ex­am­ple, Homo sapi­ens. This sys­tem of nam­ing is known as the bi­no­mial sys­tem.

Let us look at an ex­am­ple of the clas­si­fi­ca­tion of two an­i­mals, for ex­am­ple, man and dog.

See you next week!

Monacia Wil­liams is an in­de­pen­dent con­trib­u­tor. Send ques­tions and com­ments to kerry-ann.hep­burn@glean­erjm.com

Did you no­tice that man and the dog share the same king­dom, fam­ily and class, mean­ing that they have enough fea­tures in com­mon to al­low them to share these?

Let us look now at a plant.

Did you no­tice any­thing sig­nif­i­cant about this ta­ble? Our na­tional tree, the Blue Ma­hoe, and the hi­bis­cus plants are very closely re­lated. Both be­long to the genus, Hi­bis­cus! In­ter­est­ing, isn’t it?

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