Subtopic: Level of organisation

study­bud­dyshare­line

Subtopic: Lev­el of organ­i­sa­tion

Play Episode Pause Episode

Mute/Unmute Episode Rewind 10 Seconds 1x Fast Forward 10 seconds

00:00 / 5:29

Lev­els of Orga­ni­za­tion in Ani­malia

MULTICELLULARITY: All mem­bers of Ani­malia are mul­ti­cel­lu­lar.

How­ev­er, the orga­ni­za­tion of these cells varies sig­nif­i­cant­ly.

CELLULAR LEVEL OF ORGANIZATION:

Exam­ple: Sponges

Descrip­tion: Cells are arranged as loose aggre­gates. There is some divi­sion of labor among cells, but no true tis­sues are formed.

TISSUE LEVEL OF ORGANIZATION:

Exam­ple: Coe­len­ter­ates (e.g., jel­ly­fish, corals)

Descrip­tion: Cells per­form­ing sim­i­lar func­tions are grouped togeth­er to form tis­sues.

This rep­re­sents a more com­plex orga­ni­za­tion than the cel­lu­lar lev­el.

ORGAN LEVEL OF ORGANIZATION:

Exam­ple: Platy­helminthes (flat­worms) and oth­er high­er phy­la

Descrip­tion: Tis­sues are orga­nized into organs, each spe­cial­ized for a par­tic­u­lar func­tion. This is a more com­plex lev­el than the tis­sue lev­el.

ORGAN SYSTEM LEVEL OF ORGANIZATION:

Exam­ple: Annelids (seg­ment­ed worms), Arthro­pods (insects, crus­taceans), Mol­luscs (snails, clams), Echin­o­derms (starfish, sea urchins), and Chor­dates (ver­te­brates)

Descrip­tion: Organs are asso­ci­at­ed to form func­tion­al sys­tems, each respon­si­ble for a spe­cif­ic phys­i­o­log­i­cal func­tion (e.g., diges­tive sys­tem, cir­cu­la­to­ry sys­tem, res­pi­ra­to­ry sys­tem). This is the high­est lev­el of orga­ni­za­tion in ani­mals.

NOTE: Organ sys­tems exhib­it vary­ing degrees of com­plex­i­ty across dif­fer­ent ani­mal groups.

For exam­ple, the diges­tive sys­tem of a flat­worm is sim­pler than the diges­tive sys­tem of a mam­mal.