Kingdom animalia

Question 1

main physical features of cnidarians

Answer 1

1- diploblastic
2- little differentiation
3- body supported by aqueous medium (hydrostatic skeleton)
4- hydrostatic skeleton also formed by fluid filled enteron
5- have tentacles and show radial symmetry

Question 2

Main physical features of platyhelminthes

Answer 2

1- triploblastic
2-flattened body (dorsoventrally) shape allows for exchange of materials by diffusion
3- well differentiated organ systems (but one opening to gut)
4- they are aceolomate (no body cavity)
5- no specialaised skeletal system but mesoderm helps to provide support

Question 3

Main physical features of annelida

Answer 3

1- clearly segmented with bilateral symmetry
2- triploblastic with mouth and anus
3- well developed tissue differentiation
4- they are ceolomate as the mesoderm contains a body cavity containing well differentiated systems
5- locomotion relies on the action of muscles on the hydrostatic skeleton aided by external chatea

Question 4

Main physical features of anthropods

Answer 4

1- bilateral symmetry
2- fixed number of metameric segments
3- insects all have clearly defined head, thorax and abdomen
4- have a through gut with mouth and anus
5- insects have exoskeleton composed of chitin which can limit size but is waterproof

Question 5

Main physical features of chordata

Answer 5

1- bilateral symmetry and metamerically segmented
2- triploblastic and ceolomate with the mesoderm containing well differentiated systems such as the digestive, circulatory and reproductive systems
3- they have an internal skeleton and post-anal tail at some species of their life cycle
4- the skeleton consists of an internal jointed system of calcified bone
5- the segmentation is best described as a secondary adaptation for swimming

Question 6

how cniadarians obtain and digest food

Answer 6

1- stinging cells paralyse live prey and bring it into the gut by tentacles
2- the gut cavity is a single sac like, fluid filled gut called an enteron
3- initial digestion is by extracellular secretions
4- final digestion phases are intracellular, following endocytosis
5-

Question 7

How platyhelminthes obtain and digest food

Answer 7

1- flattered dorsoventrally
2- bilateral symmetry
3- they are detritivores
4- food is brought into and out of the gut through a single opening
5- the gut displays branching to distribute products of digestion

Question 8

How annelids obtain and digest food

Answer 8

1- they are metamerically segmented and ceolomate with space between the body surface and gut
2- they have a one way gut (separate mouth and anus)
3- This allow for regional specification
4- they contain a muscular pharynx and gizzard, oesophagus crop and intestine for absorption
5- they are detritivores