Theory question 104
Cell Structure and Organisation(a) (i) Name the four levels of organisation in living organisms (ii) Explain two of the levels of organisations named in (a) (i) above. (iii) State the level of organisation of Euglena, onion bulb and blood
(b) Give four advantages of complexity of organisation in higher organisms.
(c) (i) State one advantage Amoeba has over a cell of a lizard, in relation to their levels of organisation (ii) Give two reasons for the advantage.
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(a)(i) Cell; tissue; organ; system (organ system). (Organism may also be named.)
(ii) Any two: cell – the basic unit of life that can carry out all life processes, e.g. Amoeba; tissue – a group of similar cells doing the same job, e.g. xylem, epithelium; organ – several tissues working together for a function, e.g. heart, leaf; system – several organs working together, e.g. digestive system.
(iii) Euglena – cell level; onion bulb – organ level; blood – tissue level.
(b) Any four: division of labour – each part specialises and works more efficiently; organisms can grow larger; better adaptation to many environments; cells can specialise (e.g. nerve, muscle); body is less affected by small changes outside (internal environment controlled); injury to some cells is not fatal; longer life span.
(c)(i) Amoeba can live on its own and carry out all life processes, while a lizard's cell cannot survive alone (it is specialised).
(ii) Any two: Amoeba is a complete organism; it has a large surface area to volume ratio for diffusion of food, gases and wastes; it is not specialised, so it feeds, respires, excretes and reproduces by itself; a lizard cell depends on other cells/tissues for food and removal of waste.
Cell → tissue → organ → system → organism.