Theory question 106
Ecosystem and Ecological Factors(a) (i) Define the term hydrosphere (ii) Give three examples of hydrosphere
(b) (i) State the two laws of thermodynamics (ii) Use the second law of thermodynamics to explain the energy flow across trophic levels
(c) (i) Name two local biotic communities in Nigeria and associate each type with a particular state in Nigeria (ii) List three factors that affect organisms in the marine habitat (iii) State three adaptive features of sea weeds.
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(a)(i) The hydrosphere is the water part of the earth's surface.
(ii) Any three: oceans/seas, rivers, lakes, ponds, streams, lagoons.
(b)(i) First law: energy can neither be created nor destroyed, but can be changed from one form to another. Second law: whenever energy is changed from one form to another, some of it is lost as heat, so no transfer is 100% efficient.
(ii) At each trophic level much of the energy taken in is lost as heat in respiration (and in waste), so only a small part (about 10%) passes to the next level; energy therefore decreases up the food chain, which limits the number of trophic levels.
(c)(i) Any two with a matching state: tropical rainforest – e.g. Ondo/Cross River/Edo; mangrove swamp – e.g. Rivers/Bayelsa/Lagos; Guinea savanna – e.g. Kwara/Niger/Kaduna; Sudan savanna – e.g. Kano/Sokoto; Sahel savanna – e.g. Borno; montane forest – e.g. Plateau/Taraba.
(ii) Any three: salinity; temperature; light/turbidity; waves and tides; dissolved oxygen; pressure/depth; ocean currents.
(iii) Any three: holdfasts to anchor them to rocks; air bladders to float near the light; slimy/mucilaginous covering to resist drying at low tide; tough flexible body that resists wave action; extra pigments to absorb light under water.
Second law: energy is lost as heat at every transfer.