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A LOCAL ECOSYSTEM REVIEW QUESTIONS ANSWERS a. MULTIPLE CHOICE 1) c. 2) d. 3) b. 4) a.; P = Ap/a = 30 x 20/5 = 120 5) c. 6) b. 7) a.; b. does not start with a producer, the arrows are back to front in c.; d. starts with a top order consumer instead of a producer. 8) d. 9) d. 10) a.; water is buoyant, viscous, temperatures stay relatively stable, nutrients are usually readily available, but water and oxygen are limited. b. SHORT ANSWER AND LONGER RESPONSE QUESTIONS 11) light Abiotic factor Terrestrial environment Readily available. water availability Varies oxygen availability Readily available. buoyancy Air offers little buoyancy, so terrestrial organisms must develop structures to support themselves. Air has low viscosity. viscosity nutrient availability temperature variation Varies according to the substrate material in a particular location. A large range of temperatures occur on land. Aquatic environment Light penetration decreases with increasing depth. Readily available, but access may depend on osmotic factors. Limited availability; amount of dissolved oxygen decreases with depth and increases with decreasing temperature. Water provides a high level of buoyancy. Water is more viscous than air, so it is harder to move through. Usually readily available in dissolved form. Usually experience less fluctuations than on land. REVIEW QUESTIONS ANSWERS - continued 12) gum tree borers beetles slaters pygmy possums millipedes spiders centipedes large birds bacteria and fungi 13) a. Energy and matter are lost as heat or as the result of metabolic processes before they reach the next level. b. yabbies: 30,000 kg; fish: 3000kg; eels: 300 kg; crocodiles: 30 kg 14) a. behavioural; although the actual dilation of blood vessels on the surface of the forearms to allow for evaporative cooling is a physiological adaptation. b. structural; this provides insulation by restricting heat loss c. behavioural d. physiological e. physiological f. structural g. structural h. physiological 15) a. Gause stated that interspecific competition will always result in the less competitive species dying out. The result is that similar organisms have evolved slightly different ecological requirements so that they can occupy slightly different niches. b. food, shelter, water 16) curve a): eels; curve b): crocodiles, because the population curve for the crocodile, which preys on eels, will always lag behind the curve for the eels REVIEW QUESTIONS 17) ANSWERS - continued Type of relationship predation alleopathy parasitism mutualism commensalism Definition A detrimental relationship in which one organism kills and eats another one. A detrimental relationship in which one plant reduces the growth of another one in its vicinity by secreting inhibitory chemicals. A relationship in which one organism uses another organism (the host) as its food source. The host is adversely affected, but does not usually die. A necessary beneficial relationship between two organisms; both need each other for survival. A relationship between two organisms in which one or both benefit; neither are harmed. Example crocodiles eating eels Eucalypt species producing toxic chemicals that inhibit the growth of other seedlings under them. A tapeworm feeding on digested food in the human intestine. Lichens, which are algae and fungi living together - the alga provides food and the fungus provides support and stores water. Epiphytic ferns attached to the trunks of trees as a means of support. 18) a. Some animal populations such as reideer can only survive if members of that particular species move around together in large herds as protection against predators. b. Populations of the European rabbit are not present in northern Australia because of its extended periods of hot weather which severely reduce their fertility. c. Studies of marine worms in Sydney have found that they are limited to areas with dissolved oxygen concentrations above 1.5 mg/ml. 19) a. and b. Moisture – The moisture content of the air or soil can be tested using either the probe of a data logger, or cobalt chloride paper. This paper must be stored over calcium chloride in an airtight container before use. When exposed to moisture, the paper will change from blue to a pink or white colour. The time taken for the paper to dry out again is a measure of the moisture present. Light intensity – This can be measured using the relevant probe on a data logger or a light meter. Acidity –Water can be collected in a test tube and tested with the appropriate probe on a data logger, or several drops of universal indicator solution can be added and the resulting colour checked against a pH colour chart. Soil can be mixed with water in a test tube and tested for pH in a similar manner to the above method, or wet universal indicator paper can be held against soil or rocks. 20) Random quadrats are usually wooden frames of dimensions 1m x 1m. They are thrown down randomly in the area to be studied and for each quadrat numbers of a particular species are counted several times and then averaged. After the selected number of quadrats has been sampled, an average count is taken for all of them. This will produce an average estimate of the number of the species per square metre. This number is multiplied by the total area of the region studied.