Section 1.1 Terrestrial and aquatic environments – Questions and Answers
Bk Ch1 S1.1 Q1
Define the term ‘ecosystem’.
Bk Ch1 S1.1 A1
An ecosystem is any environment containing living organisms that interact with one another and with the non-living elements of the environment.
Bk Ch1 S1.1 Q2
a Describe the differences between an organism’s environment, habitat and community.
b Define ‘ecology’.
Bk Ch1 S1.1 A2
a An organism’s environment includes all of its living and non-living surroundings in its lifetime. The habitat of an organism is the place where it lives at a particular time; an organism can have different habitats during its lifetime. A group of organisms living together in a particular place at a particular time is called a community.
b Ecology is the study of ecosystems; that is, the study of environments, the plants and animals that they contain, the interactions between organisms and the interactions between organisms and their non-living surroundings.
Bk Ch1 S1.1 Q3
The following features are part of a granite hilltop ecosystem. Identify which are biotic factors, and which are abiotic.
rain snow-grass snail air sunlight earthworm dragonfly eucalypt wind temperature frog phosphorus rock wallaby butterfly soil moss shelter altitude predator bacteria
Bk Ch1 S1.1 A3
Biotic: snow-grass, snail, earthworm, dragonfly, eucalypt, frog, rock wallaby, butterfly, moss, predator, bacteria.
Abiotic: rain, air, sunlight, wind, temperature, phosphorus, soil, shelter, altitude.
Bk Ch1 S1.1 Q4
a Distinguish between the ‘distribution’ and the ‘abundance’ of a species.
b List some factors that affect the distribution and abundance of a named aquatic organism and a named terrestrial organism.
Bk Ch1 S1.1 A4
a A species’ distribution is a description of where it is found. Abundance refers to the number of individuals of a species living in a particular area.
b Factors affecting the distribution and abundance of:
Megaptera novaeangliae (Humpback whale): Humpback whales feed exclusively on krill so are only found where this food source is plentiful, e.g. Arctic and Antarctic waters. They feed and grow in these cold waters and then need to move to warmer waters to breed. Their slow reproductive rate limits their abundance.
Rattus fuscipes (native bush rat): Amount of available water is the single most important factor. Bush rats live in a wide range of habitats from dry, sandy hills to open forests and tropical rainforests. Their diet includes a range of different foods such as insects, grasses, berries, mosses and roots.
Bk Ch1 S1.1 Q5
a Define what is meant by the ‘resources’ that an organism needs.
b Make a list of the general resources that must be available to
i a plant
ii an animal
if they are to survive in their environments.
Bk Ch1 S1.1 A5
a An organism’s resources are the elements in the environment that it uses, such as food and shelter.
b i Plants need sunlight, water, carbon dioxide for photosynthesis, oxygen for cellular respiration, suitable temperatures and soil that can provide the right mineral nutrients.
ii Animals need food for energy, oxygen for cellular respiration, water and shelter.
Bk Ch1 S1.1 Q6
a List the reasons why populations of organisms are usually estimated rather than counted.
b Explain how transects and quadrats can be used to estimate the distributions and abundances of organisms. Use diagrams in your answers.
c Animals cannot always be seen or captured during field studies. Describe other methods scientists can use to determine the presence and abundance of animals.
Bk Ch1 S1.1 A6
a Populations of organisms are usually estimated rather than counted because it is impractical to count every individual in a community, especially when the area in question is large. Attempting to count every individual in a large area can also cause damage to an ecosystem.
b A transect (shown below) is a narrow strip or line that extends across the area being studied, from one side to the other. All the organisms that can be found along the transect are recorded. In this way an estimate of the distribution of species can be achieved.
A quadrat (shown below) is a small plot marked out in a much larger area. A quadrat is representative of the whole area. The number of organisms within the quadrat is counted, giving the number of organisms per unit area, usually per square metre. When the quadrat size is compared with the total area under study an estimate of the abundance of organisms can be calculated.
c Other methods used to determine the presence and abundance of animals include:
• scat analysis: studying droppings (scats) is a useful way of identifying animals and, in the case of carnivores, the kinds of animals that they have eaten
• track analysis: observation of footprints can help identify animals
• remains such as bones, which can be compared with museum specimens
• recognising the calls of animals such as birds and frogs
• the use of still or video cameras to record animals in the area
• analysis of other material left by animals such as fur or feathers.
Bk Ch1 S1.1 Q7
a Define ’photosynthesis’.
b Explain the significance of photosynthesis for organisms in ecosystems.
Bk Ch1 S1.1 A7
a Photosynthesis is the process in which plants use the energy from sunlight to combine carbon dioxide and water to form carbohydrates and oxygen.
b All organisms depend on the process of photosynthesis for their survival. Photosynthesis provides the energy that plants and animals need to maintain themselves and grow. When plants are consumed by herbivores the energy-rich compounds made in photosynthesis by the plant become incorporated into the flesh of the animal. In the same way energy is passed on to animals that eat the herbivores.
Bk Ch1 S1.1 Q8
a Describe the process of aerobic cellular respiration and write down the balanced chemical equation for this process.
b List the ways living organisms use the energy made available through cellular respiration.
Bk Ch1 S11 A8
a Aerobic cellular respiration is the process by which cells break down glucose molecules to release energy; in aerobic respiration the glucose is combined with oxygen, and carbon dioxide and water are produced.
38ADP + 38P + C6H12O6 + 6O2 6CO2 + 6H2O + 38ATP
b Living organisms use the energy made available through cellular respiration to build complex molecules such as proteins, lipids and carbohydrates; energy is used for growth, repair and maintenance of damaged or worn-out cells, active transport of materials across cell membranes, functioning of all cells and in particular specialised cells that use extra energy, for example nerve, muscle, liver and kidney cells; energy is also needed to transport materials within organisms.
1.1 Terrestrial and aquatic QA page of
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