CTS Guide: Interdependence in Ecosystems, pp 120-121
Interactions with Living and Nonliving Components
A study by the Department of Education in England of age 5-11 children showed that that they are likely to learn that living things depend on their environment to survive; that animals (including humans) need air, water, and nutrients from food to keep them alive; and that plants need air, water and light (to make their own food), plus nutrients from soil (Department for Education, 2013).
Decomposers and Importance of Microorganisms
(See Decomposition and Decay)
Food Webs and Food Chains
(See Food Chains and Food Webs)
Organisms, Populations, and Communities
A study by Leach at al. (1992) showed few students used the idea of interdependence to explain changes in populations of organisms. When students are asked to predict possible effects of a change in a population within a food web, they tend to focus only on single food chains within the web and struggle to trace changes through more than one chain.
An older study showed some students think that a change in the population of one species only those species directly related to it and some think that a change in the prey population has no effect on the predator population (Griffiths and Grant 1985).
Driver et al. (1994) found that students at age 11 are more familiar with the everyday use of terms such as ‘population’, ‘community’ and ‘environment’ rather than the ecological use of the terms.
Adeniyi’s (1985) study found that Nigerian students used everyday meanings of ecological terms such as populations and communities instead of scientific meanings. 25% of the students thought community meant people living together and many could not distinguish between population and community.
Predation
Some students see the top predator as having overall dominance over all other organisms in a food web (Allen, 2010).
Adeniyi’s (1985) study found that some students think stronger organisms have more energy and that energy adds up in a top predator from all the other organisms in the food chain.
Griffiths and Grant (1985) reported that 20% of the 15-year-olds they studied thought that a population higher on a food chain preys on all the other populations before it.