Abstract

This unit begins by examining what makes something ‘alive’ and then looks at the place of living things in the environment. The PowerPoint presentation then provides a bigger view, looking at the origin of bio-diversity through evolution. The usefulness of considering that transfer of material (biomass) along food chains - rather than energy, as is often the case - is stressed. Useful resource material in the form of PowerPoint presentations is provided and can be adapted for particular courses. It introduces the significance of feedback and unpredictability in relation to evolving systems and, with reference to major environmental changes, recognises the role of ‘takeover bids’ in establishing new and stable communities. This leads to o consideration of our own 'human footprints' and to issues of sustainability. Consideration of the development of childrens ideas of living things in their environment and of practical experiences useful in teaching are supported by a compilation of some useful resources.

This is one of 17articles on www.scitutors.org.uk/ whose main aim is to support the processes of teaching/learning between the science education tutor and the trainee science teachers with a focus on “teachers’ knowledge and understanding”. During a primary or secondary BEd, PGCE or GTP we hope that those learning to become science teachers will be able to challenge their own understanding of science and scientific concepts. Unit K0 specifically explores general issues relating to all the knowledge units - to the learning of science.

Standards: This unit specifically addresses Q14 but, appropriately used can contribute to and provide evidence of competence for many others of the standards especially Q4,6,7,8,18, 22 and 25.

Key words: Living, Environment, Food chain, Interdependence, Sustainability.

Introduction
Living things in their environment
The conceptual barriers to understanding
Progression in children's ideas
Giving Practical experiences
Useful References

1.0 Introduction

A few primary teachers will have completed some post 16 study or even have a degree in biology, and about half of the secondary science teachers will have a degree with some biology content. However that means that a substantial number of trainee teachers of both primary and secondary phases will have an understanding of Biology equivalent only to a grade C at GCSE. The aim of these five ‘biology’ units is to provide support for these trainees (via their tutors) so that they can either teach to GCSE level, or acquire an understanding at that level so they have the confidence to teach at primary school. The emphasis is on the conceptual changes needed by learners (tutors, teachers and their pupils) to come to an understanding of living things.

2.0 Living things in their environment

Although the National Curriculum is constantly changing, the underlying ideas that we need to introduce children to are going to remain largely unchanged, though we might need to change the emphasis and importance we attach to them. These concepts/ideas are taken from the NC orders 2000 for KS4 double award and KS3, from section 5 of life processes and living things:

habitats support a diversity of plants and animals that are interdependent (KS3) and how the distribution and relative abundance of organisms in habitats can be explained using ideas of interdependence, adaptation, competition and predation
the ways in which living things and the environment can be protected (KS3) and how the impact of humans on the environment depends on social and economic factors, including population size, industrial processes and levels of consumption and waste
the importance of sustainable development
some organisms are adapted to survive daily and seasonal changes in their habitats (KS3)
predation and competition for resources affect the size of populations [for example, bacteria, growth of vegetation] (KS3) Energy and nutrient transfer

food chains can be described quantitatively using pyramids of numbers (KS3) and of biomass (KS4)
toxic materials can accumulate in food chains.(KS3)
energy(*) is transferred through an ecosystem
the role of microbes and other organisms in the decomposition of organic materials and in the cycling of carbon and nitrogen
food production and distribution systems can be managed to improve the efficiency of energy transfers.

It is biomass that is transferred through an ecosystem. Some of this food material (and in some cases less than 10%) is used for making new biomass for the new organism and the rest is used as a fuel for respiration. Energy is associated with the fuel and oxygen needed for respiration, but it is a confusing short cut to call this food or fuel “energy”, or even to say the food contains energy. This is discussed in more detail in section 3 below - conceptual barriers.

The PowerPoint presentation in download 2 explores living things in their environment from an issues based approach. Having covered the fundamental conceptual aspects of the topic (as outlined in the remainder of this unit) this presentation can be used to progress the trainee teacher’s thinking within this area. Most slides are accompanied by explanatory notes which will guide you through the presentation. It would however be useful to read chapter 7 of Littledyke et al (2000) and the Biodiversity element of the ‘Science Issues’ CD Rom, before embarking on the presentation.

Having established what the trainees understand by the term ‘biodiversity’, the presentation explores a timeline of events leading to the formation of Earth and life as we know it. It introduces the significance of feedback and unpredictability in relation to evolving systems and, with reference to major environmental changes, recognises the role of ‘takeover bids’ in establishing new and stable communities. The focus turns to the inter-relatedness of the four key components of the Earth and how they impact one on the other. As members of the biosphere we too are influenced by changes in the three remaining components, but we also leave a significant environmental footprint with practically everything we do. This impact is explored and discussed in some length towards the end of the presentation.

Download K2.5_2.0a 'Biodiversity (not genetics)'

3.0 The conceptual barriers to understanding

Download 3 contains a set of discussion questions that can be used with trainee teachers, both primary and secondary, followed by a discussion of the questions outlining some of the difficulties trainees may encounter in their subject knowledge.

The final question in this download: “Why is it better to talk of biomass passing along a food chain than talking of energy flow?” makes the distinction between matter (made of atoms) and energy (measured in Joules). In this world of ours it is matter that gets cycled (never used up) and these cycles are driven by energy which gets degraded to waste heat and exported to the universe (for natural phenomena, such as life and climate the energy comes mainly, and ultimately from the sun - the rock cycle is also driven by energy from inside the earth’s crust.). It is matter that ‘flows’ along food chains - biomass in fact. If the next organism wants to use some of this biomass for fuel, then it is respired (normally involving a reaction where it is joined to oxygen), and it returns to the atmosphere in the form of carbon dioxide. If it is used for growth it remains as biomass - available for the next organism on the food chain (or a detrivores if the biomass drops off as, for example, shedded skin).

Download K2.5_3.0a 'Living things'

4.0 Progression in children's ideas

In this section we outline some of the conceptual barriers to understanding ideas about living things, and suggest how children’s ideas will develop through their time in school.

Young children may believe that anything that is active in any way, such as making a noise or moving, is alive. They tend to think that anything that moves is ‘alive’. Even as they get older children may only refine this belief to all things that move by themselves, such as rivers and streams, as well as animals, are alive, but the idea that plants are alive is hard for them - after all they do not appear to move by themselves.

Download 3 above warns that children may have a very limited view of the word ‘plant’ (restricted to pot plants, not trees, flowers, vegetable crops etc).

The word animal seems to serve a wide function for very young children - before they learn different categories (bird, reptile, insect etc). By the time they leave primary school pupils may have a very narrow view of ‘animal’ using it mostly for mammals only, and in contrast to humans. As they learn about food chains and webs ‘animal’ gradually begins to stand for all consumer organisms, including humans.

Some of the main ideas about plants and animals and the way they interact in their environment are explored in download 4

Download K2.5_4.0a ' Living things in their environment'

5.0 Giving Practical experiences

The following activities are suitable for outside the classroom/lab.

Clearly getting trainee teachers out into the environment - visiting different ecosystems and getting them to appreciate and identify the variety of living things there - is essential. See download 3 above. In their turn they will do the same to their pupils. This simple activity can be carried out by asking students to examine the trees on the campus or in their school environment.

Pleurococcus & Lichen distribution to assess those factors that affect the distribution of different organisms. http://www.studentcentral.co.uk/GCSE/Biology/Green_Plants_as_Organisms/Investigating_thegrowth_of_pleurococcus_L105991.html

These activities can be carried out in the classroom after samples are collected from the grounds:

Population dynamics of the holly leaf miner
http://www.field-studies-council.org/outdoorscience/london/hampsteadheath/holly.htm

Investigations with duckweed (Lemna minor)Estimating the number and biomass of a population of plants
http://www-saps.plantsci.cam.ac.uk/worksheets/ssheets/ssheet21.htm

The following activities are suitable for the classroom/lab.

Factors affecting the decay of food. (note the health and safety points).

Samples of bread can be treated according to the conditions outlined in Download 5 and placed in sealed plastic bags. These can be left for two weeks and the development of decay observed. On health and safety grounds the bags should not be opened and should be double wrapped before disposing of with the normal laboratory waste. Consider trying a variety of processed bread as well as homemade varieties. How long will ‘value bread’ remain mould free?

Photosynthesis... using algae wrapped in jelly balls
http://www-saps.plantsci.cam.ac.uk/worksheets/ssheets/ssheet23.htm

6.0 Useful References

Dickinson, G. and Murphy, K - Ecosystems, London, Routledge, 1998 (A useful resource for post 16 level work)
Littledyke, M., Ross, K., and Lakin, L (2000) Science Knowledge and the Environment, London, David Fulton (Chapter 7 gives some background information about the major issues concerning living things in their environment)
Willaims,G - Techniques and Fieldwork in Ecology, Collins Educational, 1991 (A general book outlining many skills and procedures for ecological work at secondary level)

Websites:

Nature detectives and the Woodland Trust. For the Foundation Stage and Key Stages 1 and 2, these two sites give a colourful and accessible introduction to environmental issues and activities. They would also be useful for Key Stage 3.
The British Ecological Society education pages have a range of classroom activities and background information suitable across the key stages.
The Field Studies Council (FSC) is an educational charity committed to bringing environmental understanding to all. The organisation provides information and opportunities for people of all ages and abilities to discover, explore, be inspired by, and understand the natural environment. Their outdoor classroom pages include information about suitable activities for use across the key stages and details about their publications (including their range of identification keys)
Science Issues and the National Curriculum. CD Rom (available from www.glos.ac.uk/science-issues)

Section Developed by:

Liz Lakin, St Martin’s College, Ambleside
(and Keith Ross, University of Gloucestershire)
September 2006

Published: 20 Sep 2006, Last Updated: 13 Sep 2008

Downloads in this Unit: