Publication Extract

The following extract is the introduction, from the BES Publication, "Brine Shrimp Ecology"

INTRODUCTION

Seeing is believing: ecosystems made easy

Whatever the age or ability of the students, the first encounter with a bottle ecosystem conveys much more than several pages in a text book. All sorts of difficult concepts suddenly become obvious because so much happens before your eyes. Like a rainforest, the bottle contains primary producers (microscopic algae), primary consumers (the brine shrimps), and decomposers (micro-organisms). Provided the bottle ecosystem has an external source of light energy it is self- sustaining. The brine shrimps never need feeding and never run out of oxygen because the algae on which they feed carry out photosynthesis, grow and multiply by asexual reproduction. The algae never run out of carbon dioxide, water or mineral salts because they are recycled. There are micro-organisms in the water which cause decay of dead algae, dead shrimps, shrimp droppings and even dead micro-organisms. When the population density of brine shrimps is low there is abundant food - everyone can see the green colour of the water. The brine shrimps can be seen mating and eggs can be seen, which soon hatch. The population increases exponentially until mounting competition for food (the green colour of the water disappears) halts further expansion. The populations fluctuate in a way reminiscent of the text book predator-prey graphs (although this is actually a grazing example) and over time may tend towards an equilibrium.

This book offers you:

• Information on how to set up your Bottle
• Ecosystem and how to look after it
• Student activity sheets for 13 practical activities
• Teacher's notes for each practical activity
• Secondary data analysis exercises for extension work and homework ideas with answers and teacher's notes
• Background information for students planning investigations
• Photocopiable illustrations for students or to make into overhead transparencies
• Brine shrimp investigations for course work assessment
• Background ecological information for teachers
• Laboratory technician's guide.

The brine shrimp ecosystem is effectively a salt lake community in an aquarium on the sunny side of the lab. In winter the organisms in it may need extra heat or light, but, once built up, the community is essentially a self-sustaining entity; indeed, the tank (like a salt lake) even has the advantage of being able to dry up completely and be revived. From a parent brine shrimp tank smaller shrimp ecosystems in plastic bottles may easily be set up. Students can take home these bottle ecosystems. They are virtually costless and provide an enduring source of fascination. Whilst the individual shrimps and small ecosystems may eventually 'die', the larger tank system endures and cultures from it have spread from school to school over more than a decade. This is the material resource behind this book.

It is hoped that this book will be found useful by those who teach ecology as part of the science curriculum or of environmental education at many levels throughout the World. It was, however, originally developed to address the Science National Curriculum of England and Wales for pupils at Key Stage 3 (11-14 years of age) and Key Stage 4 (14-16 years).

• provides an investigative laboratory based approach to practical work
• supports the teaching of knowledge and understanding of ecology within the science curriculum
• offers opportunities for course work assessment.
  the word 'assessment' refers here to a type of teacher-assessed investigative practical work which contributes towards the final grade in the General Certificate of Secondary Education (GCSE), a public examination taken in a number of subjects, including Science, at age 16 at the end of statutory education in England and Wales.

The Brine Shrimp Ecology book is essentially focused on investigations. Many of the classroom or laboratory activities are set out as directed investigations. Here students get the opportunity to learn about techniques, hypothesis testing, controlling and manipulating variables, handling and analysing data, and the evaluation of conclusions. Other activities are less prescriptive and encourage a more individual approach, with the possibility of assessment in some, if not all, of the Science 1 skills. From this, students can progress to whole investigations with access to the highest levels. Here again this book supports them by providing a mine of secondary sources, both as background information and references, as well as details of techniques. The use of Brine Shrimp Ecology investigations for assessment specifically within the National Curriculum of England and Wales is further discussed in section 6, which includes some exemplar material.

The exercises in this book support the teaching of the following ecological concepts:

• ecosystems
• adaptation to environment
• abiotic factors in ecosystems
• food chains, energy and biotic interactions
• reproduction
• population dynamics: competition and predation
• photosynthesis and requirements for plant growth
• importance of micro-organisms in decay and recycling
• effects of pollution on ecosystems.

Risk advice

This symbol draws attention to a potential hazard which a teacher would be advised to consider in his or her risk assessment. Whilst every effort has been made to make sure that the activities in this book are safe in normal teaching conditions neither the authors nor the publisher can accept any liability for injuries suffered while carrying out these activities. It remains the responsibility of the teacher working within the policy statements of the school to do a risk assessment depending on particular circum- stances. An activity which can be relatively safe in one situation may be considered too dangerous in another.

Animal welfare issue

This symbol draws attention to a possible animal welfare issue which a teacher may wish to consider before undertaking an activity, or may wish to discuss with her or his class before embarking on it. It is hoped that none of the activities in this book lead to stress or other suffering of brine shrimps, but the final decision rests with the teacher. Our experience has been that students become quite fond of their shrimps and that the activities usually increase not only their fascination but their respect for living animals, both from conservation and welfare points of view.

Photocopying

Although the British Ecological Society retains copyright on all these materials they may be freely photocopied within an institution purchasing the book.

Copyright: BES Brine Shrimp Ecology Project: Homerton College Cambridge