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Terrestrial ecosystems

Qualification dates
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This module considers the interactions between terrestrial organisms and their environments – that together form ecosystems, ranging from simple microbial communities to tropical rainforests. We could even consider earth as a whole ecosystem. The module will introduce you to key ecosystem concepts, and develop your understanding of the stability and resilience of ecosystems to disturbances such as disease and pollution. You’ll learn how ecosystem function depends on exchanges of water, energy and nutrients; and gain practical experience with current research techniques, including real-time monitoring and computer modelling. Finally, you’ll gain experience in writing professional-style reports on ecological systems.

What you will study

Understanding the structure and function of terrestrial ecosystems is the key to explaining how life on Earth has persisted in the past and how it might respond to change in the future. Ecosystem science takes a holistic view of organisms and the environment. The module reflects that view, illustrating the importance of interactions between the elements of ecosystems in determining the properties of the system as a whole.

The module is composed of four blocks that take you progressively from basic systems and processes up to the complexity of the global scale. An introductory block defines what the term ‘ecosystem’ means and presents a range of examples, describing their biotic (living) and abiotic (non-living) components. The second block addresses the cycling of energy, water, carbon and inorganic nutrients through these systems. You’ll reflect on how these flows control the type and number of organisms inhabiting the system, and how the presence of living organisms in turn affects the cycling of energy and matter. The third block explores the stability and resilience of ecosystems to both natural and human-induced disturbances such as fire, disease and environmental change. The final block looks at our planet as a whole to investigate the interdependence of the sub-systems within it.

Throughout, the module illustrates the four core concepts of definition, cycling, resilience and interdependence with examples from around the world, using the full range of online media. The module emphasises the nature of data obtained in environmental studies with its inherent variability. To understand our environment scientifically, manipulation and statistical interpretation of data are essential. It will introduce you to a number of statistical techniques, accessed via spreadsheets (including regression) to develop and enhance your professional skills in critically analysing statistical output.

Running through most of the module is a practical activity revolving around the monitoring and analysis of data on living trees. This will include basic observations of trees in your locality, and accessing and processing data from trees fitted with various monitoring devices on the OU campus and elsewhere. You’ll pool and jointly analyse data with other students on the module and gain assessment credit for reporting on your experiments.

Another theme of the module is the use of modelling. Predictive modelling of ecosystem response is now an essential tool in ecosystem science. The module illustrates different types of models, exploring their inputs, components and assumptions so you can correctly interpret the output. There are both spreadsheet-based ecological models and more complex Earth-system models that you’ll engage with to explore how different systems respond to external influences.

Entry requirements

You must have passed one of the following:

  • Environmental science (S206 or SXF206), or the discontinued module S216
  • Questions in science (S111), Science:concepts and practice (S112), Environment: journeys through a changing world (U116), or one of the discontinued modules S103 or S104; plus an OU level 2 science module

You’ll need to be familiar with basic mathematics and statistics concepts from OU level 2 environment modules, including the basics of probability, statistical distributions and hypothesis testing. You’ll also need to be familiar with basic concepts from OU level 1 biology, notably photosynthesis and respiration. You’ll need no specific knowledge of modelling.

Check that you’re ready for S397 with our quiz Are You Ready For S397? You can find it on the S397 preparation website.

If you’re not sure you’re ready, talk to an adviser.

What's included

All study materials are available online, and are provided through the module website. Where possible, the materials will also be available in Microsoft Word format and as PDFs.

The following elements are all thoroughly integrated into the online materials:

  • online text covering core ecosystem science concepts and techniques
  • graphical and audio-visual supporting materials
  • interactive modelling exercises using simple spreadsheet models
  • more complex computer modelling exercises
  • practical experiments with real-time ecosystem monitoring systems
  • designing and performing ecological investigations
  • collaborative work through small online groups
  • small and larger group tutorials
  • integrated assessment
  • professional-style report writing.

Computing requirements

A computing device with a browser and broadband internet access is required for this module. Any modern browser will be suitable for most computer activities. Functionality may be limited on mobile devices.

Any additional software will be provided, or is generally freely available. However, some activities may have more specific requirements. For this reason, you will need to be able to install and run additional software on a device that meets the requirements below.

A desktop or laptop computer with either an up-to-date version of Windows or macOS.

The screen of the device must have a resolution of at least 1024 pixels horizontally and 768 pixels vertically.

To join in the spoken conversation in our online rooms we recommend a headset (headphones or earphones with an integrated microphone).

Our Skills for OU study website has further information including computing skills for study, computer security, acquiring a computer and Microsoft software offers for students.

Teaching and assessment

Support from your tutor

You'll have a named tutor who will support your studies and mark and comment on your assignment work; you can also seek academic advice and guidance from them. Your tutor will offer support through email, telephone and online forum discussions. Additionally, there will be online tutorials. We'll advertise tutorials before the module starts; S397 tutors will take them, but depending on the tutorial, not necessarily your own named tutor. We recommend you book online to attend these tutorials.


You can find the assessment details for this module in the facts box.

You must use the online eTMA system to submit your tutor-marked assignments (TMAs).

The module is assessed though TMAs and an end-of-module assessment involving activities integrated into the text and collected at the end of each block.

If you have a disability

The OU strives to make all aspects of study accessible to everyone and this Accessibility Statement outlines what studying S397 involves. You should use this information to inform your study preparations and any discussions with us about how we can meet your needs.

Future availability

Terrestrial ecosystems (S397) starts once a year – in October.

This page describes the module that will start in October 2020.

We expect it to start for the last time in October 2027.

Course work includes:

3 Tutor-marked assignments (TMAs)
End-of-module assessment
No residential school