You will be asked to answer two questions from a choice of four.

Each question will be on a different theme which make up the unit

As ecosystem science is an integrated subject there will be some overlap between the questions

However, do focus on the main topic when answering.

No. Last year this was permitted, however this year no notes can be used

This does not imply that notes should not be produced prior to the exam.

Make notes on key words and concepts.

Make sure that you can use the key words appropriately and link them together when answering the questions.

You do not need to use references in an exam. However, you do need to indicate that any information you include comes from a reliable source.

Exams are stressful. No one enjoys taking an exam. Ideally, they would not exist.

However, exams ensure that personalised engagement with the subject matter can be evaluated.

Exams test underlying knowledge of the subject, understanding of key concepts, the ability to think critically, additional research and reading into the topic and the ability to organise information and concepts to make a structured argument.

Failing exams completely only rarely occurs and only happens if there has been a lack of engagement (e.g lack of lecture attendance that has not been notified and agreed to)

You can fail if …

• You don’t turn up to the exam

• You only answer one question

• Your answers are very brief (only one or two short paragraphs)

• The answers are not relevant to the topic at all

• The answers do not mention any of the key concepts and/or display very major misunderstandings of them.

No. Not at all. Ecosystem science is very complex. No one understands everything about ecosystems. There are many different takes on all topics within the field.

Major misunderstandings involve over simplification and the trivialisation of complexity. Awareness that a topic is inherently difficult to pin down and fully understand shows thought and reflection.

Turn up!

Answer both questions

Include keywords and key concepts taken from the lecture slides.

Provide evidence of awareness of the basic definitions of the terms

Avoid expressing only un-evidenced opinions.

Your own opinions and ideas should underlie your answers, but there must be some indication that they are based on science and evidence.

Marks are awarded through providing answers that show greater knowledge and understanding than the baseline required to pass

A good answer will provide evidence of

• Critical appraisal of ideas and evidence

• Reading which goes beyond the material in the lecture slides.

• The organisation of ideas to form a logical argument.

• Clear formal expression that follows a scientific style

Exam questions tend to ask for discussion and critical appraisal.

Both concepts are asking for a similar approach to be adopted

Discussion and critical appraisal show academic rigour and maturity.

A discussion between two or more people usually involves some differences between their “takes” on a topic.

It does not necessarily imply a difference of “opinion,” although it might.

Differences can arise in the interpretation of the terms used and the interpretation of evidence.

When asked to “discuss” a topic in an exam, you should aim to show awareness of why different takes might arise. You do not need to “take sides.”

An example might be the utility of models as predictive tools. No two scientists would fully “agree” on this complex topic.

This is similar to the concept of a discussion but it focuses more on the evidence.

Ecosystems are very diverse, so evidence provided through a study of one ecosystem may appear to be contradicted by evidence provided through a study of a different system

A “compare and contrast” approach would lead to critical appraisal.

An example might be the fragility of ecosystems. Some ecosystems display greater fragility than others, so empirical (real world) studies provide diverse and sometimes contradictory results.

Population modelling

Biogeochemical cycles

Ecosystem fragility

Trophic interactions

The different types of models (compartment-flow models, Individual based models, matrix models, stochastic models etc)

Fundamental concepts (birth rates, mortality rates, carrying capacity)

An understanding of key models (logistic equation, Lotka-Volterra models etc)

Awareness of the strengths and weaknesses of models in general and different approaches to modelling.

Ability to discuss the utility of models. Can they be used for prediction?

What is a biogeochemical cycle?

Key components of the carbon cycle

Key components of the nitrogen cycle

Anthropogenic influences on cycles (inputs of nitrogen to ecosystems and inputs of carbon dioxide to the atmosphere)

Eutrophication and its impacts on ecosystems (phosphorous can be mentioned here)

Cycles and modelling (simple diagrams of cycles might help illustrate an answer)

Definitions of the terms used. Inherent fragility vs fragility as a result of human influences

Counterparts to fragility. Resistance, resilience and stability

Homoeostasis, tipping points and hysteresis

Perturbations of ecosystem and the response to them

Management options to avoid undesired fragility

Example studies. Salt marches, heathlands, forests, tundra, coral reefs, tropical ecosystems etc.

Key components of a trophic web

Top down control vs bottom up control

Interactions between species

Differences between aquatic systems (phytoplankton as primary producers) and terrestrial systems (vascular plants as primary producers)

Keystone species. Trophic cascades.

Classic examples (starfish, sea otters, wolves)

The lecture slides extend all the key points made above into a framework for research.

Lectures include links to suggested reading

A good “seminal” paper on any of the topics will provide an in depth conceptual framework

A good review paper will provide many examples

Look out for discussion points in the literature. Spot where differences of interpretation arise and note down both (or many) different perspectives.

Think about your own viewpoint. Is it based on evidence? Can you provide evidence from high quality peer reviewed studies in support?

Think about viewpoints that may differ from yours. Are they based on evidence or on more nebulous “worldviews”

How have models (e.g. Gaia’s use of daisy world) and conceptual diagrams (e.g. “ball and cup” for tipping points) been used to support arguments. How much empirical (i.e. “real world”) evidence has been produced to support them

Think and read.

Yes! We can all have our own opinions. These motivate research. No one is completely objective, nor should they be.

However, the best place for an opinion is at the end of an answer. “On the balance of evidence” or “after evaluating different perspectives” …. then state a conclusion.

For example, after writing a longish piece of work evaluating the evidence on species extinction I might be prepared to state that “On the balance of evidence it is more likely that biodiversity loss over the next decade will occur in tropical ecosystems than in temperate ecosystems.” This would be an expression of opinion. It would not be used as the opening sentence of an essay.

No. Not at all. Scientific opinions are always held very weakly and must be open to challenges.

For example. In my own opinion, based on the current balance of evidence, I might feel that direct habitat destruction is a more important threat to ecosystems than climate change. That would be my opinion. It could easily change, as evidence of extinctions due to climate change emerge. (Note that this is an example that will not be in an exam question, directly).

However, I would never open an essay by writing “Habitat destruction is a greater threat to biodiversity than climate change.” If I did this, then I would be expressing my subjective opinion without any evidence. So, if you did the same I would still criticise the essay for offering unfounded opinions, even if I might personally agree with them.

On the other hand, if you weighed up the evidence carefully and concluded that climate change was a greater threat, then you would have shown an ability to discuss a topic and critically appraise evidence. You would thus get a high mark (for this hypothetical question), even though your final conclusion might differ from my personal opinion.

Stop worrying

Even if you have not sat exams since GCSE’s. Stop worrying.

Exams really measure engagement with a subject. If you found the subject interesting and relevant, you are likely to produce an interesting and relevant answer.

If you found it boring and irrelevant, you can still do well in an exam if you put in the groundwork.

The lecture slides contain all the key ingredients to pass. If you have read them all then you will not fail. If you have read the references, then you are certain to get a good mark.

No one expects perfection under exam conditions. Exams are marked accordingly.

Be prepared.

Answer the questions you are set.

Keep calm.