Preparing for Marine Ecology Rocky Shore Investigations

Session outline: What is ecology? What determines the population size of a community? What determines the population structure of a community? Is ecology really that important? How to collect your own ecological data, draw conclusions from it, and write up a scientific investigation

What is ecology? Ecology is the study of how living things interact with one another and their environment Ecologists often write about the distribution of organisms in an ecosystem, trying to link why organisms are found where they are to biological pressures and environmental factors How do they do it?

How is ecology carried out? Ecologists cannot count EVERY animal or plant on the rocky shore because of large numbers and/or difficulty in finding every single one Instead, they study a small area or “slice” of the rocky shore for example in great detail and assume that the “slice” tells us something about the ecosystem as a whole The “slice” is called a transect For the first point, ask pupils to think about how long it would take to count every single tiny barnacle on the rocky shore!

Example: experimental design for the rocky shore Example: experimental design for the rocky shore. Variable – Shore Height Quadrats High shore Transect So say we wanted to see how the abundance of plants and animals on the rocky shore changed with shore height. First we would take the slice of our habitat by running a transect line from the high shore to the low shore. Then we would pick three to five shore heights to assess. Next what would we do? Would we just pick a random spot and count everything? No. We would use something called a quadrat to record the abundance (% cover or numbers present) in a quadrat. Ask pupils questions like: Do you think we should randomly place our quadrats or measure the distance at each shore height? Do you think we should do just one quadrat or several? – because rocky shores are patchy ecosystems, made up of several different habitats each with their unique set of environmental and biological pressures we need to sample using multiple quadrats to build a better representation of what communities are present in each habitat, or even the ecosystem and therefore we can draw more accurate conclusion from our data. Low shore

Population size is determined by… - How many predators the species has and how well it can avoid them - How well adapted the species is to its environment - The better adapted, the more likely it is to survive and pass its genes onto the next generation Population Size 1. Predation 3. Adaptation 2. Competition We use quadrats is ecological investigations, such as those on the rocky shore, because organisms are not spread evenly over a habitat as pupils may have learned if you ran the adapting to the extreme resource in Module D. Population size is largely determined by how well organisms can adapt to environmental and biological factors. When predation pops up, ask pupils to think about the ways organisms might avoid being eaten e.g. startle/escape responses, mucus secretion – bad taste, Hard outer shell, mutual relationships e.g. between hermit crabs and anemones. For further reference to adaptations to being an effective predator and an evasive prey in the marine environment please use the Dog eat dogfish world resource in module D. When competition pops up, ask pupils what else organisms on the rocky shore might compete for. Competition will ultimately limit the number of each species that can live in a particular habitat – Ask what the major one is for rocky shore - space When adaptation comes up, ask pupils what an organisms environment is (i.e. their surroundings). Ask them to think of some of the environmental factors present on rocky shores organisms might have to adapt to. - How much competition there is from other organisms for resources in short supply e.g. food, shelter - Stronger competitors will survive and pass their genes to the next generation

Population structure Clumped Evenly spread Randomly spread So with all these environmental and biological pressures, what do you think the logical population structure of organisms on the rocky shore will be? Different organisms therefore can tolerate environmental and biological conditions in different habitats and this results in an uneven distribution of organisms on the rocky. This particularly occurs because rocky shores are dominated by several types of habitats each with their own unique suite of environmental and biological factors As such, the determines what life can live there. Clumped most common distribution on the rocky shore – Groups of animals close together all competing for the same resources e.g. a population of Barnacles on the rocky shore Evenly spread – Population structure is common in large carnivores e.g. large crabs Randomly spread – Only occurs where there are plenty of resources and fierce competition Question – Which structure(s) do you think are most likely to be present on the rocky shore for example?

Why is Ecology important? Helps us monitor changes in habitats that may have a huge impact on the wider-ecosystem and mans use of the marine environment Some examples include: Climate change Overfishing Pollution Collecting data on the relative abundance of plants and animals on the rocky shore over time could tell us whether native organisms are moving further north due to increasing sea surface temperatures We can search for non-native species to tell us whether warming seas is causing species not naturally found on the shore to settle We can monitor levels of pollution and determine safe limits of disposal If you did the food for thought resource in module D you could ask pupils to recall the impacts of man on certain components of marine food webs, making sure pupils emphasise that effecting one organism on the rocky shore for example will likely have knock on effects on every other organism because every plant and animal in a community is interconnected through feeding relationships.

A little more data collection is sometimes needed Sometimes ecologists also need to collect information about the environmental factors in a habitat as well as the organisms that live there Examples include: Light intensity Temperature Salinity pH Oxygen concentration Often though, noting down the environmental conditions in each habitat you study will likely be enough information to draw conclusions from your data The last bullet point can be removed if you do not intend to go out in the field. This resource pack provides an outline for carrying out a limpet shell shape investigation which is suitable for most rocky shores in the UK. The investigation provided for in this presentation is limpet shell shape. However, if you are teaching lower ability/younger key stage pupils and you plan on taking them onto the rocky shore, why not use the rocky shore organism identification pack included in this resource. It provides an ID guide that can be printed and laminated suitable for identifying organisms from most rocky shores in the UK, as well as a simple field sheet for jotting down the organisms found in each habitat on the rocky shore, and a quadrat sheet. The latter is optional but gives pupils experience in using quadrats correctly from a young age. We propose pupils throw one quadrat in each habitat and draw out the organisms found inside. They can label their quadrat drawings or develop a key for them.

Your turn to become Marine Ecologists! Limpet shell shape Limpet shell shape varies on the upper and lower shore because of several environmental factors. Limpets on the upper shore tend to have taller, pointy shells, whereas limpets on the lower shore tend to have flatter, more streamlined shells Why do you think this is? Think about the environmental factors acting on the upper and lower shore What would be your prediction? How would you test this statement was true? How would you collect your data? The limpet shell shape template can be downloaded for pupils from this resource pack. Limpet shell shape varies between the lower shore and the upper shore. This is due to environmental factors. Upper shore limpets are subjected to long periods out of water, where temperature varies greatly and there is a high risk from drying out (desiccation). By having tall and pointy shells limpets on the upper shore are able to conserve much more water, reducing the risk of drying out. By storing more water, limpets are also able to store enough oxygenated sea water to respire throughout the low tide. Lower shore limpets on the rocky shore on the other hand have very flat and pointy shells. This is because wave crash and the whipping action of seaweeds for example would easily knock them off the rocks. As lower shore limpets don’t need to conserve water because they are covered the majority of the time, they have more flattened and streamlined shells to reduce resistance to wave crash and therefore reduce the risk of being washed away. To test the hypothesis that there is a difference between limpet shell shapes on the lower vs. the upper shore we would need to collect some primary data. The best way to do this is to measure the shell heights of 50 limpets, as well as the diameter on both the lower and the upper shore using a pair of callipers (rulers also work but callipers are ideal). Measure shell height in mm. Use a transect tape laid out across the lower and upper shore to randomly record individuals. This makes the data more reliable. Quadrats could be randomly thrown and all the limpets within each quadrat recorded to ensure a randomised sample. Throw quadrats until 50 limpets have been recorded at both the lower and the upper shore. Remind pupils that we are merely using quadrats to record a random sample and not to assess the abundance of limpet populations on the rocky shore. The last thing to think about is limpet shell diameter. Recording juvenile limpets in the population recording would make this investigation bias. Pupils will therefore need to eliminate a size class lower than 20mm to ensure only adult limpets are recorded. Pupils could be asked to look up limpet size classes as an extra activity before going out in the field. Tide tables will be available from your local borough council.

The five golden rules of rocky shore investigations 1 - Try to disturb the ecosystem as little as possible 2 - Only remove small samples if absolutely necessary and always put them back after you have finished with them 3 - Always turn rocks back over when looking for organisms 4 – Don’t run around on the rocky shore, it is a slippery and therefore dangerous environment 5 – Don’t go into the sea!

Graphing your data Scatter graph? Line graph? Bar Chart? Histogram? Think about the type of data you collected. Is it continuous data (i.e. is it a list of numbers) or discrete data (i.e. in categories). What type of graph would show your trends best, if there are any? Line graph? Scatter graph? Bar Chart? Pupils should have data suitable for a scatter graph. Ask pupils to plot shell diameter on the x axis and shell height on the y axis. Pupils will need to plot low shore values and high shore values as separate series’. An example of what the graph should look like can be seen on the graph reference sheet provided in this resource pack. This can be done by hand or on Excel to test pupils’ ICT skills. Graphing using ICT is available as an activity in this resource pack and can be carried out before undertaking this investigation on the rocky shore. Histogram?

Writing up your investigation Key sections to include: An Introduction Write a few sentences about limpets, what environmental factors might affect their population size on the lower vs. the upper shore, and how limpets might be adapted to live on the rocky shore in each habitat you study A Prediction (hypothesis) State the question you are investigating (hypothesis) and predict what you think the results might be A Method Explain what you did and how you did it A Results section Produce a suitable graph of results and explain briefly what the graph shows A Conclusion Conclude as to what you found and state whether or not your prediction was correct. If it wasn’t correct, briefly explain why This slide provides guidance notes on how to write up an investigation.