Amy

__Write a report on the Bonnie Vale Excursion. R____eport on one aspect:__

During our recent excursion to Bonnie Vale our class studied food chains as well as interactions beteween different species. We used the surrounding mangroves to find naturally occurring examples of these.

__**Activity 6**__

Food chains

A __Food chain__ shows how each living thing gets its food. Some animals eat plants and some animals eat other animals. All food chains begin with a producer. Plants are called **producers** because they are able to use light energy, from the Sun, to produce food (sugar) from carbon dioxide and water. Animals cannot make their own food so they must eat plants and/or other animals. They are called **consumers** (An arrow leads on to represent the flow of energy and matter between organisms). During the excursion to Bonnie Vale we examined the environment to discover a series of food chains that were occurring in the community. On the sheet that was given was a series of food chains and each had a producer, consumer and decomposer. We had to write down 3 different food chains. One example that we did on the day was: The interactions between species are quite complex within a community. Although food chains are useful to represent the flow of energy and biomass, interactions can be represented in a more realistic way through constructing a food web.
 * Mangroves are eaten by crabs. Crabs are then eaten by fish and fish are then eaten by cormorants.

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__**Activity 7**__

Interactions between different species.

During our excursion to Bonnievale we also studied the types of interactions between species, and learnt that no species can exist independent of others. Two beneficial interactions are mutualism and commensalism. An example of mutualism that we noted was crabs digging into the soil for shelter and protection. Not only does this benefit the crab, it also oxygenates the soil, benefiting the plants that grow there. Commensal interactions could also be seen at the mangroves, which is a relationship where one organism gains benefit and the other is neither helped nor harmed- oysters clung to mangrove roots, using them as an anchorage point.

Mutualism – a loose association between two organisms, from which both gain a benefit. E.g. Crabs burrowing in the soil

Commensalism – A close association between two organisms from which one gains a benefit and the other is neither harmed nor helped. E.g. Oysters on mangrove roots and lichen on trees.



** Lichen on trees **

Three detrimental relationships are competition, parasitism and alleopathy. Competition is a type of organism to organism relationship from the same or different species. For example, deers and wallabies in the area compete for food. Parasitism is where one species relies on another for nutrition (E.G. mosquitoes feeding off humans, or fig trees strangling and taking the nutrients from eucalypt trees. Both of which we saw at Bonnie Vale ). Alleopathy is when one species of plant stops another growing by releasing biomolecules. Alleochemicals stops the growth of the other plant (casuarina).



These pictures both depict examples of parasitic relationships. Our field study at Bonnie Vale allowed us to apply the knowledge we have learnt in class, and also taught us more about the types of relationships and interactions that can occur in a local ecosystem. **By Amy Turner, Helena Tome, Kiralee Martin, Sophie Gollan and Caitlan Deeth.**