Ecology feedback for the practice exams

Question One Students were required to have identified and provide a reason why the upper/lower bands are identified as it is.

1. Many students did not: Have 3 factors (either abiotic/biotic) AND/OR Identified at least 2 adaptations for an organisms survival in their community. (This prevents them from gaining an Achieved.) It is very important as the question asks that they need to Identify (Achieved) and Explain (Merit) 2 Biotic factors, 2 Abiotic factors and 3 adaptations of organisms to live successfully.

2. Biotic and Abiotic factors. Biotic factors looks at the relationship of an organism to other organisms (same or different species) to how they can be distributed along each band. – Not necessarily the biology features (adaptations) for its survival. Abiotic factors look at the non-living factors like (wind action, wave action, water and tide levels, exposure to sunlight, temperature). Majority of the students identified Abiotic factors compared to biotic factors. Only a few students had explained on how these factors set the upper limit and lower limits to zones. (For Merit and Excellence)

3. Adaptations The majority of students identified adaptations (mainly structural) as well as explained why they are important for their survival in their particular zone. Common examples are the shells for whelks and periwinkles for protection against predators and over exposure to the heat/sun.

Errors: Majority of students used the inter-tidal zones as their example. However, a few students used a forest community. They discussed the community pattern relating more to Stratification, rather than Zonation (Not Achieved) Did not write enough points on factors OR adaptations for Achieved. Students have not explained why these factors OR adaptations are important for setting upper/lower limits for organisms in their zones. (For Merit) Students wrote in detail 2 factors instead of at least 3 factors OR have written 3+ factors in detail but have “contradicted” themselves (For Excellence)

Question 2 Most Students that answered this question did not answer all the 3 parts in explaining 1) How energy enters 2) How energy passes through the community and 3) How energy leaves the community. (Subjecting them to NA)

They were required to make note of 2/3 points for achieved. If those 2/3 points were explained in detail explaining may lead to Merit/Excellence. 1) Why the process of photosynthesis is important for the food web and linking light energy converting it to chemical energy (in food/starch/glucose) 2) How energy is passed on from producer to consumer(s) AND relating it to why they need it for a particular life process. (At least 1 life process is named e.g. growth, reproduction, movement….) 3) How energy is lost in detail (via Respiration, Excretion, Decomposition (Decay) – they must make note that “Heat” energy is lost by these processes.

For excellence, students must have all 3 explained points correct and not that the flow of energy moves through a community (uni-directional), and does not recycle like nutrients. Students that Gained Merit either: Named 2 or 3 explained points and did not mention how energy flows in a community Named 3 points and explained points and the excellence but have misinterpreted (confusion) ideas or contradicted themselves in their answer.

Question 3 Only a few students were able to answer the question properly. The question asks for TWO reasons for the success of possums in NZ AND TWO reasons on why they need to be controlled in NZ. Many students that gained a Not Achieved for this question either: Answered two reasons for one of the two parts to the question and/or Gave one reason for one point OR both points (Not Achieved as it has not answered the questions asked) Students that gained A/M/E answered what was required from the Question

Student who gained Merit & Excellence explained their reasons and related them to: – Declining populations to native organisms (plants/animals) – may lead into extinction (endangered species) via outcompeting, predation, antibiosis, exploitation, destruction of habitat… – Stability of food chains/webs has been negatively affected. Feeding relationships have altered over time. – Abiotic factors (e.g. climate) and natural resources being suitable for their population – NZ tourism and farming affected cause financial crisis

Students that gained Excellence in this question had given a comprehensive answer in relating to the reduction of Biodiversity in NZ native forests as a result of possum activity and population numbers. – Maybe an opinion of what may happen over time if the control of possums is not effective

Overall Approximately 30% of the Bio201 students passed the exam.