IB ESS HL 2 Ecology Questions

sun/sunlight/solar radiation/insolation;

removal of organisms from the lake/removal of fish/fishing/removal of reeds/run-off/outfall/outflow/loss of heat (to environment);

Marking guidance:

Do not accept only 'respiration/evaporation/transpiration' Accept any other appropriate response.

Accept any appropriate food chain from Figure: Example of a lake ecosystem with four different trophic levels and correct direction of arrows indicating flow.
eg phytoplankton (diatoms) → zooplankton → small fish (perch) → bird (kingfisher);

increase in secondary consumers/organisms in trophic level below them (eg small fish);
reduction in primary consumers/zooplankton due to increase in secondary consumers population;
less competition for other tertiary consumers;
increase in bird population due to less competition;
loss of biodiversity;

Using Figures: Figure: Figure: Figure: Mountain zones and climate in the Swiss Alps and Table: Table:Coniferous forest/grassland;

a. Zermatt is wettest in the summer months of May, June, July and August / peak precipitation in Zermatt is in May / total precipitation per year in Zermatt is $590 \mathrm{~mm} /$ maximum precipitation in Zermatt is 70 mm ;
b. Montana is wet all year / peak precipitation in Montana is in December / total precipitation per year in Montana is $830 \mathrm{~mm} /$ maximum precipitation in Montana is about 99 mm ;
c. Montana is wetter than/has more precipitation (than Zermatt) / Zermatt has less precipitation/is drier(than Montana);
d. Temperatures range from approximately $-1 /-2^{\circ} \mathrm{C}$ to $16 / 17^{\circ} \mathrm{C}$ in Montana / highest mean monthly temperature is $16^{\circ} \mathrm{C}$ in Montana;
e. Temperatures range from approximately $-3 /-4^{\circ} \mathrm{C}$ to $14^{\circ} \mathrm{C}$ in Zermatt / highest mean monthly temperature is $14^{\circ} \mathrm{C}$ in Zermatt;
f. Temperatures are colder in Zermatt (than in Montana) / Montana is warmer (than Zermatt);

Note to examiners: reserve one mark for Montana and one mark for Zermatt. While comparison terms are encouraged, they are not mandatory for this question.

a. Zonation (parallel bands of vegetation) occurs due to changing abiotic/climatic conditions (e.g. temperature, oxygen levels, carbon dioxide levels, soil depth, wind speed, aspect, water availability, nutrient availability);
b. Plants which can survive in colder conditions are found higher in the mountains (such as conifers, which begin photosynthesizing as soon as temperatures rise above $0^{\circ} \mathrm{C}$ ) / colder temperatures means that not all types of vegetation/species can grow there/changes the types of vegetation;
c. Plants (e.g. deciduous trees) which require longer growing seasons are found lower in the mountains (as the snow melts more quickly in spring) / water availability reduces with altitude which restricts the type of plant species that can grow there;
d. Soils become thinner with altitude, limiting (tree) root development, (creating alpine meadows);
e. Plants that can tolerate thin/nutrient-poor soils dominate higher elevations (leading to alpine meadows rather than dense forests);
f. South-facing slopes are warmer and snow melts more quickly, resulting in higher upper limits for each zone / north-facing slopes are cooler/retain snow longer providing shorter growing seasons and different vegetation zones compared to similar altitudes on south-facing slopes;
g. At higher altitudes, increased exposure to wind reduces tree growth/limits plant height/favours low-growing/wind-resistant species;
h. Increased UV radiation at high altitudes favours plants with protective adaptations (such as waxy leaves or compact growth);
i. With increase in altitude there is a reduction in oxygen levels which results in a change in the types of vegetation;

Note to examiners: Accept the converse where appropriate. For credit response must link to either zonation or change in vegetation type. Do not accept 'less vegetation' instead of 'changes to the type of vegetation'.

Marking guidance:

Do not accept only 'changes in vegetation occur due to changes in temperature'.

but not on the South Island.

Subtropical rainforest/shrub steppe;

Marking guidance:

Do not accept only "rainforest/subtropical forest/steppe/shrub". Only mark the first response if more than one answer is given.

a. Low/lower altitude is associated with bog/swamp/grass steppe/shrub steppe/subtropical laurel forest/subtropical rainforest/temperate broadleaf forest;
b. High/higher altitude is associated with alpine shrubland/highland steppe/temperate rainforest;
c. Mid/middle altitude is associated with temperate rainforest/temperate broadleaf forest;
d. Low/lower altitudes are associated with subtropical forests / mid/middle altitudes with temperate forests / high/higher altitudes are associated with grasslands;
e. The higher the altitude, the more grass steppe there is;
f. Zonation;

Note to examiners: accept any other reasonable responses. Do not accept just "steppe" or "rainforest", it must be specifically named for the appropriate altitude. Do not accept responses which simply state at which height range a specific vegetation type is located (e.g. Temperate broadleaf forest is located at $1000 \mathrm{~m}-1249 \mathrm{~m}$ ) as this is not a relationship.