Using the climograph, calculate the range of temperature.

Using the climograph, identify the relationship between maximum temperature and rainfall. 

Using the climograph, outline the pattern of rainfall.

Natural forests in the area around Mangalore contain hardwood trees such as teak, Tectona grandis, which are deciduous, shedding their leaves once a year. Suggest, with a reason, when this might happen.

The image shows a Gersmehl diagram of tropical rainforest.

[Source: © International Baccalaureate Organization 2019]

Explain what this diagram indicates about nutrients in this type of ecosystem.

«30 − 26 =» 4 «°C» ✔

Accept answers between 3 to 5 «°C».

maximum temperature occurs just when rainfall begins/at the onset of the rainy season/monsoon
OR
negative relationship «as maximum temperature drops, rainfall increases» ✔

OWTTE

rainfall concentrated between April to December/peaks in June-August «followed by months with little/no rainfall» ✔

OWTTE

a. dry season/Jan/Feb ✔

b. «drop leaves» to prevent water loss/transpiration «since no rainfall for almost four months» ✔

a. statement correctly explaining the quantity of nutrients in identified circle/circles ✔
eg most nutrients are stored in biomass/equal quantities of nutrients stored in soil and litter.

b. statement correctly explaining high nutrient flow/transfer of any thick/large arrow ✔
eg high transfer rate of nutrients from soil to biomass.

c. statement correctly explaining low nutrient flow/transfer of any thin arrow ✔
eg low transfer rate of nutrients from litter to the outside/another ecosystem.

d. any statement correctly comparing nutrient storage/flow rates ✔
eg higher nutrient transfer between soil and biomass than between biomass and litter OWTTE.

e. a Gersmehl diagram models «interrelationships between» nutrient stores and flows in an ecosystem ✔

Many could provide correct answers, but there were some who stated the range extremes instead of calculating the difference between them. Some also saw a correlation where there is none. 

Most outlined correctly the pattern of rainfall, but irrelevant answers were seen.

Many provided correct answers, but also an important number could not relate the process to prevention of water loss during the dry months.

Most candidates could realize that most nutrients were stored in biomass; it was nevertheless more difficult for many to explain and compare nutrient stores and flow rates using size of circles and arrows, although excellent answers were seen.