A body has been found in a city centre. A forensic botanist can work out where the person took their last breaths by examining the pollen grains in the lungs.
1 Imagine you are the forensic botanist. You need to work out where ‘Man X’ was when he died. You have found the following pollen grains in his lungs. Use the key to find out which plant each one is from. To use this type of key, start at 1, choose the correct sentence and follow the instructions on the right.
pollen grain type A
pollen grain type B
pollen grain type C / 1 Grain is divided into two or three parts. go to 2
Grain consists of one part. go to 3
2 Grain has extra part stuck in the middle. poplar tree
Grain has two extra parts sticking from sides. pine tree
3 Grain is smooth and round. go to 4
Grain has three points around edge. go to 5
4 One square mark in middle of grain. yew tree
Many small marks in middle of grain. larch tree
5 Round mark next to each point near edges. hazel tree
No round marks on grain. go to 6
6 Three square chunks cut into edge. lime tree
Three points sticking out of edge. oak tree
2 The amounts of each type of pollen found were: Pollen A – 0.002g, Pollen B – 0.001g,
Pollen C – 0.005g. Only these types of pollen were found.
a Work out the percentages of the different types of pollen found.
b Draw a pie chart showing the percentages of the different types of pollen.
c How might this information help you to work out where ‘Man X’ died?
d How does the pie chart help you to visualise the information?
3 a One of the pollen grains has ‘air sacs’ on it. What do you think they are for?
b What does a plant use pollen for?
c Roses are pollinated by insects. Trees are mainly pollinated by the wind. Why are you less likely to find rose pollen in someone’s lungs compared with tree pollen?
4 a Think up a scientific question about pollen.
b Think up a legal question that might be answered by looking at pollen.
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