Predator-prey relationshipsIB MYP Biology: Mind map

Exam questions on Predator-prey relationships

1. In a nature reserve in Canada, the populations of snowshoe hares (prey) and lynx (predators) were counted every year for 20 years. The hare population peaked at about 140 000 in year 4 and again in year 14. The lynx population peaked at about 60 000 in year 6 and again in year 16.
   Explain why each lynx peak comes after the hare peak.2 marks
2. A cheetah hunts gazelles on an African grassland. The cheetah has a streamlined body, powerful leg muscles and eyes at the front of its head. The gazelle has eyes at the sides of its head, long legs for fast running and a brown coat.
   Explain how the gazelle's brown coat helps it to survive.2 marks
3. A class investigates camouflage using paper 'insects' on a green lawn. In each trial the teacher scatters 20 green, 20 yellow and 20 red paper insects, all the same size, over the same area of the lawn. Ten students act as predators and each has 20 seconds to collect as many insects as they can. The trial is repeated three times with fresh insects. In total, the students collected 9 green, 24 yellow and 41 red insects.
   Identify the independent variable, the dependent variable and one control variable in this investigation.3 marks