The diagram shows a food web from a desert ecosystem.
How many species shown in this food web can act as secondary consumers?
A field study monitored the estimated population sizes of Fennec Foxes and Desert Kestrels in a nature reserve. The numbers were recorded annually from 2012 to 2022. The graph shows the results.
Use the food web to suggest an explanation for the decline in the number of Desert Kestrels shown in the graph.
European hedgehogs are covered in sharp spines. When threatened, they typically roll into a tight ball, completely protecting their soft head and limbs.
In natural woodlands and grasslands, where foxes and badgers live, rolling into a ball is an advantage to the hedgehogs. On busy motorways, this behavior is a disadvantage. Explain these two conclusions.
Biologists have observed that hedgehogs living near busy motorways are changing their behavior. When startled, these hedgehogs do not roll into a ball; instead, they flee quickly to the nearest cover. Scientists believe this behavioral response is genetically controlled. Explain how this flight behavior may become more common in hedgehog populations living near busy motorways. Use ideas about natural selection.