Construct two food chains ending with a tertiary consumer. Which organisms has the highest variety of predators in the food web? Suggest one way in which the ecosystem would be affected if there was a prolonged drought.

a) Construct two food chains ending with a tertiary consumer.
A tertiary consumer eats a secondary consumer.

1. Green plants $\rightarrow$ Grasshoppers $\rightarrow$ Lizards $\rightarrow$ Snakes
2. Green plants $\rightarrow$ Mice $\rightarrow$ Snakes $\rightarrow$ Hawks

b) Which organisms has the highest variety of predators in the food web.
To determine this, count the number of arrows pointing to each organism:

• Grasshoppers: Eaten by Lizards, Hawks (2 predators)
• Mice: Eaten by Domestic cat, Snakes, Hawks (3 predators)
• Lizards: Eaten by Snakes, Hawks (2 predators)
• Snakes: Eaten by Hawks (1 predator)
• Domestic cat: Eaten by Hawks (1 predator) The organism with the highest variety of predators is Mice.

c) Suggest one way in which the ecosystem would be affected if there was a prolonged drought.
A prolonged drought would lead to a significant decrease in the population of Green plants due to lack of water. This would reduce the food available for primary consumers (grasshoppers and mice), causing their populations to decline, and subsequently impacting all higher trophic levels in the food web.