Question

Cooper's hawk Fox Robin Alligator lizard Arrows show direction of energy flow. from organism consumed to consumer Earthworm Millipede Bracket tungus Bacteria, archaea Imany species Puftball Pibugs Insect larvae Imaggots) Cricket Rotting og Dead leaves Imany species Dead animals Imany species) Maple tree Leaves Example of a trophie (food) web Refer to the trophic web above. Match Case Watch Dies Whole Words manches 31 MacBooK 3 4 & 7 8 E R U F

Answer 1

There are two possible reasons for the increase in the population of a particular species in a food Web:

1. Decrease in its consumer population either due to habitat loss or unnatural reasons like hunting.
2. Or Increase in the energy supply to it, as the amount or number of prey population rise.

So, given the scenario of the increase in the population of alligator lizards:

• Large tree die off, undoubtedly will help increase the population of fungi and bacteria which act as the indirect consumer population for alligator lizards. But this should have more effect on the increase in the number of earthworms and millipedes. Also, in this case, the population of both robin bird and lizard should similar change as they are the competitive consumers. Hence, this will not contribute to the increase in the population of alligator lizards significantly.

• Invasion of new species of lizard because that will increase the inter-species competition between them for consuming food and other resources. This instead will contribute to decreasing the population of alligator lizards.

• It can not be due to the increase in the Fox(predator) population as it is its predator and instead decreases their number.

• Decrease in the population of cooper's hawk can have a significant effect on the increase in the population of the alligator lizards as it will reduce the competition between fox and cooper's hawk to feed on the robin bird. Hence, the number of suppliers for the fox increases due to which it feeds comparatively less on the alligator lizards than before and hence, resulting in the increase in their number.

Therefore, 'option d. The cooper hawk's population decreased' is the correct answer.