Human effects on ecosystemsEdexcel A-Level Biology B: Mind map

Exam questions on Human effects on ecosystems

1. A fisheries scientist monitors a stock of North Sea haddock. Over 25 years the number of boats and hours fished each year has increased, but the total annual catch has stayed about the same. The mean length of fish landed has fallen and a growing proportion of the catch is made up of immature fish.
   Explain how a fishing quota helps to make the fishery sustainable.2 marks
2. A species of tortoise is prized in the international pet trade. Its wild population has fallen sharply, and it has been listed in Appendix I of CITES. Despite this, customs officers continue to seize shipments of the animals hidden in luggage and cargo.
   Suggest why listing the tortoise in Appendix I may not on its own lead to recovery of the wild population.2 marks
3. A long-term monitoring station in a UK woodland recorded atmospheric carbon dioxide at 317 ppm in 1960 and 418 ppm in 2022. Over the same period the mean annual temperature at the site rose from 8.9 °C to 10.1 °C, and the mean date of first leafing of oak trees became 14 days earlier.
   Calculate the percentage increase in carbon dioxide concentration between 1960 and 2022, and explain how this increase may be linked to the rise in temperature.3 marks