The Nature of Science Case Study The Nile crocodile
The Nile crocodile is found throughout sub- Saharan Africa. On average it grows to 5 metres long and 225 kilograms in weight. The Nile crocodile will attack and eat almost any animal that crosses its path. It has very strong jaws and a powerful tail that it uses to move silently through the water. A transparent membrane covers its eyes under water and it has an excellent sense of smell. The location of the nostrils on the top of the head allows the Nile crocodile to swim almost completely submerged.
Fig. 15 The Nile crocodile.
Question 1. Identify (a) three physical adaptations of the Nile crocodile and (b) one characteristic of its movement that help make it a successful predator. 2. Explain how each adaptation benefits the Nile crocodile.
Science in Society Concerns are often raised about animals living in zoos where the climate is different to their natural habitat. Choose an animal that lives in a zoo or wildlife park and find out how the zoo keepers provide living conditions that suit it. What are the ethical issues (a) in favour of and (b) against keeping animals in zoos and wildlife parks?
Competition The struggle between
organisms for limited resources.
2. Investigating competition Competition occurs between members of a community whenever there is a limited supply of a resource that they need. Cactuses in a desert compete for water because there is a limited supply but do not compete for sunlight because there is plenty of sunlight. Seaweeds in the ocean compete for light because there is a limited supply of light under water but do not compete for water because there is plenty of water in the ocean.
To investigate competition within the community of organisms in your chosen habitat you will need to consider: What resources seem to be in limited supply. Which organisms appear to be competing with each other. The adaptations which allow organisms to compete successfully. Research that other scientists have carried out.
