The skeletal system includes bone and cartilage. In an adult human, there are approximately 206 bones and these have the functions of supporting the body and muscles, protecting and enclosing visceral organs, helping us to move, making blood, and providing a place to store minerals and salts. The skeletal system is clearly absolutely essential for us to survive, so what are its components and how do they work? Continue reading
The amino acids are responsible for many functions in the human body. Without amino acids, we could not survive. I will provide a brief explanation of the general structure of the twenty amino acids, and show why they are so important for life. Continue reading
The Platypus (Ornithorhynchus anatinus) has a furry body, feet that are both webbed and clawed and a toothless muzzle like a duck’s bill. Males can grow to 60cm long, weighing up to 2kg, whilst females can grow to 40cm long. They reach maturity at 2 years, but can live for over 15 years. They are found in streams and freshwater lakes in Australia from Queensland down to Tasmania. They can dive deeply but can only stay underwater for 5 minutes. Continue reading
Sharks are excellent predators and are understandably feared by many. However, more often than not, humans are not the intended targets by sharks and attacks on humans are relatively rare.
As predators, sharks have an extremely advanced sensory system. They have two nasal sacs which are lined with cells. As sea water passes over these cells, they are able to detect traces of fish flesh at concentrations of one part per ten million parts water. They are able to pick up sounds and vibrations by either pores on their head, which detect water pressure variations, or through their ears. They have pores in the skin around the snout that are sensitive to electrical fields and so can hunt fish. They also have very good vision and are able to easily distinguish moving objects from backgrounds. A further feature is that they have mirrors behind the retinas which enables better vision in the dark, however in bright light, the mirrors cloud over with black granules to adjust. Sharks also have organs that look like taste buds around their lower jaw, which are thought to be a part of a sensory system but it is unknown what it is used for. Continue reading
Australia is home to lots of different creatures, many of which can be dangerous to humans. Here, I will focus on a selection of animals that are capable of inflicting wounds: kangaroos, goannas and magpies.
The tallest species of kangaroo is the red kangaroo (Macropus rufus) and it stands at about 1.4 metres, however, when rearing up on its back legs and tail, it can be taller than 2 metres. Kangaroos frequently fight each other for mating rights and leadership status, but attacks on humans are not unheard of. When fighting, they rear up, and balance on their tail. They ‘hold onto’ their prey with sharp claws, and kick with their powerful back legs. Continue reading
The Lammergeyer is a large bird of prey. It is a vulture of the genus Gypaetus with a wingspan of nearly 3 metres. The vulture lives in harsh habitats, mainly in mountainous regions in places that have cliffs, gorges and plenty of rocky areas. One of the most amazing things about the Lammergeyer is its diet. Eighty-five to ninety per cent of its diet consists of bone from which the Lammergeyer digests the bone marrow. It searches for a dead animal, extracts a bone, which may weigh anything up to its own mass, flies really high, and releases the bone with precision so that it will crack on a rock. The Lammergeyer then finds the broken pieces and digests them. This may take a number of tries of dropping the bone before it takes a hit, and it is a skill that needs to be acquired by each individual bird. Continue reading