Ecological niche
Modern humans evolved in Africa, moving from forest to plains when their environment changed. As a result they lost the climbing adaptations of their close relatives such as the opposable big toe that looks like a thumb. Instead our whole body shape has adapted to upright locomotion, specifically long distance running. Humans needed meat to sustain their growing brains, but did not have the size, teeth or claws to hunt like other predators. Instead, as can still be seen in some modern hunter-gatherer tribes, they chase their prey over large distances until their prey collapsed from exhaustion. Humans also have other adaptations to evolving in this ecological niche. We are mostly hairless, in order to aid keeping cool in the …show more content…
The trachea plays many roles in the human body allowing it to survive. The trachea helps the human body with air conduction, the trachea function for this process is to allow air passage into the lungs for respiration, which is breathing in oxygen and exhaling carbon dioxide. When inhaling oxygen for air it travels down the trachea to bronchi then bronchioles and then to the alveoli. If damage is caused in the trachea it will cause blockage and influence it to collapse this will interfere with the normal air exchange. Another important role the trachea has is protection. The trachea protects and prevents microbes and harmful substances from going deeper into the lungs and causing malfunctions with breathing. Sometimes objects penetrate into the trachea, as an outcome coughing is produced. Coughing is the tracheas way of trying to release the objects, which are irritating it and allow gas exchange to continue. Coughing allows air to get into the lungs. The walls of trachea have ciliated hairs, which catch objects like dust from the inhaled air. This is then transported upwards the throat to either be swallowed into digestive system or removed by …show more content…
There are around 700 million alveoli in your body, which are found on the branches of bronchial passages. Oxygen from the inhaled air diffuses through the walls of the alveoli and capillaries into the red blood cells. The oxygen is then carried by the blood to the body tissues. Carbon dioxide produced by the body’s metabolism returns to the lung through the blood. It then diffuses across the capillary and alveolar walls into the air to be removed from the body. The alveoli have a structure specialised for efficient gas exchange such as, the walls are extremely thin, they have a large surface area in relation to volume, they are fluid lined which enables gases to dissolve and they are surrounded by numerous capillaries. Both alveoli and trachea are important to the human gas exchange as without them humans would not survive. We require oxygen in our body to live and