|Sinuses in the human face|
Sinuses are air-filled spaces extending from the nasal cavity into the facial bones. As well as making the facial bones lighter they give timbre to the voice and also help heat and moisturise inhaled air
Problem: Sinus problems are common in humans, usually because of inflammation caused by an opportunist infection following a cold. The problem is cause by our sinuses being poorly drained, especially when the lining is swollen or mucus production is high. These warm, moist, protein-filled spaces are an idea environment for several species of bacteria which the body finds difficult to cope with by the normal blood-born defences. White blood cells are sent into the infected sinus where they, together with dead bacteria, form pus.
In chronic infections an abscess may form which can erode the facial bone and even penetrate to the brain, causing bacterial meningitis and death.
Cause: The human face is rotated downwards by about 90 degrees compared to most mammalian facial skeletons to compensate for our upright gait. Our faces have also become flattened with the usual mammalian muzzle receding back under our noses. By normal mammalian standards, humans have a strangely deformed face. One result of this is to distort the sinuses and restrict the drainage channels.
The middle ear is an air-space between the outer ear and the inner ear where the hearing mechanism is located. A narrow tube, the Eustachian tube, connects this space with the back of the throat so that the pressure in the inner ear can be equilibrated with the outer air pressure so maintaining a constant pressure on the eardrum. This tube is normally opened during swallowing.
Problem: During a cold the Eustachian tube can become inflamed and, like the sinuses, is prone to secondary infection by opportunist bacteria. It can then become difficult to drain and equilibrate the pressure in the middle ear. This can cause severe pain and may rupture the eardrum. In children especially it may lead to 'glue ear' needing surgical insertion of grommets to keep a hole open in the eardrum to allow the inner ear to drain. In extreme cases, it can cause an abscess to form. Infection may track down the auditory nerve to the brain causing meningitis and even death
Cause: The same as with sinuses due to distortion of the bones of the skull associated with an upright gait.
3. Wisdom Teeth.
Wisdom teeth are molar teeth which normally erupt in adolescence. A few individuals fail to produce them and suffer no detectable disadvantage.
Problem: Fairly frequently, the teeth develop but fail to break through the gum. They may even grow in the wrong direction and become impacted, causing pain and difficulty chewing food. They often need to be surgically removed. Occasionally they can become infected and an abscess may form in the mandible or maxilla.
Cause: As the human face has receded from the normal mammalian skull pattern the number of teeth has been reduced. This process in incomplete.
|Human cervical spine|
The cervical vertebrae, or neck bones, carry the weight of the skull and allow the skull to rotate from side to side and to flex back and forth. To help with this the foramen magnum, a hole in the base of the skull through which the spinal cord passes, has moved under the skull compared to the normal mammalian anatomy. It is also assisted by a broad ligament which attaches to the back of the skull and runs down to the shoulder bones. This helps stabilise the skull during running.
Problem: The neck muscles frequently become fatigued causing head-ache. During rapid acceleration such as during a rear-end automobile accident, or due to a fall, the skull can hyper-extend, bending the neck backwards and fracturing one or more of the cervical vertebrae. Fragments of bone may damage or transect the spinal cord, causing paralysis or death. Arthritic problems may also develop in later life.
Cause: Adaptation to an upright gait combined with a large cranium to house a large brain has meant compromises in the basic mammalian anatomy. This process is incomplete.
The laryngopharynx is a passage common to the airway and the food passage. Air-breathing vertebrates have a basic flaw in their body plan in that the air and food passages cross in the pharynx. Protective mechanisms normally prevent food entering the airway. These may include mechanisms to close the airway during swallowing and coughing to expel inhaled food.
Problem: In humans, choking is a fairly common cause of sudden death in an otherwise healthy adult or child. Choking occurs when the air passage becomes blocked by food when the protective mechanism fail. In humans, a protective flap - the epiglottis - is present and is normally effective as the larynx is pushed up against it during swallowing. Occasionally however, this fails and food may enter the air passage. A second line defence reflex, coughing, may also fail and may make matters worse as the victim attempts to breath in in order to cough, driving the blockage further into the air passage. Vomiting, also a defence reflex, may also occur and may add to the problem as the victim is also unable to clear accumulating vomit.
Cause: As an adaption to speech, our pharynx - the space at the back of the throat between our mouth and the larynx - has lengthened creating a greater likelihood of food entering the laryngopharynx before it can be fully closed off. The protective mechanisms have lost some of their effectiveness in the process and have not yet been compensated for.
All these are perfectly understandable in terms of evolution as the advantages of the adaptations far exceed the disadvantages. The greater likelihood of survival and reproductive success of genes carried by people with these evolving adaptations outweighs the loss of some individuals due to the problems they may cause.
In terms of intelligent design, these flaws make no sense at all since an intelligent designer, especially a perfect, omniscient, omnipotent and omni-benevolent one, would have produced a faultless design in the first place.
The situation is exactly as you would expect with a mindless, utilitarian process of evolution driven by whatever works to produce more copies of the genes in the next generation, differentially selected naturally from among variants in the gene-pool.