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20 Cards in this Set
- Front
- Back
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why do single births increase the likelihood of survival for primates?
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- single foetus can obtain more nutrients from mother so will develop a bigger brain - mother can invest more time and energy in the infant so its able to learn complex behaviours |
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how does delayed puberty aid in successful reproduction?
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- ensures humans cant reproduce until they have reached social maturity themselves as caring for an infant takes a lot of responsibility |
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why is developing language an important adaptation?
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- allows communication to pass on information, wisdom and advice within group of hunters and social groups - helped to develop culture - important in forming social groups - older people would be valued for their wisdom even if they are physically useless - can explain how something should be done easier |
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explain the importance of facial expressions in communication
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- allows communication even if different languages are spoken by each individual - can convey feelings - infants can interact with their carer by using facial expressions like smiling, important in its survival as they form a close attachment bond |
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describe 2 adaptations of the human anatomy, why it developed and why they're useful |
Bipedalism - climate changes in east Africa changed dense forests into large areas of savannah so natural selection favoured those who were more adapted - enables animal to look over vegetation, fight more effectively, communication, throwing and carrying with arms Skin colour - early ancestors had black skin with large amounts of melanin, homo erectus migrated out of Africa into colder climates meaning less UV radiation, melanin in the skin prevented enough vitamin D being made of paler skin tones were favoured by natural selection - allows enough vitamin D to be made in cooler climates Surface area:volume - large surface area:volume in hotter climated so can loose more heat easily, small surface area:volumeconserves heat in colder reigions |
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where is the breathing centre?
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in the medulla of the brain |
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describe how normal breathing works?
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- causing contraction and inspiration - alveoli fill with air and stretch receptors are stimulated - sends impulses to the expiratory centre of the medulla - no more impulses sent, diaphragm and intercostal muscles relax causing expiration - stretch receptors no longer stimulated so inspiratory centre causes inspiration again |
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describe the effects of exercise on breathing rate
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- CO2 in the blood is slightly acidic, dissolves in blood plasma to form weak carbonic acid and then dissociates into hydrogen ions and hydrogencarbonate ions - high concentration of hydrogen ions reduces pH levels which are detected by chemoreceptors - send impulses to the inspiratory centre, medulla sends impulses to the diaphragm and intercostal muscles causing rate and depth of breathing to increase |
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what's the relationship between CO2 levels and controlling the heart rate?
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- nervous system can change rate of heart beat - more CO2 reduces pH which is detected by chemoreceptors which send impulses to the cardiovascular centre in the medulla - more impulses are sent along the sympathetic nerve to the SAN stimulating it to send more frequent impulses increasing heart rate -CO2 levels fall, pH increases, chemoreceptors detect this and send impulse to the cardiovascular centre - more impulses are sent along the parasympathetic nerve to the SAN slowing heart rate |
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describe the relationship between blood pressure and controlling the heart rate
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- vena cava walls are stretched causing heart rate to increase - increase of blood stretches heart muscle causing it to contract more strongly increasing the stroke volume - increased stroke volume stretches aorta and carotid artery, pressure receptors in walls detect the stretching and send impulses to the cardiovascular centre which sends more impulses along the parasympathetic nerve to slow heart rate |
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how do you work out the cardiac output?
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stroke volume x heart rate |
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what parts of the body contain chemoreceptors?
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medulla, carotid body and aortic bodies in wall of aorta |
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describe what happens to the energy released in respiration
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energy is released to add another phosphate group to ADP to form ATP |
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what is the energy from respiring a molecule like glucose converted into ATP?
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- its small and simple - can diffuse easily where needed - delivers energy in small convenient amounts |
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what happens to glucose and triglycerides during aerobic respiration?
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- obtain maximum yield of ATP - 38 molecules from one glucose molecule |
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what happens to glucose and triglycerides during anaerobic respiration?
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- glucose is respired but not broken down completely only producing 2 ATP molecules - lactate is produced - triglycerides cant be respired |
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describe the structure of haemoglobin
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- each iron ion can combine with 1 oxygen molecule - 1 haemoglobin can carry 4 oxygen molecules |
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what have studies of people who live at high altitude shown in reference to haemoglobin?
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why do some athletes train at high altitude?
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hope it will raise haemoglobin levels in their blood so they will perform better in competition |
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