| what is the ability of an organism to maintain its metabolic rate affected by | external abiotic factors
these include temperature, salinity and pH |
| what is a conformer | an organism in which its internal environment is dependant upon the external environment |
| what do behavioural responses by conformers allow them to do | behavioural responses by conformers allow them to tolerate variation in their external environment to maintain optimum metabolic rate |
| do conformers have low or high metabolic costs | low |
| do conformers have a wide or narrow range of ecological niches | narrow |
| what is meant by ecological niche | the range of temperatures at which an organism can survive |
| what is a regulator | organisms which maintain their internal environment regardless of external environment |
| how do regulators control their internal environment | they use metabolism to control their internal environment, which increases their range of possible ecological niches |
| what type of metabolic costs do regulators have and why | high metabolic costs, because the regulation of temperatures requires energy to achieve homeostasis |
| what is meant by physiological homeostasis | the maintenance of the body's internal environment within tolerable limits |
| what are thermoregulators | organisms which are able to maintain a constant body temperature regardless of the environmental temperature. They do not need to absorb heat from the surroundings because they gain heat from their own metabolism |
| what is thermoregulation | an organisms ability to control its own temperature |
| what is the hypothalamus | the temperature monitoring centre |
| how does the hypothalamus work to monitor temperature | information is communicated by electrical impulses through nerves to the effectors, which bring about corrective responses to return temperature to normal |
| name mechanisms that aid thermoregulation | hair
sweating
blood capillaries
shivering
metabolic rate |
| how does hair aid thermoregulation | when thermoreceptors in your hypothalamus detect the body temperature cooling below 37 degrees celcius, the hair erector muscles in the skin contract, the hairs stand up, which traps a layer of insulating air. |
| how does sweating aid thermoregulation | when the body temperature increases sweat glands increase the secretion of sweat onto the surface of the skin.
body heat is used to evaporate water in the sweat, cooling the skin |
| how do blood capillaries aid thermoregulation in a hot external environment | vasodilation occurs
blood vessels near the skin surface dilate which results in increased flow of warm blood to the skin surface. The heat radiates out of the skin surface which increases heat loss |
| how do blood capillaries aid thermoregulation in a cold external environment | vasocondstriction occurs
blood vessels near the skin surface constrict which results in decreased blood flow to the skin surface. Less heat radiates out of the skin surface which decreases heat loss. |
| how does shivering aid thermoregulation | when the body temperature decreasess the hypothalamus can send nerve impulses to the skeletal muscles which will make them contract and relax rapidly. This is called shivering and the muscle contraction generates heat. |
| how does metabolic rate aid thermoregulation | metabolic reactions generate heat energy.
a too high increase in body temperature results in a decreased metabolic rate, this is so that less heat is produced
a too high decrease in body temperature results in an increased metabolic rate, this is so that more heat is produced |
