key area 2.4 - conformers and regulators

Question 1

conformers

Answer 1

• internal environment is directly dependant on its external environment
• low metabolic costs since don’t use any physiological responses to maintain metabolic rate
• use behavioural responses to respond to variation in environment
• narrow range of ecological niches

Question 2

regulators

Answer 2

• organisms that can control their internal environment regardless of external environment
• they maintain a steady state of homeostasis which requires energy
• high metabolic costs due to homeostasis
• can exploit a wide range of ecological niches

Question 3

abiotic factors affecting metabolic rate

Answer 3

• temperature
• salinity
• pH

Question 4

homeostasis

Answer 4

• the bodies capability to maintain its internal environment within limits despite changes in external environments
• achieved by negative feedback control

Question 5

negative feedback control

Answer 5

• negative feedback systems contain monitoring centres with monitor internal environment and detect changes
• sensed by receptors which sends a message back to effector to trigger a corrective response to bring the factor back to its norm
• messages can either be hormones or nerve impulses

Question 6

effectors

Answer 6

• a muscle or gland which performs the body’s response to stimuli following the body’s response to a stimuli following the receipt of signals from the nervous system

Question 7

thermoregulation

Answer 7

• maintenance of mammals internal body temperature within certain tolerable limits

Question 8

hypothalamus

Answer 8

• region of the brain which of the bodies temperature monitoring centres
• contains thermoreceptors which detect changes in blood temperature
• sends out electrical impulses through nerves to the effectors which bring about corrective responses to return temperature to normal

Question 9

corrective responses to an increase in body temperature

Answer 9

• vasodilation - increased blood flow near surface of skin increases heat loss through radiation
• increased sweating - body heat evaporates water in the sweat, cooling the skin
• decreased metabolic rate - reduces heat produced as less energy will be required

Question 10

corrective responses to a decrease in body temperature

Answer 10

• vasoconstriction - reduces blood flow near the surface of the skin decreasing heat loss through radiation
• contraction of hair erector muscles - hairs are raised from skins surface which traps a layer of insulation air to reduce heat loss
• shivering - skeletal muscles around the body repeatedly contract, this muscle activity generates heat

Question 11

advantages of maintaining a constant body temperature

Answer 11

• for optimum enzyme controlled reaction rates
• rate of diffusion of gases such as CO2 and oxygen are faster at warmer temperatures
• these help maintain a high metabolic rate