2.4 Metabolism in Conformers and Regulators Flashcards
definition of the term adaptation?
special feature of an organism that helps them to survive
Give examples of external abiotic factors (environment) and if it affects metabolic rate?
external abiotic factors such as temperature, salinity and pH can affect the ability of an organism to maintain its metabolic rate
What is the internal environment?
the internal environment of an organism is made up of body cells and their surrounding tissue fluid, together with temperature, water content and glucose content
What are conformers?
conformers cannot regulate their internal environment and therefore cannot control their metabolic rate?
What do conformers body temp rely on?
depends upon the temperature of the external environment
Examples of conformers?
reptiles and invertebrates
What are advantages of conformers?
as conformers have no physiological mechanism for controlling metabolic rate, energy costs to the organism are low
What are disadvantages of conformers?
Conformers can only occupy a narrow range of ecological niches and are less able to adapt to survive any changes in the external environment
TOPTIP
Remember 3C's conformers cannot control their internal environment by physiological means
What are regulators?
In regulators metabolism is used to control the internal environment using physiological means
Examples of regulators?
mammals and birds
what is physiological homeostasis?
The internal environment remains stable despite changes in the external environment
advantages of regulators?
they can occupy a wide range of ecological niches
disadvantage of regulators?
energy costs to the organism are high due to physiological mechanisms needed to keep the internal environment stable
TOP TIP
animals can be conformers for one factor and regulators for another
Explain why conformers can only occupy a very narrow range of environments?
Conformers are less able to adapt to and survive changes to the external environment
two examples of physiological mechanisms used by regulators to control their internal environment?
control of blood water concentration
blood glucose concentration
body temperature
What is negative feedback?
any change in a condition from the optimum is detected by receptors that switch on a corrective mechanism to restore the condition to normal. The corrective mechanism is then switched off
Negative feedback sequence?
receptors - detects changes in the internal conditions outwith normal limits
message - nervous or hormonal
effectors - organ which responds
corrective response - reverses the original change
TOP TIP
negative feedback works like the thermostat in a central heating system. when the temperature in your house goes too high (that is above a set point) the thermostat switches off the heating and then switches back on when the temperature goes too low ( below the set point)
Compare thermoconformers and thermoregulators?
mammals are thermoregulators and have a homeostatic mechanism to regulate their body temperature
the body temperature of a thermoconformer changes with the temperature of the external environment
Importance of themoregulation to metabolic processes?
all chemical reactions in the body are controlled by enzymes
when body temp is below the optimum temp for enzyme function, metabolism is slow
metabolism is fastest when the body temp is close to the optimum temp for enzymes
above the optimum temperature for enzymes
above the optimum temp enzymes start to denature; metabolism slows down and eventually stops
temp also affects diffusion rates
rates of diffusion of substances such as oxygen or CO2 are faster at warmer temperatures, contributing to the ability to maintain high metabolic rates
What are responses to temperature regulation voluntary?
removing clothes, opening windows, switching off heating in response to increase in body temperature
Putting on clothes, closing windows, putting on heating in response to decreasing body temperature
Mechanism of temperature regulation sequence?
receptors - thermoreceptors in the hypothalamus in the brain
message - nervous impulses
effector - skin and body muscles
corrective response - return body temp to normal
what are responses to temperature regulation in voluntary?
Skin arterioles sweating erector pili muscles shivering metabolic rate
What happens when the body temp rises?
increase in body temperature
detected by thermoreceptors in the hypothalamus
increased sweating, body temp lowered blood diverted to skin surface, decrease in metabolic rate
body temp falls to normal
What happens when the body temp falls?
decrease in body temp
detected by thermoreceptors in the hypothalamus
decrease in sweating, body hair raised, shivering, blood diverted from skin surface, increase in metabolic rate
body temp rises to normal
Involuntary responses to temperature change
Response to decrease in body temperature?
vasoconstriction - narrowing of skin arterioles diverts blood away from the skin surface, reducing heat loss by radiation
sweating stops
erector pili muscles contract, pulling body hairs into a raised position that traps air to insulate the duvet (like a duvet)
shivering increases muscle activity and generates heat
metabolic activity increases to generate heat
Involuntary responses to temperature change
Response to increase in body temperature?
vasodilation - dilation (widening) of skin arterioles divert more blood to capillaries at the skin surface increasing heat loss by radiation
Increased sweat production causes more heat from the skin to be used to evaporate the sweat, lowering body temperature
erector pili muscles are relaxed allowing body hair to lie flat against the skin, minimising the insulating effect
no shivering
metabolic activity decreases to reduce heat production
TOP TIP
body temperature can increase due to exercise, illness and exposure to a hot environment
body temperature can decrease due to exposure to in cold external environment
TOP TIP
Giving alcohol to a person who is very cold causes vasodilation. Increasing heat loss from the body which can lead to hypothermia
TOP TIP
metabolic rate decreases when body temperature increases
metabolic rate decreases when body temperature decreases
Why is body temperature important in carrying out metabolic processes?
to provide optimum temperature for optimum enzyme activity or diffusion rates
