Chapter 16 Key Learning, Biology

Distinguish between ectotherms, heterotherms and endothermsEctotherms are generally unable to raise their body temperature by internal heat production, they are animals other then birds and mammals, they loose their body temperature to the environment rapidly, but they do not use much energy compared to endotherms but use more energy but do not loose their body temperature to the environment as rapidly. Endotherms maintain a constant body temperature that is generally higher then that of their surroundings, they create heat by internal metabolic heat production, they are mammals and birds. Heterothems are ecotherms that can stay warmer than the temperature which they live in, they can function as endotherms generating metabolic heat, the animals that can do this are some insects, some fish and some sharksExplain how disturbance and misalignment detectors work together in the negative feedback control of body temperature in mammalsNegative feedback is stimulus-response mechanisms in which the response produced reduces the effect of the original stimulus (response provides feed back that has a negative effect on the stimulus). Disturbance detectors in the skin initiates regulatory responses, if they fail to work and the temperature of the blood falls misalignment detectors in the brain will continue the responses until temperature reverts to normal. (Picture at bottom)List the factors that influence that rate of heat exchange The effective temperature difference between the animal and the temperature of the environment. The area of exposed surface. The efficiency of any insulation against heat exchange Physiological processes involving evaporation and circulatory changes. Describe how heat is lost and gained by endothermic animalsHeat is gained by endothermic animals by internal metabolic heat production, they have insulating features such as feather and fur, this is to trap in a layer of warm air keeping the endothermic animal warm. They use behavioural and physiological mechanisms to regulate heat loss of metabolic heat. Heat is lost by evaporative cooling such as sweating and panting. Sweating has salts and important minerals, when the sweat is at a low rate it is reabsorbed through the skin before passing off the body, if the sweating is increased then the body cannot reabsorb the minerals and the body looses those resources. Panting gets rid of hot air from the body and does not loose important resources. Physiological ways such as circulatory changes and counter current arrangements. Use examples to illustrate the adaptations that help organisms regulate heat exchange with their environment Lizard basking in sun - behavioural adaptation Shivering - physiological adaptation feathers and fur insulating - structural adaptation huddling - behavioural adaptation counter current arrangements of blood vessels, and circulatory changes - physiological adaptation. List the roles played by the circulatory system in temperature regulation in endothermsThe roles that circulatory system plays in temperature regulation in endotherms are selective constriction or dilution of blood vessels in the skin and in heat-generating organs, such as muscle. Which allows restriction of heat loss from blood vessels. The circulatory system plays a role in conserving temperature through counter current heat exchange, where cold blood runs in the opposite direction of warm blood and as the warm and the cold blood pass, the warm blood then transfers its heat to the cold blood regulating temperature. Contrast how salt and water balance is maintained in freshwater and marine bony fishesIn marine environments the concentrations of body fluids of marine fish is similar to that of sea, and in fresh water the concentration of body fluids of freshwater fishes is similar to that of the water, this reduces the osmotic gradient between the fish and its outside environment , which reduces that osmotic input of water into the fish. In marine bony fish are decedents of freshwater fish which means that the concentrations of their bodily fluids are more dilute then that of the sea which the live in. The body fluids of freshwater fishes are more concentrated than the water in which they live in, and marine bony fishes are less concentrated than sea water, both fishes are under osmotic stress. List the ways that terrestrial animals gain and lose water To gain water they consume water once they experience thirst, it can be gained throught food, is gained through cellular respiration and through behavioural means water is conserved. Terrestrial animals lose water through breathing by evaporation, sweating Describe how the mammalian kidney produces concentrated urineThe mammalian kidney can produce concentrated urine by actively pumping salts into the medulla of the kidney, and because of the counter-current arrangement of the loop of Henle and of blood vessels in the medulla. The loop of Henle is related to the size of the salt concentration gradient that can be generated in the medulla of the kidney, the longer the loop the larger the higher salt concentration can be achieved. Describe some adaptations that enable terrestrial mammals to minimise water loss A larger loop of Henle to allow for more concentrated urine, and less water loss. To be nocturnal to restrain from physical activity in the day