Ectotherm

√ Physiological and Structural adaptations of ectotherms and endotherms | iitutor

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• published: 28 Dec 2015
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https://www.iitutor.com In this video you will learn: Different ectothermic and endothermic adaptations. Structural and physiological adaptations for both cold and hot environments. Structural adaptation are physical features of an organism such as their shape, body, or any other structure in relation to the body that allows them to increase their chances of survival or better suit their environment. Structural adaptations that assist with temperature control include insulation such as fur, hair, feathers, insect scales and coats that enable a layer of air to be trapped to reduce the amount of heat lost. The feathers of the emu act as an insulator to reduce heat gain or loss. Blubber is another form of insulation to reduce heat loss from organisms living in water, such as the Australian fur seal. This significantly minimises heat loss. Physiological adaptations focus on the inner body functions. Metabolic activity is important for the functioning and the survival of individuals, but this activity also generates heat within the body. The rate of this activity can be altered to ensure a better chance of survival in warmer or cooler environmental conditions. Hibernation and torpor are examples where organisms lower their metabolic rate to conserve energy and, as a result, reduce the amount of metabolic heat energy that they generate within their own bodies. Hibernation is an extended period of inactivity in response to cold, where the body temperature does not drop below 30°C, but the heart rate and oxygen consumption drop considerably. Hibernation is a state of greatly reduced body activity, used to conserve food stored in the body. Some animals hibernate for part or all of the winter. The animal’s body temperature drops, its heartbeat and breathing will slow down, and it uses little energy. Examples: ants, snakes, black bears, beavers, and ground squirrels. The term aestivation is used for animals that hibernate in hot conditions. For example, the Bogong moth (Agrotis infusa) migrates to spend the summer months in caves in the Australian Alps. A state of torpor is a short-term hibernation where the body temperature drops much lower (below 30°C) mimicking the ambient temperature and the metabolism, heart rate and respiratory rate decrease, accompanied by a reduced response to external stimuli. For example the mountain pygmy possum. If the ambient temperature is high, endotherms have a physiological cooling mechanism as well—the rate of heat loss from the body can be adjusted by altering the flow of blood near the body surface. Kangaroos can release heat by their blood vessels dilating called vasodilation. This releases heat, especially in the ears as it is a thin surface and heat can easily be lost. When cool, their vessels constrict again. Endotherms eat more food than ectotherms. This higher food intake results in an increased level of metabolism, which is required to produce heat. Compared to reptiles of the same weight, mammals use at least five times more energy. There are 5 major ways animals respond to stimuli in their environment. Sweating (physiological). Sweat evaporates from the surface of the skin and it cools the animal. Shedding (structural). Shedding- animals may form thick coats of fur or feathers to insulate their body from cold weather. When it is hot, animals shed, to provide a cooling effect. Panting (physiological). Panting means to breathe heavily. This causes an increased air flow and as a result, there is an increase in evaporation from the animal’s mouth and lungs. Shivering (physiological). Shivering increases heat production. It is a natural response to a temperature drop outside the body. It increases the rate that energy is turned into heat. 5. Changing Position / Location (behavioural). By moving location, organisms can seek a cooler environment by finding shelter or shade. Can you think of different behavioural, structural or physiological adaptations that endotherms or ectotherms have to make them more suited for their environment? Endothermic and ectothermic organisms have different types of adaptations to better suit their environments. Some adaptations have an effect on the organism’s metabolism, increasing their chances of survival.