Animal Ektotherm and Animal Endotherm

A. Animal EktothermS

An ectoterm animal is an animal that relies heavily on the temperature in its outer environment to increase its body temperature because the heat generated from its entire metabolic system is small.

The ectoterm animals, all animals except the aves and mammals, are groups of animals whose body heat depends on the heat from the outside of their bodies, the environment. The power set that has a very limited so that his body temperature varies with the temperature of the environment. This causes the poikiloterm animals to have a low tolerance range, in the sense that the narrow niches of this animal are narrow. When the ambient temperature is high, beyond the limits of tolerance, the ectoterm animals will die while when the environmental temperature is lower than the optimum temperature, the activity is low and the animal becomes very slow, making it easy for the predator to catch it.

Power regulates the animal ectotherm, not from physiological adaptation but rather behavioral adaptation. For example, move to find a shady place if the day is too hot and sunbathing dipanas sun if the day is cold. Among temperatures that are too low and too high, the rate of animal metabolism ektoterm increases with rising temperatures in exponential relationships.

Examples of animals belonging to ectoterm are salmon (22 oC), saumon fish (18 oC), crapaud bufo boreas (27 oC), alligator (32-35 oC), iguana 38 oC), lezard anolois sp (30 - 33 oC), and the house fly larvae (30 - 37 o C).

 A.1. Thermoregulation of the aquatic ectoterm

The temperature in the aquatic environment is relatively stable so that the living hewah does not experience complex environmental temperature problems. In an aquatic environment, animals are unlikely to release body heat by evaporation.

A.2. Thermogulation on terrestrial ecoterm

Thermoregulation in terrestrial ectotherms In contrast to the aquatic environment, temperatures in terrestrial environments selelu change with considerable variation. Temperature changes are very easy to feel, for example by comparing the temperature of the air during the day and the night, on the same day in a city. The terrestrial environmental temperature difference between day and night is quite meaningful. The most important thing done by terrestrial terrestrial animals to obtain heat is By absorbing heat / solar radiation. Animals can increase the sun's heat absorption by altering the color of the surface of the body and facing the body toward the sun. Ectotm ectebrates, for example lizards.

B. Animal Endotherms

An endothermic animal, is an animal whose body temperature comes from the production of heat in the body, which is a by-product of tissue metabolism.
An endothermic animal is a group of animals that can regulate the production of heat from within its body to conjure or raise its body temperature, because it has high regulating power. Endothermic animals have a longer tolerance to the environment than animals ektoterm so that the basic niche of this type of animal is too long. This is influenced by the ability to regulate the production and heat release it has.

The ability to regulate production and heat release through this metabolic mechanism is due to the endothermic animals having the organs as their regulating centers, ie the hypothalamus, especially the brain as the thermostat or the body's temperature control center. The constant temperature for the body of endotherms is usually between 35-40 degrees Celsius. Because of its ability to regulate body temperature so that it is always constant, then this group is called animal regulator. For example the aves and mammals, including humans. In other terms this group of animals is referred to as the homeoterm group. Endothermic animals are animals that can regulate their body temperature so that it is constantly at its optimum temperature range.
The constancy of these body temperature results in endothermic animals capable of showing constant performance. The power of the body temperature regulator requires a relatively high cost (energy) so that the food input requirements for energy are also relatively high. Compared to an ectotherm animal comparable to the size of its body, even within the temperature range of the thermonetral zone, an endothermic animal requires much greater energy. Compared to ectoterm animals that exhibit low-cost strategies that sometimes offer low returns, endothermic animals have a high cost strategy that gives higher returns.
 Endothermic animals, under changing environmental conditions, their body temperature is constant. This is because these animals have a high ability to regulate their body temperature through changes in heat production (metabolic rate) in their own body (related to endothermic properties). Examples: Aves (birds) and mammals.

C. Body temperature

Body temperature is a balance between the acquisition of heat from within (metabolism) or outside with heat loss. To deal with very bad weather (too cold or too hot) animals need to conserve energy by means of hibernation or estivation.

C.1. Body temperature setting

The body temperature setting is a living organism mechanism to maintain the internal temperature within the tolerable range. The processes that occur in animals to regulate their body temperature to remain constant dynamic. The thermoregulation mechanism occurs by adjusting the balance between heat recovery and heat release.

The regulation of body temperature (thermoregulation), the regulation of body fluids, and excretion are the elements of homeostasis. In thermoregulation known as cold-blood animals and warm-blood animals. However, biologists prefer to use the term ectotherm and endothermic associated with the animal's main heat source. Ektotherm is an animal whose body heat comes from the environment (absorbs heat of the environment). The animal body temperature of the ectoterm tends to fluctuate, depending on the ambient temperature. Animals in this group are members of invertebrates, fish, amphibians, and reptiles. While endotherms are animals whose body heat comes from metabolism. The animal's body temperature is more constant. Endotherms are common in birds (aves), and mammals.
In regulating body temperature, the animal must regulate the heat received or lost to the environment. Mechanisms of animal body heat change can occur with 4 processes, namely conduction, convection, radiation, and evaporation. Conduction is the change of body heat of an animal by contact with an object. Convection is the transfer of heat due to the movement of air or fluid through the body surface. Radiation can transfer heat between objects that are not direct contact. For example, solar radiation. Evaporation of the process of heat loss from the liquid surface is transformed in the form of a gas.

Animals have the ability to adapt to changes in ambient temperature. For example, in cold temperatures, mammals and birds will increase the rate of metabolism with the hormonal changes involved in it, thereby increasing the production of heat. In ectoterm (eg in honeybees), adaptation to cold temperatures by grouping in the nest. Bee metabolism results in a group capable of generating heat inside the nest.

D. Differences of Endothermic Animals and Ektotherms

D.1. Ambient temperature

At very low temperatures, ectotherm animals tend to follow the ambient temperature. This causes the rate of ectoterm metabolism to drop dramatically while in endothermic animals that are able to maintain their core temperature, their metabolism rate is not too disturbed by the decrease in temperature as long as the temperature drop is still within tolerable limits.
Higher temperatures affect the level of respiration characterized by increased oxygen consumption, which means that the higher the temperature the higher the rate of oxygen consumption of an animal. High levels of oxygen consumption indicate that animals need a lot of oxygen to quickly perform metabolism in their bodies to produce the more energy the animal needs.

D.2. Avaibility of food (energy)

Endothermic animals use energy to regulate temperature. Consequently, if endoterm animals have enough energy reserves, endothermic animals can maintain their body temperature and metabolic rate, but if energy reserves are limited, endothermic animals will have difficulty maintaining their core temperatures. Likewise the opposite state of the animal ektoterm So ektoterm animal energy metabolism tends to be more efficient because the portion of energy that turns into very little heat energy.

D.3. Hypothalamic control of mammalian thermoregulation

Mammals have neurons in the hypothalamus that are sensitive to the temperature of the blood circulation. The hypothalamus also receives input from the thermoceptors throughout the body. The hypothalamus has a set point, which functions like a thermostat.

 If the temperature of the blood circulation to the hypothalamus is higher than the set point, then there will be a signal that initiates the cooling mechanism (capillary vasodilation, sweating, rapid breathing, etc.), whereas if the blood temperature is lower than the set point temperature, then the neural signal will initiate an increase in temperature With capillary vasoconstriction, chills, fat thermogenesis, etc.).

In animals ektoterm mechanism is not running, so the ectotherm is not able to regulate its own body temperature, and rely on the environmental temperature. Some ektoterm animals regulate their body temperature by way of sunbathing as the sun rises, resulting in increased metabolic rate for activity and avoiding the scorching sun during the day by shelter.