The Irritability in animals Is the property to respond to the physical and chemical changes of your internal and external environment. Thanks to this ability they can survive and adapt to the changes that occur in their environment.
Unlike single-celled organisms that generate simple responses, multicellular organisms such as animals have highly specialized receptor organs that receive stimuli and transmit them to the body to generate the response.
The nervous system and the endocrine system are responsible for receiving the stimuli and coordinating their respective response.
Irritability has a homeostatic purpose in the body, that is, to keep its constant internal conditions such as body temperature, the amount of circulating blood, the amount of oxygen that is received or the amount of water needed.
What distinguishes the irritability of living organisms from reactions in inert beings is that the response of the latter is always the same as long as a metal is in the presence of an acid than the reaction of a living being Differs.
Characteristics of irritability
The main features of irritability are:
1- It is an adaptive, non-static response. That is, it is tailored according to needs.
2- They may be different for the same type of stimulus (Ministry of Education Chile, 2017).
3- They are calibrated according to their intensity.
Complexity in the manifestations of irritability
Unicellular organisms such as bacteria manifest their irritability by changing the speed of cell division and moving away or approaching the stimulus. Their answers are not very varied or complex because they lack systems of coordination and organic integration.
For their part, the plants move away or slowly approach the stimulus ( Tropism ) Thanks to its hormonal coordination and integration system called phytohormones.
Animals are multicellular organisms and consequently have an endocrine system and a nervous system that are composed of highly specialized organs linked through a complex communication network that delivers a response in a matter of seconds.
It is called a stimulus to anything to which an organism responds or reacts (Deeptirekha, 2017).
Types of irritability
The types of irritability in animals are tactics, reflexes and instincts.
1- Tactisms
These are the innate, fixed and inevitable behavior of lower animals such as invertebrates. They are fast, broad movements that move the individual to bring him or her away from the stimulus.
If the movement leads to a stimulus approach, it is called Positive tactism .
If the movement leads to a withdrawal from the stimulus, it is called Negative Tactics.
The most common tactical agents are light, gravity, water and touch.
Fototactismo
It is the response to the variation of light, regardless of whether it is natural or artificial. If the answer is to go to the light source, it is a positive phototactism but if it is a departure, it will be a negative phototactism.
To illustrate the two phenomena above, let us remember mosquitoes and other insects flying around a light bulb of illumination; They are an exemplary case of positive phototactism. On the opposite side, the little pigs of the earth look for places dark and humid, reason why its phototactismo is negative and the hydrotactismo positive.
Gravitactism
Reaction to gravity. It can also be positive or negative, following the logic of approaching or moving away from gravity, respectively.
The ladybugs or beetles are beetles that when placed on the palm of the hand, if directed to the fingertips, presenting a negative gravitactism.
The case of earthworms that always seek to be on dry land, wet and dark is our example of positive gravitactism and negative phototactism.
Hidrotactismo
Response to water or moisture. The approach to this stimulus constitutes positive hydrotactism and its avoidance is negative hydrotactism. Earthworms and ground pigs are insects with positive hydrotactic. Spiders instead try to stay away from water sources so their hydrotactic is negative.
Tigmotactismo
Response to tactile stimuli. The centipedes or millipedes are rolled up when they feel touched (negative tigmotactismo).
Chemotherapy
Reaction to chemical stimuli. All insects repel the effect of an insecticide, moving away from the place, therefore, the insecticide produces negative quimiotactismo.
The case of positive chemotactic is that of the bees that approach certain trees by their pollen.
2- Reflections
They are involuntary, fast and pre-established animal responses of a part of the organism to certain stimuli (Ministry of Education Chile, 2017).
Most cases are about movements but can also be exclusively or include hormone secretion.
In this case, the stimulus does not travel through the neurons until the brain (central nervous system) arrives, but the receiver sends it to the spinal cord that will activate the motor neurons and these will produce the movement of the muscle (muscular tension) or Hormone secretion if the response is endocrine type. This happens within a fraction of a second.
Reflexes may be innate or acquired. Breathing, swallowing or blinking are innate or unconditioned reflexes that appear during or after birth and are performed automatically without the involvement of the brain.
In contrast, acquired reflexes or conditioned reflexes are adopted over time through a learning process in which the brain participates by establishing a relationship between a stimulus and a reinforcement.
When you exercise an innate reflex to an acquired one then it is reinforced but if the stimulus is not exercised, it eventually weakens and eventually disappears.
3- Instincts
They are innate reactions more complex and elaborate, in which several reflexes intervene (Candia, 2017). These are innate, fixed and specific behaviors that are transmitted genetically among individuals of the same species to respond in a certain way to certain stimuli.
Being a kind of genetic animal irritability for adaptive purposes, in many cases they result from the evolutionary process of the species.
Vital instincts are present in all animals while those of pleasure and social are more common in more evolved species. The cultural ones are exclusive of the human being.
Vital instincts
They are commonly known as survival instincts aimed at preserving the existence of the subject, his family or his species (EcuRed, Knowledge for all and for all, 2017). The 4 most important are:
- Nutrition instinct: Behavior acquired before hunger and thirst to supply their need for food and water.
- Sexual instinct: Erotic behavior to procreate and preserve the species.
- Fighting and flight instinct: Conduct to defend physically against an external stimulus that they perceive as threatening.
- Denim Instinct and Heat Search: Another behavior to protect your physical integrity in the inclemency of the weather.
Instincts of pleasure
Pleasure instincts are often the sophisticated version of vital instincts to increase the general degree of well-being.
Sex is a vital instinct that becomes a pleasurable one when the procreative purpose is abandoned and adopted exclusively for recreational purposes as is the case in humans and dolphins.
Social instincts
They are the behaviors of the individual within a collectivity and the role it has within it. The solitary behavior of certain species, the instinct of collectivity in others, the range of authority of one (s) over another (s) within a group are examples of social instinct.
4- Learning
It is the adoption of a new pattern of behavior as a result of their interaction with the outside world. It is common in vertebrate complexes such as reptiles, birds and mammals.
The way to obtain food or how to fly are compulsory"lessons"for many pups who learn from their parents.
5-Reasoning
It is the capacity to solve complex problems or to give adequate answers to new situations not previously faced (Ministry of Education Chile, 2017).
This process involves using previously acquired knowledge in a new situation, minimizing the margin of error.
There is an academic debate about whether this faculty is shared by more developed mammals or only humans, as gorillas, chimpanzees and dolphins show patterns of"reasoning,"only inferior to humans.
References
- Contreras Rivera, J. (15 of 7 of 217). Irritability and Nervous System . Retrieved from College San Sebastián de los Andes: ssla.cl
- Deeptirekha, J. (15 of 7 of 2017). Response and Coordination in Plant and Animals . Obtained from Biology Discussion: biologydiscussion.com
- EcuRed. Knowledge with all and for all. (15 of 7 of 2017). Instinct . Obtained from EcuRed. Knowledge with all and for all: ecured.cu
- Ministry of Education Chile. (15 of 7 of 2017). Irritability, fundamental property of living beings. Retrieved from the Educational Platform of the Chilean Ministry of Education: ftp.e-mineduc.cl
- Monge-Nájera, J., Patricia, G. F., & Rivas Rossi, M. (2005). Irritability and homeostasis. In J. Monge-Nájera, G. F. Patricia, & M. Rivas Rossi, General biology (Pages 47-49). San José: Editorial State University at a Distance.