What is the Difference Between Response and Adaptation

The main difference between response and adaptation is that the response is how an organism reacts to a stimulus. But, adaptation is a change or the process of change by which a particular population becomes better suited to its environment in terms of natural selection. Furthermore, a response is mainly a minute change in the internal environment of an organism, and it is usually reversible while adaptation is a kind of beneficial mutation in terms of survival or reproduction and it is irreversible. Also, a response is responsible for maintaining homeostasis while an adaptation contributes to evolution through speciation. 

Response and adaptation are two reactions of living beings to a particular change in the external environment. Thus, they are responsible for helping living beings to fit their external environment better. 

Key Areas Covered 

1. What is a Response
     – Definition, Features, Importance
2. What is an Adaptation
     – Definition, Features, Importance
3. What are the Similarities Between Response and Adaptation
     – Outline of Common Features
4. What is the Difference Between Response and Adaptation
     – Comparison of Key Differences

Key Terms 

Adaptation, Evolution, Homeostasis, Mutation, Response, Stimulus

What is a Response 

A response is a reaction manifested by a living organism as a result of the recognition of an internal or external stimulus. A response can be either physiological, cellular or behavioral-based on the nature of the stimulus. Generally, the maintenance of homeostasis or in other words, a stable physiological environment inside the body, occurs through positive and negative feedback loops. Some examples of such physiological conditions maintained in optimal values in the body include blood sugar level, body temperature, fluid balance, pH of the extracellular fluids, ion concentration, etc.

Moreover, the central nervous system is responsible for coordinating stimuli and their corresponding responses in the cellular and behavioral basis. Basically, the main components of the central nervous system include the brain and spinal cord. Typically, the brain coordinates voluntary responses, while the spinal cord coordinates involuntary responses. 

Figure 1: Involuntary Response

Furthermore, sensory organs transmit nerve impulses to the central nervous system through afferent or sensory nerves. After processing the information, the brain transmits nerve impulses corresponding to the voluntary responses to the effector organs, through efferent or motor nerves. The stimuli transmitted to the spinal cord travel either through somatic or visceral reflexes to the effector organs since they generate involuntary responses.  

What is an Adaptation 

Adaptation is the emergence of new characteristics to best suit the changes in the environment or habitat. All adaptations have gone through natural selection to select only the best-suited changes. Moreover, all adaptations arise in the phenotypic level under the influence of environmental factors on the expression of the existing genes. 

In general, adaptive traits can be either morphological, physiological or behavioral. Basically, the structural changes in the environment include the physical features of a particular organism such as shape, color, body covering or internal organization. Usually, camouflage is an example of structural adaptation.

Figure 2: Camouflage of a Lizard

On the other hand, growth, development, and homeostasis are the physiological characters that can be changed through adaptations. Patterns of vocalization, searching for food, and mating patterns are the behavioral features that can be changed. Generally, mimicry is an example of behavioral changes that serve as adaptations to the environment.  

Similarities Between Response and Adaptation  

• Response and adaptation are two reactions of living beings to a particular change in the external environment. 
• Hence, they are responsible for better suiting the living beings to their external environment.  
• Moreover, these reactions of organisms can be either physiological, cellular or behavioral. 

Difference Between Response and Adaptation 

Definition 

Response refers to any behavior of a living organism that results from an external or internal stimulus while adaptation refers to the inherited characteristics of a species, which develops over time in a response to an environmental factor, enabling it to let the species survive.  

Significance 

The response is how an organism reacts to a stimulus while an adaptation is a change or the process of change by which a species becomes better suited to its environment in terms of natural selection. 

Correspondence 

Moreover, the response is mainly a minute change in the internal environment of an organism, while adaptation is a kind of beneficial mutation in terms of survival or reproduction.  

Type of Organisms  

While response mainly occurs in an individual organism, adaptation occurs in a population. 

Type of Environment Being Changed 

The response results in regards to either internal or external environment while adaptation results in regards to a change in the external environment. 

Type of Change 

Furthermore, the response is either a physiological, cellular or behavioral change while an adaptation may be the changes in morphological, cellular or behavior of organisms over time. 

Changes in the genetic Content 

A response does not involve changes in the genetic content of an organism. In contrast, adaptation is responsible for changing the genetic content while selecting the best phenotypes for the environment through natural selection. 

Speed 

Also, a response arises quickly while adaptation takes time. 

Reversibility 

While a response is reversible, adaptation is irreversible. 

Importance 

A response is responsible for maintaining homeostasis while an adaptation contributes to evolution through speciation. 

Conclusion 

In brief, a response is a reaction of mainly an individual organism as an answer to the changes in either internal or external environment. Generally, it occurs by changing the biochemical reactions or physical changes. Therefore, a response usually occurs quickly and is reversible. In comparison, adaptation is a reaction to a change in the external environment. However, it occurs through genetic mutations, which are then selected by natural selection. Thus, adaptation is a slow process, which is irreversible. Hence, the main difference between response and adaptation is the type of reaction to the change. 

References:

1. Cornell, Brent. “Stimulus-Response.” BioNinja, Available Here.
2. BREGLIANO Jean-Claude (2019), Adaptation: responding to environmental challenges, Encyclopedia of the Environment, [online ISSN 2555-0950].

Image Courtesy:

1. “Imgnotraçat arc reflex eng” By MartaAguayo – Own work (CC BY-SA 3.0) via Commons Wikimedia    
2. “camouflage-adaptation-lizard-1591469” By dimitrisvetsikas1969 / 13646 (Pixabay License) via Pixabay