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Conformation: Definition, Types of conformers, Pros and cons of conformation, Evolutionary trends, Adaptations in Conformers, Practice Problems and FAQs

Conformation: Definition, Types of conformers, Pros and cons of conformation, Evolutionary trends, Adaptations in Conformers, Practice Problems and FAQs

Isn’t it annoying to sweat profusely in the summer months? But as soon as the cold sets in during the winters we start shivering, right? Have you ever investigated the reasons behind these phenomena? So, the main reason as to why we shiver in winters and sweat in summers is that our body tends to maintain a constant body temperature. Indeed a very fascinating mechanism. During summers, sweating leads to evaporative cooling while in winters shivering helps generate heat in our body.

But have you ever seen a lizard sweating in summers? The question might sound very funny but the answer is of course no, right! The reason being they don’t have a mechanism to regulate their internal environment (such as body temperature) and keep it steady. Instead, these organisms try to conform to the changes in the external environment and are collectively called conformers.

Then the obvious question is how do the lizards in hot deserts cool themselves down? How are they able to survive in such a harsh climate? The answer being they have special behavioural practices which help them to be warm. Let’s dig deeper into the details of conformers as well as some very interesting examples of their behaviours.

Table of contents

  • Definition
  • Types of conformers
  • Pros and cons of conformation
  • Why didn’t Conformers evolve into Regulators?
  • Adaptations in Conformers
  • Practice problems
  • FAQs


The organisms which cannot maintain a constant internal body environment or homoeostasis and survive by conforming to their external environment are collectively called conformers. This phenomenon of alteration of body parameters like temperature and osmolarity with the environment is called conformation.

Lack of ability to maintain homeostasis doesn’t allow them to have a constant body temperature or osmolarity, which change with the ambient environmental conditions. Around ninety nine per cent of animals and almost all plants inhabiting the Earth are conformers.

Types of conformers

Organisms can be conformers based on two broad aspects. One is with respect to body temperature while the second is with respect to osmolarity.


The organisms which permit their body temperature to fluctuate with the ambient temperature are called thermoconformers. Thus their body temperature is usually equal to the environmental temperature in case they don’t exhibit behavioural means to combat the stress.

A thermoconforming animal is said to be cold-blooded and is usually called an ectotherm or poikilotherm. Few examples of these cold-blooded animals include most fishes, amphibians, reptiles etc.

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                                          Fig: Some common thermoconformers


Osmoconformers are marine organisms which cannot modulate their osmolarity with the changing osmolarity of their surrounding aqueous environment. Thus they maintain a fixed internal environment, being isotonic to their external surroundings. This makes the osmotic pressure in the organism's cells equal to the external environment. Reduction in osmotic gradient helps minimise the net influx and efflux of water into and out of cells, without requiring much ion transports which are active processes.

However, the types of ions contributing to osmolarity varies between osmoconformer’s body and the surrounding environment. Most marine invertebrates such as jellyfishes, starfishes, etc and craniates such as sharks, hagfishes, etc are osmoconformers.

                                       Fig: Some common osmoconformers

Pros and cons of conformers

The conformers face a severe disadvantage when compared to regulators. This is because they cannot regulate and maintain constant internal conditions. This makes it difficult for them to encounter stressful conditions and extremely unfavourable environments. They are usually stenothermal (organisms which can tolerate a narrow range of temperature) and stenohaline (organisms which can tolerate a narrow range of osmolarity). Thus they have a limited distribution over Earth in a narrow ecological niche.

                                 Fig: Distribution of conformers and regulators on the Earth

However, the advantage of conformation or being a conformer is none but saving energy. Regulation is an energetically expensive process as a lot of energy is utilised in homeostasis. These energy currencies can be saved by the conformers. Most of the ectotherms can use around 50% of the energy that they derive from their food for their growth as well as reproduction. This permits ectotherms to survive on much less food than similarly sized endotherms. On the other hand, endotherms like humans need to use about ninety percent of their energy for homeostasis, leaving much less available for growth and reproduction.

Why didn’t Conformers evolve into Regulators?

It is indeed true that the conformers face real challenges in the harsh environment. In spite of this, they aren’t evolving and transforming themselves into regulators. The reason can be understood with the help of a clear analogy. In a hot country like ours, does everyone have an air-conditioner in their homes? Indeed no! Many cannot afford it. Similarly, the conformers cannot afford to thermoregulate. Thermoregulation is an extremely energy expensive process for most organisms. This is very true for small animals like hummingbirds and shrews.

                       Fig: The surface area of hummingbirds is larger compared to their volume

It is known that the loss of heat is a function of surface area. Since the small-sized creatures have very less volume compared to the surface area of their body, heat loss occurs rapidly when they are exposed to cold conditions. Thus, to maintain a constant body temperature they have to spend a lot of energy to generate body heat through metabolic processes. This is energetically very expensive for them and is one of the major reasons why hummingbirds and shrews have been conformers throughout.

                            Fig: Surface area/volume ratio of different animals

Adaptations in Conformers

Conformers have certain behavioural as well as biochemical strategies which make them suitable to sustain in the harsh environmental conditions. The behavioural responses help conformers to survive under extreme circumstances. Some of the examples of conformers undergoing behavioural and biochemical changes have been discussed below.

Lizards are ectotherms and conformers. A common way by which the lizards living in cold environments maintain their body temperature is by basking in the sun or absorbing heat energy from the ground on which they are lying.

                        Fig: Lizard basking in the sun

Those lizards inhabiting the hot deserts need to encounter the harsh and extremely high temperature during the day. Under this condition, they try to lower their body temperature either by living in shade or by burrowing under the sand and penetrating into bottom layers so as to cool themselves down.

                         Fig: Behavioural adaptations in lizards to keep themselves cool

Spider crabs are osmoconformers and are able to combat the stress and fluctuations in salinity by losing or gaining water. This uptake or loss depends on the salinity of the external environment so as to match the osmolarity.

                                                              Fig: Spider crabs

Ectotherms like fishes thriving in regions of seasonal temperature fluctuations avoid the extremes by adapting certain strategies. In winters, fishes usually rest at the bottom of the water body and become less active to some degree. This helps them conserve energy.

Additionally, certain poikilotherms have biochemical strategies which permit them to overcome the effects of extreme temperatures. In conditions of high temperature, these organisms release heat-shock proteins. Heat-shock proteins are special proteins that help to stabilise other vital proteins of the body on excessive heat exposure. Extremes of heat can cause denaturation of proteins leading to the loss of functionality of the enzymes. The presence of heat-shock proteins in an animal prevents denaturation of those proteins keeping their molecular structures intact. Thus the ectotherm or poikilotherm (conformer) can survive under excessive heat as well.

Another interesting strategy employed by ectotherms inhabiting freezing environments is altering their body biochemistry. Those species develop certain strategies which help restrict or prevent ice crystallisation in their cells and tissues.

In addition to this, many conformers inhabiting freezing conditions manufacture cryoprotectants and circulate throughout the body. These substances protect their cells from freezing by lowering the freezing point of water to a point that cannot probably be achieved in that environment. As water constitutes a remarkable fraction of the body of a living organism, preventing freezing of water helps preserve the structural integrity of the cells and tissues. Wood frogs are good examples of conformers surviving in winters. They manufacture excess sugars, mostly by converting glycogen into glucose, that protects the animal’s body to a significant extent. Ray-finned fishes living in polar marine environments contain large amounts of salts in their body as well as produce glycoproteins serving as a cryoprotectant. These collectively help the fish avoid freezing.

                                                        Fig: Wood frogs

Practice problems

1. Given below is a graph. Select the correct set of organisms whose responses to the external environment are correctly depicted by A and B.

  1. A - Man, B - Dolphin
  2. A - Starfish, B - Man
  3. A - Man, B - Squirt
  4. A - Lion, B - Starfish

Solution: Line A represents thermoconformers, the organisms whose body temperature changes with the temperature in the surroundings. Starfish is a conformer. Hence, A is the graph of starfish’s response to the changing temperature.

Line B represents thermoregulators, the organisms whose body temperature doesn't change with the temperature in the surroundings. Man is a regulator. Hence, B is the graph of the man’s response to the changing temperature. Thus, the correct option is b.

2. List one demerit that the regulators face when compared to the conformers.

Answer: Regulators spend a significant amount of energy on maintaining the homeostasis. Around 98% of their energy is utilised to maintain their body temperature. Hence, they are left with a very meagre fraction of energy which they derive from food for their growth and development.

3. You are given two unknown organisms- X and Y. Organism X has a total body surface area of 20 m2 while organism Y has a total body surface area of 225 m2. Both of them weigh the same. Which of them will face difficulty to cope with external temperature if shifted to the polar region.

Answer: Organism Y has more Surface area: Volume ratio compared to organism Y. So, if they are shifted to polar regions, organism Y loses more heat when compared to organism X. Thus, Y will face more difficulty to cope up with the environmental stress as it will be energy expensive for Y.

4. Among regulators and conformers, which is likely to grow more if the same quantity of food is supplied to them?

Answer: Conformers are likely to grow more than the regulators if the same quantity of food is supplied to them. This is because conformers are left with more energy to spend for growth and reproduction as they don’t perform homeostasis which is an energy-expensive process.


1. Why are very small animals rarely found in polar regions?
Heat loss is a function of the surface area of the body. Smaller organisms have increased surface area than the proportionate volume of their body. Thus they tend to lose heat more quickly when exposed to cold environments like polar regions. Also, maintaining body temperature is an energetically expensive process for them, which they usually cannot afford. Thus the small animals are rarely found in the polar regions.

2. What are partial conformers?
Partial conformers are those organisms which have evolved and gained the ability to regulate over a narrow range of environmental conditions, beyond which they become conformers.

3. Enlist two differences between regulators and conformers.



Maintain constant body temperature

Body temperature changes with environment

Consume large amount of energy

Consume lesser amount of energy

Wider range of distribution (euryhaline, eurythermal)

Narrow range of distribution (stenohaline, stenothermal)

More active

Less active

4. How is the word “conformation” related to molecules?
Conformation is any of the infinite possible spatial arrangements of atoms in a molecule which is a product of possible rotation of the constituent atoms or groups of atoms about the linking single bonds.

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