Reptiles - Characteristics of Reptiles

len Alfred Ajibola - Tue, 16th April, 2019 @ 20:32: PM

Topics in Biology

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Academic Questions in Biology

Please check out our Test Your Knowledge page to see all Questions and Answers

Which of the following is a category of long bones?

  • A. Stunted long bones
  • B. Reduced long bones
  • C. Giant long bones
  • D. Bended long bones
  • E. Curved long bones
  • F. Elongated long bones

The end product of photosynthesis is _____.

  • A. O2
  • B. C​​​​​​2​​​​C5OH
  • C. H2​​​​​O
  • D. CO2
  • E. C6H12O6
  • F. C2H5COOH

The above diagram illustrates a _____.

  • A. Food Chain
  • B. Food Web
  • C. Food Pyramid
  • D. Food Link
  • E. Food Hub
  • F. Food zone

The living cells that makes up cartilages are called _____.

  • A. osteocytes
  • B. osteoblasts
  • C. osteoclasts
  • D. chondroblasts
  • E. chrondocytes
  • F. Osteoprogenitor cells

Which of the following statement is incorrect with regards to chitin?

  • A. Ecdysis is a term associated with chitin
  • B. It is a skeletal material
  • C. It is a type of skeleton
  • D. It is present outside the organism
  • E. It does not grow when the organism grows
  • It is present in ants

Which of the following is NOT a function of the human skeleton?

  • A. Gives Shape
  • B. Provides Protection
  • C. Aids in Locomotion
  • D. Supports Movement
  • E. Assists in Inhalation and Exahalation
  • F. None of the above
  • G. All of the above

Organisms that manufacture their own food through the help of sunlight or chemicals are best referred to as _____.

  • A. autotrophs
  • B. chemosynthetic
  • C. photosynthentic
  • D. chemoautotrophs
  • E. photoautotrophs
  • F. chemoautotrophs

Organisms that begins a food chain and also manufacture their food through photosynthesis are best referred to as _____.

  • A. heterotrophs
  • B. autotrophs
  • C. homotrophs
  • D. producers
  • E. photosynthetic
  • F. chemosynthetic

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What are Reptiles?

Reptiles are vertebrate (animals with backbone) that belong to the class reptilia. In Latin, "reptile" means creeping animals.

Reptiles are believed to have evolved from a certain vertebrate called reptiliomorph, more than 300 million years ago. They were initially aquatic animals (lived in water) and with time they became adapted to the terrestrial habitat (land).

Please read on the Introduction to Biology and the Basic Characteristics of Life here.

Certain reptiles hibernates while others brumate.

During hibernation, an organism stays in a sleep-like state without food for a long period of time by surviving from its fat reserve.

Brumation on the other hand is similar to hibernation except that the animals are neither asleep nor live off their fat reserve, rather their metabolic processes become very reduced resulting in the sluggishness of such animals.

Please read on the Characteristics of Protists here.


Characteristics of Reptiles

Below are some of the characteristics or features of reptiles.

  • All reptiles are Vertebrates

An animal is said to be a vertebrate if it has a backbone or vertebral column.

Reptiles, Pisces (fishes), Amphibians (toads and frogs), Aves (birds) and Mammals are all vertebrates.

Reptile's Backbone - Len Academy
Photo of a Frilled Lizard's Skeleton

The backbone of reptiles begins from the lower end of their skull and runs throughout their body length. Present inside the backbone is the spinal cord which constitutes a part of the central nervous system.

Please read on Skeleton and Skeletal Materials here.

Please read on the Bones of the Human Body here.


  • They are cold blooded animals

Reptiles cannot physiologically regulate their body temperature. To explain this, let's briefly consider humans who have got a defined body temperature of 36.5oC.

This stability in the human temperature is made possible via a process termed homeostasis, regardless of where they may find themselves (whether in cold or warm conditions).

Please read on Homeostasis and the Negative Feedback Mechanism here.

In the case of reptiles, the weather condition determines their body temperature. When it’s warm, their temperature increases and when cold, it decreases.

When the weather becomes too hot, they tend to move into shady places or water in order to lower it. We can therefore conclude that their body temperature is dependent on their environment.

Cold blooded animals are also referred to as Poikilotherms or Poikilothermic animals or Ectotherms or Ectothermic animals

Note: Although most enzymes work best at a specific temperature, that isn’t the case in reptiles. Their metabolic enzymes can work efficiently over a wide range of temperatures.

Please read on Concept of Heat and Temperature here.


  • Their bodies are covered in Scales or Scutes

Unlike mammals whose bodies are covered in hair/fur or birds whose bodies are covered in feathers (and their legs scale), all reptiles have their bodies covered in scales or scutes. The scales/scutes protects them from the dangers of their external environment.

The chelonians (reptiles like turtles and tortoises) in addition to having scales and scutes also possesses a hard protective shell called carapases that gives an extra protection to their upper bodies.

Snake's Scale - Len Academy
Photo of a Snake's Scale

Scales are generally composed of keratin and can either be tubular or ossified in appearance. In addition to providing protection and movement, they also prevent loss of water to the environment; and this is one reason why some reptiles (certain snakes for instance) are capable of surviving in deserts.

Crocodile Scute - Len Academy
Photo of a Crocodile's Scute

The scutes are different from scales because they give more protection; and appear more like a dermal armor. They are found in tortoises, turtles and crocodiles.

Please read on Amazing Facts in Biology here.


  • They are mostly oviparous while some may be ovoviviparous or viviparous

Most reptiles are oviparous animals. This imply that they lay eggs which are covered in shells.

A few are ovoviviparous (that is, the eggs remain in the mother’s womb until they are ready to hatch) while others are viviparous, meaning that the young ones are born alive.

Some reptiles will incubate their eggs either by laying on them or by burying them below the earth until they hatch.

Finally, certain reptiles will look after their young ones but only for a short period of time.


  • They undergo moulting or Ecdysis

Moulting, also called Ecdysis is a process whereby animals shed their skin. This process of moulting is apparent in insects and reptiles. They remove the uppermost layer of their skin each time it gets worn out.

Parasites on the skins of reptiles are removed through the process of moulting.

Lizard shed their skins in patches while crocodiles shed the individual scales.


Other characteristics of reptiles include:

  • They Respirate via their Lungs.
  • They have three chambered heart.
  • Most are tetrapods (have four legs). Snakes are exceptions.
  • Most are carnivores with the exception of turtles and tortoises which feed on plant.
  • They are not hermaphrodites; that is, the male and females are separate.

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All voluntary and concious activity of right handed people are controlled from the left part or hemisphere of the brain

A snail can actually sleep for 3 years 😁

An adult human being is composed of about 60% water. In fact, a newly born baby is composed of about 80% of water. This will drop to 65% after a year and finally to about 60% as the child ages

Without saliva, food can never be enjoyed. Food becomes tasteless since saliva is needed to dissolve the chemicals present in food onto the tongue’s taste buds.

Saliva also contains an enzyme called salivary amylase or "ptyalin" which helps to digest cooked starch to maltose. Maltose is a double sugar or disaccharide. Please read on sugars here


For a thing to be considered Living, it must possess all the Basic Characteristics of Life. These include:

  1. Movement

  2. Respiration

  3. Nutrition

  4. Irritability or Sensitivity

  5. Growth

  6. Excretion

  7. Reproduction

  8. Death

  9. Adaptation

  10. Competition

Please read the explanations on all the Basic Characteristics of Life here

During strenuous exercises like sprinting or 🏃 running, your body may actually work in the shortage of oxygen. During this time, your body owes oxygen (called oxygen debt) and it must be replenished or repayed after the exercise is stopped. This is why you breathe excess of oxygen after you stopped the exercise.

This is the concept of anaerobic respiration

A food Chain is a diagram that shows the relationship between plants and animals within a habitat on the basis of how they rely on each other for food.

Note: Habitat is a place where an organism live. It is of three types:

  • Terrestrial (Land)
  • Aquatic (Water)
  • Arboreal (🌲 Treetops)

You can read on Food Chain here

The term Biology originated from two Greek words. They are:

  • Bios: means life. 
  • Logos: means knowledge or to study.

Biology can therefore be defined is the study of life

Anything that has life is generally considered as a living organism (or organism) 🌱🐐🐓. All living organisms must be able to carry the following activities:

  1. Movement
  2. Respiration
  3. Nutrition
  4. Irritability or Sensitivity
  5. Growth
  6. Excretion
  7. Reproduction
  8. Death
  9. Adaptation
  10. Competition

The above listed points are often regarded as the basic characteristics of life. You can memorize them using the acronym (MR. NIGER DAC).

You can read on the introduction to Biology and the basic characteristics of life here

The gas used in the manufacture of food by plants is Carbon dioxide or Carbon(IV)oxide or CO2. 

Plants manufacture food through a process called photosynthesis. Please read on photosynthesis here

Note: Plants are the only orgnisms that take away CO2 from the atmosphere