Cold-Blooded Animals

Cold-blooded animals are those whose body temperature is affected easily by the external body temperature. In contrast, warm-blooded animals are not affected by external body temperature. Learning about this also brings us to the fact that the animals being talked about majorly are vertebrates whose demarcating feature is the presence of the notochord and the vertebral column. 

Therefore, learning about vertebral columns is our next step. The vertebral column is the bony structure that functions as the body’s endoskeleton and harbours the spinal cord, which plays sensory roles. We then go forward to understand the structure of the lumbar vertebra. 

Living systems thrive or perish based on their ability to maintain homeostasis in every situation. And a significant factor affecting this ability is the temperature outside the body. Therefore, if one has to survive in a given condition or with rapidly changing climatic conditions, they have to learn to adapt accordingly. The animals have been classified into warm-blooded and cold-blooded based on this very ability as to how well they survive in conjunction with the external temperature. 

Warm-blooded animals or homeotherms are the ones that can maintain a constant internal temperature irrespective of the temperature outside. On the other hand, cold-blooded animals or poikilotherms are those animals whose body temperature is the same as the temperature outside. 

Warm And Cold-Blooded Animals

Warm-blooded animals and cold-blooded animals or homeotherms and poikilotherms classify animals based on how external temperature influences the internal temperature of their body. The warm-blooded animals or homeotherms can maintain a constant internal body temperature no matter what the temperature on the outside is. Examples of warm-blooded animals include birds and animals. 

On the other hand, cold-blooded animals are those who do not maintain a constant internal body temperature. Still, their body temperature keeps on changing based on the external temperature. The cold-blooded animals, therefore, can’t survive in extremes of temperatures. Examples of cold-blooded animals include fish, reptiles, amphibians and other invertebrates. Three thermoregulation mechanisms can be employed: Poikilothermy, Ectothermy, and Heterothermy. Therefore, cold-blooded animals must depend on more external factors to control their body temperature. For example, lizards and crocodiles stay in water during hot seasons and migrate towards land by burrowing pits during the cold seasons to get warmth.   

Vertebrates

In the classification of warm and cold-blooded, vertebrates are the ones that are mainly getting segregated into the two categories since all the invertebrates are cold-blooded. Therefore, we shall now have a look at who are vertebrates. 

Vertebrates are animals that have a well defined vertebral column. These include fish, amphibians, reptiles, birds and mammals. Vertebrates are characterised by a well-defined vertebral column, sensory organs, brain, and head. Around 45,000 species are known to belong to the vertebrates class.  

Given the above information with a scientific touch, vertebrates are bilaterally symmetrical. They have internal skeletal support with a skull inside, which presents a brain, spinal cord, and sensory system. 

Therefore, they have been classified into various classes, which goes as:

• Class Pisces (fish)
• Class Amphibia (amphibians)
• Class Reptilia (reptiles)
• Class Aves (birds)
• Class Mammalia (mammals)

Structure Of Vertebra

Since the defining factor for an animal to be called a vertebrate is the presence of a vertebral column, understanding the structure of the vertebral column is the next step ahead. The vertebral column is a bony structure playing an essential role in functioning as the endoskeleton in the human body. It comprises 33 small bones called vertebrae and can be divided into five regions: Cervical, Thoracic, Lumbar, Sacrum and Coccyx. Each vertebra is attached to the other one through hyaline cartilage. 

The vertebral column has 4 main functions:

1. Protection
2. Support 
3. Axis
4. Movement

Lumbar Vertebra

The lumbar vertebra is located in the bottom section of the vertebral column. Lumbar vertebrae are five in number and are the largest to support the whole body’s weight. The first lumbar vertebra is roughly in line with the 9th rib and the last lumbar vertebra is present near the pelvic bones. 

Conclusion

In short, it can be said that cold-blooded animals cannot maintain their internal body temperature at a constant level and are dependent on external factors for making a move about it. For example, lizards show different behaviours in summer and winters, like staying in water or migrating towards land. On the other hand, Warm-blooded animals can maintain their internal body temperature. Warm-blooded animals include birds and mammals, while reptiles, fishes, amphibians, and invertebrates are cold-blooded. 

Vertebrates include fishes, reptiles, amphibians, birds and mammals. These are distinguished from invertebrates based on the presence of vertebral column invertebrates. The vertebral column has 5 different regions and comprises 23 vertebrae in total. The lumbar vertebrae are the ones with the most significant size since they bear most of the weight of the human body and defy the gravitational forces.