All animals, irrespective of their categorization as mammals, reptiles, arthropods, or aves, require three vital components for survival: the ability to consume food, respire, and engage in reproduction.
Mammals, scientifically known as Mammalia, are named after their possession of mammary glands. These unique glands produce milk solely to nourish their offspring. Except for marine mammals, all mammals are warm-blooded and generally have a covering of hair.
Mammals typically have live births, although there are exceptions like the platypus which lays eggs. However, even after hatching, these females have mammary glands and produce milk for their offspring. Mammals also have a four-chambered heart and a muscular diaphragm that separates their chest from the abdominal cavity. The mammal category includes species such as dogs, cats, horses, beavers, dolphins, bats, and humans.
Reptiles, also called Reptil in Latin, derive their name from the term “Reptus” which signifies crawling. They are a distinct species of animals characterized by dry, scaly skin without hair. These creatures are cold-blooded and rely on external heat sources such as the sun or warm rocks to regulate their body temperature. Consequently, they primarily inhabit warm and arid environments. With the exception of snakes, most reptiles possess elongated tails and compact bodies supported by four small limbs. While certain reptiles reside in aquatic habitats, they still require regular access to air. Unlike mammals, reptiles lay eggs on land rather than giving birth to live offspring.
The female typically buries the eggs in warm dirt or sand for incubation. Unlike mammals, reptiles do not have mammary glands, so their offspring must learn to find food independently and do not rely on their mother for nourishment. The Reptile class encompasses turtles, alligators, snakes, lizards, and various species that make up more than 80% of all animal species – Arthropods. Arthropod is derived from the Latin word “Arthropoda,” which means foot since these creatures often possess numerous legs and feet, hence justifying their name. Arthropods are invertebrates i.e., they lack a backbone.
Arthropods possess a jointed exoskeleton, or shell, that facilitates their movement. During growth, arthropods shed their old exoskeleton and replace it with a larger one. These creatures lay eggs and provide parental care, although the offspring become self-sufficient upon hatching.
The Arthropod class includes insects, spiders, centipedes, and crabs. Aves, also known as Birds, are a fascinating and diverse animal species. They are warm-blooded and lay eggs. Birds have feathers and wings as their forelimbs. Like mammals, birds have a four-chambered heart. They have a relatively large brain with acute hearing but a less developed sense of smell. Aves are highly adapted for flight; their feathers provide protection against cold and wet conditions while also being strong. Birds are famous for their melodious songs, usually limited to or better in males.
Most bird species construct nests, which differ in size, shape, color, and quantity depending on the species. The parents care for their offspring until they mature. The Aves class encompasses geese, flamingos, hummingbirds, and penguins – each of these species is distinctive and essential to the planet. The absence of these diverse creatures would deprive the world of its present variety and beauty.