Railway Science (Biology – Animal Kingdom) (Part-II)

Reptiles typically have dry and rough skin covered with scales, which helps to prevent water loss and protect their bodies. The presence of scales is a characteristic feature of reptiles, providing them with a waterproof barrier and protection from the environment.

Mammals or Mammalia class of animal kingdom are found in a variety of habitats such as polar ice caps, deserts, mountains, forests, grasslands and dark caves.

These are true fish belonging to the class Chondrichthyes, which includes sharks. They have skeletons made of cartilage instead of bone.

This is the largest phylum of Animalia which includes insects. Over two-thirds of all named species on earth are arthropods. The body of arthropods is covered by an exoskeleton of Chitin. Examples: Economically important insects - Apis (Honey bee), Bombyx (Silkworm), Laccifer (Lac insect). Vectors - Anopheles, Culex and Aedes (Mosquitoes).

Tendons are fibrous connective tissues that connect muscles to bones. Ligaments connect bone to bone. Areolar connective tissue is found between the skin and muscles, around blood vessels and nerves in the bone marrow. It fills the space inside the organs, supports internal organs and helps in repair of tissues.

R.H. Whittaker (1969) proposed a Five Kingdom Classification. The kingdoms defined by him were named Monera, Protista, Fungi, Plantae and Animalia. Kingdoms (cell wall) : Monera (Noncellulosic (polysaccharide + amino acid)), Protista (sometimes present), Fungi (Present with chitin), Plantae (present (cellulose)), Animalia (Absent).

Amphibia class of animals belong to the phylum Chordata of the animal kingdom that live both on land and in water. Amphibians are cold-blooded vertebrates (vertebrates have backbones) that don’t have Scales.
Heart is three chambered (two auricles and one ventricle) in Amphibia class animals. Bryophytes are amphibians of plant kingdom as they complete their life cycle in both water and on land.

Arthropoda is the largest phylum of Animalia which includes insects. They have an organ-system level of organisation. They are bilaterally symmetrical, triploblastic, segmented and coelomate animals, their bodies are covered by a chitinous exoskeleton. The body consists of the head, thorax and abdomen. Examples of Arthropoda: Locust, Butterfly, Scorpion and Prawn.

Stratified squamous epithelium: This type of epithelium usually has protective functions, including protection against microorganisms from invading underlying tissue and/or protection against water loss.
Adipose tissue (Body fat)- It is a connective tissue that extends throughout your body. Striated muscles are highly organised tissues that convert chemical energy to physical work.

Platypuses belong to a unique group of mammals called monotremes. These mammals are distinguished by their ability to lay eggs instead of giving birth to live young.