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Taxonomy and Earth's Biodiversity

All the species of animals are placed under the Kingdom Animalia. These species although may seem very different, all are multi-cellular and eukaryotic thus they share more similarities as they do on differences. For example, they all have organs which help them in the digestion of the food. The study below considers compares the characteristics of two animals from different species (University of Michigan, 2010).

List of species

  • Mammals: Human and Whale
  • Insects: beetle and coach roach
  • Birds: chicken and pigeon
  • Echinoderms: Sea star and sea lilies

Mammals: Human and Whale

All mammals are vertebrates because they possess a backbone. Both whale and humans are mammals irrespective of their differences and similarities. Human belong to the class of the placentals because they give birth to the young ones while the whales are in the category of the monotremes because they lay eggs. Humans have mammary glands while the whales do not have and the body of the whale is covered by the scales while that of human is covered by skin. Whales live in water while humans stay in the dry lands and have high thinking capacity hence can be able to live under any climatic condition.  They both belong to the Kingdom: Animalia, Phylum: Chordate, Class: Mammalia andhave middle ear bones. They are placed in this order because of their body structures and their unique characteristics. They are the air-breathing mammals and have a neocortex region in the brain. Crocodile and hyena belongs to the same order as whale and human and both whales and crocodile share most of the characterises while humans and hyenas have many similar characteristics (Wilson & Reeder, 2005).  

Insects: beetle and coach roach

The insects account for the greatest number of the species in the animals across the earth and their species varies with the form, shapes and sizes. The general characteristics of insects include: they are invertebrates since they have no backbone; they mostly have three basic body parts: head, thorax and abdomen.

Differences between the two insects

The beetles have sheath wings or the hard forewings which cover the whole body called elytra while coach roaches do not have the sheath wings. The beetles mostly move by flying while the coach roaches walk although they fly under special circumstances. To fly the beetles hold their elytra to balance then uses the membranous hindwings in flight. The coach roaches mostly are domestic and depend on the remains of the food used by humans while beetles attach the other invertebrates in plants and soil thus some are parasitic depending on the decaying organic matter or other insects. Beetle belongs to the order Coleopteran while coach roach belong to the order Blattodea but they are all in the class insect.

Beetle belong to coleopter because it has the sheath wings which covers the whole body while coach roach is under order blattodea because of their body structure: they have flattened body, have compound eyes ,long antennae and two pairs of membranous wings. The termites also belong to the same order as coach roaches and the weevils belong to the order Coleoptera because they also have theelytra (Richardson, 2004).

Birds: chicken and pigeon

Birds are vertebrates because they possess the backbone.  Both the chicken and pigeon have almost all characters in common: both are modified for flight although chicken mostly walk due to its body mass.  They both have horny beak and no teeth and large muscular stomach and strong skeleton. The different in their characteristics is that chicken are domestic while the pigeons are wild  and pigeons mostly move by flying while chicken walk or run and only fly on special cases.

Chicken belong to the order of Galliformes because they are heavy bodied and ground feeding domestic birds while pigeon belong to the order Columbiformes because they are monogamous and capable of drinking water without tilting their heads up. Doves also belong to columbiformes order as pigeons and turkeys, quails and pheasants belong to the order galliformes as chicken (Tory, Alden & Sill, 2003).

Echinoderms: Sea star and sea lilies

These are phylum of marine animals which are most. The sea star and the lilies are found in the deepest parts of the sea. As the name suggests they have spiny skin and the structure of their bodies are characterised by five rays which are connected to a central disc. They have no eyes, heart and brain although the brittle stars have senses.  

Sea lilies fed on the plankton and waste deposited in the sea, planktons are microscopic substances such as plants and animals drifted in the water while the sea stars consume anything which it catches like molluscs, worms, crustaceans and even other sea stars. The sea lilies feed with their feet through the food grooves lined along tube feet and are organized in groups of threes while the sea stars hold food with their five arms. Sea star belongs to the order Asteroidea while sea lilies belong to the order crinidea based on their physical characteristics.

Brittle star belongs to the same order as sea star while sea cucumber is another echinoderm which belongs to the same order as sea lilies (Nichols, 2009).


Kingdom Animalia is a very unique kingdom and it is the largest in the ecosystem, all the animal species in it are eukaryotic and multicellular.  The species discussed in the study are some of the numerous classifications and orders belonging to the kingdom. Although some may seem similar, each posses a unique characteristic which distinguishes them from the other species.

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