Taxonomy and Biodiversity

The world is full of millions of living things and this has created a huge task for humankind. We are just beginning to find and categorize all of the different species and types of life on Earth. This brings us to the fascinating career of taxonomy. Taxonomists classify all living things in a hierarchical way. This hierarchy starts with Domain and moves down through different levels (Kingdom, Divisions, Classes, Orders, Families, and Genera) all the way to Species. Let us look at eight different species that belong to the Kingdom Animalia.

The criteria required to be classified in the Kingdom Animalia is that an organism must be multicellular, consist of eukaryotic cells, and digest food outside their cells to absorb nutrients (Whittaker, 1969). We will look at two species that fit this criteria from four classes of animals; mammals, insects, birds, and echinoderms. For the mammal class we will consider horses and dolphins. For the insect class: butterflies and ants. For the bird class: bald eagles and ostriches. For the echinoderm class: sand dollars and starfish.

All mammals share many characteristics; including three middle ear bones, hair and modified sweat glands for producing milk (Animal Diversity, 2010). Yet they can be completely different at first glance. At first glance a horse and a dolphin seem to be opposite creatures in both form and function. Horse have four legs and walk on land while dolphins have fins and swim in the ocean. However, they both breathe oxygen and give birth to live young. They do belong to different orders; horses belong to the order perissodactyla which includes rhinoceroses and tapirs, while dolphins belong to the order cetacean which also includes whales and porpoises (Animal Diversity, 2010).

All insects also share characteristics; a three part body consisting of a head, thorax and abdomen along with antennae and a pair of large eyes. Yet, they can also be completely different; look at the butterfly and the ant. The butterfly has antennae and large eyes same as the ant but butterflies can fly in the air while some ants are bound to land. Butterflies also go through a metamorphosis in which they change form caterpillar form into winged creatures while the ant is born the way they are. The butterfly is classified under the order of lepidoptera which also includes moths and oak worms while the ant is classified under the order hymenoptera which also includes creatures such as bees and wasps (Animal Diversity, 2010).

All birds share some common characteristics such as feathers and wings, but are completely different. Take into account the differences and similarities between the eagle and the ostrich. The eagle belongs to the order falconiformes which also include falcons and hawks. These birds, including the eagle, are considered birds of prey which mean they use their flight to catch prey and are carnivorous (Animal Diversity, 2010). Ostriches on the other hand are land bound creature whose diet consists mainly of grasses, seeds and bushes (although