Universe the Home of Living Things
The universe more precisely the planet earth supports lives of living things. Living things requires oxygen, food, standard temperature that supports life, habitat, and gravity among other factors for them to survive. Such exists on the planet earth. The earth thus is the only planet sustaining life. The living things in the universe have characteristics such as respiration, reproduction, movement and locomotion, sensitivity, growth, nutrition as well as excretion.
Living things in the earth are divided into three main groups based on their genetic similarities. The groups are:
- Archea (Archeabacteria) – this consists of bacteria that have the ability to survive in very extreme environments.
- Eubacteria – composed of bacteria that exists in our normal daily life.
- Eukaryote – consists of living things in the world that can be seen and even touched. This category consists of the kingdoms Animalia, Fungi, Plantae, and Protista.
These three groups form the six kingdoms of classification two among them being kingdom Animalia and kingdom Plantae. Classification in the kingdom is based on how the organisms obtain their food, body structure amongst as well as a number of cells.Apart from kingdom, there are six more levels of classification of living things these are; phylum, classes, order, family, genus, and species.
Phylum follows kingdom in the classification. Phylum attempts to find some physical similarities in the organisms within the same kingdom. The similarity proves that such organisms share a common ancestry origin. Some of the known phylum include:
- Acanthocephalan; composed of thorny-headed worms.
- Acoelomorpha; they do not have alimentary canal or gut.
- Annelida; have circular body segments.
- Arthropoda has segmented bodies and jointed limbs body consisting of an exoskeleton.
- Brachiopoda; have got a ring of ciliated tentacles around their mouth.
Generally, phylum is around 35 the above are just but a few examples.
Classes is a way of dividing phylum into more similar features. Members of the same class have got more similar characteristics as compared to general characteristics of the phylum. Example the human beings belong to the mammal class because they give birth and breastfeed their young ones, other organisms in the class mammals includes monkeys, baboons, cows, horses, and all others having the mammary glands.
Order is a sub-division of organisms within the same class. Use of taxonomy key determines to which order the organisms belong to. Taxonomy is but just a check list having characteristics to which organisms have. Using this characteristic in the taxonomy together with the observable characteristics then the classification of organisms becomes very easy.
Families is next classification after order. Organisms in the same family have distinct features and are more similar as compared to the organisms in the same order. Example the human beings belongs to the family hominidae, together with apes.
Organisms in the same family are further classified into Genus. Genus is very specific and few organisms belong to the same genus. Genus is always used in the determination of the first part of the two names when using taxonomy to classify organisms.
The lowest class of classification is the species. Members of the same species can freely interbreed to give birth to an offspring.