Classification 1

- The rhizoids as in moss plant
- Fronds in ferns
- The type of root; tap root, adventitious, fibrous, prop, buttress roots.
- Stem presence and type.
- Presence or absence of flowers
- Type of leaves; simple or compound; leaf venation- parallel or net work veined.
- Presence and types of fruits and cones.

- Tentacles in hydra
- Body covering- feathers, scales, hair or fur
- Shells in snails
- Wings in birds
- Proglotids in tapeworms
- Mammary glands in mammals
- Locomotory structures
- Body pigmentation

- Classification systems improve our ability to explain relationships among things.
- Classification helps in identifying living organisms into their correct groups for reference.
- Classification helps in avoiding chaos and confusion when dealing with animals as it arranges the information on organisms in an orderly manner.
- Classification brings together living organisms with similar characteristics together but separate those with different features.
- Taxonomic systems provide relatively stable, unique, and unequivocal names for organisms
- It makes the study of such a wide variety of organisms easy.
- It projects before us a good picture of all life forms at a glance.
- It helps us understand the interrelationship among different groups of organisms.
- It serves as a base for the development of other biological sciences such as biogeography etc.
- Various fields of applied biology such as agriculture, public health and environmental biology depend on classification of pests, disease vectors, pathogens and components of an ecosystem.

- Taxonomic units of classification refer to the groups or taxa into which organisms are placed as a matter of convenience.
- Grouping of organisms in these groups is based on easily observable characteristics that are common in that group.
- Living organisms which share a lot of characteristics are placed in the same group.
- Each taxonomic unit reflects the position of an organism in relation to the others in the classification scheme.
- In a classification scheme, a hierarchy of groups is recognized and it proceeds from the first largest and highest group, the kingdom to the smallest and lowest unit, the species.

a) Kingdom Monera - This is composed of microscopic unicellular organisms mainly bacteria
b) Kingdom Protoctista - This kingdom is comprised of members who are microscopic. Though, some are large enough to be seen with the naked eyes. Members of this kingdom include algae and protozoa e.g Amoeba
c) Kingdom Fungi - Members of this kingdom comprises the mushrooms, toadstools, moulds and yeast.
d) Kingdom Plantae - This kingdom comprises the moss plant, ferns, maize plants, hibiscus, meru oak tree etc.
e) Kingdom Animalia – Members of this kingdom include the tapeworms, hydra, fishes, human beings, lizards, earthworms etc.

- In hierarchy of classification, a kingdom is further divided into several phyla (plural of phylum) or divisions (in plants).
- Within the phyla or divisions, organisms are further sorted out into groups known as classes based on their similarities and mode of life.
- Each class is further subdivided into small groups called orders based on structural similarities.
- Orders subdivide into families which are subdivided into genera (plural for genus).
- Genera are then subdivided into smaller units of classification called the species.

* Organisms can further be classified based on the differences in colour or forms. In humans, this gives the races, in animals the term used is breed while in plants, variety is preferred. In bacteria, the term strain is used to describe the variant forms.
* Members of different but very closely related species can breed but the resulting offspring will be sterile (infertile). In particular, a mule is a sterile offspring between a horse and a donkey. Moving from kingdom to species, it is important to note that the number of organisms in each taxon decreases. The similarities, however, increase as one moves from kingdom to species.

- Scientific naming involves assigning an organism two names in Latin language which was developed by Carolus Linnaeus in the 18th century
- The specific name adopts two names. This implies that the specific scientific name of an organism has two names. This double naming system is known as binomial nomenclature.
- In binomial nomenclature, an organism is assigned its genus name and species name.

Rules of Binomial Nomenclature

1. The first part of the scientific name is that of the genus name which should begin with a capital letter. The second name is that of species. The species name should be written in small letters e.g. a) Maize- Zea mays, b) Lion- Panthera leo
2. When printed in books and other printed works, the scientific names should be printed in italics. However, in handwritten manuscripts and typed works, the genus and species names should be underlined separately.
3. The specific name is frequently written with the name of the scientist who first adequately described and named the organism e.g. Balanus balanoides
4. Scientists must give a latinised name for a newly described animal or plant species where a Latin name is missing

Scientific names assigned to organisms can be:
- Descriptive
- Geographical
- Commemorative