Structural Organisation in Animals and Plants

The body of a living organism comprises various kinds of cells. These cells are the basis of structural organisation in animals and plants. In the human body, there are about 200 different types of specialised cells. Cells of one or more kinds are characteristically arranged. They cooperate together for the performance of a specific role. Such a group of cells is called a tissue. The different types of cells and tissues lead to diverse forms of life on Earth. This diversification happens in terms of both morphological (external) features and anatomical (internal) features. Keep reading to find out more about the structural organisation in animals and plants.

The Basic Plant Organs

Every plant has three basic organs—roots, stems, and leaves. Plants may differ in texture, appearance, and types, but these three parts are common among all plants. This is an important distinction in the structural organisation in animals and plants.

Roots: This refers to the portions that are underground. In contrast, the shoot system is the portion of plants that is above the ground and involves stems and leaves.

Stems:  This refers to the rising cylinder extensions whose formation takes place from the plumule of the embryo of a germinating seed. They are positively phototropic, negatively geotropic, and negatively hydrotropic.

Leaves: They refer to the principal lateral appendage structures that arise out of a vascular plant stem. Typically they are green in colour and have a blade-like appearance.  

Anatomy of Plants

The word Anatomy means ‘dissection’ in its Greek origin.

Plants, just like animals, have cells as the basic unit. This is one aspect of similarity between the structural organisation in animals and plants. In plants, the organisation of cells leads to the formation of tissues. The organisation of these tissues, in turn, leads to the formation of organs. 

Anatomy of Flowering Plants

There are differences in the internal structures of the different organs in a plant. When looking at the anatomy of flowering plants, there is an amazing exhibition of the arrangement of the internal structures. The three basic plant organs in flowering plants comprise three types of ground, vascular and dermal tissues.

Structural Organisation in Animals

An animal body comprises a great number of cells. The organisation of these cells takes place in tissues. A tissue, essentially speaking, is a group of cells that all have similar functions and appearance. In turn, the organisation of tissues takes place in organs.  

Groups of organs that work together in animals result in the formation of organ systems.  For example, the lungs are an organ of the respiratory organ system, while the skin is an organ of the integumentary organ system.

The main difference between the structural organisation in animals and plants is the presence of specialised, complex organ systems in the former. The formation of animals takes place from limited types of cells and tissue types. For example, lungs and blood vessels are formed of similar basic types, but they have different functions.  

Four main types of animal tissues make the structural organisation in animals and plants different. Their classification is as follows:

•     Epithelial
•     Connective
•     Muscular 
•     Nervous/Neural

Epithelial Tissues:

Epithelial tissues or epithelia cover the outside of an animal’s body. Their occurrence takes place as a sheet of cells. These tissues are responsible for lining up the organs and cavities within the body.

Epithelial cells are characterised as close-packed together. Due to this, they serve the role of being a barrier against various types of harm like fluid loss, pathogen attack and mechanical injury. Epithelial cells also form a sort of interfacing with the environment.

Connective Tissues:

Connective tissues are the most abundant in complex animals’ bodies.  Also, their distribution is the widest in such animals. Their main function is to offer linkage and support to the other tissues or organs of the body. 

Muscular Tissues:

Muscular tissues are responsible for nearly all types of body movement in animals. Each muscle comprises several fibres that are long and cylindrical in appearance. The arrangement of such fibres is in parallel arrays. 

Contraction (shortening) and relaxation (lengthening) of muscle fibres take place due to stimulation by neurotransmitter signals. Their action causes the movement of the animal body. 

Neural Tissue:

Nervous tissues contain neurons that facilitate various functions like receiving, processing, and transmission of information. This is made possible due to these neurons’ transmission of nerve impulses. Neurons are the basic unit of an animal’s body neural system.

Conclusion

The basis of the structural organisation in animals and plants are cells. A living organism’s body comprises various kinds of cells. A tissue refers to a group of cells that cooperate together for the performance of a particular role in the body. The diverse forms of life on Earth which we see are due to the different types of cells and tissues. Plants have three basic organs which are roots, stems and leaves. There is a fascinating arrangement of the internal structures in flowering plants. The specialised complex organ systems of animals are formed from a limited set of tissue types. Four main types of animal tissues are- epithelial, connective, muscular and nervous/neural.