Organization of life is defined as the existence of life from a single-celled organism to a multicelled organisms with a complex form that perform different functions

Levels of Organization

1  First level (cell): A cell, which is the functional and structural unit of protoplasm bounded by a membrane, is the first level of organization. It contains the nucleus and cytoplasmic materials. Some living things or organisms exist as a cell capable of carrying out all the characteristics of living things. They have cytoplasmic structures such as pseudopodia, cilia, flagella and vacuoles, e.t.c. amoeba, paramecium, and Euglena.

2. Second level (Tissue): A tissue is a collection of cells that are similar in structure and perform similar the same position in the body in which they exist. The only organism that exists at the tissue level is the hydra. Examples of tissues are blood, xylem tissue, phloem tissue, parenchyma, and collenchyma.

3. Third level (Organ): An organ is a collection of different tissues that perform a common function or functions, some organs can carry out more than one function, for example kidney excretes metabolic of water in the body. Examples of organs are the root, stem, leaves, bulb, nose, ears, brain, spinal cords, taste buds, ovaries, and urinary bladder

4. Fourth level (System): A system is a set of organs that cooperate to carry out one of the vital functions of life. For example, the digestive system is made up of organs such as the mouth, oesophagus, stomach, pancreas, duodenum, and ileum, the large intestine, and the anus.

Complexity of organization in higher organizations

The advancement in the evolutionary trend of both plants and animals shows that there is a gradual complexity in the organization from one level to the next, unicellular to multicellular, and their bodies show advancement over the unicellular organism. Their bodies are performing different functions. The specialized parts are made up of tissues, organs, and systems which make up higher organisms more efficient in carrying out various activities of life

Advantages of Complexity

• There is a specialization of various cells
• Division is allowed for the efficient exploitation of the environment
• It increases adaptation to the environment
• It leads to an increase in the size of organisms
• In unicellular organisms, all other activities stop when reproduction is about to take place, but complex organisms do not.

Disadvantages of Complexity

• Individual cells are not capable of existing independently and therefore depend on one another for activities to exist
• Area to volume diminishes
• In higher organisms ability to regenerate decreases

Questions to practice

1a.  State one difference each between hydra and mammals concerning:

• Level of Organizations
• Body symmetry
• Number of body layers

b.) State 4 advantages of the body complexity of higher animals

c.) In terms of body complexity, relate the body functions of higher animals and the Amoeba

d.) In tabular forms, group the following objects according to their level of organization. Blood cell, blood, onion bulb, leaf, stem, ear, tongue, amoeba, paramecium, Nervous system, respiratory system, hydra, and mango fruit

2a. State five differences between monocotyledonea and dicotyledonea

b. State the principal features of the following groups of organisms

i. Co-elenterata     ii, Amphibia iii. Fishes iv. Reptiles  v. Bird   vi. Mammals