THE CELL

Long ago as far back as 1665, an English scientist named Robert Hooke discovered the honey comb structure of the cell. He proceeded to magnify and expand his observations and discovery in his book 'Micrographia' and he also mentioned that cells had components. He was the first man to make this discovery, so he was tagged as the father of cells.

Funnily enough, until after a long time of his discovery before other discoveries were made. Other scientists include:

Felix Dujardin: Unlike Hooke, he was a French biologist who in 1835 discovered that the cell was up of living substances. He named that living substance protoplasm.

Mathias Schledien and Theodor Schawnn: The dup were both Germans and weready botanist and zoologist respectively. They made their discoveries individually but were combined because their discoveries are in the same line. Mathias, the botanist, in1838 discovered that the buddies of plants were made of cells. While Theodor, the zoologist, in 1839 discovered the bodies of animals were made of cells. These two theories led to the postulation of Cell theory in 1839. (Same year with Theodor Schwann's theory).

The Cell Theory
This theory as postulated in1839 states that:
I. The cell is the structural and functional unit of life.
II. All living things are made up of cells.
III. All cells come from previously existing cells.
IV. There is no life apart from the life of cells.
V. All living things are either unicellular or multicellular.

Another scientist that worked on the cell was:

Rudolf Von Virchow: Just like the others, he was also a German but a biologist. In 1855, he concluded that no new cells are formed, all cells come from previously existing cells.

These were the notable scientists who worked on the cell. If you're not in the field of science, you must be wondering what exactly is this cell that I am made up of. Don't be too in a haste to look down, anyway, it's just below.

What is a cell?
A cell is defined as the basic structural, functional and biological unit of life. You can also refer to it as the basic unit of life. This means anything at all tagged living must be made up of cells. The cells carry out life processes or activities such as Movement, Respiration, Nutrition, Growth.....

Cells can be classified in two ways:

I. Based on number of cells.
II. Based on the form in which they exist.

BASED ON NUMBER OF CELLS
In this classification, living organisms have two groups that is:

I. Unicellular Organisms: Organisms in this group have only a single cell. Examples are Amoeba, Paramecium, Euglena, Chlamydomonas.

II. Multi-cellular Organisms: Organisms in this group have two or more cells. Examples include: Hydra, fish, Spirogyra, Volvox, fish, birds and the list won't be complete without Man.

BASED ON THE FORM IN WHICH THEY EXIST
Cells can exist in four forms which are:

As independent free living organism: The independent and free living organisms are organisms that possess a single cell yet carry out all life processes on their own independently. Example of the process include; feeding, movement, growth, excretion, reproduction.... Examples include:

I. Amoeba: An irregularly shaped organism that changes shape regularly. The protoplasm contains the nucleus and cytoplasm. It uses the pseudopodium for movement.

II. Euglena: Euglena is a protist having the characteristics of both plant and animal. The organism possess flagellum, eye spot, gullet which are human characteristics and also it has chloroplasts, paramylum granules which are only possessed by plants.

As a colony:
Organisms existing as a colony are joined or mershed together which means they can not be differentiated from each other. Also know that the aggregation of two or more independent cells is called a colony. Examples include Volvox, Sponges, pandorina...

Pandorina

As a filament:
Organisms found here are joined end to end in a continuous network. All filamentous cells are multi cellular. Examples are the Spirogyra, zygnema, oscillateria....

Spirogyra

As part of a Living Organism:
As I said earlier, the cell makes up the human but not directly.There is an hierarchy:

The cells arranged and performing a specific function is called a tissue. A group of similar tissues in an organism performing a specific function is called an organ. A group of organs which work together to perform a specific function is a system.

All free hand sketches were made by me and the inspiration was gotten from @suesa.

Source: Lecture notes on 'THE CELL' by Mr. Ayo Ademefun

Thanks for your time! .

Index
Biologist- A scientist that specializes in the aspect of biology.
Botanist-A scientist that specializes in the aspect of plants.
Zoologist-A scientist that specializes in the aspect of animals.

GIF made by @foundation