Levels of biological organizations

Levels of biological organizations.

The study of biology at different levels is called biological organizations. Biological level starts from the very basic level of sub-atomic and atomic particles to the organism itself After that, community, population and entire world are studied. The organisms have to perform different complicated processes. Therefore organization is not simple It is highly complex. These processes differentiate the living things from the non-living things. A living thing has a regulatory mechanism. This mechanism interacts with the environment So it maintains the structures and functions of the organism.

Bioelements.

The elements found in the living organisms are called bioelements. A living thing is composed of a living substance called protoplasm. Hundreds of chemical reactions take place in this protoplasm of the simple organisms. There are 92 chemical elements. Only 16 elements are used in the chemical compounds in the living organisms. These 16 elements are called bioelements.The properties of these 16 bioelements are different from the properties of the elements present in the non-living organism. Due to these special properties these elements form the basis of life. There are two types of bioelements:

Major bioelements.

The elements present in larger quantity in the body are called major bioelements. These are only 6 bioelements. They form the 99% body of the human. These are carbon (65%), carbon (18%), hydrogen (10%), nitrogen (3%), calcium (2%),phosphorus (1%).

Trace bioelements.

The elements present in smaller quantity in the body are called trace bioelements. These are ten bioelements. These are Potassium (0.35%), Sulphur (0.25%), chlorine (0.15), sodium (0.15%), magnesium (0.05%), inon (0.004) copper, manganese, zinc and iodine.

The biological organization can be divided into the following levels:

1. Atomic and subatomic levels.

All the living and non-living organisms are made up of atoms. These atoms are composed of subatomic particles like proton, electron and neutron.

Chart: Biological organization.

Biosphere.

The part of earth inhabited by living organisms is called biosphere. It both the living and non-living components

Ecosystem

A community together with its nonliving surroundings is called ecosystem.

Community.

Two or more populations of different species Living and interacting in the same area.

Population.

Members of one species inhabiting the same area

Species.

Very similar, potentially interbreed organisms

Multicellular Organisms.

An individual living thing composed of many cells.

Organ system.

Two or more organs working together in the in the execution of specific body function.

Organ.

A structure normally composed of several of several tissue types. It forms a functional unit.

Tissue.

A group of similar cells that perform a specific function.

Cell.

The unit of life.

Organelles

A structure within a cell that performs a specific function.

Micro and Macromolecules.

A combination of atoms.

Atom.

The smallest particle of an element that retains the properties of the element.

Subatomíc Particles.

Particle that make up an atom.

2. Molecular Level

The atoms combine with each other to form molecules. Molecules are formed by covalent or ionic bonds. Most of the biological molecules contain Hydrogen, Carbon, Nitrogen, Phosphorous and sulphur.  These biological molecules can form different types of bonds So they form complex compounds, There are two types of biological molecules.
(a). Micromolecules:  They have low molecular weight like CO2, H2O etc.
(b) Macromolecules:  They have high molecular weight like starch, protein etc.
There are two types of molecules in the living organisms.
።  Organic molecules: The molecules containing both carbon and hydrogen together are called organic molecules.

።  Inorganic molecules: The molecules without carbon and hydrogen together are called inorganic molecules.

An organism is made up of a large number of different types of micro and macromolecules. Some of these molecules are glucose, amino acids, fatty acids glycerol, and nucleotides like ATP, ADP, and AMP etc.

3. Organelles and Cell Level

Cell is unit of structure and functions of the organisms. Different type of micro and macromolecules arrange to form cells and their organelles. There are two types of organisms:

።  Unicellular organism: They are composed of single cell like bacteria and protozoan

።  Multicellular organisms: There are composed of many cells like fungi plants and animals.
    Cell membrane is present in all cells. There are two types of cells: prokaryotic and eukaryotic              cells.Therefore the organisms are divided into two groups on the basis of this difference:
።  Prokaryotes: The organisms without well defined. nucleus are called prokaryotes. They have a  few organelles.
።  Eukaryotes: The organisms with well defined nucleus are called eukaryotes. They have large              number of membranous organelles.
Organelles
The sub-cellular structures of the cell are called organelles.  These organelles are mitochondria, Golgi complex, endoplasmic reticulum, ribosome etc. These organelles perform different functions in the cells. Organelles are arranged specifically in the cells. Thus there is a division of labour within the cell.

4.Tissue Level 

group of similar cells, having same origin and performing same function is called tissue.  Each tissue performs a specific function e.g.
።  Muscle tissues are used for contractions
።  Gland tissues are used for secretions
።  Xylem tissues are used for the conduction of water
።  Phloem tissues are used for the transport of food i, e sugar

5. Organ and Organ System Level

A group of different tissues, performing same function is called organ.

Organ performs specific functions, For example, stomach is an organ. It digests protein food. It has different tissues: Its secretary epithelium tissue secretes gastric juice. Its muscular tissues contract the wall of stomach. So food is mixed with the enzymes.
(a) Organ formation in Animals
Cells form different organs in the bodies of the animals. These organs function efficiently, Organ formation is more complex in animals, Animals form organ systems like digestive system, Different organs in an organ system complete one process like digestion. The organ system of the animals performs more functions and activities than the plants.
(b) Organ formation in plants
The plants have less complex organ level organizations than the animals. There is no organ system formation in the plant body. Mostly, the body of a plant can be divided in to root, stem, leaves and reproductive struckures Each of these structures performs a specific function. Root fixes the plant. It also stores food and absorbs minerals. The shoot or stem supports all the plant. The leaves synthesize food. Flowers or other reproductive structures are used for

reproduction.

6. Individual Level (whole organism)

The various organs and organ systems join to form an Individual or whole organism. The whole organism has certain special characteristics. Therefore each individual looks different from the members of the same species. All the systems in an organism coordinate with one another, For example, if a man exercises continuously, the working of muscles increases, His muscles need more oxygen. So the rate of respiration and heart beat increases, Nervous system and endocrine system are used for coordination in the animals. On the other hand, in plants some hormones are involved in the

regulation of the long-term activities, The organism acts a whole, it also shows response to change in environment as a whole.

7.Population

A population is a group of living organisms of the same species located in the same place at the same time. Examples: the number of rats in a field of rice, the number of students in the biology class or population of humans in a city.

Population is a higher level of organization than organism. Population is a group of same species. The organisms start living together. Thus a population is formed A population has following characteristics or parameters:

።  Gene frequency: Number of genes of a character in a population.

።  Gene flow: Movements of genes between different populations like, migrations.

።  Age distribution:  Different age structures in a population.

።  Population density: Number of organisms in a unit area.

።  Population pressures: Effects of populations on other populations and environment.

8.Community

The populations of different species (plants and animal) living in the same habitat form a community.  There is a continuous change in abiotic (non-living) factors in a community like change in environment. So populations of that community also changes. Communities may be simple or

complex.

።  Simple community: An isolated community is called simple community. The change of environment shows great effects on the simple communities.

።  Complex community: Interrelated communities form complex communities.