Describe the levels of organization of life.

Describe the levels of organization of life.

The study of biological organization at different levels helps biologists to understand different phenomena of life. Biological organization goes from simpler to complex levels i.e. from subatomic level to biophere. Subatomic particles make atoms and atoms make molecules. Different molecules of life make organelles and different organelles assemble together to from the simplest living unit i.e. the cell.Cells sre organized in the form of tissues and different coordinating tissues make an organ. Organs performing relative functions make organ system and different organ aystems make a complete andividual. Individuals of the same species live together and make a population. Populations of different species living in the same habitat constitute a community. The part of the Earth inhabited by different organisms or communities is know as biosphere.

1. Subatomic and Atomic level
2. Molecular level
3. Organelles and cell level
4. Tissue level

Subatomic and Atomic level

All tyres of matter are made up of elements and there are about 92 kinds of elements,found in nature. Each element is made up of a single kind of atom ('a':not,'tom':cut). These atoms are actully the structures formed by many subatomic particles. The most stable subatomic partcles are electrons, protons orbit in energy levels (electron shells) around the nucleus. The number of electrons in the outermost shell determines the manner in which atoms react with each other. Out of the 92 kinds of elements that occur in nature, 16 are called bioelements. These take part in making the body mass of a living organism. Out of these bioelements only six (O,C,H,N,CA,&P) make 99% of the total mass. Other ten (K,S,Cl,Na,Mg,Fe,Cu,Mn,Zn,&I) collectively make 01% of the total mass.

Molecular level

 In organisms, bioelements usually do not occur in isolated forms. Rather,atoms of different bioelements combine through ionic or covalent bonding. The stable particle formed by the bonding between different elements, is called as molecule.A molecule is the smallest part of a compound that retains the properties of that cpmpound . Bioelements share their atoms in making biomolecules of life.Biological molecules:An organisms is formed by enormous number of biomolecules of hundreds of different types. These molecules are the building material and are themselves constructed in great variety and complexity due to specific bonding arrangements.

biomolecules may be classified as:

1. Micromolecules
2. Macromolecules

• Micromolecules

Micromolecules are with low molecular weight e.g. glucose,amino acids,fatty acids etc.

• Macromolecules

Macromolecules are with low molecular weight e.g. starch,proteins,lipids, etc.

Organelles and Cell level

1. Prokaryotes
2. Eukaryotes

An enormous number of biomolecules become associated in a particular way and form organelles. The organelles are actully sub-cellular structures and when they assamble together, cells are formed.Each type of organelle is specialized to perform a specific function.For example; mitochondria are specialized for cellular respiration and ribosomes are specialized for protien synthesis. All function of the cell are accomplished by these specialized structure. It is an example of the divison of labour within the cell.

• Prokaryotes

have only limited number and type of organelles in their cells.They are made up of simple cells which lack membrance bounded organelles e.g. mitochondria,Golgi complex.

• Eukaryotes

have large number and type of organelles in their cells. they are made up of complex cells which have lack membrance bounded organelles. In the case of bacteria and most protests, the entire organisms consists of a single cell. They are called unicellular organisms.in the case of most fungi,animals and plants,the organisms consists of up to trillions of cells.They are called multicellular organisms.

Tissue level

1. Plant tissues
2. Animals tissues

In multicellular prganisms, similar cells (performing similar functions) are organized into groups, called tissues.

• Plant tissues

Plant tissues are divided into different types e.g. epidermal tissue, ground tissue.

• Animals tissues

These are also of different e.g. nervous tissue and muscular tissues.