The Living World Notes Free Download – NEET & Medical Exam 2021

The Living World Notes

The Living World Notes: Biology Notes is based on important topics that comes under various Medical Entrance Exam (NEET, AIIMS, JIPMER, PGIMER), CBSE Board, ICSE Board, Class 12th, 11th.

We are providing you Important Biology – The Living World Notes PDF which will be beneficial for you to crack your exam. These Notes are generalize is nature and you can always combine them with your own solving methods. Let’s take a look at the Biology Notes on The Living World Notes.

[su_box title=”Criteria that Determines What Is Living”]Listed below are the criteria deciding if a thing is living or non-living:

• A living thing is able to maintain the body’s internal environment which is referred to as homeostasis.

• Must be capable of disintegrating or building-up nutrients to perform metabolic processes
• Living things possess a highly organized structure
• Must be able to adapt to changes in the environment
• Must be capable of increasing in mass and size Must be capable of responding to external stimuli.[/su_box]

Main characteristics of living

The main characteristics of living are:
(i) Growth
(ii) Reproduction
(iii) Metabolism
(iv) Cellular organization
(v) Consciousness

→ Those characteristics which have no exception is called defining property of life.
→ Growth and Reproduction are not the defining property of life as well as metabolism, cellula organization, consciousness is the defining property of life.

(i) Growth
→ Overall increase in mass or size of tissue or organism or its parts is called growth.
→ Increase in mass and increase in number are the twin characteristics of growth. This is an irreversible permanent increase in size of the organ or its part or even of an individual cell.

Growth is of two types:

• Intrinsic growth: Growth from inside of the body of living organism. This is the defining prope
life.

• Extrinsic growth: Growth from outside of the body of the organism. Like accumulation of ma on any body surface . Non-living exhibits this type of growth.

Intrinsic Growth is of two types:

• Indeterminate growth\Unlimited growth: Growth which occurs continuously throughout th span. It occurs only in plants.

• Determinate growth\ limited growth: Growth which occurs only up to certain age. It occurs in animals. Cell division occurs only in certain tissues to replace lost cells

(ii) Reproduction
→ Production of new individual or progeny is called as reproduction.
→ Reproduction in case of multicellular organism is production of progeny possessing feature more or less similar to those of parents.
→ Reproduction in case of unicellular organism like bacteria, unicellular algae or amoeba is increaser in number of cell. Means in unicellular organism the growth and reproduction are synonyms or same.
→ Reproduction is not found in any nonliving object. There are many living organism which ca
not reproduce like mules, sterile human couples, worker bees. This is also not taken as defining property of life.

Reproduction is of two types:

• Asexual reproduction: Reproduction in which fertilization or gametic fusion and meiosis is n involved is called asexual reproduction.
(a) By Asexual spores: In algae and fungi.
(b) By Budding: In Yeast and Hydra.
(c) By Fragmentation: In filamentous Algae, Fungi and Protonema of moss plants.
(d) By True Regeneration: Fragmented organism regenerate the lost parts of its body and became new organism i.e. Planaria.
→ Regeneration is a process in which only lost part of the body is repaired or regenerated

• Sexual Reproduction: Reproduction in which gametes are formed by meiosis and fertilizatio takes place to form progeny is called as sexual reproduction.

(iii) Metabolism
→ The sum total of all the chemical reaction occurring in our body is metabolism.
→ All organism, both unicellular as well as multicellular exhibit metabolism. No nonliving objec show metabolism

(iv) Cellular organization
→ Cell is the basis unit of life. All organisms are composed of cells.
→ Some are composed of single cell and are called as unicellular organism while other are composed of many cells, are called multicellular organism.
→ Unicellular organism is capable of independent existence and performing essential functio life. Anything less than a complete structure of a cell, does not ensure independent living.
→ Cell is the fundamental structure and functional structural and functional unit of all living organism. This is the defining property of life.

(v)Consciousness

It is a property by the virtue of which an organism reacts to an external stimulus or change in environment. It is a typical property of living organisms. They have the ability to sense any change in their environment.