Diversity in the Living World
The Living World
What is Living
Diversity in the living world
The living world is very wonderful. It contains wide range of life forms. 1.1
What is living – Living organisms are self-replicating, evolving and self-regulating interactive systems capable of responding to external stimuli. Living organisms exhibit following distinctive characteristics.
All Living Organisms grow:
Twin characters of growth are increase in (a) mass and (b) number of individuals. Cell division leads to growth of an organism.
External Growth is shown in non-living bodies where the accumulation of material on the surface takes place thereby increasing the mass.
Internal Growth is a process in which the mass of living bodies grows by cell division.
Growth - by Cell Division
Animals – It is up to a certain age
Plants – Continues through out their life span
All Living Organisms Reproduce:
Organisms reproduce or replicate both by sexual and asexual means.
In unicellular organisms growth and reproduction are synonymous.
Organisms such as sterile working bees, mules are living but don’t reproduce. So it can’t be a defining factor for life.
No non-living organism is capable of reproducing itself.
All living organisms are made up of chemicals.
These chemicals are constantly being made and changed into other bio-molecules. These conversions are chemical reactions or metabolic reactions.
Thousands of metabolic reactions occur simultaneously in all the living organisms. The sum total of all the chemical reactions inside our body is metabolism.
Cellular organization of body is the defining feature of life forms.
The most obvious and technically complicated feature of all living organisms is their ability to sense their surroundings and environment and respond to these environmental stimuli (physical, chemical, biological).
Consciousness is also a defining feature of living organisms.
All living phenomena are due to underlying interactions. Properties of tissues are not present in the constituent cells but arise as a result of interactions among the constituent cells. Properties of cellular organelles are not present in the molecular constituents of the organelles but arise because of interactions among the molecular components comprising the organelle. This phenomenon is true for the hierarchy of organizational complexity at all levels. 1.2
Diversity in the living world
We can see a large variety of living organisms around us.
Species - each different kind of plant, animal or organism represents a species.
The number of species that are known and described range between 1.7 – 1.8 million.
Biodiversity – is the number and types of organisms present on earth.
Nomenclature – Is the process to standardize the naming of living organisms such that a particular organism is known by the same name all over the world.
Identification: Describing an organism correctly and knowing to what organism the name is attached to. It is an essential function of nomenclature.
ICBN – International Code for Botanical Nomenclature – for plants scientific names are based on agreed principles and criteria provided by ICBN.
ICZN – International Code for Zoological Nomenclature – for animals scientific names are given by ICZN evolved by animal taxonomists.
Biologists follow universally accepted principles for providing scientific to living organisms.
Each name has two components (a) the Generic name (b) the Specific Epithet.
This system of providing the name with two components is called binomial nomenclature.
This naming system, given by Carolus Linnaeus is being practices by biologists all over the world.
Universal Rules of Nomenclature
Biological names are generally in Latin and written in italics. They are Latinized...
Please join StudyMode to read the full document