How can we say that living organisms grow by cell division?
In in vitro cultures by simply counting number of cells.
In majority of higher animals and plants growth and reproduction are mutually exclusive events.
Why is not growth a defining feature of living organisms?
Conditions under which growth can be observed have to be defined.
Growth is a characteristic of living system which is internal but their is also external growth in mountains, boulders and sand mounds.
A dead organism doesn't grow.
Why is reproduction not a defining feature of living organisms?
First we are not very clear about growth and reproduction.
For example, in unicellular organisms like bacteria, amoebas, algae reproduction is synonymous to cell number increase.
Further, their are many organisms which do not reproduce like moles, worker bees, sterile human couple etc.
But it is true that no non living organisms can replicate or reproduce.
Why is cellular organisation or metabolism defining feature of life?
No non living object can exhibit metabolism even though they can be demonstrated outside the body.
Such a reaction is not a living thing but surely a living reaction.
Photoperiod affects reproduction in seasonal breeders bot plants and animals. True/ False
True
How is consciousness a defining feature?
Because they respond to external stimuli which other non living objects don't do.
What a person in coma considered?
Living though he or she has lost self consciousness.
1)Living organisms are self replicating, evolving and self regulating interactive systems capable of responding to external stimuli.
2) Properties of tissue are not present in constituent cells but arise as a result of interaction among constituent cells.
3) Properties of cellular organelles are not present in the molecular constituent of organelle but arise as a result of interactions among molecular components comprising cells.
Higher the category, greater is the difficulty of determining the relationship to other taxa at same level.
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