INTRODUCTION
living – plants, animals and microbes
characteristics of living organisms
- Growth
- Reproduction
- Metabolism
- Consciousness
- Cellular organisation
GROWTH
Increase in mass and no. of cells individuals are twin characteristics of living things
| INTRINSIC GROWTH | EXTRINSIC GROWTH |
|---|---|
| occurs from inside (living) | occurs from outside (non-living things) |
| increase in mass e.g. living things | reversible e.g – mountains |
IMPORTANT POINTS –
In plants, growth occurs throughout life span
in animals – up to certain age
In unicellular organisms – Growth & reproduction are mutually inclusive events
In all living organisms’ growth occurs by cell division
growth is not a defining property, but intrinsic growth is defining property.
in multicellular organisms, growth and reproduction – exclusive events
REPRODUCTION
producing similar kind of individuals is known as reproduction
exceptions are mule, worker bees (female), sterile human couples.
reproduction is not defining property.
| ASEXUAL | SEXUAL |
|---|---|
| Single parent is involved | two parents |
| occurs with or without involvement of gamete formation | involve formation and fusion of gametes |
Binary fission – unicellular, bacteria, amoeba
Budding – hydra
Fragmentation – spirogyra (filamentous algae), fungi, protonema of bryophytes
True regeneration – planaria(flatworm)
METABOLISM
all living organisms made up of cell
made up of thousands of chemicals and molecules
shows thousands of chemical reactions
metabolism is the sum total of chemical reactions occurring simultaneously in living organisms
| ANABOLISM (endergonic) | CATABOLISM (exergonic) |
|---|---|
| simple – complex | complex – simple |
| e.g. – photosynthesis CO2 + H20 = glucose |
e.g. – respiration glucose = CO2 + H2O + ATP |
it is defining property
Isolated metabolic reactions performed in a test tube are neither living nor non-living
isolated metabolic reactions occurring in vitro (in lab) are not living thing/system but surely a living reaction
CONSCIOUSNESS
Ability to sense the surroundings and respond to environmental stimulus which may be physical, chemical or biological.
some plants like – soyabean, radish and some animal like – horse, sheep, goat are seasonal breeders and reproduce at specific season.
Reproductive behavior changes by the effect of photoperiod.
so, photoperiod effects reproduction
NOTE- only humans are self-consciousness
sense surrounding and memorize the event
due to complex brain
hence absent in coma lying person – Patient lying in hospital in comma.
CELLULAR ORGANISATION
all living organisms are made up of cells.
it is defining property.
THANK YOU
HAVE A NICE DAY & DROP A COMMENT BELOW
YOU CAN REQUEST A TOPIC ON MAIL AND AS WELL AS IN A COMMENT BOX
STAY TUNED FOR MORE TOPICS LIKE THIS AND DON’T FORGET TO SHARE THIS
