Living World Reproduction Reproduction is one of the fundamental characteristic features of living organisms. It is the tendency of a living organism to perpetuate its own species. There are two types of reproduction namely asexual and sexual (Figure . ).
Nucleus (a) (b) (c) (d) Figure . : Types of Asexual Reproduction (a) Conidia formation- Penicillium , (b) Budding-Yeast, (c) Fragmentation- Spirogyra, (d) Regeneration- Planaria Asexual reproduction refers to the production of the progeny possessing features more or less similar to those of parents. The sexual reproduction brings out variation through recombination. Asexual reproduction in living organisms occurs by the production of conidia ( Aspergillus, Penicillium ), budding ( Hydra and Yeast), binary fission (Bacteria and Amoeba ) fragmentation ( Spirogyra ), protonema (Mosses) and regeneration ( Planaria ).
Exceptions are the sterile worker bees and mules. Response to stimuli All organisms are capable of sensing their environment and respond to various physical, chemical and biological stimuli. Animals sense . Attributes of living organisms The attributes of living organisms are given below and is represented in Figure .
. Excretion Irritability Respiration Metabolism ATTRIBUTES OF LIVING ORGANISMS Movement Nutrition Growth Reproduction Figure . : Attributes of living organisms Growth Growth is an intrinsic property of all living organisms through which they can increase cells both in number and mass. Unicellular and multicellular organisms grow by cell division.
In plants, growth is indefinite and occurs throughout their life. In animals, growth is definite and occurs for some period. Growth in non-living objects is extrinsic . Mountains, boulders and sand mounds grow by simple aggregation of material on the surface.
Living cells grow by the addition of new protoplasm within the cells. Therefore, growth in living thing is intrinsic . In unicellular organisms like Bacteria and Amoeba growth occurs by cell division and such cell division also leads to the growth of their population. Hence, growth and reproduction are mutually inclusive events.
Cellular structure All living organisms are made up of cells which may be prokaryotic or eukaryotic. Prokaryotes are unicellular, lack membrane bound nuclei and organelles like mitochondria,