CBSE Class 10 Biology How Do Organisms Reproduce Notes - Simple to learn and understand concepts for CBSE students by the best teachers in Delhi.
Class X: Biology
Chapter 8: How do organisms reproduce?
Points to remember
1) Reproduction is the biological process by which new individuals of the same kind are produced.
2) Reproduction is not essential for the survival of an organism, but is vital for the survival of a species.
3) Reproduction produces identical copies of the body design.
4) DNA is the informational macromolecule of our body. It provides information for protein synthesis.
5) During cellular reproduction, DNA duplication occurs followed by creation of an additional cellular apparatus.
6) The process of DNA copying is not accurate, resulting in variations arising during reproduction, which is the basis for evolution.
7) Variations may or may not be beneficial for the individual, but help in the survival of the species during adverse conditions.
8) Depending on their body design, the modes of reproduction differ in different organisms.
9) Reproduction is broadly divided into asexual and sexual reproduction.
10) Fission, fragmentation, regeneration, budding, vegetative propagation and spore formation are various modes of asexual reproduction.
11) Fission occurs in unicellular organisms like bacteria and protozoa through simple cell division. Depending on the number of individuals formed, fission may be binary or multiple fission.
12) On maturation, certain multi-cellular organisms (with simple body makeup) break up into smaller fragments, each of which develops into new individual. This reproductive method is called fragmentation.
13) Simple reproductive methods cannot occur in higher multi- cellular organisms, since they have a complex and carefully organized body structure.
14) In complex multi-cellular organism, reproduction is brought about by a single, specialized cell type that is capable of proliferating and forming all other cell types of the body.
15) Regeneration is found in many completely differentiated simple organisms, like Hydra and Planaria. If such an organism is split into several parts, most of the parts will develop into complete organisms.
16) Regeneration involves specialized totipotent cells which proliferate and differentiate to form the complete body.
17) Certain organisms like Hydra produce buds on their body surface, which mature into new individuals and separate from parent body.
18) Vegetative propagation is used by many plants, especially those incapable of producing seeds. Here, new plants are produced from roots, stems or leaves of parent plant. This reproductive method is widely used by plant breeders.
19) Spore formation is an asexual mode of reproduction found in certain multicellular organisms like Rhizopus. The thick walled spores have the capacity to develop into new individuals
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