Important Notes for CBSE Class 10 Science Chapter 8 – How do Organism Reproduce. How do Organism Reproduce Class 10 Notes and Study Material Download in PDF form.
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How do Organism Reproduce Class 10 Notes
Reproduction
The term ‘Reproduction’ is essential to all living organisms. Every living organisms have differential ability to make their own progeny. Therefore the reproduction can be defined as generation or production of new progeny from itself. Reproduction is very important stage of life for continuation in generation. The living organisms have different methods of reproduction, the methods of reproduction vary from organism to organism. There are 2 different types of reproduction such as asexual method of reproduction and sexual method of reproduction. Some living organisms have ability that according to the favorable environment, presence of nutrients they can switch to asexual or sexual method of reproduction.
Asexual method of reproduction
The asexual reproduction is one of the simplest type of reproduction occurs in lower living organisms. In asexual reproduction no gametes involved, no fusion of gametes, it is uniparental. They have ability to reproduce small sized and large number of progenies in shorter period of time. For example : Bacteria.
There are various types of asexual reproduction such asbudding, vegetative reproduction, binary fission, regeneration, fragmentation and parthenogenesis.
Budding
In budding there is unequal division of the parent body, that is new outgrowth arises from animal body, it can be seen in both prokaryotes and eukaryotes. The major example of budding is yeast.
By this process budding occurs. It is basically the outgrowth from parent or specifically yeast. Therefore the division and reproduction occurs. The asymmetrical division of cell will start from particular site on parent’s cell.The initiation of formation of new outgrowth from parent cell.The division in cytoplasm take place and the new outgrowth separate from the parent cell called as budding.The examples of organisms are Hydra, yeast, bacteria, etc.
Spore formation
Spore formation also called as sporogenesis, in which spores released from the living organism body such as single celled organism for reproduction, this spores can be transmitted through air, water and insect medium. More appropriate example of spore formation is Rhizopus.
Advantages of spore formation are
a) The large number of spores will produced in short period of time
b) For the spore formation, less energy will required.
Regeneration
Regeneration can be defined as generation or formation of a new organ from the lost or damaged part of the body. Such type of organism have ability to regenerate their organs. For example : Planaria.
a) The planaria can be considered as model organ for the process of regeneration.
b) The planaria have ability to release their damaged parts as depicted in diagram.
c) If due to mechanical injury or any cause, the cut in the body can occur.
d) Under such conditions, the part of organism can again be regenerated.
Fragmentation
As we have seen other methods, fragmentation can be considered as the example of sexual reproduction. The process of fragmentation can form entire organism. The fragmentation can also occur in broken parts to form the part of the body. For example : Spirogyra
Sexual reproduction in flowering plants
Properties of sexual reproduction:
1)Formation of gametes takes place.
2) Two parents involved.
3) Sexual reproduction occurs when male gamete fuses with the female gamete that is fusion of gametes.
4) Sexual reproduction occurs in higher organism such as plants, animals and humans.
After the asexual reproduction the advanced form of reproduction present in plants and animals with the gamete fusion called as sexual reproduction. It is characterized by involvement and fusion of gametes. Two sexes are involved. In case of the plant male reproductive organ and female reproductive organ are involved. male reproductive organ are anther and filaments whereas female reproductive organ are ovary, style, stigma and ovule. In case of the plant reproduction two phases are involved gametophytic phase and sporophytic phase.
1)The sexual reproduction takes place in flowering plants. Flower is the reproductive organ for sexual reproduction.
2) Sexual reproduction in flowering plant occurs in two generations such as gametophytic generations and sporophytic generation.
3) The gametophytic generation involves a single set of chromosome called as haploid (n). Haploid denoted as “n”.
4) Sporophytic generation of the plants involves fusion of gametes and producing diploid state. Diploid can be denoted as (2n).
5) Both the generators are required for sexual reproduction. Therefore, the alteration n gametophytic and sporophyte generation called as sexual life cycle of flowering plant.
Reproduction in human beings
In humans the reproduction is most complex type of reproduction contains both the sexes. In both sexes separate male reproductive organ and female reproductive organ and systems are present. In case of male testis, seminal vesicle, prostrate gland, epididymis, spermatic cord, ejaculatory duct and urethra present.
In case of female ovaries, hormones, uterine tube, uterus, vulva and vagina are present.
The process of formation of sperm called spermatogenesis. Each sperm is about 60 ꭒm in length. The sperm is a sex cell therefore its division takes place through meiosis. Meiosis is the process for the division of germ cells. The sperm contains mitochondria, which gives energy for the mobility of sperm.
The production of female gamete or egg in the ovaries called oogenesis. The spermatogenesis process differs from oogenesis in terms of production of gametes. The male gamete (sperm) produced at the stage of puberty where the female gametes produced before the birth.