This post provides you a general and basic facts related to reproduction. Enjoy reading......!
2. It may take place along single plane eg- Leishmania
Reproduction
Biological process by which a living organism produces an offspring similar to itself is called Reproduction.
In this process, Genetic Information transferred from the parents to the offspring in the form of DNA
DNA (Deoxyribonucleic acid) - It is a genetic material found in chromosomes present in the nucleus of a cell
Reproduction may be classified into Two groups or types: - Asexual and Sexual reproduction.
Asexual reproduction
It Does not involve the fusion of gametes
It Requires only one parent
Offspring’s produced are exact copies of their parents. They are called Clones.
Modes of asexual reproduction : Asexual reproduction is of the following types:
1. Fission- The type of reproduction in which parent organisms divide into 2 or more than 2 parts and each part gives rise to new daughter organisms is called fission. It involves cell division or splitting of cells.
o It is of two types:
Binary fission : The type of asexual reproduction in which parent organisms divide into 2 parts and each part gives rise to new daughter organisms is called binary fission.
2. It may take place along single plane eg- Leishmania
3. It may take place along Longitudinal plane e.g., Euglena
Multiple fission: The type of reproduction in which parent organisms divide into more than 2 parts and each part gives rise to new daughter organisms is called fission. It involves cell division or splitting of cells.e.g., Plasmodium
| Multiple fission in Plasmodium |
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| multiple fission in Plasmodium |
o Fragmentation- New organisms are formed from fragments of parents. e.g., lichens
o Regeneration- New organisms are formed from body parts. e.g., Planaria
o Budding- New individuals form protrusion called buds. e.g., Hydra, Yeast
o Vegetative propagation- New plants are formed from the vegetative parts such as leaves, roots and stems .e.g., Bryophyllum, potato, ginger etc
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| Bryophyllum Leaf showing vegetative reproduction |
o Spore formation- Large number of spores produced in sporangia. e.g., Rhizopus
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| spore formation in Rhizopus |
Sexual reproduction
It Involves fusion of male and female gametes- male gametes or sperms and female gametes of eggs or ova.
It Requires two parents- male and female
It Allows more variations in offsprings
Sexual reproduction in plants
o Angiosperms- flowering plants belong to Angiosperms. Flower is the modified shoot and the reproductive part of the plants.
o Parts of flowers– A typical flower consists of four parts:
- Calyx which consists of sepals
- Corolla which consists of petals
- Androecium which consists of stamens and
- Gynoecium which consists of carpels or pistils.
Stamens: Male reproductive parts of flowers are called stamens. They have 3 parts: anther, connective and filament.
Carpels: Female reproductive parts of flowers and consists of style, stigma, and ovary
o Bisexual flowers: Both stamens and carpels are present e.g., Hibiscus
o Unisexual flowers: Either stamen or carpel is present e.g., corn
o Pollen released from the bursting of anther, which contains male gametes
o Each ovule contains one egg cell or female gamete
o Pollination: transfer of pollens from the anther of one flower to the stigma of the same or different flower
o Fertilization: Process of fusion of male and female gametes
o After fertilization: zygote = embryo, ovule = seed, ovary = fruit
Sexual reproduction in animals
o Puberty: A period of physical change by which a child’s body becomes an adult’s body and capable of reproduction
o Secondary sex characteristics: The body changes during puberty
o Male reproductive organs: Pair of testes, vas deferens, prostate gland, seminal vesicles
o Testes: Produce sperms and hormone testosterone
o Sperms: Contain male gametes
o Female reproductive organs: Pair of ovaries, pair of oviducts, uterus, and vagina
o Ovaries contain thousands of eggs
o Sperms enter the female body through the vagina
o Fertilization: The process of fusion of the nucleus of the sperm with the ovum to form a zygote
o Zygote divides to form an embryo
o Embryo implanted in the uterus
o Foetus develops inside the mother’s body for nine months
o Menstruation: If the egg is not fertilized, then the uterus lining breaks down and is released in the form of blood and mucous through the vagina
o Sexually transmitted diseases: Infections that get transferred through sexual contact e.g., herpes, HIV-AIDS, syphilis, gonorrhea etc.
o Contraceptive methods help avoid pregnancy: These include natural methods, barrier methods, oral contraceptives, implants, and surgical methods
BEST OF LUCK
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