What Do We mean by Life Span? . The duration from birth to the natural death of an organism is known as its life span. Life Span varies from organism to organism. It may be a few minutes to several thousand years. Below are phases of Life : In an organism, there are 4 phases of life:
- Juvenile/Vegetative Phase
- Reproductive Phase
- Ageing / Senescence Phase
- Death Phase
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What is Reproduction in Organisms? What are its Types?
Reproduction in organisms is the biological process in which new individuals are formed from their parents.
Asexual Reproduction and Sexual Reproduction
What is Asexual Reproduction and What are its types.
Asexual Reproduction is defined as the formation of an organism from a single parent. It does not require the fusion of gametes. An Organism that is produced by asexual reproduction in organisms is genetically referred to as a “clone.”
- Fission
- Budding
- Regeneration
- Fragmentation
- Sporulation
- Vegetative Propagation
Fission & Types of Fission | Reproduction in Organisms
- The breakdown of a cell is called Fission.
- In Fission, an organism gives rise to new individuals through the division of a parent cell.
- When the new individuals are formed, the parent cell loses its identity.
Fission has two kinds. Binary Fission and Multiple Fission
What is Binary Fission? When a parent cell breaks into two halves and produces two daughter cells is called binary Fission.
Types of Binary Fission: Binary Fission has four types as per their plane of division:
- Irregular binary Fission: E.g., Amoeba
- Longitudinal binary Fission: E.g., Euglena
- Transverse binary Fission: E.g., Paramecium
- Oblique binary Fission: E.g., Ceratium
What is Multiple Fission?
When a parent cell breaks down into more than two cells is called multiple Fission. E.g. Plasmodium.
Budding & Its Types | Reproduction in Organisms
Budding is defined as when a new organism is produced from a particular site of its parent body. Budding has two types:
- Exogenous or External
- Endogenous or Internal
What is Exogenous Budding?
When a bud produced from the outgrowth (external part) of their parent cell is called exogenous budding. E.g., Yeast and Hydra.
What is Endogenous Budding?
- When a bud is produced inside the parent cell is called Endogenous budding.
- In this type of budding, the buds are known as gemmules. And the whole process is called Gemmulation. E.g., Spongilla and Ephydatia.
Fragmentation
- Fragmentation is the process by which a part of the parent body is broken down and gives rise to new individuals through mitosis.
- Fragmentation can happen naturally or through predators. It can intentionally or unintentionally occur.
E.g., Spirogyra, molds, lichens, and cyanobacteria
Regeneration- Regeneration is the process by which a part of the body is cut down and then regenerates after some time. E.g., Lizard and Starfish.
Sporulation or Spore formation
- Sporulation is the process by which the spores are produced due to the breakdown or rupturing of the spore cases.
- Each spore forms a new individual.
E.g., Bread mold and Penicillium.
Vegetative Propagation & It’s Types
It’s another type of reproduction in organisms. Vegetative propagation is the process in which non-reproductive parts of plants are involved in the formation of new plants. For example: stems, roots, and leaves. Vegetative Propagation has two types: Natural and Artificial
What is Natural Vegetative Propagation?
When a new individual is produced without human involvement by stem, roots and leaves, then it is called natural vegetative propagation. A few examples of natural vegetative propagation
- Roots: In some plants, like Dahlia, asparagus, and sweet potato, have tuberous roots that contain food and produce new plants from them.
- Leaves: In some plants, leaves have small buds in their margins, and they will grow into new plants when the leaves fall. E.g., Bryophyllum.
- Stems: In many plants, like ginger, strawberries, potatoes, onions, water
- Hyacinth and others have stems in the form of nodes that store nutrients, and they give rise to new plants.
What is Artificial Vegetative Propagation? When a new individual is produced by human involvement, though stems, roots and leaves. A few examples of artificial Vegetative Propagation
- Cutting: When a part of a plant is cut off and planted in a suitable rooting medium. E.g.: Rose and Sugarcane
- Grafting: When a rooted plant is attached to a non-rooted plant, or a new plant is called grafting. E.g.: mango, apple, and rose.
Layering & It’s Types
When a plant is bent to the ground and in contact with the soil, the new individual starts growing—E.g, grapes and jasmine. Layering has four types:
- Simple layering
- Compound layering
- Mound layering
- Air Layering
- Tissue Culture: When small pieces of plant tissue give rise to various plantlets when they are sown in a sterile and nutrient-rich medium in controlled laboratory conditions. E.g.: Bananas, Orchids, and Oil Palm.
Advantages of Asexual Reproduction
- It is helpful in rapid population growth in a favorable environment.
- In this, energy efficiency is not required, or very little energy is required.
- With the help of asexual Reproduction, we get the new individuals the same as their parent cell and the traits are passed easily from generation to generation.
- It is helpful in agriculture by giving a crop that has desired characteristics.
- In this type of reproduction in organisms, new individuals mature faster than in sexual Reproduction.
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