[Biology Class Notes] on Pollination By Birds Pdf for Exam

Pollination is the process of transferring pollen grains from a flower’s male anther to its female stigma. Every living organism, including plants, strives to produce offspring for the next generation. Plants can produce offspring in a variety of ways, one of which is by producing seeds. Seeds contain the genetic information required to create a new plant.

Flowers are the tools that plants use to produce seeds. The diagram below depicts the basic parts of a flower.

Pollen can only be transferred between flowers of the same species to produce seeds. A species is defined as a population of individuals capable of freely interbreeding with one another but who do not interbreed with members of other species due to geographic, reproductive, or other barriers.

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How Does Pollen Grains Get From one Flower to Another Flower? 

Flowers must rely on pollen vectors to spread pollen. Wind, water, birds, insects, butterflies, bats, and other animals that visit flowers are examples of vectors. Pollinators can be either animals or insects that transfer pollen from one plant to another.

Pollination is usually an unintended result of an animal’s activity on a flower. When pollen grains attach themselves to the animal’s body, it is often eating or collecting pollen for its protein and other nutritional properties, or it is sipping nectar from the flower. When the animal visits another flower for the same reason, then what happens is there are chances that the pollen might fall off onto the flower’s stigma, resulting in the flower’s successful reproduction.

According to the animated image, pollen from Flower 1’s anthers is deposited on Flower 2’s stigma. Pollen may “germinate” on the stigma, which means that a “pollen tube” forms on the sticky surface of the stigma and grows down into the plant’s ovule.

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This growth can result in: Successful fertilisation of the flower and the growth of seeds and fruit; or, a plant that is only partially fertilised, resulting in the fruit and/or seeds not fully developing; or, a plant that is only partially fertilised, resulting in the fruit and/or seeds not fully developing; or, a plant that is only partially fertilised, resulting in the fruit and/or seeds not fully developing; or the plant may not be pollinated at all and may not reproduce at all.

Plants Can Be:

Advantages and Disadvantages of Self-pollination

• Self-pollination ensures the abolition of recessive traits.

• When compared to cross-pollination, pollen grain waste is very low.

• The purity of the race is maintained during the self-pollinating process because there is no diversity in the genes.

• External factors such as wind, water, and other pollinating agents are not involved in self-pollination.

• Self-pollination ensures that even small amounts of pollen grains produced by plants have a high success rate in pollination. 

Disadvantages

The main disadvantage of self-pollinating is that there is no gene mixing. As a result, the race’s vigour and vitality are diminished.The immune system of the offspring is weakened as a result.

Cross-Pollinating –  which means that the plant needs a vector or a catalyst (a pollinator or the wind) to get the pollen to another flower of the same species.

Let’s discuss the Advantages and Disadvantages of Cross-pollination

Advantages

• The seeds that are produced have a high level of vigour and vitality.

• Through the process of cross-pollination, all unisexual plants can reproduce.

• As a result of genetic recombination, recessive traits in the lineage are eliminated.

• This process strengthens the offspring’s resistance to diseases and other environmental factors.

• Cross-pollination introduces new genes into a species sequence primarily through fertilisation between genetically different gametes.

Disadvantages

• There is a significant amount of pollen grain waste in this process.

• Because of genetic recombination during meiosis, there is a chance that good qualities will be lost and unwanted characteristics will be added to offspring.

Pollinating Birds

“Ornithophily” refers to the act of pollination by birds. Hummingbirds, spiderhunters, sunbirds, honeycreepers, as well as honeyeaters are the most common pollinators. Hummingbirds are the world’s smallest birds, weighing as little as 2.5 grammes, or the weight of a penny.

Pollination is essential for flowering plants to survive. Because most flowering plants cannot pollinate themselves, they must rely on other animals. Many small birds, such as sunbirds and hummingbirds, play an important pollination role.

Plants that are pollinated by birds are built to accommodate them, such as having a sturdy structure to support perching and flowers with a re-curved, tube-like shape that does not tangle the birds. The flowers are also shaped in such a way that a bird’s beak can reach them. These plants also have brightly coloured nectar-containing flowers.

Process of Pollination By Birds

The pollination process in birds is as follows:

1. Birds visit flowers in search of energy-rich nectar.

2. Most flowers pollinated by birds contain nectar deep within the flower.

3. When a bird tries to reach the nectar, pollen adheres to its head, neck, and back.

4. When birds visit other plants, they spread pollen.