quiz class 7 science chapter 12
Answers
(b) A flower may have either male or female reproductive parts. Such a flower is called __unisexual__.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as __pollination__.
(d) The fusion of male and female gametes is termed as __fertilisation__.
(e) Seed dispersal takes place by means of __wind__, __water__ and __animals__.
Question 2: Describe the different methods of asexual reproduction. Give examples.
Answer: The various modes of asexual reproduction in plants are as follows:
(i)Vegetative propagation: It is the ability of a plant to produce new plants from roots, stems, leaves, and buds. Vegetative propagation is divided into two types.
Natural vegetative propagation: This type of vegetative propagation occurs easily in nature and involves simple vegetative parts. Potato plant sprouting from an eye is a common example.Artificial vegetative propagation: This type of vegetative propagation is performed manually and generally occurs in laboratory conditions. The formation of a complete plant from a stem cutting of rose is a common example of this method.
(ii) Budding:It involves the formation of a new individual from a bulb-like projection called a bud. The bud grows and gets detached from the parent to form a new individual. It is commonly observed in yeast.
(iii)Fragmentation:It is a form of asexual reproduction where a new organism is formed from the fragments of the parent body. It is the only mode of asexual reproduction in Spirogyra.
(iv)Spore formation:Many non-flowering plants reproduce through spore formation. Spores are tiny cells protected by a thick wall. Fungi such as bread moulds reproduce asexually using this method.
Question 3: Explain what you understand by sexual reproduction.
Answer: Sexual reproduction is a process which involves production of seeds. It requires two parents. Most plants reproduce sexually with the help of flowers. The main function of a flower is to reproduce and therefore develop new seeds that can grow into new plants.
Question 4: State the main difference between asexual and sexual reproduction.
Answer: Differences between sexual and asexual reproduction:
Asexual reproductionSexual reproductionIt requires only one parent.It requires two parents.In asexual reproduction, newlydeveloped plants are identical to the
parent and to each other.
In sexual reproduction, newly developed plantsare not identical to parents.Special reproductive parts are notrequired for asexual reproduction.Flower is the reproductive part of a plant whichcontains the sexual organs of a plant. These are
important for sexual reproduction.
Examples are yeast, rose, jasmine,potato, etc.Examples are flowering plants, such as Hibiscus,corn, papaya, etc.
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Answer:
Decribe the different methods of sexual reproduction
Ans Different methods of auxual reproduction legitative propagation. It is a type of asexual
reproduction in which new plants are produced from roots,stem,leaves and seeds
. Budding - It involves the formation of individual from a bulb-like,projection called a bud
fragmenstation- In this method, the body of parent breaks into small pieces called fragment and each fragmentation grow up to become a new plant.
spores formation -in this method the parent plant produces hundred of tiny spores which can grow into a new plant.
state main difference between asexual and sexual reproduction.
asexual reproduction- it require only one parent.
new individual formed is completely identical to its parent. special reproductive organs are not required. example-yeast, rose,etc.
sexual reproduction- it require male and female parent. new individual formed is not completely identical to its special reproductive organs are required. example- insect ,animal, human being