Oviparous animals lay eggs outside their body. As a result, the eggs of these animals are under continuous threat from various environmental factors. On the other hand, in viviparous animals, the development of the egg takes place inside the body of the female. Hence, the offspring of an egg-layingRead more
Oviparous animals lay eggs outside their body. As a result, the eggs of these animals are under continuous threat from various environmental factors. On the other hand, in viviparous animals, the development of the egg takes place inside the body of the female. Hence, the offspring of an egg-laying or oviparous animal is at greater risk as compared to the offspring of a viviparous animal, which gives birth to its young ones.
Cucurbit plant bears unisexual flowers as these flowers have either the stamen or the pistil. The staminate flowers bear bright, yellow coloured petals along with stamens that represent the male reproductive structure. On the other hand, the pistillate flowers bear only the pistil that represents thRead more
Cucurbit plant bears unisexual flowers as these flowers have either the stamen or the pistil. The staminate flowers bear bright, yellow coloured petals along with stamens that represent the male reproductive structure. On the other hand, the pistillate flowers bear only the pistil that represents the female reproductive structure.
Other examples of plants that bear unisexual flowers are corn, papaya, cucumber, etc.
A flower that contains both the male and female reproductive structure (stamen and pistil) is called a bisexual flower. Examples of plants bearing bisexual flowers are: 1. Water lily ( Nymphaea odorata) 2. Rose (Rosa multiflora ) 3. Hibiscus (Hibiscus Rosa-sinensis ) 4. Mustard ( Brassica nigra) 5.Read more
A flower that contains both the male and female reproductive structure (stamen and pistil) is called a bisexual flower. Examples of plants bearing bisexual flowers are:
1. Water lily ( Nymphaea odorata)
2. Rose (Rosa multiflora )
3. Hibiscus (Hibiscus Rosa-sinensis )
4. Mustard ( Brassica nigra)
5. Petunia (Petunia hybrida)
Fertilization is the process of the fusion of the male and the female gamete to form a diploid zygote. After fertilization, the zygote divides several times to form an embryo. The fertilized ovule forms a seed. The seed contains an embryo, enclosed in a protective covering, called the seed coat. AsRead more
Fertilization is the process of the fusion of the male and the female gamete to form a diploid zygote. After fertilization, the zygote divides several times to form an embryo. The fertilized ovule forms a seed. The seed contains an embryo, enclosed in a protective covering, called the seed coat. As the seed grows further, other floral parts wither and fall off. This leads to the growth of the ovary, which enlarges and ripens to become a fruit with a thick wall called the pericarp.
Gametogenesis:- It is the process of the formation of haploid male and female gametes from diploid meiocytes through the process of meiosis. Embryogenesis:- It is the process of the development of the embryo from the repeated mitotic divisions of the diploid zygote. For more answers visit to websiteRead more
Gametogenesis:- It is the process of the formation of haploid male and female gametes from diploid meiocytes through the process of meiosis.
Embryogenesis:- It is the process of the development of the embryo from the repeated mitotic divisions of the diploid zygote.
Zoospore:- 1. A zoospore is a motile asexual spore that utilizes the flagella for movement. 2. It is an asexual reproductive structure. Zygote:- 1. A zygote is a non-motile diploid cell formed as a result of fertilization. 2. It is formed as a result of sexual reproduction. For more answers visit toRead more
Zoospore:-
1. A zoospore is a motile asexual spore that utilizes the flagella for movement.
2. It is an asexual reproductive structure.
Zygote:-
1. A zygote is a non-motile diploid cell formed as a result of fertilization.
2. It is formed as a result of sexual reproduction.
External fertilization is the process in which the fusion of the male and the female gamete takes place outside the female body in an external medium, generally water. Fish, frog, starfish are some organisms that exhibit external fertilization. Disadvantages of external fertilization:- In external fRead more
External fertilization is the process in which the fusion of the male and the female gamete takes place outside the female body in an external medium, generally water.
Fish, frog, starfish are some organisms that exhibit external fertilization.
Disadvantages of external fertilization:-
In external fertilization, eggs have less chances of fertilization. This can lead to the wastage of a large number of eggs produced during the process.
Further, there is an absence of proper parental care to the offspring, which results in a low rate of survival in the progenies.
Meiosis is a process of reductional division in which the amount of genetic material is reduced. Gametogenesis is the process of the formation of gametes. Gametes produced by organisms are haploids (containing only one set of chromosomes), while the body of an organism is diploid. Therefore, for proRead more
Meiosis is a process of reductional division in which the amount of genetic material is reduced. Gametogenesis is the process of the formation of gametes. Gametes produced by organisms are haploids (containing only one set of chromosomes), while the body of an organism is diploid. Therefore, for producing haploid gametes (gametogenesis), the germ cells of an organism undergo meiosis. During the process, the meiocytes of an organism undergo two successive nuclear and cell divisions with a single cycle of DNA replication to form the haploid gametes.
Although sexual reproduction involves more time and energy, higher organisms have resorted to sexual reproduction in spite of its complexity. This is because this mode of reproduction helps introduce new variations in progenies through the combination of the DNA from two (usually) different individuRead more
Although sexual reproduction involves more time and energy, higher organisms have resorted to sexual reproduction in spite of its complexity. This is because this mode of reproduction helps introduce new variations in progenies through the combination of the DNA from two (usually) different individuals. These variations allow the individual to cope with various environmental conditions and thus, make the organism better suited for the environment. Variations also lead to the evolution of better organisms and therefore, provide better chances of survival. On the other hand, asexual reproduction does not provide genetic differences in the individuals produced.
(a) Juvenile phase:- It is the period of growth in an individual organism after its birth and before it reaches reproductive maturity. (b) Reproductive phase:- It is the period when an individual organism reproduces sexually. (c) Senescent phase:- It is the period when an organism grows old and loseRead more
(a) Juvenile phase:- It is the period of growth in an individual organism after its birth and before it reaches reproductive maturity.
(b) Reproductive phase:- It is the period when an individual organism reproduces sexually.
(c) Senescent phase:- It is the period when an organism grows old and loses the ability to reproduce.
Why are offspring of oviparous animals at a greater risk as compared to offspring of viviparous animals?
Oviparous animals lay eggs outside their body. As a result, the eggs of these animals are under continuous threat from various environmental factors. On the other hand, in viviparous animals, the development of the egg takes place inside the body of the female. Hence, the offspring of an egg-layingRead more
Oviparous animals lay eggs outside their body. As a result, the eggs of these animals are under continuous threat from various environmental factors. On the other hand, in viviparous animals, the development of the egg takes place inside the body of the female. Hence, the offspring of an egg-laying or oviparous animal is at greater risk as compared to the offspring of a viviparous animal, which gives birth to its young ones.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/
Examine a few flowers of any cucurbit plant and try to identify the staminate and pistillate flowers. Do you know any other plant that bears unisexual flowers?
Cucurbit plant bears unisexual flowers as these flowers have either the stamen or the pistil. The staminate flowers bear bright, yellow coloured petals along with stamens that represent the male reproductive structure. On the other hand, the pistillate flowers bear only the pistil that represents thRead more
Cucurbit plant bears unisexual flowers as these flowers have either the stamen or the pistil. The staminate flowers bear bright, yellow coloured petals along with stamens that represent the male reproductive structure. On the other hand, the pistillate flowers bear only the pistil that represents the female reproductive structure.
Other examples of plants that bear unisexual flowers are corn, papaya, cucumber, etc.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/
What is a bisexual flower? Collect five bisexual flowers from your neighbourhood and with the help of your teacher find out their common and scientific names.
A flower that contains both the male and female reproductive structure (stamen and pistil) is called a bisexual flower. Examples of plants bearing bisexual flowers are: 1. Water lily ( Nymphaea odorata) 2. Rose (Rosa multiflora ) 3. Hibiscus (Hibiscus Rosa-sinensis ) 4. Mustard ( Brassica nigra) 5.Read more
A flower that contains both the male and female reproductive structure (stamen and pistil) is called a bisexual flower. Examples of plants bearing bisexual flowers are:
1. Water lily ( Nymphaea odorata)
2. Rose (Rosa multiflora )
3. Hibiscus (Hibiscus Rosa-sinensis )
4. Mustard ( Brassica nigra)
5. Petunia (Petunia hybrida)
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/
Describe the post-fertilization changes in a flower.
Fertilization is the process of the fusion of the male and the female gamete to form a diploid zygote. After fertilization, the zygote divides several times to form an embryo. The fertilized ovule forms a seed. The seed contains an embryo, enclosed in a protective covering, called the seed coat. AsRead more
Fertilization is the process of the fusion of the male and the female gamete to form a diploid zygote. After fertilization, the zygote divides several times to form an embryo. The fertilized ovule forms a seed. The seed contains an embryo, enclosed in a protective covering, called the seed coat. As the seed grows further, other floral parts wither and fall off. This leads to the growth of the ovary, which enlarges and ripens to become a fruit with a thick wall called the pericarp.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/
Differentiate between gametogenesis from embryogenesis.
Gametogenesis:- It is the process of the formation of haploid male and female gametes from diploid meiocytes through the process of meiosis. Embryogenesis:- It is the process of the development of the embryo from the repeated mitotic divisions of the diploid zygote. For more answers visit to websiteRead more
Gametogenesis:- It is the process of the formation of haploid male and female gametes from diploid meiocytes through the process of meiosis.
Embryogenesis:- It is the process of the development of the embryo from the repeated mitotic divisions of the diploid zygote.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/
Differentiate between a zoospore and a zygote.
Zoospore:- 1. A zoospore is a motile asexual spore that utilizes the flagella for movement. 2. It is an asexual reproductive structure. Zygote:- 1. A zygote is a non-motile diploid cell formed as a result of fertilization. 2. It is formed as a result of sexual reproduction. For more answers visit toRead more
Zoospore:-
1. A zoospore is a motile asexual spore that utilizes the flagella for movement.
2. It is an asexual reproductive structure.
Zygote:-
1. A zygote is a non-motile diploid cell formed as a result of fertilization.
2. It is formed as a result of sexual reproduction.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/
Define external fertilization. Mention its disadvantages.
External fertilization is the process in which the fusion of the male and the female gamete takes place outside the female body in an external medium, generally water. Fish, frog, starfish are some organisms that exhibit external fertilization. Disadvantages of external fertilization:- In external fRead more
External fertilization is the process in which the fusion of the male and the female gamete takes place outside the female body in an external medium, generally water.
Fish, frog, starfish are some organisms that exhibit external fertilization.
Disadvantages of external fertilization:-
In external fertilization, eggs have less chances of fertilization. This can lead to the wastage of a large number of eggs produced during the process.
Further, there is an absence of proper parental care to the offspring, which results in a low rate of survival in the progenies.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/
Explain why meiosis and gametogenesis are always interlinked?
Meiosis is a process of reductional division in which the amount of genetic material is reduced. Gametogenesis is the process of the formation of gametes. Gametes produced by organisms are haploids (containing only one set of chromosomes), while the body of an organism is diploid. Therefore, for proRead more
Meiosis is a process of reductional division in which the amount of genetic material is reduced. Gametogenesis is the process of the formation of gametes. Gametes produced by organisms are haploids (containing only one set of chromosomes), while the body of an organism is diploid. Therefore, for producing haploid gametes (gametogenesis), the germ cells of an organism undergo meiosis. During the process, the meiocytes of an organism undergo two successive nuclear and cell divisions with a single cycle of DNA replication to form the haploid gametes.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/
Higher organisms have resorted to sexual reproduction in spite of its complexity. Why?
Although sexual reproduction involves more time and energy, higher organisms have resorted to sexual reproduction in spite of its complexity. This is because this mode of reproduction helps introduce new variations in progenies through the combination of the DNA from two (usually) different individuRead more
Although sexual reproduction involves more time and energy, higher organisms have resorted to sexual reproduction in spite of its complexity. This is because this mode of reproduction helps introduce new variations in progenies through the combination of the DNA from two (usually) different individuals. These variations allow the individual to cope with various environmental conditions and thus, make the organism better suited for the environment. Variations also lead to the evolution of better organisms and therefore, provide better chances of survival. On the other hand, asexual reproduction does not provide genetic differences in the individuals produced.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/
Define: (a) Juvenile phase, (b) Reproductive phase, (c) Senescent phase.
(a) Juvenile phase:- It is the period of growth in an individual organism after its birth and before it reaches reproductive maturity. (b) Reproductive phase:- It is the period when an individual organism reproduces sexually. (c) Senescent phase:- It is the period when an organism grows old and loseRead more
(a) Juvenile phase:- It is the period of growth in an individual organism after its birth and before it reaches reproductive maturity.
(b) Reproductive phase:- It is the period when an individual organism reproduces sexually.
(c) Senescent phase:- It is the period when an organism grows old and loses the ability to reproduce.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-1/