Sexual and asexual reproduction - class-IX

Asexual reproduction is a common method of reproduction by which offspring arise from a single parent and inherit the genes of that parent only. An important form of fission (a type of asexual reproduction) is binary fission, where the parent organism is replaced by two daughter organisms. Only prokaryotes (the archaea and the bacteria) reproduce asexually through binary fission. Eukaryotes (unicellular fungi) may reproduce in a functionally similar manner by mitosis. Multiple fission at the cellular level occurs in many protists, e.g. algae. The nucleus of the parent cell divides several times by mitosis, producing several nuclei. The cytoplasm then separates, creating multiple daughter cells.

Sexual reproduction involves both meiosis and mitosis. Meiosis occurs at the time of gamete formation. Repeated mitotic divisions occur in the zygote to form an embryo.

Binary fission is a method of separating a body into two new bodies. In this process, an organism duplicates its genetic material and divides into two parts where every new organism receives one copy of DNA. 

Haploid-diploid mechanism or Haplodiploidy is a unique phenomenon
in which an unfertilized egg develops into a male and a fertilized egg
develops into a female. Therefore, the female is diploid (2n), and the
male is haploid (n). Eggs are formed by meiosis and sperms by mitosis. Fertilization restores the diploid number of  chromosomes in the zygote
which gives rise to the female, If the egg is not fertilized, it will
still develop but into a male (arrhenotoky or
arrhenotokous parthenogenesis). It is seen in hymenopterous insects,
such as bees, wasps, saw flies and ants. So, the correct answer is 'Honeybees, ants and wasps'.

(i) sexual reproduction does not require two individuals because the fusion of two gametes released from the same plant can take place.

The panmictic plant is a plant which has immense potential to breed. It undergoes random meeting which has no mating restrictions, neither genetic nor behavioural. The mating takes place by sexual reproduction. Due to mating by sexual reproduction, recombination takes place and eventually, leads to genetic variation. It causes the change in the genetic pool.

Sexual reproduction is a biological process that creates a new organism by combining the genetic material of two organisms, by the fusion of one gamete from each. Motile male gamete generally fertilizes with nonmotile female gamete in this process.
Thus, the correct answer is option A.

Sexual reproduction is a form of reproduction where the two reproductive gametes obtained from both the parents fuse together, to form a zygote. The gametes involve a large ovum (or egg) obtained from female and a male's smaller sperm. Each gamete contains half the number of chromosomes of normal cells.

• Reproduction in man is only sexual. After insemination, there is a fusion of sperm and ovum in the oviduct. This process is called fertilization. After fertilization, implantation takes place in the uterus and the development and the growth of the fetus occurs there.

The type of reproduction in which no gametes are involved and the new organisms emerge from a single parent only is called asexual reproduction. There is no fusion of gametes in asexual reproduction and the chromosome number also remains constant. Various types of asexual reproduction include division, budding, spore formation, etc.

Apospory is the development of gametophyte without meiosis forming haploid spores. 

Sexual reproduction is a characteristic of most of the higher life forms. Sexual reproduction characteristically involves reduction division or meiosis to form haploid cells and syngamy or fertilisation to form a zygote. Asexual reproduction is a means of reproduction without involving meiosis or fertilization. Most of the unicellular organisms show asexual reproduction. Vegetative reproduction is a type of asexual reproduction. The term vegetative reproduction is used in the context of plants only. Plants propagate rapidly through vegetative propagation. For example, suckers, rhizomes, runners etc.

Sexual reproduction involves the formation of haploid gametes. The gametes are produced by a specialised type of cell division called meiosis. The meiosis is a special type of division because it is reductional division and it involves crossing over. The crossing over involves the exchange of chromosomal segments between non-sister chromatids of a homologous pair of chromosome. The crossing over results in new genetic combinations. The rearrangement of genetic material every time crossing over occurs produces new combinations thus leading to the generation of variations in a sexually reproducing population.

• Sexual reproduction involves the formation and fusion of gametes.
• This requires formation of gametes with meiosis in diploid organisms or meiosis taking place in zygote if the organism is haploid. 
• Due to meiosis, only 50% of the genetic material is passed to the next generation and fusion of gametes results in a unique combination of the genome. 
• While asexual reproduction results in offsprings with exact genetic material as their parent reducing chances of variations.

• Reproduction is the process by which new individual organisms or 'offsprings' are produced from their 'parents' and thus, 
• it is a fundamental feature of all known life, each individual organism exists as a result of reproduction.

• Unicellular organisms generally divide by asexual reproduction which involves budding, binary fission, multiple fission, fragmentation, spore formation.
• Multicellular organisms can divide by sexual as well as asexual methods. For example, vegetative propagation in all plants is a means of asexual reproduction while all higher animals reproduce sexually.

• Sexual reproduction is a biological process that creates a new organism by combining the genetic material of two organisms in a process that starts with meiosis. Hence, it is the cause of variation.

Fertilization is a process of fusion of gametes to produce new individual, which is generally the form of sexual reproduction.
Asexual reproduction is a mode of reproduction by which single parent produces new individuals without fertilization. And so in asexual reproduction, fertilization essentially is not required.
Thus, the correct answer is option C.

• Reproduction is the biological process of the production of new individual organisms or 'offsprings' from their parents. 
• It is essential for an organism to ensure its species to survive to the next generation.

• Fertilization is fusion of male and female gamete which is the key step involved in sexual reproduction.
• Asexual reproduction does not involve formation of gametes or fertilization. Here, a single organism can produce offsprings.

For the spread of mold, the presence of moisture and a large number of spores are required. Asexual reproduction is a form of reproduction by which offspring arise from a single organism and inherit the genes of that parent only. It does not involve the formation of gametes. Binary fission is a form of asexual reproduction whereby the parent cell divides to form two daughter cells. Thus, the correct answer is option C.

Reproduction is broadly categorized into asexual reproduction (involving one parent) and sexual reproduction (involving two parents and gamete fusion). Both are fundamental modes of biological reproduction.

In asexual reproduction only one parent is involved so there is no fusion of two cells, the daughter cells produced by asexual reproduction are genetically identical to the parent cells variations enable organisms to adopt and survive in changing environment and it helps to prevent the complete extinction of specters. so lack of genetic variation is the disadvantage.
 Whereas rapid reproduction is the advantage of asexual reproduction.

Sexual reproduction involves fusion of the sex cells - the sperm and egg. This fusion leads to mixing of genes of 2 sex cells. The resultant offspring has a mixture of genes from both father and mother. This leads to more genetic variation. In asexual reproduction, there is no mixture of genes. Hence no genetic variation or diversity. Thus, the correct answer is option B.

Sexual reproduction involves the fusion of gametes from two parents, which leads to genetic variation through the recombination of alleles during meiosis. This is a primary advantage of sexual reproduction over asexual reproduction.

Flowers contain the reproductive structures: stamens (male) and carpels (female). Stamens produce pollen grains, which contain two sperm cells, while carpels contain the egg cells. Seeds develop following pollination and fertilization (fusion of the male and female gametes). So the correct option is "Flower".

When two parents are involved in reproduction, the method is called sexual reproduction. The male and female gametes fuse during fertilization to produce the zygote. The zygote subsequently develops into an embryo which further develops into a new individual. So the correct option is "Reproduction".

Vegetative propagation is a form of asexual reproduction where plants grow from vegetative parts like stems, roots, or leaves without seeds. Since asexual reproduction is the broader category that includes vegetative propagation, both options A and C are correct.

A group of organisms, genetically related with one another and are formed from a single parent by means of asexual reproduction. In the genetic clone, all progeny are morphologically and genetically related with one another.

So,
the correct answer is 'plants produced by asexual means’

The process of formation of offsprings or progeny is called Reproduction. It may be vegetative or asexual or sexual types. The progeny formed by vegetative or asexual methods are looks like parents, but progeny formed by sexual reproduction shows variations with parents.

So, the correct option is ‘All the above’

Scattering of seeds ensures the spread of species over the maximum area which protects it and it also prevents the growth of the same plant at one place and reduces the competition of food and other resources hence reduces competition and over-crowding.

In many dioecious species, the application of auxins like IAA (Indole-3-acetic acid) can induce the development of male flowers on genetically female plants by altering hormonal balance.

• Sexual reproduction is a mode of reproduction where new organisms are produced by the exchange of genetic material during fertilization. 
• Vegetative propagation and budding are forms of asexual reproduction and there is no exchange of genetic material in asexual reproduction.

In asexual reproduction, a single parent is involved to produce offsprings by fission, budding, or regeneration. While in sexual reproduction, gametes are produced by both the parents which fuses to form a zygote.
Thus, the correct answer is option D.

• In sexual reproduction, two individuals are involved and there is the genetic exchange between the male and female. 
• As there is an exchange of genetic material, the offspring, won't have exactly the same material as either of his parents. 
• There will be a different genetic content of each offspring, every time. As a result, there is no genetic sameness instead, sexual reproduction leads to variation.

Asexual reproduction is a mode of reproduction in which single parent produces offspring and inherit their genes. Asexual reproduction never involves in ploidy or reduction. The offsprings will be an exact copy of their parent and their siblings as well.
Thus, the correct answer is the option C.

During gamete formation, there is meiosis in which mother cell divides into 4 cells having a half number of chromosomes. In fertilization, male and female gametes fuse to form a zygote having the same number of chromosomes as parents. Hence, the number of chromosomes remains constant.

In asexual reproduction, the only single parent is involved and progeny develops directly from its parent by cell division, fragmentation, budding, etc. passing the same genes from generation to generations. Thus offspring formed by asexual reproduction have similarities among themselves. 

• Sexual reproduction is a form of reproduction which involves the fusion of male and female gametes to form a zygote in a process called fertilization. Their looks are not exactly like their parents. 
• In sexual reproduction, there is increased variation in the population giving the species a better chance of survival in changing conditions. The offsprings are often more vigorous and flamboyant, meaning they go to great lengths to find a mate.

Seed is the product of ripened ovule after fertilization by pollen grains. These seeds further grow into a new plant. Some plants are reproduced without forming seeds but through the asexual reproduction. New sugarcane plants are produced from a mature sugarcane stem, rose from branch and potato from another potato. 

Meiosis does not occur during asexual reproduction. Meiosis is the process of producing gametes which is occur in sexual reproduction. On the other hand, mitosis is simply the process of cell division in asexual reproduction. This is the process that animals are going through during regeneration.