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B6 B) Reproduction
B6 B) Reproduction
There are two forms of reproduction; sexual reproduction and asexual reproduction.
Sexual Reproduction
Two individuals are required for sexual reproduction; a male (father) and a female (mother). The genetic information from these two individuals is combined to produce offspring that are genetically different to the parents. Sexual reproduction involves gametes, which are sex cells. For animals (including humans), the female gametes are eggs, and the male gametes are sperm. Gametes have half the normal number of chromosomes. Gametes are produced by a process known as meiosis.
Half of the chromosomes for the offspring come from the male gamete (sperm) and the other half of the chromosomes come from the female gamete (egg). Humans have 23 pairs of chromosomes (or 46 chromosomes in total); 23 chromosomes come from the sperm and the other 23 chromosomes come from the egg. The egg and the sperm fuse together through fertilisation forming a cell with the full number of chromosomes (23 pairs of chromosomes/ 46 chromosomes in total).
The genetic material for the offspring from sexual reproduction is different to the genetic material of the parents. This results in variation in the offspring. Some of the characteristics in the offspring will be inherited from the father and other characteristics will be inherited from the mother.
Two individuals are required for sexual reproduction; a male (father) and a female (mother). The genetic information from these two individuals is combined to produce offspring that are genetically different to the parents. Sexual reproduction involves gametes, which are sex cells. For animals (including humans), the female gametes are eggs, and the male gametes are sperm. Gametes have half the normal number of chromosomes. Gametes are produced by a process known as meiosis.
Half of the chromosomes for the offspring come from the male gamete (sperm) and the other half of the chromosomes come from the female gamete (egg). Humans have 23 pairs of chromosomes (or 46 chromosomes in total); 23 chromosomes come from the sperm and the other 23 chromosomes come from the egg. The egg and the sperm fuse together through fertilisation forming a cell with the full number of chromosomes (23 pairs of chromosomes/ 46 chromosomes in total).
The genetic material for the offspring from sexual reproduction is different to the genetic material of the parents. This results in variation in the offspring. Some of the characteristics in the offspring will be inherited from the father and other characteristics will be inherited from the mother.
Flowering plants can reproduce sexually. Plants have egg cells and pollen (the male gamete).
An advantage of sexual reproduction is that it brings variation into a population. Variation allows species to adapt to new or changing environments, which may give them a survival advantage. Also, variation in the offspring may mean that diseases are less likely to affect an entire population because the population is genetically different (if the population was genetically identical, a disease may wipe out/ affect an entire population).
One disadvantage of sexual reproduction is that it takes time and energy to find a mate. Another disadvantage is that sexual reproduction cannot be done if you are in isolation as a male and a female are required for sexual reproduction; you cannot undertake sexual reproduction if you cannot find a mate. A final disadvantage is that the sexual reproduction process is quite long in comparison to asexual reproduction.
An advantage of sexual reproduction is that it brings variation into a population. Variation allows species to adapt to new or changing environments, which may give them a survival advantage. Also, variation in the offspring may mean that diseases are less likely to affect an entire population because the population is genetically different (if the population was genetically identical, a disease may wipe out/ affect an entire population).
One disadvantage of sexual reproduction is that it takes time and energy to find a mate. Another disadvantage is that sexual reproduction cannot be done if you are in isolation as a male and a female are required for sexual reproduction; you cannot undertake sexual reproduction if you cannot find a mate. A final disadvantage is that the sexual reproduction process is quite long in comparison to asexual reproduction.
Asexual Reproduction
Asexual reproduction only requires one parent. The offspring produced by asexual reproduction are genetically identical to the parent, which means that there is no genetic variation with asexual reproduction. No gametes are involved in asexual reproduction.
During asexual reproduction, the cell (known as the parent cell) makes an exact copy of itself by copying all of the genetic material and dividing to create two genetically identical cells (known as daughter cells); this process is known as mitosis. The mitosis/ asexual reproduction process then repeats itself again and again. Asexual reproduction/ mitosis is how plants and animals grow and replace old cells.
Asexual reproduction can also occur in plants that produce runners. The runners produced are genetically identical to the plant that the runners have come off. Strawberry plants produce runners.
Asexual reproduction only requires one parent. The offspring produced by asexual reproduction are genetically identical to the parent, which means that there is no genetic variation with asexual reproduction. No gametes are involved in asexual reproduction.
During asexual reproduction, the cell (known as the parent cell) makes an exact copy of itself by copying all of the genetic material and dividing to create two genetically identical cells (known as daughter cells); this process is known as mitosis. The mitosis/ asexual reproduction process then repeats itself again and again. Asexual reproduction/ mitosis is how plants and animals grow and replace old cells.
Asexual reproduction can also occur in plants that produce runners. The runners produced are genetically identical to the plant that the runners have come off. Strawberry plants produce runners.
One advantage of asexual reproduction is that it is a very quick process, which means that an organism can rapidly increase their population. Also, only one parent is needed for asexual reproduction, which means that you can reproduce if you are in isolation, and you do not need to waste time and energy to find a mate.
However, a negative of asexual reproduction is that there is no genetic variation in the offspring/ population because all of the offspring are genetically identical. This means that the organism may be only suited to one habitat/ less able to cope with different environments. Also, the population may be more susceptible to a disease, which could wipe out/ affect the entire population
However, a negative of asexual reproduction is that there is no genetic variation in the offspring/ population because all of the offspring are genetically identical. This means that the organism may be only suited to one habitat/ less able to cope with different environments. Also, the population may be more susceptible to a disease, which could wipe out/ affect the entire population