The advantages and disadvantages of sexual and asexual reproduction

The advantages and disadvantages of sexual and asexual reproduction

Sexual reproduction involves the fusion of two gametes. The advantages of sexual reproduction are that the offspring may inherit beneficial qualities from both parents, and that there is greater genetic variation among the offspring. Genetic variation increases the chances of a species’ survival as some individual organisms will be better adapted to changes in the environment. The disadvantages of sexual reproduction is that two parents are required, so it will be disadvantageous in a very competitive environment.

Asexual reproduction, on the other hand, does not involve gametes as the offspring arise from the parent through cell division. Thus the advantages of asexual reproduction are that only one parent is required, and that beneficial qualities are more likely to be passed on to the offspring since all offspring are genetically identical to the parent. However, the disadvantage of having genetically identical offspring is that there is less variation, so the organism will be less adapted to changes in the environment.

• Reproduction is the production of new organisms. Reproduction is necessary to ensure the continuity of species.
• Asexual reproduction produces genetically identical offspring from one parent by mitosis. Genetically identical offspring are called clones.
• Sexual reproduction involves the fusion of two gametes to form a zygote, producing genetically dissimilar offspring from two parents. Gametes are special reproductive cells produced by meiosis. 
• The process by which the nucleus of the male gamete fuses with the nucleus of the female gamete to form a zygote is called fertilisation. 

Determining Sex of Offspring

Specification:

• Recall that the sex of a person is controlled by one pair of chromosomes, XX in a female and XY in a male
• Describe the determination of the sex of offspring at fertilisation, using a genetic diagram

 

Definitions:

Autosomes/Autosomal Chromosomes: Chromosomes in a cell other than the sex chromosomes

Sex chromosomes:

• Human males have an X chromosome and a much shorter Y chromosome in each somatic cell. The X chromosome contains more genes than the Y chromosome.
• Females have a pair of X chromosomes.
• Human somatic cells have 22 pairs of autosomal chromosomes and a pair of sex chromosomes, X and Y.
   
  Determining Sex:
• During gamete production, the female gametes or eggs contain an X chromosome each.
• However, the male will produce two types of sperm-one containing an X chromosome, the other, the Y chromosome.
• When male and female gametes fuse during fertilisation, there is a 50% chance that the offspring could be male or female.
• A baby girl inherits one X chromosome from her mother and another from her father.
• A baby boy receives an X chromosome from his mother and a Y chromosome from his father.