Edexcel IGCSE Biology

Revision Notes

1.1.6 Living Organisms: Reproduction & Growth

Reproduction

  • Reproduction is the process that leads to the production of more of the same kind of organism
  • Reproduction is fundamental to the survival of a population and ultimately, the species
  • There are different types of reproduction: sexual and asexual

Sexual Reproduction

  • In this type of reproduction, the male and female gametes fuse together
    • In humans, the male gamete is the sperm and the female gamete is the egg
    • In plants, the male gamete is in the pollen grains and the female gamete is the ovule
  • The DNA of the offspring is composed of both maternal and paternal DNA

Sexual reproduction in humans, IGCSE & GCSE Biology revision notes
Sexual reproduction involves the fusing of two gametes to form a zygote that contains DNA from both parents

Asexual reproduction

  • Cells or whole organisms can also reproduce using asexual reproduction
  • Mitosis is an example of asexual reproduction
  • There is only one parent involved so an exact clone is produced
  • The DNA of offspring is identical to parental DNA
    • Plants can reproduce asexually through tubers, budding or runners
    • Single-celled organisms such as bacteria or amoeba reproduce asexually

Binary fission in bacteria, IGCSE & GCSE Biology revision notes
Asexual reproduction in bacteria involves creating exact copies of the parent cell

Growth

  • Growth is defined as a permanent increase in size
  • In animals, an individual grows larger between the zygote and adult stage with changes in proportion or shape
  • In plants, an individual grows larger throughout their whole life with new shoots, leaves, branches etc forming year after year

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Ruth graduated from Sheffield University with a degree in Biology and went on to teach Science in London whilst also completing an MA in innovation in Education. With 10 years of teaching experience across the 3 key science disciplines, Ruth decided to set up a tutoring business to support students in her local area. Ruth has worked with several exam boards and loves to use her experience to produce educational materials which make the mark schemes accessible to all students.
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