Plants, Sexual/Asexual Reproduction in Plants (8B Science)

• Plant kingdom


  Organisms that have green leaves, cell walls made of cellulose and can photosynthesise
• Groups organisms are classified into

  • Kingdoms
  • Genus
  • Species
• Scientific name


  Two-word name used to identify each species
• Biodiversity


  The range of species in an area
• Reasons to preserve biodiversity

  • Organisms depend on one another (they are interdependent)
  • We won't be able to make use of organisms if they become extinct
  • More biodiverse areas recover better from natural disasters
• Sexual reproduction in plants

  1. Gametes fuse to produce a zygote

  2. Zygote uses cell division to grow into an embryo

  3. Embryo grows into an adult and becomes a parent
• Inherited variation


  Differences in characteristics from both parents
• Female reproductive organ


  • Stigma
  • Style
  • Carpel
  • Ovary
  • Ovule (contains egg cell)
• Male reproductive organ


  • Anther (makes pollen grains)
  • Filament
• Pollination


  1. Pollen grains carried from anther to stigma

  2. Usually by insects or wind
• Adaptations to attract insects for pollination

  • Brightly coloured and scented petals
  • Nectary produces sugary nectar
  • Feathery stigmas catch pollen
• Adaptations to wind pollination

  • Large anthers and stigmas hang outside flower
  • Anthers make large amounts of small, smooth, light pollen grains
• Fertilisation


  1. Pollen tube grows from pollen grain into ovule

  2. Male gamete nucleus joins with egg cell nucleus to form zygote
• Seed formation


  1. Zygote grows into embryo

  2. Ovule becomes a seed, containing embryo and food store
• Seed dispersal methods


  • Eaten by animals (e.g. apples)
  • Carried on animal fur (e.g. burdock)
  • Carried by wind (e.g. dandelion)
  • Explode and scatter (e.g. lupins)
• Seed germination


  1. Requires water, oxygen, warmth (WOW)

  2. Water allows chemical reactions to start

  3. Oxygen needed for respiration

  4. Warmth speeds up chemical reactions
• Plant growth from seed

  1. Root grows first

  2. Shoot grows

  3. New leaves open and photosynthesis starts

  4. Glucose from photosynthesis turned into starch for storage
• Requirements for plant growth

  • Light
  • Air
  • Water
  • Warmth
  • Nutrients (mineral salts)
• Asexual reproduction in plants


  One parent plant produces offspring (e.g. runners, tubers)
• Sampling


  Using a small sample of a population to estimate the characteristics of the larger population
• The more samples taken, the more accurate the estimate but the longer it takes
• Ovules are found inside the ovary.
• Pollen grains are produced by anther.
• Stigma is where pollen lands on female reproductive organ.