Plant biodiversity

• Spores/seeds of bryophyte 


  Reproduce by means of spores found in spore capsules
• Vascular Tissue of bryophyte 


  • None present
• Habitat of bryophyte 


  Damp, shady places
• Reproduction of bryophyte 


  1. Sexual: Depends on water for sexual reproduction. Sperm cell swims from male to female to reach the ovum.

  2. Asexual: By means of spores, need dry weather for release from the capsule.
• Bryophytes structure and examples 


  • E.g. mosses, liverworts, hornworts
  • Thallus-no true roots, stems or leaves
  • Rhizoids anchor the plant to the ground
  • Gametophyte is the dominant generation
  • Leaf-like structures which increase surface area for photosynthesis
  • Water is absorbed from any part of the plant
• Gymnosperm Spores/Seeds

  • Seeds are naked and borne on cones and have wings for wind dispersal
  • When seeds are blown out of the female cone they land on the ground and will only germinate when conditions are favourable
• Gymnosperm Vascular Tissue

  • Well developed consisting of xylem and phloem which undergo secondary thickening
• Gymnosperm Reproduction

  1. Male gametophytes (pollen) are delivered to female gametophytes

  2. Fertilization occurs and does not depend on water

  3. If the seed germinates a sporophyte is formed
• Gymnosperms structure and examples 


  • E.g. conifers (pine trees), cycads, gingophytes (ginko biloba), gnetophytes (welwitschia)
  • True stems, leaves and roots
  • Pine tree sporophyte
  • Reproduces by spores which are produced in cones
  • Top-root system
  • Needle-shaped leaves with thick cuticle, sunken stomata, evergreen
  • Sporophyte is the dominant generation
• Pteridophyte Spores/seeds

  • Small brown patches on lower surface of pinnae - sori
  • Sporangia in sori produce spores
  • Spores germinate into gametophytes- this is asexual reproduction (takes place in dry weather)
• Pteridophyte Reproduction

  1. Water is needed for fertilisation

  2. Male gametes swim to female gametes

  3. Fertilization occurs and gives rise to the sporophyte plants
• Pteridophyte Vascular Tissue

  • Well developed-contains xylem and phloem
• Pteridophytes structure and examples 


  • E.g. ferns, horsetails, whisk ferns
  • Leaves - fronds
  • Stem - rhizome, stores food
  • Roots - adventitious roots
  • Fronds divided into leaves, leaflets, pinnae
  • Fronds have a cuticle, contain stomata
• Angiosperm Seeds/spores

  • Spores produced in flowers
  • Flowers produce seeds in fruits which arise from the ovaries of flowers
• Angiosperm Reproduction

  1. Male spores produced in the stamen (pollen)

  2. Female spores produced in the pistil (ovule)

  3. Pollen grains transported to other flowers by insects or wind (pollination)

  4. Fertilization occurs when two gametophytes fuse

  5. Fertilized egg develops into a tiny embryo inside a seed

  6. Germinating seed grows into a new sporophyte plant
• Angiosperms examples and structures 


  • E.g. Roses, Daisies, grasses and maples
  • Divided into monocots and dicots
  • Have true leaves and well developed roots
  • Plants we see = dominant phase sporophytes
  • Separate male and female gametophyte
  • Flower is the reproductive organ which contains male and female gametes
• Angiosperm Vascular Tissue

  • Well developed consisting of xylem and phloem
  • Dicots undergo secondary thickening
• There is a progressive development in aspects of plant structure and life cycle from bryophytes to angiosperms
• This progressive development includes reduction in dependence on water for sexual reproduction and increased dispersal of spores/seeds
• These progressive trends of land plants suggest an evolutionary relationship with all of them arising from a common ancestor
• Evolutionary relationships between different species can be shown by means of diagrams and phylogenetic trees
• Angiosperm habitat

  Mostly terrestrial but can be hydrophytes and xerophytes
• Pteridophytes habitat

  Moist, shady places like forests
• Gymnosperm habitats

  windy,cold,dry areas
• Types of reproduction


  • Asexual
  • Sexual
• Sexual reproduction


  • Gametes (sperm, ovum) are formed
  • One sperm cell fertilizes one ovum resulting in formation of a zygote
  • From the zygote an adult made up of millions of cells develops
  • Non-identical individuals are formed
  • There is genetic variation
• Asexual reproduction


  • In plants it is known as vegetative reproduction
  • Individuals are identical to one another and the parents
  • Spores, cones and flowers as well as parts of gametophytes possess the reproductive structures
  • Roots, stems and leaves are the vegetative parts
  • When new organisms arise from the vegetative structure, original reproduction occurs
• Sexual reproduction advantages

  • offspring produced are genetically different from one another and their parents- individuals may find condition suitable and survive
  • zygote is covered by thick protective coat which allows it to survive in unfavourable conditions
• Sexual reproduction disadvantages

  • chances of reproduction occurring is reduced is population size is small
• Asexual reproduction advantages

  • take place quickly allowing pioneer speckles to establish themselves in a new habitat
  • ensures that if parents are successful in habitat, offspring will also be
• Asexual reproduction disadvantages

  • all offspring are genetically identical
  • if conditions in habitat change or one plant gets a disease it is likely most members of population will also be affected