IB DP Biology: SL复习笔记5.2.3 Plant Phyla Features

• All plants belong to the plant kingdom
• Within the plant kingdom are several phyla (singular phylum)
• Some plant phyla are small
  • E.g. the Glaucophytes contain only 70 species and the Gingkophytes contains only 1 living species
• There are four major plant phyla
  • Bryophytes (20 000 species)
  • Filicinophytes (10 000 species)
  • Coniferophytes (600 species)
  • Angiospermophytes (352 000 species)
• Each of the four main phyla can be identified by their characteristics

Bryophytes

• The bryophytes include mosses, liverworts, and hornworts
• They are small, terrestrial plants
• They have no vascular tissue
• Cambium tissue is also absent
  • Cambium is a tissue containing stem cells that differentiate into xylem and phloem cells
• Reproduction takes place via spores
  • Spores are produced in and dispersed from spore capsules
• Bryophytes do not produce flowers, pollen, ovules, seeds, or fruits
• No true roots are present, but hair-like structures called rhizoids anchor plants in the soil

The bryophytes include mosses and liverworts

Filicinophytes

• Filiconophytes are the ferns
• Ferns are mainly terrestrial and have vascular tissue
• Roots, stems, and leaves are present
  • Fern leaves are divided structures known as fronds
• Cambium tissue is absent
• Reproduction takes place via spores
  • Spores are produced in and dispersed from structures on the underside of fronds called sporangia
• Filicinophytes do not produce flowers, pollen, ovules, seeds, or fruits

The filicinophytes are the ferns

Coniferophytes

• More commonly referred to as the conifers, the coniferophytes are usually tall, straight, trees
• Roots, stems, and leaves are present
• Vascular tissue is present, as well as cambium tissue
• Reproduction is carried out via pollen and ovules
  • Pollen is produced in male cones and ovules are produced in female cones
    • Pollen is the male gamete and ovules are the female gamete
  • No flowers are present
  • Both male and female cones are present on each tree
  • Pollen is carried from one cone to another by the wind in order for fertilisation to take place
• Seeds develop after fertilisation inside cones and are dispersed by falling to the ground or by animals
• Most coniferophytes are evergreen (i.e. they retain their leaves all year round)

Coniferophytes reproduce via pollen and ovules that are produced inside cones

Angiospermophytes

• Often referred to as angiosperms, these are flowering plants
• This is an incredibly diverse phylum, with examples including grasses, shrubs, and non-coniferous trees
• Roots, stems, and leaves are present
• Vascular and cambium tissues are present
• Reproduction is carried out via pollen and ovules
  • Flowers produce pollen and also contain ovules within an ovary
  • Fertilisation occurs when pollen is transferred from one flower to another by e.g.
    • Insects
    • Animals
    • Wind
  • Seeds form and are dispersed via fruits which develop from the ovaries of flowers

Angiospermophytes reproduce via pollen and ovules produced in flowers

Plant Phyla Features Table