Plant Classification & Reproduction

Plants can be classified into 2 main groups: Non-seed plants  mosses = no vascular systems  ferns = vascular systems but no seeds Seed plants  Gymnosperms = complex vascular system + bare seed (cone)  Angiosperm = complex vascular system + enclosed seed within a flower

Reproduction terminology Alternation of Generation Any life cycle that involves sexual and asexual reproduction The life cycle of all plants have 2 phases: Asexual reproduction  new plant produced from one parent plant only (genetically identical to parent)  Sporophyte  form of plant that reproduces asexually Sexual reproduction  new plant produced by union of a male and female sex cell (NOT genetically identical)  Gametophyte  form of plant that reproduces sexually ( egg + sperm –-- fertilization ----  zygote  embryo  new sporophyte)

Non-seed plant Fern  have large leafy fronds, rhizomes (underground stems) and generally prefer warm moist climates. Needs water for reproduction. Life Cycle  Sporophyte – large and photosynthetic Produces spores asexually  Gametophyte – separate small plant (1cm diameter) from the sporophyte produces zygote sexually

Seed plants Gymnosperms  woody trees or shrubs (conifers) that produce seeds that are NOT in an enclosed structure. Wind needed for pollination. Life Cycle  Sporophyte = large trees that produce cones Produces pollen and eggs  Gametophyte = microscopic plant found on specialized structure on the sporophyte Produces seeds

Angiosperms  flowering plants. Can be pollinated by insects and wind. Life Cycle  Sporophyte = flowering plant produces pollen and eggs  Gametophyte = pollen and egg found in the flowers produces seeds

… these are the parts of the flower Male reproductive part = stamen which are made up of…  filament - stalk  anther – produces pollen grains Female reproductive part = Pistil which is made up of…  style – stalk  stigma – sticky surface at tip of style  ovary – organ that contain the egg style

Fern Vs. Angiosperm Comparison of their life Cycles page 279 figure 8 and page 283 figure 6

FernAngiosperm Spore produced on fern frondFlowers on the sporophyte produce pollen Spores released and develop into a small gametophyte Pollen is carried to other flower Gametophyte produces egg and sperm Egg and sperm unit and create a zygote Pollen grain grows down style to reach the ovary. Sperm in the pollen grain then fertilizes the egg Zygote develops and seed is formed. Zygote develops into mature sporophyte (fern) The seed is released and develops into a new sporophyte