i. bryophytes - mosses = many plants growing in a tight pack. no waxy cuticle and do not retain...
TRANSCRIPT
I. Bryophytes - mosses = many plants growing in a tight pack.
• No waxy cuticle and do not retain developing embryos w/i mother plant’s gametangium.
• Need water to reproduce; sperm are flagellated, must swim through water to reach eggs
• No vascular tissue to carry water(grow low to ground) and lack lignin
• Like damp, shady places
• Green spongy plant = gametophyte (male & female are separate plant shoots)(n)
• Taller brown shoot with a capsule, grows out of gametohyte = sporophyte (2n)
Alternation of Generations -
2 generations that take turns producing each other
• Gametophytes produce eggs and sperm; must unite to form a zygote, which forms new sporophytes.
• Sporophytes produce spores
• Spores can develop into a new organism without uniting, & have a tough coat to resist harsh environments.
• The new organism then produces gametophytes again.
• Gametophyte = larger more obvious plant in mosses
• Moss- Gametophyte (left) and Archegonium (female gametophyte) (right)
(Antheridium = male gametopyte.)
• Sporophyte generation (left) and Sporangia (right)
• Moss is cool! E.C. for bringing in moss with both generations. (In late spring.)
• II. Ferns - diverse with 12,000 species, most in tropics, many in temperate woodlands of U.S.
• Evolution of vascular tissue (xylem and phloem)
• Sperm are still flagellated-must swim through a film of water to fertilize eggs
• Are still seedless - have spores
• During Carboniferous Period, ferns in swamp forests converted to coal - (black sedimentary rock made up of fossilized plant material)
• Alternation of
Generations in ferns.
• Sporophytes are diploid and gametophytes are haploid
• Sporophyte is the dominant stage in ferns. (Gametophyte was dominant in mosses)
• Heart shaped gametophyte = prothallus