Transcript Plant Life Cycles

Plant Diversity
and Life Cycles
Biology 2
Chapter 29
LycophytaNonvascular Plants
• Plants which lack xylem and
phloem, the vascular tissues which
carry water and sugars to all parts
of the plant.
• Lack true leaves, roots and stems
• Hornworts, liverworts and
mosses
Hornworts
Liverworts
Mosses
Life Cycle of Mosses
• The dominant form of a moss is a
clump of leafy green
gametophytes which produces the
sperm and the egg
• Have alternation of generations
• The alternate form is called the
sporophyte and produces the
spores
Antheridium
•The male reproductive
structures that produce
hundreds of flagellated
sperm by mitosis
Archegonium
•The female reproductive
structure that produces a
single egg by mitosis
Fertilization
• When sperm unites with the egg
and begins dividing to form the
zygote
haploid
haploid
diploid
Sporophyte
• Grows from the tip of a
gametophyte and remains
attached to it
• Forms the spores by meiosis
which are released and grow to
produce the gametophyte
Seedless Vascular Plants
• Plants which reproduce by spores
and lack vascular tissue
• Ferns, horsetails and whisk ferns
Pterophyta
• Ferns
Life Cycle of a Fern
• Has alternation of generations
• The sporophyte is the
dominant form
• The gametophyte is tiny and
forms the antheridia and
archegonia
Sori
•Located on the
underside of a fern
frond and contain the
sporangia where the
spores are formed
Sphenophyta
• Horsetails, Equisetum
Equisetum
Psilophyta
• Whisk ferns