Page 265 - Microsoft Word - LessonPlan-Overview.doc
P. 265
Cells that have two sets of plant. These plants can also
chromosomes are called diploid. reproduce sexually, meaning two
parents are involved.
The sporophyte now undergoes a
process known a meiosis, in which For nonvascular plants, the
a cell divides to form cells with half gametophyte generation is most
the number of chromosomes. important, and when most people
Through meiosis, the diploid talk about the plant, they are
sporophyte produces haploid talking about the gametophyte
spores. Spores undergo mitosis generation. The male
producing a haploid gametophyte, gametophyte produces a sperm
and the process begins again. with a tail called a flagellum. The
sperm must swim to the egg made
Plants typically do not spend the by the female gametophyte.
same amount of time in the
sporophyte and gametophyte For this reason, sexual
generations. Some plants are reproduction in nonvascular plants
mainly sporophytes, while others can only happen in moist
are mainly gametophytes. Plants environments. Once the sperm
with flowers are mainly reaches the egg, it forms a
sporophytes, with the female sporophyte. The sporophyte is
gametophyte remaining in the dependent on the gametophyte
sporophyte, and with pollen as the and only exists to make spores so
male gametophyte. that a new gametophyte can be
formed.
Reproduction in Seedless
Plants
Plants reproduce differently
depending on which group they
belong to. Seedless nonvascular
plants can reproduce asexually,
meaning only one parent is
necessary.
Hornworts and liverworts can both Figure 10 – The spore of nonvascular
undergo fragmentation, where a plants (seen here under magnification)
small bit of the plant is broken off, produces a new gametophyte.
eventually forming an entirely new
© 2011 Supercharged Science www.ScienceLearningSpace.com
667
