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Biology for Advanced Level Secondary Schools
(f) They have a well-developed and
independent sporophyte generation, Exercise 3.12
since the gametophyte withers and
dies as the young leaves of sporophyte 1. You are consulted by a friend who is
grow. raising ferns in his garden for the first
time. He needs your advice on what
(g) They have cuticle in their leaves to appropriate measures he should take
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prevent excessive water loss. to rescue his fern plants, that appear to
(h) Archegonia secrete a chemical, which have a lot of dust brown spots on the
attracts antherozoids to swim towards lower side of the leaves, which were
the egg during fertilisation. not there when they were young. Based
on your knowledge of ferns, advise him
accordingly.
Activity 3.7: Observation of fern plants 2. Give reasons as to why ferns are
Materials considered to have evolved from
Mature fern plant (Dryopteris sp.) and bryophytes.
hand lens or light microscope 3. In what ways is a fern plant more
Procedure adapted to terrestrial environment than
(a) Collect a mature fern plant bryophytes?
(Dryopteris sp.) from a damp
shaded area such as in the forest, 3.6.3 Division Coniferophyta
floor or water canal or river bank. Coniferophyta is a division of the kingdom
Plantae, which belongs to a broad group of
(b) Uproot the plant with a small part non-flowering seed bearing plants, referred
of the rhizome and roots. to as gymnosperms. The word gymnosperms
(c) Carefully examine the collected originated from a combination of two Greek
fern plant. Take note of the fronds words Gymnos meaning ‘naked’ and sperma
(leaves) arising from the horizontal meaning ‘seed.’ Theophrastus was the first
stem (rhizome). person to use this term in his book “Enquiry
(d) Turn the frond and observe its lower into plants” referring to plants producing
side with the aid of a hand lens naked seeds. Under gymnosperms, there
or section of a frond under a light are four groups namely:
microscope. Note small dark or (a) Conifers; the cone bearing plants, such
brown patches on the lower side of as cypresses; example: Cupressus
mature fronds. Each discrete patch species (Figure 3.26), pines; example:
is called sorus. Pinus sylvestris, and Spruce; Picea
species, which are the most abundant
Question gymnospermous species.
Describe the morphology of the collected
fern plant.
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