7. Is this a plant?
• Ascophyllum nodosum
• This is a seaweed of the
northern Atlantic Ocean,
also known as
Norwegian Kelp, Knotted
Kelp, knotted wrack or
egg wrack. It is not a
plant but rather a large
common brown algae.
8. Land vs. Water
• Land existence makes photosynthesis more
effective. Water filters light.
• Carbon dioxide and oxygen are in higher
concentrations and diffuse more rapidly in air.
• Land plants have adaptations to reduce the loss
• Leaves are covered with a waxy cuticle that holds
• The leaves have openings know as stomata that
open and close to regulate gas and water
10. Relationship to Algae
• Plants are believed to be closely related to
• Both use chlorophylls a and b.
• Both use starch as the food reserve.
• The cell walls of both contains cellulose.
• Both form a cell plate during cell division.
• Unlike green algae, plants have sex organs
with an outer layer of reproductive cells.
11. Alternation of Generations
• The sporophyte
generation is a
haploid spores by
meiotic cell division.
• The gametophyte
generation is a
gametes by mitotic
• The division hepatophyta contains 10,000 species
• This name comes from the liver shaped lobes of
• Marchantia, for example has a flat lobed thallus
about a centimeter in length. The upper surface
of the thallus is smooth the lower surface bears
numerous rhizoids projecting into the soil.
• It reproduces sexually and asexually.
• Rhizoids are the rootlike hairs that anchor the
bryophytes and absorb water and minerals
from the soil.
• Asexual reproduction involves gemmae in
gemmae cups on the upper surface of the
• Sexual reproduction depends on antheridia and
• Antheridia are on disk-headed stalks and produce
• Archegonia are on umbrella-headed stalks and
• A Zygote develops into a tiny sporophyte
composed of a foot, short stalk, and capsule.
• Spores produced within the capsule of the
gametophyte are disseminated by the wind.
• Division Bryophyta
• Interestingly, Spanish Moss is not a bryophyte but
rather a member of Bromeliaceae, the same
family that contains pineapples.
• There are about 12,000 species of mosses in the
• Mosses are found in the Arctic through the
tropics to parts of the Antarctic.
• Moss prefers damp shaded localities; however
some survive in desserts while others live in bogs
• Mosses can store large quantities of water in
their cells. When dried out they become
dormant, but turn green again after some rain.
• Most mosses can reproduce asexually by fragmentation.
• The moss life cycle begins with an algalike protenema developing
from germination of a haploid spore.
• Three days of favorable growing conditions produce uprights shoots
covered with leafy structures.
• Rhizoids anchor the protonema, to which the shoots are attached.
• The shoots bear antheridia and archegonia at their tips.
• Antheridia produce flagellated sperm which need external water to
reach eggs in archegonia.
• Fertilization results in a diploid zygote that undergoes mitotic
division to develop a sporophyte.
• The sporophyte consists of a foot, stalk, and upper capusle
(sporangium) where spores are produced.
• The sporophyte is initially green and photosynthetic; at maturity it
is brown and non-photosynthetic.
21. Nonvascular Plants
• Lack specialized tissues for transporting water,
minerals, and organic nutrients
• They lack true roots, stems, and leaves, although
they have rootlike, stemlike, or leaflike structures.
• The gametophyte is the dominant generation.
• Flagellated sperm swims to the vicinity of the egg
in a continuous film of water.
• The sporophyte is attached to and derives
nourishments form the photosynthetic
22. Vascular Plants
• Xylem is a vascular
tissue that conducts
water and minerals up
from the soil.
• Phloem is a vascular
tissue that transports
organic nutrients from
one part of the plant to
23. Organs of Vascular Plants
• Roots absorb water and minerals from the soil
• Stems conduct water and mineral to leaves
and conduct organic nutrients from leaves to
• Leaves are adapted to maximize
photosynthetic activity; they are covered by a
• Leaves have openings (stomates) that open
and close to regulate water and gas exchange.
24. Reproduction of Vascular Plants
• The diploid sporophyte generation is
dominant; this is the generation that has
• Seedless vascular plants (ferns and their allies)
disperse their species by producing
• In seed plants there is a separate
microgametophyte (male) and
25. Whisk ferns (division Psilotophyta)
• Occur in Arizona, Texas,
Hawaii, and Puerto Rico
• Have no leaves or roots,
posses a branched
rhizome with rhizoids
and a mycorrhizal fungus
that helps gather
• Aeriel stems with tiny
scales fork repeatedly
and carry on
26. Club Mosses (division Lycopodophyta)
• ~ 1,000 species of club
• Tightly packed, scalelike
microphylls cover stems
and branches; each
contains one strand of
• Most live in tropics or
subtropics as epiphytes,
plants that live on trees
without harming them.