Quiz three: Lecture four slides
DOMAIN EUKARYA
KINGDOM PLANTAE
PHYLUM RHODOPHYTA (red algae)
Slide 1: Chondrus crispus: this species, commonly called Irish moss, is commercially important. It is
harvested along the sublittoral zones of the rocky temperate shores of the north Atlantic. The
carageenans are used as a thickener and is found in such foods such as ice cream. It is extracted from
this alga’s cell walls. The name carageenan is derived from the name of the Irish village Carragheen,
where Irish moss is found in abundance.
Slide 2: Palmaria palmata: commonly known as dulse; this red alga is edible. It is also found along the
rocky temperate shorelines of the north Atlantic.
Slide 3: Encrusting coralline algae: your book shows a picture of coralline algae that produce a thallus.
Some coralline algae are encrusting; their cells form a crust across rock surfaces or in this case, on the
glass of an aquarium.
PHYLUM CHLOROPHYTA (green algae)
Slide 4: Chlamydomonas: this single celled green alga is very important in biological studies. It has two
flagella and a single horseshoe shaped chloroplast. Notice how small this organism is.
Slide 5: Volvox: the individual cells of this colonial green alga look very much like a colony of
Chlamydomonas. However, the cells that make up Volvox species have become so dependent upon
their colonial arrangement that they cannot exist independently.
The small spheres inside the larger
spheres are daughter colonies that develop by mitosis of specialized cells within the mother colony.
Slide 6: Ulva: this is a multicellular green alga. Its common name is sea lettuce, which should be
obvious by its appearance. Ulva is often found along temperate rocky shores such as New England.
Ulva species produce gametes that look just like Chlamydomonas cells!
PHYLUM CHLOROPHYTA
CLASS CHAROPHYCEAE
Slide 7: Chara: a great deal of evidence suggests that organisms within the class Charophyceae share a
most recent common ancestor with land plants. Organisms within the genus Chara have the common
name stonewort because of its coarse texture, which is due to large amounts of calcium carbonate
deposited on the surface of the plant.
SEEDLESS NONVASCULAR PLANTS
PHYLUM HEPATOPHYTA (liverworts)
Slide 8: Marchantia: Notice the flat thalloid gametophyte as well as the male and female gametangia.
The antheridiophores have a flat, smooth top shape and produce antheridia, which in turn produce
sperm; the archegoniophores look a bit like a small palm tree and produce archegonia, which in turn
produce eggs. The sporophyte will grow attached to and dependent on the archegonia. Note also the
gemmules, sometimes called gemmae cups, which are asexual reproductive structures.
PHYLUM ANTHOCEROPHYTA (hornworts)
Slide 9: Anthoceros: the green sporophytes look like long blades of grass; they are growing out of the
gametophytes. Is the sporophyte haploid or diploid?
PHYLUM BRYOPHYTA (true mosses)
Slide 10: Polytrichum: notice the sporophyte (composed of the seta and capsule) growing from the
female gametophyte. The sporangium is called a capsule (what occurs inside the capsule)? Unlike
liverworts and hornworts, true mosses tend to grow more vertically and the sporophyte does not usually
conduct photosynthesis.
Slide 11: Sphagnum: commonly called peat moss, this species produces acids that slow decomposition.
It is found living in moist cool environments (such as in Ireland) and is harvested for energy—it’s dried
and burnt. Can you recognize the sporophyte (with its seta and capsule) and the gametophyte?
SEEDLESS VASCULAR PLANTS
PHYLUM LYCOPHYTA (club mosses and quillworts)
Slide 12: Club moss: club mosses are named for their club shaped strobili; the strobili are clusters of
sporophylls. Remember phyll is Greek for leaf. Thus a sporophyll is a leaf specialized to bear sporangia;
pack a lot of sporophylls together in one structure and it is called a strobilus—i.e., a cone!
PHYLUM PSILOPHYTA (whisk ferns)
Slide 13: Psilotum: notice the dichotomously branched stems (stems branching from one to two) and
the yellow knob composed of three fused sporangia. These two characteristics are very
plesiomorphic. In addition they do not produce roots, and they have scale-like microphylls.
PHYLUM SPHENOPHYTA (horse tails)
Slide 14: Equisetum: horse tails have both vegetative and fertile shoots. The fertile shoots are easy to
find because of the strobilus at the end of the shoot. The nodes and internodes give these plants a
jointed appearance and so they are sometimes referred to as arthrophytes (jointed plants). They were
once used as scouring rushes for pots and pans.
PHYLUM PTEROPHYTA (ferns)
Slide 15: Prothallus: within the Phyla Lycophyta, Psilophyta and Sphenophyta we only examined the
sporophytic part of the lifecycle. For phylum Pterophyta we will discuss the entire lifecycle including the
gametophyte and the sporophyte. The gametophytic part of the lifecycle within phylum Pterophyta is
called the prothallus. The prothallus is heart-shaped and produces both antheridia and archegonia,
which means fern spores are homosporous. The root-like structures on the prothallus are called
rhizoids and relative to their cellular structure and organization, are not true roots—although they have a
similar function, attachment and uptake of nutrients.
Slide 16: Young sporophyte: sperm are flagellated and swim to the egg within the archegonia. After
syngamy the sporophyte starts to grow—it can be seen here growing out of the prothallus.
Slide 17: Fiddleheads: as the sporophyte continues to grow it will form this highly coiled structure
appropriately named a fiddlehead.
Slide 18: Fern fronds: the leaves of ferns are called fronds and the fronds represent the sporophytic
generation. Notice the dots on the underside of the leaves. These are called sori and contain many
small, individual sporangia.
Slide 19: Fern sori (close-up): another picture of the sori. As noted each sorus will contain many
sporangia that will produce spores. The spores are eventually released. If they land in a suitable habitat
they will develop into a gametophyte (prothallus) and the life cycle is complete.