Ch 27: Seedless Plants

Plant

a complex multicellular eukaryote that has *cellulose cell walls*, *chlorophylls a and b* and carotenoids, and carotenes (orange pigments)

Lignin

a strengthening polymer in the walls of cells that function for support and conduction; the stiffening property of lignin enabled plants to grow tall, which let them maximize light interception

In plant life cycles a) the first products of meiosis are gametes b) spores are part of the diploid sporophyte generation c) the embryo gives rise to a zygote d) the first stage in the diploid sporophyte generation is the prothallus

*d) the first stage in the diploid sporophyte generation is the zygote*

These plants have vascularized stems but lack true roots and leaves. a) mosses b) club mosses c) horsetails d) whisk ferns e) hornworts

*d) whisk ferns*

The _____________ is the first stage in the sporophyte generation.

*diploid zygote* - the zygote divides by mitosis and develops into a multicellular embryo, the young sporophyte plant

The plant life cycle alternates between _________________ generations.

*haploid and diploid*

The fern gametophyte is known as the __________.

*prothallus*

Archegonia

female gametangia

Gametangium

sex organs

Gametophyte generation

the haploid portion of the life cycle; *gives rise to haploid gametes by mitosis*

*Four major groups of plants exist today*. Name them.

*Bryophytes (nonvascular plants), seedless vascular plants, gymnosperms, & angiosperms* - land plants probably descended from a group of green algae called *charophytes* or stoneworts -bryophytes rely on diffusion and osmosis to obtain needed materials; *may have been the earliest plants to colonize land* - vascular plants contain *xylem and phloem* - A key step in the evolution of vascular plants was the ability to produce *lignin* -seedless vascular plants arose and diversified during the Silurian and Devonian periods of the Paleozoic era -gymnosperms appeared at the end of the Devonian period -angiosperms arose during the early Cretaceous period of the Mesozoic era

The green, gametangia-bearing moss plant a) is the haploid gametophyte generation b) is the diploid sporophyte generation c) is called the protonema d) contains cells with single large chloroplasts e) a and c

*a) is the haploid gametophyte generation*

A strengthening compound found in cell walls of vascular plants is a) chitin b) lignin c) cutin d) cellulose e) carotenoid

*b) lignin*

What is the difference between green algae and plants?

All plants develop from multicellular *embryos* that are enclosed in maternal tissues - referred to as embryophytes

The nonvascular plants include...

Phylum Hepatophyta (liverworts) Phylum Anthocerotophyta (hornworts) Phylum Bryophyta (mosses)

The archaeplastids include...

red algae, green algae, and land plants

True or False? Modern green algae share many biochemical and metabolic traits with modern plants.

*True* Both contain: - chlorophylls a and b and carotenoids such as xanthophylls (yellow pigments) and carotenes (orange pigments) - store excess carbohydrates as starch - cellulose is the major component of their cell walls - share certain details of cell division, including the formation of a cell plate during cytokinesis

The waxy layer that covers aerial parts of plants is the a) cuticle b) archegonium c) protonema d) stoma e) thallus

*a) cuticle*

Which of the following is NOT a characteristic of plants? a) cuticle b) unicellular gametangia c) stomata d) multicellular embryo e) alteration of generations

*b) unicellular gametangia*

With of the following statements about ferns isn't true? a) ferns have motile sperm cells that swim through water to the egg-containing archegonium b) ferns are vascular plants c) ferns are the most economically important group of bryophytes d) the fern sporophyte consists of a rhizome, roots, and fronds e) the diversity of ferns is greatest in the tropics

*c) ferns are the most economically important group of bryophytes*

These plants have hollow, jointed stems that are impregnated with silica. a) mosses b) club mosses c) horsetails d) whisk ferns e) hornworts

*c) horsetails*

___ is a leaf that arose from a branch system. a) antheridium b) microphyll c) megaphyll d) sorus e) microspore

*c) megaphyll*

The bryophytes a) include mosses, liverworts, and hornworts b) include whisk ferns, horsetails, and club mosses c) are small plants that lack a vascular system d) a and c e) b and c

*d) a and c*

Plants probably descended from a group of green algae called a) rhyniophphytes b) Calamites c) epiphytes d) charophytes e) club mosses

*d) charophytes*

Phloem

conducts dissolved organic molecules such as sugar

Xylem

conducts water and dissolved minerals

Antheridia

male gametangia

Sporophyte generation

the diploid portion of the life cycle; *occurs when two gametes fuse; produces haploid spores by the process of meiosis, these spores represent the beginning of the gametophyte generation*

Bryophytes

• "moss plant" • the dominant stage is the gametophyte (leafy plant) - bryophytes divided into liverworts, hornworts, and mosses - moss gametophytes are differentiated into "leaves" and "stems" • no true roots, stems, or leaves

Describe the moss life cycle.

• Male and female gametophytes • Gametophyte is dominant, photosynthetic • Sporophyte is attached to and nutritionally dependent on gametophyte

Describe characteristics of nonvascular plants.

• No true roots, stems, or leaves - Rhizoids anchor the plant in the soil • No vascular tissue • Gametophyte is dominant • Moist habitats • Limited size • No seeds

Describe the characteristics of seedless vascular plants (ferns and fern allies)

• Vascular tissue - Xylem and phloem • Roots, stems, leaves • Dominant sporophyte

Club Moss

• lycophytes • small plants with rhizomes and short, erect branches - evergreen • considered to be a *fern ally* because these plants are not moss