Describe the life cycle of nonvascular plants, emphasizing the roles of gametophyte and sporophyte generations.
Nonvascular plants have a gametophyte-dominant life cycle. Haploid spores develop into gametophytes, which produce gametes in antheridia (sperm) and archegonia (eggs). Sperm require water to reach eggs for fertilization, forming a diploid zygote that grows into a sporophyte. The sporophyte produces haploid spores by meiosis, continuing the cycle.
How do monoecious and dioecious nonvascular plants differ in their reproductive structures?
Monoecious nonvascular plants have both antheridia (male) and archegonia (female) on the same gametophyte, while dioecious plants have male and female gametophytes on separate individuals.
What is the dominant generation in the life cycle of nonvascular plants?
The gametophyte is the dominant generation in nonvascular plants, meaning it is the most visible and long-lived stage.
What structures produce sperm and eggs in nonvascular plants, and what are their names?
Sperm are produced in antheridia (male gametangia), and eggs are produced in archegonia (female gametangia).
Why is water necessary for fertilization in nonvascular plants?
Water is needed for the sperm to swim from the antheridium to the archegonium to fertilize the egg.
Describe the main parts of a nonvascular plant sporophyte.
The sporophyte consists of a foot (attaches to and absorbs nutrients from the gametophyte), a seta (stalk), and a capsule (sporangium) where spores are produced.
What is the function of rhizoids in nonvascular plants?
Rhizoids anchor the plant and function similarly to roots, but they lack vascular tissue.
What is a protonema, and what role does it play in the life cycle of nonvascular plants?
A protonema is a chain of cells that grows from a spore and develops into the mature gametophyte.
How do monoecious and dioecious nonvascular plants differ?
Monoecious nonvascular plants have both antheridia and archegonia on the same gametophyte, while dioecious plants have male and female gametophytes on separate individuals.
How are spores produced in the sporophyte generation of nonvascular plants?
Spores are produced in the capsule of the sporophyte by meiosis, and these haploid spores grow into new gametophytes.