Download Title - Iowa State University

Leader:
Course:
Instructor:
Date:
Week 3, Session 2
Chapter 29
Supplemental Instruction
Iowa State University
Kelsey
Bio 211 (5)
Dr. Holscher
9-10-09
1. What is the dominant stage (sporophyte/gametophyte) in non-vascular plants
(bryophytes)?
gametophyte
2. What is the dominant stage (sporophyte/gametophyte) in vascular plants?
sporophyte
3. Match the structure to the definition:
i. peristome ___c____
ii. rhizoid ___a_____
iii. stomata ___f____
iv. sori ___b____
v. lignin ___d_____
vi. sporophylls __e_____
a. Anchor in mosses that keeps
gametophytes in place
b. Found on ferns, contain
sporangia that disperse bisexual
spores
c. Found on mosses, releases
haploid male and female spores
d. Structural component of xylem
that allows the plant to grow tall
e. Modified leaves that bear
sporangia, can be circular or coneshaped
f. Pores that enable gas exchange
in some species of nonvascular
plants
4. __Xylem___________ carries water and minerals through tracheids in plants.
5. __Phloem___________ distributes sugar and amino acids in plants.
6. True or false: Homosporous plants produce two types of spores that develop into a
bisexual gametophyte. ____false_______
a. If this is false, make it a true statement: Homosporous plants produce one type of
spore that develops into a bisexual gamete.
7. True or false: All seed plants (and a few seedless plants) are heterosporous. __true_____
Supplemental Instruction
1060 Hixson-Lied Student Success Center  294-6624  www.si.iastate.edu
a. If this is false, make it a true statement:
N/A
Discussion Questions:
1. How do bryophtes differ from other plants?
Bryophytes don’t have an extensive vascular system. They have a dominant gametophyte
stage. They do not have seeds. Hornworts and moss (not liverworts) sporophyte stages
have stomata.
2. What does it mean for something to be haploid? Diploid? Are humans haploid or diploid?
Do we have both types of cells?
Haploid: has only one set of chromosomes.
Diploid: has two sets of chromosomes.
Humans are diploid. We have both haploid and diploid cells. Our somatic (body) cells are
diploid, our reproductive cells (gametes: sperm and eggs) are haploid.
3. In alternation of generations, which stages are haploid and which are diploid? What
happens that changes a plant from a haploid stage to a diploid stage? What changes a
plant from a diploid stage to a haploid stage?
Haploid stages: gametophyte, gametes, spores
Diploid stages: zygote, sporophyte
Fertilization changes a plant from a haploid stage to a diploid stage. Meiosis changes a
plant from a diploid stage to a haploid stage.
4. What process does the gametophyte undergo to produce haploid gametes? What process
does the sporophyte undergo to produce haploid spores? How does the gametophyte stage
change to the sporophyte stage?
Mitosis causes the gametophyte to produce haploid gametes. The sporophyte undergoes
meiosis to produce haploid spores. The gametophyte stage changes to the sporophyte
stage through the joining of two gametes to form a zygote (fertilization), and mitosis of
the zygote.
5. What is different about how gametes and spores develop into sporophytes and
gametophytes, respectively?
One haploid gamete must join together with a haploid second gamete and undergo
fertilization to develop a zygote that becomes a diploid sporophyte.
One haploid spore can develop into a haploid gametophyte independently. It does not
need to join together with anything else.