Biology AP Period 4
#22 Liem Nguyen
2/1/10
Homework #29 (090220): Chapter 29 (due Friday 90220)
Total points: 40 for Attempt on all questions
Concept Map: 10 Points
Chapter 29: Plant Diversity I: How Plants Colonized Land
Objectives
An Overview of Land Plant Evolution
1. Describe four shared derived homologies that link charophyceans and land
plants.
rose shaped complexes (synthesize cellulose microfibrils)
peroxisome enzyme (minimize loss of organic products)
flagellated sperm (resembles charophycean)
formation of a phragmoplast
Charophyceans and land plants both have rosette shaped arrays of proteins in
the plasma membrane that synthesize the cellulose microfibrils of the cell walls.
Peroxisome enzymes of both contain enzymes that help minimize the loss of
organic products from photorespiration. Also, in species of land plants that have
flagellated spore, the structure of the sperm resembles charophycean.
2. Distinguish among the kingdoms Plantae, Streptophyta, and Viridiplantae.
Note which of these is used in the textbook.
Embryophytes (plants)
include green algae (Streptophyta)
chlorophytes (Viridiplante kingdom)
Plantae are associated with embyophyes. Some biologists think that the
boundaries should include green algae, which would be Streptophyta. Also,
others suggest that it should also include chlorophytes in a Viridiplante kingdom.
The one in the book uses the kingdom Plante as the formal name.
3. Describe five characteristics that distinguish land plants from charophycean
algae. Explain how these features are adaptive for life on land.
apical meristems (land plants cant move to gain nutrients)
alternation of generations (not charophyceans)
walled spores (sporopollenin)
gametangia (fertilized egg)
multicellular embryo (plant tissues provide nutrients)
Five key traits appear in all land plants, but are absent in the charophyceans.
They are apical meristems, alternation of generations, walled spores,
multicellular gametangia and nulticellular embryos. Apical stems derived because
on land plants cannot move to gain nutrients. Because algae, but not
charophyceans have alternation of generations, we know that it was derived on
land. The sporopollenin makes it so that the spores are resistant to harsh
weather and can travel in dry air without harm. Gametangia make it possible for
the egg to be fertilized. Embryos derived because the parental tissues provide it
with nutrients.
4. Define and distinguish among the stages of the alternation of generations life
cycle.
gametophyte (haploid single set of chromosomes)
sporophyte (spore producing generation)
haploid/diploid (development during meiosis)
The cells of the gametophyte are haploid and have a single set of chromosomes.
There is a haploid gamete that fuses during fertilization. Mitotic division of the
zygote produces sporophyte, the spore producing generation. Meiosis in
sporophyte produces haploid spores that develop into a new organism.
5. Describe evidence that suggests that plants arose roughly 475 million years
ago.
fossils of plant spore (found in Oman)
490-425 million years ago
study of molecular clock
The evidence that suggests that plants arose roughly 475 million years ago
mainly lies upon the discovery of fossils of plant spores that were found in Oman.
These fossils of plant spores were found in rock that was 475 million years old.
Also, the molecular clock showed that the early ancestors of plants existed
mostly around 490-425 million years ago.
Bryophytes
6. List and distinguish among the three phyla of bryophytes. Briefly describe the
characteristics of each group.
3 phyla Hepatophyta, Anthocerophyta, Bryophyta
(phylum) liverworts, hornworts, mosses
Bryophytes are all non-vascular, seedless plants. The three phyla of bryophytes
are Hepatophyta, Anthocerophyta, and Bryophyta. Each phylum is a little
different in the form and structure of their seeds. Their traits are also slightly
different.
7. Distinguish between the phylum Bryophyta and the bryophytes.
non-vascular, seedless (bryophyte)
evolved after splitting from modern ancestors
separate of evolution
ancestors of modern vascular plants
special traits (Bryophyta phylum)
A bryophyte is any non-vascular, seedless plant. Plants in the Bryophyta phylum
are different because they evolved after splitting from the modern vascular
plants ancestors. Due to this separation of evolution, the plants in the Bryophyta
phylum have their own special traits.
8. Explain why bryophyte rhizoids are not considered roots.
lack a role in the process of water and nutrient consumption
lack in roots, no specialized conducting cells
Bryophyte rhizoids are not considered roots. The reasoning behind that decision
is that these bryophyte rhizoids lack a role in the process of water and nutrient
consumption. They also lack tissue in the roots and have no specialized
conducting cells.
9. Explain why most bryophytes grow close to the ground.
moist soil (tree bark)
few cells thick (unable to support tall plant)
germinate/become gametophytes
no vascular tissue
Bryophytes are only dispersed to a favorable habitat, including moist soil or tree
bark, which allows them to germinate and become gametophytes. Most
bryophytes grow near the ground because most of them are only a few cells thick
and are unable to support a tall plant. The second is that the bryophyte does not
have vascular tissue.
10. Diagram the life cycle of a bryophyte. Label the gametophyte and sporophyte
stages and the locations of gamete production, fertilization, and spore
production.
spores develop (archegonia/antherdia)
Buds become gametophytes
sperm fertilizes the egg
diploid zygote becomes sporophyte embryo
sporophyte is dependent on gametophyte
Meiosis occurs and spores develop
11. Describe the ecological and economic significance of bryophytes.
animal homes (forests and wetlands)
absorb radiation (in deserts)
peat store carbon (fuel source)
soil conditioner (fertilizer)
Bryophytes are common in forests and wetlands, providing homes for tiny
animals. Also, moss can be used to absorb radiation in deserts. Peat can store
carbon and has been used as a fuel source for some time now. It is also used as
a soil conditioner to fertilize it properly.
The Origin and Diversity of Vascular Plants
12. Describe the five traits that characterize modern vascular plants. Explain how
these characteristics have contributed to their success on land.
life cycles: sporophytes dominant
xylem and phloem transportation
root and leaf evolution
variation of sporophylls and spores
The life cycles with dominant sporophytes show that the sporophyte generation is
the larger and more complex generation in the alternation of generations. The
xylem and phloem transportation system allows nutrients to be transferred from
the roots, which have also evolved to allow more absorption of nutrients as well
as water. The leaves have evolved as well to be able to capture more solar
energy, out helping with photosynthesis. Sporophylls and spores have varied
from gymnosperm as well as parts of flowers.
13. Distinguish between microphylls and megaphylls.
Both contributed to evolution of leaves
microphylls in lycophytes
megaphylls in other vascular plants
single vein and branched
Microphylls and megaphylls both contributed to the evolution of leaves.
Microphylls are found in all lycophytes, and they are small, usually spine-shaped
leaves with a single vein. Almost all other vascular plants have megaphylls,
leaves with a highly branched vascular system.
14. Distinguish between the homosporous and heterosporous condition.
most seedless vascular plants homosporous
homosporous one sporophyll
hetersporous two sporophylls
Most seedless vascular plant species are homosporous, having on type of
sporophyll producing one type of spore that typically develops into a bisexual
gametophyete, as in most ferns. Hetersporous species have two types of
sporophylls, megasporangia and microsporangia, and produces two kinds of
spores, megaspores and microspores.
15. Explain why seedless vascular plants are most commonly found in damp
habitats.
flagellated sperm in seedless vascular plants
fertilize through water (swimming sperm)
fragile gametophytes (damp environments)
Seedless vascular plants have flagellated sperm that must swim through a film of
water to reach eggs. Due to these swimming sperm, as well as their fragile
gametophytes, living seedless vascular plants are most common in damp
environments.
16. Name the two clades of living seedless vascular plants.
lycophytes (club mosses)
pterophytes (whisk ferns)
lycophytes are most primitive
pterophytes similar molecularly
Lycophytes, such as club mosses, spike mosses, and quillworts, are the most
primitive group of vascular plants. Giant ones thrived for millions of year, but died
out and now only small lycophytes survive. Pterophytes are different
appearance-wise, but similar molecularly. They consist of whisk ferns, horsetails,
and ferns.
17. Explain how vascular plants differ from bryophytes.
Vascular complex vascular tissue
Bryophyte called nonvascular plants
lack innovations, roots, true leaves
could be or not be monophyletic
evidence disagrees
Vascular plants have a complex vascular tissue, but bryophytes do not, which is
why they are sometimes called nonvascular plants. They also lack innovations
such as roots and true leaves, unlike vascular plants. Bryophytes could be or not
be monophyletic, but evidence disagrees.
18. Distinguish between giant and small lycophytes.
both have different functions
giant lycophyte larger in size
small lycophyte smaller in size
both have different structures
Both types have different functions and different structures. Giant lycophytes, as
the name suggests, are larger in size, while the small lycophytes are smaller in
size.
19. Explain why whisk ferns are no longer considered to be living fossils.
analyses of DNA sequences, fern structure
ancestors true roots, leaves
lost during evolution
Psilotum, Tmesipteris closely related to ferns
Analyses of DNA sequences and fern structure are contradictory to whisk ferns
being living fossils. The ancestors true roots and leaves could have been lost
during evolution. Psilotum and Tmesipteris are closely related to ferns.
20. Describe the production and dispersal of fern spores.
sporocytes generate fern spores
outer tissues of sporangium protect developing spores until release of fern
spores
Sporocytes generate fern spores. The outer tissues of the sporangium protect
the developing spores until their release into the air.
21. Clarify the meaning of these pairs of terms:
a. homosporous and heterosporous
homosporous: one type of sporophyll produces one type of spore
heterosporous: two types of sporophylls, produce two types of spores
b. bryophyte and phylum Bryophyta
bryophyte: all nonvascular plants
phylum Bryophyta: formal taxonomic name
c. rhizoid and root
roots: composed of tissues
rhizoid: long, tubular single cells
a. Homosprous means having one type of sporophyll that produces one type of
spore. Heterosporous means having two types of sporophylls that produce two
types of spores.
b. A bryophyte means all nonvascular plants, whereas the phylum Bryophyta is
the formal taxonomic name.
c. A rhizoid is a long, tubular cell, but a root is composed of tissues.
Concept Map Words:
alternation of
generations
angiosperm
antheridium
apical meristem
archegonium
bryophyte
calyptra
capsule
cuticle
embryophyte
foot
gametangia
gametophore
gametophyte
gymnosperm
heterosporous
homosporous
hornwort
leaf
lignin
liverwort
lycophyte
megaphyll
megaspore
microphyll
microspore
moss
peat
peristome
phloem
phragmoplast
placental transfer cell
protonema
pterophyte
rhizoid
root
rosette cellulosesynthesizing complex
seed
seedless vascular
plants
seta
sorus
sporangium
spore
sporocyte
sporophyll
sporophyte
sporopollenin
stoma
strobili
tracheid
vascular plant
vascular tissue
xylem
Memorize the Word Roots
-angio 5 vessel (gametangia: the reproductive organ of bryophytes,
consisting of the male antheridium and female archegonium; a
multichambered jacket of sterile cells in which gametes are formed)
bryo- 5 moss; -phyte 5 plant (bryophytes: the mosses, liverworts, and
hornworts; a group of nonvascular plants that inhabit the land but lack
many of the terrestrial adaptations of vascular plants)
gymno- 5 naked; -sperm 5 seed (gymnosperm: a vascular plant that bears
naked seeds not enclosed in any specialized chambers)
hetero- 5 different; -sporo 5 a seed (heterosporous: referring to plants in
which the sporophyte produces two kinds of spores that develop into
unisexual gametophytes, either female or male)
homo- 5 like (homosporous: referring to plants in which a single type of
spore develops into a bisexual gametophyte having both male and female
sex organs)
mega- 5 large (megaspores: a spore from a heterosporous plant that
develops into a female gametophyte bearing archegonia)
micro- 5 small; -phyll 5 leaf (microphylls: the small leaves of lycophytes
that have only a single, unbranched vein)
peri- 5 around; -stoma 5 mouth (peristome: the upper part of the moss
capsule often specialized for gradual spore discharge)
-phore 5 bearer (gametophore: the mature gamete-producing structure of
a gametophyte body of a moss)
phragmo- 5 a partition; -plast 5 formed, molded (phragmoplast: an
alignment of cytoskeletal elements and Golgi-derived vesicles across the
midline of a dividing plant cell)
proto- 5 first; -nema 5 thread (protonema: a mass of green, branched,
one-cell-thick filaments produced by germinating moss spores)
pter- 5 fern (pteridophytes: seedless plants with true roots with lignified
vascular tissue; the group includes ferns, whisk ferns, and horsetails)
rhizo- 5 root; -oid 5 like, form (rhizoids: long, tubular single cells or
filaments of cells that anchor bryophytes to the ground)