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Lab Review for Plant Diversity
Pieces of this lesson may be incorporated into your own lessons for delivery in lab
or discussion. It is associated with a slide show which may ne accessed at
http://botit.botany.wisc.edu/review/
I. Plants have an alternation of generations (images 1a through 1f):
All plants have an alternation of generations. Gametes are produced by a
haploid plant termed the gametophyte through mitosis. Spores are
produced by a diploid plant termed a sporophyte through meiosis.
Plants together with the Charophycean green algae form a clade. The
Charophycean green algae do not have an alternation of generations, but
have zygotic meiosis. The sporophytic generation in plants can be thought of
as an adaptation for life on land. By generating multiple diploid cells through
mitosis after fertilization, more spores are generated for each fertilization
event (a more improbable event on land). At the start of plant evolution, the
gametophyte was certainly the preeminent vegetative stage associated with
dependent spore-generating sporophytes. The life cycle of Riccia most closely
matches this hypothesis.
This condition was flipped by the differing selective pressures of the
reproductive cycle between the sporophyte and gametophyte. Plants are
oogamous and require films of water for swimming sperm. As relative
humidity decreases with elevation, it is maladaptive for gametophytes to
become large. However, it is adaptive for sporophytes to become large as
height is adaptive in that its spores are more effectively dispersed.1a = Fern
life cycle
1b = Chara: one generation
1ba = habit of Riccia gametophyte
1bb = Riccia archegonium
1bc = Riccia antheridium
1bd = Riccia young sporophyte
1ba = Riccia Mature sporophyte with meiospores
1c = Moss view of 2 generations
1d = Psilotum life cycle
1e = Conifer Life Cycle
1f = Angiosperm life cycle
II. Know these clades
Liverworts - (starts at 2a) simple plants without vascular tissue or stomata.
Gametophytes are independent, the sporophytes are dependent all their lives
on the gametophyte. You should recognize Marchantia, air pores of the
thallus, archegoniophores, archegonia (with neck, venter and egg),
antheridiophores, and antheridia, sporophytes with sporangium containing
spores:
2a =Thallus of Marchantia
2b =XS of Thallus: air pore of Marchantia
2c =Structures of life cycle of Marchantia
Hornworts - (starts at 2c) simple plants without vascular tissue. Chloroplasts
have pyrenoids and sporophytes have stomata. Gametophytes are
independent, the sporophytes are dependent all their lives on the
gametophyte:
2d. Hornwort, 2 generations
2e. Hornwort, Algal-like chloroplasts of gametophyte
2f. Hornwort, stoma of sporophyte
Mosses - (starts at 2f) more complex with stomata, and conductive tissues
homologous to xylem and phloem, but still considered to be a non-vascular
plant. Gametophytes are independent, the sporophytes are dependent all their
lives on the gametophyte. You should recognize gametophytes vs sporophyte,
archegonia (with venter, neck and egg), antheridia, and sporophyte with
sporangium, and protonemeta as the first stage of growth of the
gametophyte:
2g. Mosses, view of two generations
2h. Mosses, view of two generations
2i. Mosses, protonemata
Lycophytes- (starts at 2j) A group of vascular plants. Both the gametophyte
and sporophyte are independent, but the gametophyte is reduced. Only the
sporophyte has vascular tissues. The leaves are microphylls and are not
homologous to the leaves of other plants. These leaves do not have leaf gaps
or axillary buds. Branching occurs by the splitting of the apical meristem
giving rise to a dichotomous fork. You should recognize homosporous
examples as club mosses and the heterosporous genus, Selaginella.:
2j. Club moss sporophytes
2k. Club moss microphyll xs
2l. Selaginella with strobili - habit
2m. Selaginella strobili l.s
Ferns and their Relatives
Ferns - (starts at 2n) A group of vascular plants. Both the
gametophyte and sporophyte are independent, but the gametophyte is
reduced. Only the sporophyte has vascular tissues. You should recognize a
sporophyte, and the parts of a sporophyte (rhizome, frond=leaf, sori), and the
tissues of the rhizome, and the sporangia and spores. You should recognize a
gametophyte with its archegonia (with neck, venter and egg) and antheridia.
2n. Fern life cycle
2o. Fern sporophyte - morphology
2p. Fern sporophyte - xs rhizome
2q. Fern sporophyte - sorus l.s.
2r. Fern l.s. sporangium
Wisk Ferns - (starts at 2s) A group of structurally simple ferns. Both
the gametophyte and sporophyte are independent, but the gametophyte is
reduced. Only the sporophyte has vascular tissues. The sporophyte lacks
leaves and roots, branching occurs through the dichotomous splitting of the
apical meristem of the stem. You should recognize Psilotum, and the
sporangium of Psilotum.
2s. Habit of Psilotum
2t. Sporangium of Psilotum
Horsetails - (starts at 2u) A group of structurally complex ferns. Both
the gametophyte and sporophyte are independent, but the gametophyte is
reduced. Only the sporophyte has
vascular tissues. The sporophyte has
both leaves and roots. The leaves are whorled and are non-photosynthetic.
There are buds associated with the nodes that can give rise to whorls of
branches. You should recognize Equisetum:
2u. Habit of Equisetum
2v. Whorled branches of of Equisetum
2w. Wholed fused leaves of Equisetum
Conifers - (starts at 3a) Seed plants. As with all seed plants these are
heterosporous. The gametophytes are greatly reduced and are dependent on
the sporophytes which are vascular plants. The microgametophyte is the
pollen grain. The megagametophyte is retained in the megasporangium
surrounded by an integument. Together, these form an ovule. The nutritive
tissue in the seed is the megagametophyte. Conifers have compound ovulate
cones consisting of seed scale complexes. You should recognize Pinus.
3a. Pine life cycle
3b. Pine ovule
3c. Pine ovulate cone
3d. Red Pine - habit
Cycads - (starts at 3e) Seed plants. As with all seed plants these are
heterosporous. The gametophytes are greatly reduced and are dependent on
the sporophytes which are vascular plants. The microgametophyte is the
pollen grain. The megagametophyte is retained in the megasporangium
surrounded by an integument. Together, these form an ovule. The nutritive
tissue in the seed is the megagametophyte. Cycads have megasporophylls as
well as microsporophylls which may be arranged into terminal clusters
forming cones (strobili). Cycads have pinnately compound leaves and look
palm-like.
3e. Cycas - habit
3f. Cycas - megasporophylls
3g. Cycas - microsporophylls
Ginkgoes (starts at 3h) Seed plants. As with all seed plants
these are
heterosporous. The gametophytes are greatly reduced and are dependent on
the sporophytes which are vascular plants. The microgametophyte is the
pollen grain. The megagametophyte is retained in the megasporangium
surrounded by an integument. Together, these form an ovule. The nutritive
tissue in the seed is the megagametophyte. There is only one surviving
species, Ginkgo biloba which you should recognize.
3h. Ginkgo - habit
3i. Ginkgo - ovules and leaf
3j. Ginkgo - ‘ripe’ ovules
Gnetophytes - (starts at 3k) Seed plants. As with all seed plants these are
heterosporous. The gametophytes are greatly reduced and are dependent on
the sporophytes which are vascular plants. The microgametophyte is the
pollen grain. The megagametophyte is retained in the megasporangium
surrounded by an integument. Together, these form an ovule. The nutritive
tissue in the seed is the megagametophyte. This consists of three different
genera which are radically different in appearance. If you see two of these
genera you should be able to recognize these to this group.
3k. Gnetum - habit with ovules
3l. Ephedra - habit
3m. Welwitschia male female plants
Flowering Plants (starts at 3n) Seed plants. As with all seed plants these are
heterosporous. The gametophytes are greatly reduced and are dependent on
the sporophytes which are vascular plants. The microgametophyte is the
pollen grain. The megagametophyte is retained in the megasporangium
surrounded by an integument. Together, these form an ovule. The nutritive
tissue in the seed is not a megagametophyte. Angiosperms are unique in that
their ovules are enclosed in a megasporophyll, the carpel, and by double
fertilization. Pollination results in the union of one sperm nucleus with the
egg to produce the zygote; and in the union of another sperm with two polar
nuclei giving rise to a primary endosperm nucleus. The primary endosperm
nucleus develops into endosperm. Double fertilization destroys the
megagametophye. Nutritive tissue in the mature seed consists either of
endosperm, or else of cotyledons which are the seed leaves of the embryo. In
angiosperms the carpel matures into a fruit.
3n. Angiosperm life cycle
3o. Lily Flowers
3p. Pollen grain
3q. Embryo sac
3r. Ovary xs
3s. Ovules
3t. Double fertilization
3u. Fruit
III.
Understand/recognize these concepts/structures (Starts at 4a)
1. Archegonium (4a - 4c)
12. Cone = strobilus (4r - 4ra)
2. Archegoniophore (4ea)
13. Corolla (4rz)
3. Antheridium (4f-4h)
14. Dioecious (4sa-4t)
4. Antheridiophore (4i)
15. Double Fertilization (4u)
5. Aggregate fruit (4j)
16. Egg (4v-4x)
6. Androecium (4k)
17. Embryo (4z-5a)
7. Anther (4l)
18. Embryo Sac (5az)
8. Berry (4m)
19. Endosperm (5ba)
9. Calyx (4n)
20. fertilization=syngamy (5bb)
10. Capsule (4o)
21. Follicle (5c)
11. Carpel (4p)
22. Fruit (5d)
23. Flower
Complete (5e)
Incomplete but perfect (5f)
Imperfect (5g)
Monoecious (5h-5ha)
Dioecious (5i)
24. Gametophyte (5j)
25. Grain (5k)
26. Gynoecium (5l)
27. Heterospory (5m)
28. Inferior (5n)
29. Integument (5o)
30. Locule (5p)
31. Megaspore (5q)
32. Megaspore Mother Cell (5r)
33. Megasporangium (5s)
34. Megasporophyll (5t)
35. Megagametophyte (5u)
36. Microspore (5v)
37. Microsporangium (5w)
38. Microsporophyll (5x)
37. Microgametophyte (5y)
38. Microspore Mother Cell (5z)
39. Monoecious (6a)
40. Multiple Fruit (6b)
41. Nucellus=megasporangium of a
seed plant (see megasporangium)
(6bz)
42. Nut (6c)
43. Ovary (6d)
44. Ovule (6da)
45. Petals (6e)
46. Pistil (6f)
47. Pollen Grain (6g)
48. Pollen Tube (6h)
49 Pollination (6i)
50. Primary Endosperm Nucleus (6j)
51. Pyrenoid (6k)
52. Samara (6l)
53. Seed (6m)
54. Sepal (6o)
55.
56.
57.
58.
59.
59.
60.
Pome (6p)
Receptacle (6pz)
Stoma (6q)
Stigma (6r)
Style (6r)
Tapetum (6s)
Tube Cell (6t)