What constitutes a What constitutes a plant? plant? 29-30: Kingdom 29-30: Kingdom Plantae Plantae What are the reproductive trends in What are the reproductive trends in plants? plants? What are the evolutionary trends in What are the evolutionary trends in plants? plants?
29-30: Kingdom Plantae. What constitutes a plant?. What are the evolutionary trends in plants?. What are the reproductive trends in plants?. The Netherlands. What constitutes a plant?. Plants are: Multicellular Eukaryotes Photosynthetic autotrophs - PowerPoint PPT Presentation
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What constitutes a plant?What constitutes a plant?
29-30: Kingdom Plantae29-30: Kingdom Plantae
What are the reproductive trends in plants?What are the reproductive trends in plants?
What are the evolutionary trends in plants?What are the evolutionary trends in plants?
Algae may also have these characteristics. Algae may also have these characteristics. Plants appear to have developed from algae.Plants appear to have developed from algae.
Other features that plants and algae have in common:Other features that plants and algae have in common:Presence of chrolophyll b as an accessory pigmentPresence of chrolophyll b as an accessory pigmentCellulose cell wallsCellulose cell wallsStarch as storage product of surplus carbohydratesStarch as storage product of surplus carbohydrates
Plants occur both on land and in water. Algae only in the presence Plants occur both on land and in water. Algae only in the presence of water.of water.
29.4 Where is the line dividing land plants from algae?
Three possible plant kingdoms?
Embryophytes: Plants with embryos
Figure 29.7 Some highlights of plant evolution
1. Walled spores toughened by sporopollenin
2. Multicellular, dependent embryos
3. Apical meristems (root, shoot)
4. Presence of a waxy cuticle
[See book p. 602-603]
29.5. Walled spores produced in sporangia.
Spores are haploid reproductive cells that can grow into gametophytes (n) by mitosis. Sporopollenin makes the walls of spores very tough and protects them against dehydration
Multicellular, dependent embryos
Develop from zygotes that are retained within tissue from the female parent
29.5. Apical meristem
Figure 35.18. Leaf anatomy (incl. waxy cuticle)
Figure 3.3 Vascular tissue – support against gravity and transport system in plants
Xylem: Water conducting cells
PhloemCambium
Lignin: Hard material embedded in cellulose cell walls for structural support
Figure 29.5 Alternation of generations: a generalized scheme
A hypothetical mechanism for the origin of alternation of generations in the ancestor of plants
Figure 29.7 Some highlights of plant evolution
Table 29.1Ten Phyla (Divisions) of Extant Plants (Embryophytes)
Figure 29.3 CharophyceansThe closest algal relatives of land plants
Chara (top), Coleochaete orbicularis (bottom)
29.4
Chara
Figure 29.7 Some highlights of plant evolution
29.9. Bryophytes
Liverworts
MossesHornworts
Figure 29.8 The life cycle of a moss (Polytrichum)
Figure 29.8 The life cycle of a moss (Polytrichum)
Moss life cycle
protonemasporangium
archegonium
spores
gametophyte sporophyte
Marchantia, a liverwort
Gametangia: Archegonium of Marchantia (left), Anteridium of a hornwort (right)
A moss sporangium with a “spore-shaker” tip
Bryophytes
Liverworts
MossesHornworts
Sphagnum, or peat moss: Peat bog in Oneida County, Wisconsin (top), close-up of Sphagnum (bottom left), Sphagnum "leaf" (bottom right)
A peat moss bog in Norway
Carbon reservoir may help stabilize global atmospheric CO2
29.11. More than 2000-year old bog mummy preserved in acid, oxygen poor Sphagnum wetlands
29.11. Peat, partially decayed organic material, harvested from peat moss (Sphagnum) wetlands. Decomposition is slow due to cold temperatures, acid conditions and little oxygen.
Figure 29.7 Some highlights of plant evolution
Xylem cells in angiosperms (see also Fig 35.10)
Lignin
Seedless Vascular plants- Ferns
Figure 29.16 Lycophyta and Pterophyta. Artist’s conception of a Carboniferous forest based on fossil evidence (some 350 million yrs B.P.)
29.15. Lycophytes: club "moss" (top left), many are epiphytesPterophytes: whisk fern (top right), horsetail (bottom left), fern (bottom right)