ch5 evolution of woody and seed plants
TRANSCRIPT
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
1/66
Chapter 5
Evolution of Woody andSeed Plants
Michael G. Simpson
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
2/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
3/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
4/66
Evolution ofwood from
secondary xylem of
vascular cambium
enabled plants to growvery tall, as large trees.
Illustrated: Sequoiadendron giganteum, giant
sequoia, largest non-clonal organism on
earth; most tissue dead secondary xylem
(wood).
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
5/66
Divisions ofvascular cambium mostly tangential (some radial)
2 xylem > inside, 2 phloem > outside: bifacial growth.
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
6/66
Secondary growth from lateral meristems:
vascular cambium & cork cambium.
Vascular cambium: 2 xylem > inside; 2 phloem > outside:
= bifacial growth.
Tissue to outside (cortex, older 2 phloem) gradually crushed.
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
7/66
In most temperate regions (growth season / winter) and some tropical
regions (dry/wet season), seasonal annual rings form.
Annual rings can be used to date wood.
Dendrochronology study of wood in relation to time and
environment/climate.
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
8/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
9/66
cork cambium
- like vascular cambium bifacialcork> outside, phelloderm> inside
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
10/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
11/66
Seed
= embryo enclosed by nutritive tissue,
surrounded by seed coat
Ovule
= immature seed (prior to
fertilization/maturation)
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
12/66
Seed Evolution
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
13/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
14/66
Heterospory
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
15/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
16/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
17/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
18/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
19/66
micropyle hole in integument,
where pollen enters (gymnosperms)
telomes & lagenostome found in
fossil (extinct) taxa, functioned in
pollen capture
pollination droplet secreted frommicropyle; pollen grains stick to, are
pulled inside as droplet evaporates.
Ginko biloba
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
20/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
21/66
Pollen grains develop from microspores by mitotic divisions/differentiation.
[When haploid nucleus ofmicrospore starts to divide mitotically, it becomes a pollen grain.]
Pollen grains = immature endosporic male gametophytes
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
22/66
Pollen tube haustorial (parasitic, feeding off tissues) in Gymnosperms
-In cycads & Ginkgo sperm delivered to fertilization chamber, wheresperm swims to archgonium = zooidogamy.
-In conifers (incl. Gnetales) tube grows directly to archegonium =
siphonogamy.
Pollen tube exosporic, tube-like extension frompollen grain.
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
23/66
Ovule development
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
24/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
25/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
26/66
Adaptive significance ofseeds
1) Protection ofembryo (seed coat)
2) Nutrition ofembryo (nutritive tissue=female
gametophyte in Gymnosperms)
3) Dispersal unit(e.g., fleshy, carried by animals; winged,
transported by wind)
4)D
ormancy mechanisms (seed coat inv
olv
ed inpreventing germination except when conditions right)
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
27/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
28/66
eustele single ring ofvascular bundles
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
29/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
30/66
Archeopteris large tree, wood
like a conifer, leaves like a fern;
some heterosporous.
Medullosa a tree fern, bore
seeds, but with fern-like foliage.
Two fossil (extinct) lignophytes:
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
31/66
Gymnospermae (naked seed) seeds not enclosed by carpel;
sister to Angiospermae.
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
32/66
Cycadophyta - Cycads
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
33/66
Cycadophyta Cycads
-trunks short(rarely elongate, tree-like)
-leaves pinnate (rarely bipinnate),
coriaceous, with circinate
vernation (like ferns)
-dioecious (separate male & femaleindividuals)
-sperm motile
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
34/66
Cone = determinate shoot systems, consisting of a single axis
with sporophylls = modified leaves with attached sporangia.
Pollen cones (male) bear
microsporophylls, with
microsporangia.
Ovulate / seed cones
(female) bear
megasporophylls,
with ovules/seeds.
pollen cone
seed cone
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
35/66
Cycadophyta Cycads
Cycadaceae:
female plantswithout cones;
seeds born on
megasporophylls
from stem axis.
One genus: Cycas
Cycas revoluta
sago-palm-starch derived from
pith > flour, bread.
[C. media
-edible seeds]
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
36/66
Cycadophyta Cycads
Zamiaceae:
female plantswith seed
cones;
leaves pinnate
or bipinnate
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
37/66
Cycadophyta Cycads
Zamiaceae:
female plantswith seed
cones;
leaves pinnate
or bipinnate
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
38/66
Ginkgophyta Maidenhair Trees
One family:GinkgoaceaeMaidenhair Tree
family
One species
(monotypic):
Ginkgo biloba
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
39/66
Ginkgophyta - Ginkgo biloba
- tree with short shoots
- leaves obtriangular
- venation dichotomous
- dioecious
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
40/66
Ginkgo biloba
Pollen cones catkin-like: axis bearing stalk-like
microsporophylls, each with two microsporangia.
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
41/66
Ginkgo biloba
Ovulate reproductive structures: stalk bearing two, erect
ovules, each with basal collar. Seeds fetid (butyric acid).
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
42/66
Coniferae conifers
Apomorphy:pollen tubesiphonogamous
-leaves simple
Three groups:
Pinopsida
Cupressopsida
Gnetales
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
43/66
Pinaceae: Pinus
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
44/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
45/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
46/66
Mystery of the conifer cone: compound
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
47/66
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
48/66
Evolution ofthe conifer cone:
Compound structure (axis bearing two components):
bract homologous with leaf
ovuliferous scale homologous with shoot system
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
49/66
Coniferae conifers
P
inopsida:
One family:
Pinaceae
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
50/66
Pinaceae
-pollen cones with
2 microsporangia
/ microsporophyll
-pollen grains of
some taxa saccate
(with 2 bladders)
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
51/66
Pinaceae
-seeds usu. 2 per
ovuliferous scale,
inverted, winged.
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
52/66
Pinaceae
-leaves linear to acicular
(needle-shaped)
- in some taxa,
short shoots
(e.g., Cedrus)
or
determinate fascicles
(Pinus).
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
53/66
Pinaceae
Include:
Abies fir
Cedrus cedar
Larix larchPinus pine
PseudotsugaDouglas-
fir
Tsuga - hemlock
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
54/66
Coniferae conifers
Cupressopsida
5-6 families
We will cover 4:
Araucariaceae
Podocarpaceae
Cupressaceae
Taxaceae
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
55/66
Araucariaceae
-leaves broad to acicular
-microsporangia
numerous (5-20) permicrosporophyll
-ovule 1 per scale
Includes:Araucaria heterophylla
Norfolk Island-Pine
Araucaria bidwillii
bunya-bunya
Agathis australis
kauri
C
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
56/66
Cupressaceae
-leaves linear, acicular, or
subulate, spiral, opposite,or whorled
-branches flattened in
some, resembling pinnate
leaves in some
-seed cones with numerous
seeds per scale (2-20)
-pollen not saccate
Includes:
Cupressus cedar
Juniperus -juniper
Sequoia sempervirens
redwood
Sequoiadendron giganteum
giant sequoia
Taxodium bald-cypress
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
57/66
Podocarpaceae
-leaves linear, elliptic, or
subulate
-seed cones usu. fleshy,
often reduced, in some
subtended by fleshy
receptacle, seed may be
enveloped by fleshy
epimatium derived from
scale
Includes:
Podocarpus, e.g., P.
gracilior
Phyllocladus spp.
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
58/66
Taxaceae
Yew family
-seed cones usu.
reduced to 1 ovule
-seed surrounded by
fleshy aril
Includes:
Taxus yew
taxol derived from T.
brevifolia, used to treat
ovarian cancer
C if if
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
59/66
Coniferae conifers
Gnetales:
3 families:
Ephedraceae
Gnetaceae
Welwitschiaceae
All dioecious
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
60/66
Gnetales:
Apomorphies:
1)Pollen striate
2)Vessels porate
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
61/66
Gnetales
Gnetaceae
One genus: Gnetum (ca. 30 spp.)
Gnetum tropical vines [trees, shrubs],
leaves simple, opposite
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
62/66
Gnetales
Ephedraceae
One genus:
E
phedr
a (35-45 spp.)Morman Tea
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
63/66
Ephedra Morman-TeaShrubs
Deserts of S.W. North America,
W. South America, N. Africa, and Eurasia
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
64/66
Ephedra
- pollen coneswith stalk-like
microsporan-
giophore,
bearing
synangia
- seeds of seed
cones with
fleshy, connate
bracteoles and
micropylar
tube
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
65/66
GnetalesWelwitschiaceae
One genus/species:
Welwitschia
mirabilis
-native to deserts
ofNamibia
-
8/3/2019 Ch5 Evolution of Woody and Seed Plants
66/66