Switching gears from algae to angiosperms
Angiosperm Characteristics
1) Pigments:
blade
flower
leaves
2) Chloroplast structure:
stem
holdfast
3) Storage product:
roots/rhizomes
• Less tissue specialization
• Happy in salt water
• More tissue specialization
• Stressed by salt water
4) Flagella:
5) Mitosis:
1
2
Groups (Kingdom)
DOMAIN
1.Bacteria- cyanobacteria (blue green algae)
2.Archae
3.Eukaryotes
1. Alveolates- dinoflagellates
Brief history of photosynthetic organisms on earth
3.45 bya = Cyanobacteria appear and introduce photosynthesis
1.5 bya = first Eukaryotes appeared (nuclear envelope and ER
thought to come from invagination of plasma membrane)
2. Stramenopiles- diatoms, heterokonyophyta
0.9 bya = first multicellular algae (Rhodophyta - Red algae)
3. Rhizaria- unicellular amoeboids
800 mya = earliest Chlorophyta (Green algae)
4. Excavates- unicellular flagellates
400-500 mya = plants on land – derived from Charophyceae
5. Plantae- rhodophyta, chlorophyta, seagrasses
250 mya = earliest Heterokontophyta (Brown algae)
6. Amoebozoans- slimemolds
100 mya = earliest seagrasses (angiosperms)
7. Fungi- heterotrophs with extracellular digestion
8. Choanoflagellates - unicellular
9. Animals- multicellular heterotrophs
3
4
1
Zonation PatternsUnicellular, freshwater
Chloroplast peptidoglycan
Plantae
physical factors and biotic interactions
Glaucophytes
Rhodophyta
Chlorophytes
phycoerythrin
Chl b,
Starchamylose &
amlyopectin
Charophytes
Embryo,
cuticle
Land Plants
5
Adapted from Sadava 2014
Zonation Patterns
physical
factors
biotic
interactions
Mangals
biotic
interactions
physical
factors
Mangroves & associated tidal marsh communities
Dave Lohse
8
2
Mangal Distribution
Mangal taxonomy
Domain Eukaryote
Kingdom/Clade Plantae
Phylum/Division Magnoliophyta - angiosperms
Class Magnoliopsida
Order Malpighiales
Family Rhizophoracea
Genus
Rhizopora
species
mangle- red mangrove
9
- Tropical tidal habitats
- 40 species of Mangroves dominate 75% of the tropical
coastline between 25 N & 25 S
- Orders Myrtales & Rhizophrales make up 50% of the species
10
Mangrove Forest Classification
Mangal Genera Share the following features:
1. Species restricted to mangals.
2. Trees exhibit major role in community structure.
3. Morphological specializations, including aerial roots
& vivipary
4. Plants exhibit salt- exclusion physiology
5. Taxonomic isolation from terrestrial relatives
at the level of genera
1 Coastal Fringe- along protected shoreline berms
2 Overwash- low intertidal
3 Riverine- along streams and rivers and extend several
miles inland
4 Basin- occur in a depression behind a berm or fringing
mangals, connected to streams or tidal creeks
5 Scrub- occur where abiotic conditions are severe due
to limited water
6 Hammock- inland tropical wetlands, isolated by fresh water
11
12
3
Adaptations of Mangroves
1. Mechanical adaptations for attachment in soft sediment
2. Aerial roots are common & specialized for diffusion of
gases to subterranean portions.
3. Vivipary- germination of seedlings while fruit remains
attached to tree
4. Seeds & seedlings can survive in salt water & disperse
via salt water
5. Xerophytic modifications- survive with little fresh
water
13
Mangrove Leaves
6. Halophytic modifications- survive with high amounts of
14
salt
Mangrove trunks & bark
evergreen
complex leaf anatomy
thick outer walls & cuticles
salt is accumulated in leaves causing succulence and
eventually shed
glandular hairs- function in salt excretion
lenticles- ”cork warts” secrete water & chloride
hypodermis upper layer contains tannins
lower layer contain hydrocytes- water containing cells
15
lenticles- dense masses of cells that results in breaks
in the bark
- function in gas exchange
- critical for root survival
16
4
Zonation patterns
40% of root is used for gas exchange
Upper limit determined by biotic interactions
Lower limit determined by abiotic factors
17
Rhizopora mangle- red mangrove
18
Lacunae- gas exchange
Red Bark & Leathery Leaves
Vivipary-seedling germinate from fruit while
attached to tree
Enlargement of airspaces
Air spaces forming channels in
leaves, stems and roots
Also have a structural role
Stilt roots- develop from the stem “prop”
- develop from a branch “drop”
Lacunae- gas exchange
19
20
5
Avicennia germinans- black mangrove
Aerenchyma tissue- gas exchange
Hair on leaves- salt secretion
Cryptovivipary-embryo grows out of the seed
but not the fruit before dropping
Formed by cell separation
Mechanism for root aeration in low
oxygen concentrations
Aerenchyma tissue- gas exchange
Cable root with Pneumatophores- extend 10-20 cm
above root function in gas exchange
21
Avicennia marina- white mangrove
22
Mangal Macroalgae
important primary producers
epiphytic algae on roots = to the leaf litter from the tree
Stilt or Cable roots
Nectaries at base of leaves secrete sugar
Hair on leaves- salt secretion
23
24
6
Water Regulation & Osmoregulation
facultative halophytes- competitive exclusion limits
them to saline habitats
slow growth because they spend a lot of energy dealing
with salt
salt secretors- Avicennia- 33% of the salt
non secretors- Rhizophora - exclude 90% of salt
Ecological roles of Mangals
1. Coastal Resilience
2. Filtering land runoff
3. Stabilization of sediments
4. Trapping sediments
5. Primary Production
6. Nursery Habitats
25
Coastal Resilience & Mangroves
26
Loss of Mangals
Storm surge- low pressure & high winds raise water level at the coast
-peak water levels can exceed 7m in heightflooding
Mangroves can reduce storm surge and surface waves
extraction, pollution & reclimation
Has lead to declines of finfish & commercial shrimp
these species depend on detrital & benthic microalgae
Long term pollution from oil spills cause mutations in the trees
Habitat Loss
seagrass 1.5% yr
mangroves 1.8% yr
tropical forests 0.5% yr
27
28
7
Seagrass Leaf Diagram
Bundle sheath- containing
lacunae
phloem & xylem
aerenchyma
Fiber bundles
Wheat
stomata
29
8