CH 29: Algae Flashcards
What are algae?
photosynthetic and nonvascular plants.
-called seaweeds due to attachment to underwater surface
What makes algae different from higher plants?
1) Not vascular (no xylem or phloem)
2) No true roots, stems, leaves
3) No complex tissue around zygote (like seeds)
Difference between Algae and Seagrass?
Seagrass are more advanced
- Seagrass have roots whereas algae have holdfasts
- Seagrass have leaves and flowers
What are the three main divisions of algae?
1) Chlorophyta
2) Rhodophyta
3) Phaeophyta
What is the basic structure of algae?
1) Thallus
2) Blade/Lamina
3) Stipe
4) Pneumatocyst
5) Holdfast
What is the thallus?
Body of algae not differentiated into roots, stems or leaves
What is the Blade/lumina?
Branches that originate from the stipe or holdfast
What is the Stipe?
joins the blade to the holdfast
What is the pneumatocyst?
spherical bladders filled with gas allow algae to remain upright
What is the Holdfast?
root-like structures that fasten the algae to the hard substrate
What are the types of macroalgae morphology?
1) Filamentous - daughter cells remain attached and share cell walls
2) Foliose - algae with flattened or membranous blade
3) Tubular - cylindrical and smooth surfaced
How does macroalgae grow?
1) Apical cellular growth
2) Parenchymatous growth
3) Intercalary growth
What is Apical cellular growth?
Cells located at the tip of a branch
– Meristem: regions of specialized tissues whose
cells undergo cell division
What is Parenchymatous growth?
where cell division is not restricted to any particular
cell
-cell division occurs sideways to form sheets
-occurs in all three directions
What is Intercalary growth?
growth occurs at the intercalary meristem (in between two bamboo shoots) not at the apical meristem
Where is the Apical Cell located?
Apical cell (apical meristem) at the tip of a root or shoot -Apical=Apex
What are the characteristics of Division Chlorophyta?
1) Green Algae (green due to chloroplast)
2) Unicellular freshwater species
3) Higher plants evolved from green algae
4) Autotrophic
- Osmotrophic: organic carbon imported from environment into cells
- Photoheterophic: light captured and used as energy source to take up carbon from environment
Is Chlorophyta a monophyletic group?
Yes
What are Ulvophyceans?
Largest and most conspicuous green algae group
-wide diversity in morphology
What are the characteristics of Division Rhodophyta?
-Deepest growing algae
-Found in acidic hotsprings
-
What are the characteristics of Division Phaeophyta?
Grow very fast and very large (giant kelp)
-cellular specialization (pneumatocysts)
What are Laminariales?
Order of Phaeophyta containing kelps
- Have Holdfast, Stipe, Blade
- Intercalary meristem located between stipe/blade
