Marine algae

1. Marine Algae
The Seaweeds

2. Algae Anatomy
(Thallus)

3. •Holdfast – serves as an
anchor to help hold the
algae to the bottom, a rock,
etc.
•Blade – a place where
photosynthesis can occur;
there’s a wide variety of
shapes and sizes of blades
•Stipe – provides support
and structure for the algae
•Air Bladder (aka Float) – a
structure that assists in
buoyancy for the algae
(why?)
•Thallus – the entire body
structure of the seaweed

4. Kingdom=? Protista, Plantae, Other?
•Autotrophs
•Live attached to rocks or floating
•Reproduction is usually sexual, frequently through
spores
•Huge diversity, found nearly everywhere on earth
•3 types

5. A) Green – Chlorophytes
•Least common; need lots of light
•Possibly land plants evolved from this type of algae
•Deep to bright green due to chlorophyll
•Ex: Sea lettuce, Mermaid’s Hair

6. B) Red - Rhodophytes
•Common; can handle low light (found deepest)
•Contain pigments (phycoerythryn, phycocyanin)
•Don’t always look red!
•Examples: Gracillaria, Nori

7. C) Brown - Phaeophytes
•Common in cold water, rocky shores to 60’ deep
•Olive color due to pigment xanthophyll
•Examples: Ascophyllum (rockweed), Kelp

8. Comparisons Between Algae & Land Plants
-Water usually
unlimited
-Supported by
stipes
-Anchored by
holdfast
-No seeds &
flowers
-Blades
Autotrophs –
perform
photosynthesis
-Water usually
limited
-Supported by
trunks & stems
-Anchored by
roots
-Flowers & seeds
-Leaves