Download Algae - Mr. Lesiuk

UNIT 4
KINGDOM
PLANTAE
BOTANY : The
study of plant
physiology, plant
anatomy, plant
morphology,
plant taxonomy;
including plant
genetics, ecology
and cytology.
PLANTAE: A TRUE PLANT IS A
MULTICELLULAR AUTOTROPHIC
TERRESTRIAL ORGANISM THAT POSSESSES
CHLOROPHYLL “a” AND “b” CONTAINED IN
CHLOROPLASTS AND SHOWS STRUCTURAL
DIFFERENTIATION – with true roots, stems and
leaves.
Some taxanomic systems consider some of the most primitive
plants not to belong to kingdom plantae at all. Instead they
throw these organisms into Kingdom Protista. For example:
Some algae are multicellular, autotrophic, possess chlorophyll
“a” and “b”, terrestrial and show structural differentiation.
The majority are aquatic, none of them possess vascular roots,
stems and leaves. Where do we put them? Are they a
multicellular protist or a very simple type of plant?
ALGAE
Cyanobacteria
Plant-like
Protists
Multicellular Protist or Primitive
Aquatic Plant?
Algae
Algal Characteristics
• Vary in size from
nanoplankton (< 2 µm
cyanobacteria ) to Giant kelps
(> 70 m long). Possess a cell
wall.
• Contain pigments
• chlorophylls a, and many
often have another
chlorophyll, like b, c, or d
and accessory red, blue
and brown photosynthetic
pigments
Algae - What are they?
• Primitive plants
• No true roots, only attachment
structures (Holdfasts)
• Produce spores (not seeds)–
motile or non-motile
• Most have sexual and asexual
reproduction
• Non-vascular, do not possess
an internal transport system.
Algae vs. ‘REAL’
plants
Similarities and differences:
• Both are photoautotrophic
• Similar metabolic functions to higher
plants eg. photosynthesis
• different anatomical structures,
reproductive structures.
• different reproduction.
• No true roots, stems leaves.
• Non-vascular, therefore nutrient
uptake over surface. And wastes
washed away from surface by
aquatic environment
Classification - a few Algal Phyla
• Cyanophyta: Blue-green or Cyanobacteria.
Prokaryotic. Marine, FW and terrestrial.
• Pyrrophyta, Chrysophyta, Euglenophyta: Marine
and FW phytoplankton – Photosynthetic Protists.
KINGDOM PLANTAE:
• Rhodophyta: Red algae. Mostly marine.
• Phaeophyta: Brown algae. Mostly marine.
• Chlorophyta: Green algae. Marine, FW and
terrestrial.
The role of these pigments is to absorb light
- In water the problem is that red and violet wavelengths do not
penetrate the vertical column very well. So Chlorophylls do not
work well at greater depths. Algae that inhabit greater depths do so
with the help of accessory pigments, these algae take on a variety of
colours.
-Chlorophyta – Contain
Chlorophyll a + b. So green
wavelengths reflect. They store
their products of photosynthesis
as starch.
- Phaeophyta – Contain
Chlorophylls a + c as well as an
accessory pigment Fucoxanthin.
So yellow and brown
wavelengths reflect. Store food
as starch and as oil.
Rhodophyta - Contain
Chlorophyll a + (d) as well as
accessory pigment Phycobillins.
These phycobillins are
specialized for absorbing blue
light, which allows them to
inhabit the deepest depths.
Where do Algae live?
Marine habitats:
• seaweeds, phytoplankton
Freshwater habitats:
• streams, rivers, lakes
and ponds
Terrestrial habitats:
• stone walls, tree bark,
leaves, in lichens, on
snow
Marine Biomes
Freshwater habitats
Terrestrial habitats
How do algae function?
Photoautotrophs: 6C02 + 6H20 
C6H1206 + O2
• use carbon, light, and water
• produce chemical energy
(carbohydrates) and produce O2 as
a by-product.
• Basic storage products:
carbohydrates as starch or
converted to fats as oil
• Require nutrients: N, P and
minerals.
Why are ALGAE important?
Ecological importance of algae
a) Production of Oxygen as ‘byproduct’ of photosynthesis:
• All aerobic heterotrophic
organisms require O2,
• e.g. fungi and animals need O2, to
run cellular respiration to stay alive
b) Production of biomass:
• autotrophic organisms
- represent the base of the food
chain/web,
particularly in aquatic
environments.
Algal diversity
• Algae ARE NOT a single phylogenetic
grouping, but give rise to several independent
evolutionary lines. Our focus is on
“CHLOROPHYTA” as it is believed to give rise
to the terrestrial plants.
• Very diverse, very well adapted to certain
environments,
• Range from unicellular,  colonial 
multicellular
• e.g. marine, freshwater, terrestrial;
• often extreme habitats
• CHLOROPHYTES share Similarities to
true plants – Same two chlorophylls a
and b, Store products of photosynthesis
as starch, cell wall primarily made of
cellulose.
Algal construction types : Morphology
1. Unicellular algae
2. Colonies
3. Filaments
4. Multicellular
Unicellular algae
• ‘Microalgae’ - some may form colonies
Algal colonies
e.g. Chlorophyta: Volvox (Order Volvocales)
http://www.youtube.com/watch?v=w8O4OolGcPg
- 500-5000 cells per colony.
- Colonies spherical up to 1.5 mm diameter.
- Individual cells surrounded by a mucilaginous sphere
- marine and freshwater
Volvox colony – with Daughter colonies
Filamentous algae
• Unbranched filaments
• Branched filaments
• Different branches can have different
morphologies:
MULTICELLULAR - Macroscopic
Why are algae important?
• Primary producers, basis of food webs,
“FORESTS/GRASSES OF THE SEA”
• Pioneer Species: on rocky shores, mudflats,
hot springs, lichen communities, 'snow algae'
• O2 production and carbon fixation in aquatic
habitats.
• Rare autotrophic organisms in extreme
habitats.
Examples of ecological importance
•
•
•
•
•
Red tides, other algal blooms
Hot springs
Kelp forests
Rocky shore ecology
Aquaculture
Cyanobacterial bloom
Extreme halophytes
Uses of Seaweeds
• Present
• Food
• Hydrocolloids and some
chemical substances
• Fertilizers
• Potential
• Source of
energy/compost by
digestion
• Waste-water treatment
Algae as human food
•
•
•
•
Annual value is about US$6 billion
Main market and production area is Asia
“Mariculture” has become very important
Main high-value species are ‘Nori’, ‘Kombu’ and
‘Wakame’ (Porphyra, Laminaria and Undaria)
• Mainly used as a subsidiary food: adding relish, taste
and 'feel' to food
• European and North American market presently very
small but has potential