Transcript Cyanobacteria and Algae Chapters 13

Cyanobacteria &
Algae
Cyanobacteria
~3,500 mya cyanobacteria evolved
Stromatolites
• Stromatolites are produced when colonies of
cyanobacteria bind calcium–rich sediments.
Stromatolites
• Cyanobacteria have an abundant fossil record,
evidence that cyanobacteria was prevalent
throughout this time period
Stromatolites
Early Earth’s Atmosphere
Cyanobacteria
• Earth’s early atmosphere practically devoid of
free Oxygen.
• Cyanobacteria first photosynthetic organism
to evolve (~3,500 mya) on earth
• Cyanobacteria played the decisive role in
elevating the level of oxygen in the
atmosphere of early Earth, staging it for the
arrival of life as we know it on this planet!
HOORAY FOR CYANOBACTERIA!
Cyanobacteria
• Earth’s early atmosphere practically devoid of
free Oxygen.
• Cyanobacteria first photosynthetic organism
to evolve (~3,500 mya) on earth
• Cyanobacteria played the decisive role in
elevating the level of oxygen in the
atmosphere of early Earth, staging it for the
arrival of life as we know it on this planet!
HOORAY FOR CYANOBACTERIA!
FIRST POLLUTION CRISIS!
~3,500 mya cyanobacteria evolved
Oscillatoria
• Filamentous
Cyanobacteria
• The cells are
usually joined only
by their walls or
mucilaginous
sheaths.
• Each cell leads an
independent life.
Nostoc
filamentous
cyanobacteria
in a ball!
Freshwater
habitats
Many Cyanobacteria fix nitrogen
• Plants (and other organisms) need
nitrogen for survival.
• Nitrogen gas, in the atmosphere, is not in
form plants can take up.
• Many cyanobacteria can convert the
nitrogen gas to ammonium, a useable
form of nitrogen! (“Nitrogen fixation”)
Anabaena
• Rice can often be grown continuously on the same
land without the addition of fertilizers because of
the presence of nitrogen-fixing cyanobacteria, such
as Anabaena, in the rice paddies.
Algae
Phycology: the study of algae
Phylum Dinophyta:
the Dinoflagellates
• Closely related to
some protozoa
(“animal-like protists).
• 2000-4000 species
known
• Found in marine and
freshwater habitats
(most are marine)
Phylum Dinophyta:
the Dinoflagellates
• Most are unicellular
biflagellates
• Flagella beat in two
grooves, causing
whirling-forward motion
• Greek word dinos:
‘whirling’
• Latin flagellum:
diminutive term for whip
Theca: stiff cellulose plates
“coat of armor”
(Gonyaulax polyedra)
Not all Dinoflagellates have theca
Bioluminescent marine dinoflagellate
(Noctiluca scintillans)
Dinoflagellate nutrition
• Only about half of all dinoflagellate species
are photosynthetic.
• Non-photosynthetic dinoflagellates (and some
photosynthetic dinoflags) obtain nutrition
either by ingesting solid food particles or by
absorbing dissolved organic compounds.
Dinoflagellate nutrition
• 20% produce highly toxic compounds
• Pfiesteria piscicida produce a toxic substance
that paralyzes the fishes’ respiratory systems,
and then feeds on the fish.
Symbiosis with Dinoflagellates
• Symbiotic relationship
with sponges, jellyfish,
sea anemones, corals,
octopuses and squids,
snails, etc…)
• In coral polyps, the
dinoflagellates produce
glycerol, which is used
for coral respiration
• The coral produces
amino acids for the
dinoflagellates
Bioluminescent Dinoflagellates
• When disturbed (by a
wave, or other physical
aggitation), some
dinoflagellates produce
bioluminescent compounds
• Thought to serve as
protection against
predators by startling them.
Phylum Euglenophyta (Euglenoids)
• 900 known species
• Habitat: mostly
freshwater, some
marine
• About 1/3 of the genera
in the phylum are
photosynthetic.
• Euglenoides are
flagellated and
unicellular (except for
one colonial genus)
Phylum Bacillariophyta (Diatoms)
• Over 100,000 living species
• Habitat: Marine &
Freshwater
• Unicellular of colonial, lack
flagella
• Important components of
the phytoplankton, a
primary source of food for
marine and freshwater
aquatic animals.
• Provide carbohydrates, fatty
acids, and vitamins to
animals
Phylum Bacillariophyta (Diatoms)
• Unique structure of
two-part cell walls,
that overlap each
other like a petri dish.
• Each part is called a
frustule and is made of
silica.
• Species distinguished
by frustule
ornamentation.
Phylum Bacillariophyta (Diatoms)
• Diatomaceous earth (DE): fine,
crumbly, yet abrasive substance
made from silica frustules of
diatoms that have accumulated in
ocean sediments over millions of
years.
• Used as silver polish, filtering
material, natural insecticide, used in
cosmetics, used to rid intestinal
worms and parasites from animals
and humans, used as an insulating
material.
Phylum Chrysophyta (Chrysophytes)
• About 1000 species
• Habitat: Mainly freshwater, few
marine
• Unicellular or colonial, flagella
• Many have characteristic gold
color (Greek chrysos, “gold,” and
phyton, “plant”)
• i.e. Dinobryon, a colony of single
cells living in tubes. Each cell can
consume 36 bacteria/hour.
• Major consumer of bacteria in
cooler North American lakes
Phylum Phaeophyta (Brown Algae)
• About 1500 species, most
multicellular
• Almost entirely marine
• Dominate rocky shores in
cool climates
• Range in size to
microscopic (Ectocarpus)
to as much as 195 feet
and 650 lbs (kelp)!
• Greek: phaeo, “darkcolored”
Kelps and Rockweed
Laminaria sp.
Holdfast
Fucus sp.
Fucus sp.
Phylum Phaeophyta (Brown Algae)
• Algin: mucilaginous material used
economically as a stabilizer and
emulsifier for some foods and for
paint, and as coating for paper
• In the cell, algin provides flexibility
and toughness to allow the algae
to withstand stress from waves
• Also helps prevent drying when the
algae are exposed during low tides.
Phylum Rhodophyta (Red Aglae)
• 4000-6000
species, mostly
multicelluar
• Habitat: Mainly
marine, about 100
freshwater
• Many tropical
species, many
found in coral
reefs
Phylum Rhodophyta (Red Aglae)
• Carageenan: gelatinous extracts from red
algae (i.e. Chondrus crispus)
• Used as food additives for hundreds of years.
• Used in Products such as ice cream, pudding,
condensed milk, toothpaste, shampoo, soy
milk, artificial Alien saliva.
Phylum Chlorophyta (Green Algae)
• 17,000 species (multicellular and unicellular)
• Habitat: Marine and Freshwater, some
terrestrial (in the soil, in snow, on tree
trunks…), some living symbiotically with other
organisms.
Closest relatives to plants
• Class Charophyceae within the phylum
Chlorophyta (green algae) includes members
that most closely resemble true plants.
• Bryophytes (mosses, etc.) probably derived
from an extinct member of Charophyceae
Class.
• The Order Charales possess traits found
otherwise only in true plants (i.e. mosses and
vascular plants).
Chara (class Charophyceae)
• Chara aka “stonewort” (Class
Charophyceae) grows in shallow
waters of temperate lakes.
• Very closely related to true
plants as evidenced by DNA
analysis and several other
characteristics
Chara
sperm
• Branched growth
• Retention of egg
Moss
sperm
• Sperm morphology
• Numerous chloroplasts per cell
We Love Algae