Transcript Bacteria, Protists, and Algae - University of San Diego Home Pages

Bacteria, Protists, Algae,
and
Marine Plants
ENV 121 Lab
Tree of
Life
Figure 4.24
Definitions:
Prokaryotes:
Unicellular organisms
whose cells do not have a
nucleus or other organelles,
simple
Eukaryotes:
Unicellular or multicellular
organisms with cells possessing
a nucleus and other organelles
that are enclosed by membranes
Definitions:
Nutrition:
Process by which an organism obtains
from its environment
1. Energy
2. Chemical elements (carbon)
needed for its survival and growth.
Definitions:
1. Energy
Phototroph:
organisms using sunlight as a source of energy
Chemotroph:
organisms using chemicals as a source of energy
i.e. hydrogen sulfide, ammonia, methane gas
Definitions:
2. Obtain Carbon molecules
Autotroph:
organisms capable of synthesizing their own food
from simple inorganic molecules (e.g. carbon from CO2)
Heterotroph:
organisms that obtain food from organic compounds (i.e.
other living organisms) (e.g. carbon from glucose)
Definitions:
Primary Producers
organisms that manufacture organic matter
from CO2, usually by photosynthesis
Tree of
Life
Figure 4.24
Domain Archaea
• Oldest group of organisms (3.8 billion years)
• Prokaryotic cells
• DNA analysis – more closely related to eukaryotes
• Heterotrophs or Autotrophs
important decomposers, nitrogen fixers
Domain Archaea
Autotrophs: “extremophiles”
Methanogens – chemoautotrophs that produce methane
gas from CO2 and hydrogen gas.
Halophiles – live in high salt environments, some are
photoautotrophs (performing photosynthesis)
Thermophiles – live in environments of very high
temperatures, like hot springs or near hydrothermal vents.
Domain Bacteria
Structure:
• unicellular
• Size ranges from 0.5 to 15 μm, among smallest living
organisms
• Prokaryotic cells
• Shapes include: spheres, spirals, rods, and rings
Reproduction:
• Simple asexual division
• Generation time = 1-3 hrs.
Domain Bacteria
• Most are heterotrophs
- important decomposers, some are nitrogen fixers
- degrade pollutants
• Some are Autotrophs:
Photosynthetic bacteria contain chlorophyll a
Chemosynthetic bacteria use energy released by
breakdown of ammonia, hydrogen sulfide and other sulfur
or iron compounds
Domain Bacteria
• Cyanobacteria (formerly “blue-green algae”)
• most primitive plant-like organisms
• Photoautotrophic bacteria
• Prokaryotic cells
• Pigments: chlorophyll a, phycocyanin, and phycoerythrin
• Important role in O2 accumulation in our atmosphere, some
carry out nitrogen fixation
• Solitary or colonial
****DRAWING****
Domain Bacteria
Prochlorococcus
Synechococcus
Kingdom Protista
General information:
• Often separated into many different Kingdoms
• Variation in cellular anatomy, ecological role, and
life cycles
• Planktonic, unicellular, and multicellular
Structure:
• Mostly unicellular – complex an organism as any
whole plant or animal
• Size range: 0.8 to 2,000 μm (=2mm), larger than
bacteria
Kingdom Protista
Feeding:
• Some are photoautotrophs  phytoplankton
• Some are heterotrophs  zooplankton
• Others are mixotrophs  Euglena sp.
Locomotion:
• Flagella or cilia
Kingdom Protista
Phytoplankton:
•Make up ~1% of global chlorophyll biomass, but are
responsible for ~50% global photosynthesis
• Are the base of the oceanic food web
• Regulate global climate
• Sink for atmospheric CO2
Chl a Absorbance
Photosynthetic
Protists:
Diatoms: (Class Bacillariophyta)
• ~ 12,000 species, half are marine
• Unicellular, but aggregate
• Centric (cylindrical): planktonic
• Pennate (boat-shaped): benthic
• Enclosed by cell walls made of
silica (SiO2)
•Yellow and brown color 
carotenoid pigment is fucoxanthin
Fig. 5.5
Photosynthetic Protists:
Diatoms
• “Shell”  Frustule
• light passes through holes
• perforations allow gasses and nutrients
• Frustules of dead diatoms  diatomaceous ooze
• Important primary producers – temperate and polar regions
• Can produce domoic acid
Reproduction:
Asexual = Cell division
Sexual  egg + sperm in auxospore stage
****DRAWING****
Photosynthetic Protists:
Fig. 5.7
Dinoflagellates: (Class Dinoflagellata)
• ~ 1,200 species, all marine
• Important primary producers –
Warm regions
• Unicellular
• 2 unequal flagella
Gonyaulax polyedra
• External cell wall armored
with plates made of cellulose or naked
• Have chlorophyll, can also ingest food particles
• Have Chlorophyll a, Chlorophyll c2, and peridinin
Photosynthetic Protists:
Dinoflagellates
• Massive blooms cause “red tides”
• Some release toxins that cause shellfish
poisoning (PSP, NSP, DSP)
• Some bioluminesce
• Some are symbiotic to other organisms and called zooxanthellae
****DRAWING*****
Zooxanthellae from anemone,
Bartholomea annulata
Photo by DC Tulipani, 8/2003
http://www.whoi.edu/redtide/
Photosynthetic Protists:
Coccolithophores: (Class Haptophyta)
• Covered with small calcareous coccoliths
• Flagellates
• Major source of primary production
• <20µm in diameter
Non-photosynthetic Protists (Zooplankton):
Foraminiferans: (Phylum Granuloreticulosa)
• foramen = little hole, ferre = to bear
• Planktonic protozoans (animal-like protists),
exclusively marine
• Shells (tests) made of calcium carbonate
(CaCO3)
• “Amoeba with a shell”
• Pseudopodia
• Shells of planktonic forams sink to bottom to
form foraminiferan ooze
Non-photosynthetic Protists:
Foraminiferans
• Most live on bottom, free or attached
• Important contributors in coral reefs and sandy beaches (Bermuda’s
“pink” beaches)
****DRAWING****
http://earthguide.ucsd.edu/earthguide/imagelibrary/orbulinauniversa.html
http://www.ucl.ac.uk/GeolSci/micropal/foram.html
Non-photosynthetic Protists:
Radiolarians (Phylum Polycystina)
• Planktonic, marine
• Secrete tests made of silica (SiO2)
• Tests typically spherical with
radiating spines
• psuedopodia – diatoms (Why?)
• Open waters throughout ocean
• Shells settle to bottom and form
siliceous ooze, called radiolarian ooze
****DRAWING****
Fig. 5.11
Non-photosynthetic Protists:
Genus Euglena
• ~150 species, freshwater
• Flagellum used for locomotion
• Mixotrophs:
• Contain chlorophyll  photosynthesize
• Some eat small particles of living matter
Euglena acus
Euglena spirogyra
Photosynthetic Protists: Multicellular Algae
General Structure:
•More complex than
unicellular algae
•Still lack the highly
specialized structures
and reproductive
mechanisms of land
plants
Fig. 6.1
Photosynthetic Protists:
Multicellular Algae
Phylum Chlorophyta: “Green algae”
• Contain chlorophyll a – no pigment to mask
• Unicellular (3 examples - DRAWINGS)
Ulva sp.
• Desmids
• Volvox sp.
• Cladophora sp.
• Multicellular (2 examples - DRAWINGS)
• Ulva sp.
• Codium sp.
Codium fragile
Photosynthetic Protists:
Multicellular Algae
Class Phaeophyta: “Brown algae”
• Multicellular, mostly marine
• Olive-green to dark brown color from carotenoid
pigment: Fucoxanthin
• Also have chlorophyll a and c
• Often dominant primary producers on temperate and
polar rocky shores
• 2 examples - DRAWINGS
• Macrocystis pyrifera
• Egregia sp.
Pelagophycus
Pelagophycus
Macrocystis
Egregia
Photosynthetic Protists: Multicellular Algae
Phylum Rhodophyta: “Red algae”
• Essentially marine, all multicellular
• Common, more species than green/brown combined
• Contain red pigments called phycobilins
• Most are soft bodied,
• some coralline reds encrusted with hard calcium
carbonate, Why?
• 2 examples – DRAWINGS
• Corallina sp. (calcified)
Pelagophycus
Halimeda
Porphyra