Features of Kingdom Protista
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All members have eukaryotic cells.
Individual life cycles vary considerably, but
reproduction is generally by cell division and
sexual processes.
Most multicellular members produce some
motile cells.
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Outline
Phylum Chlorophyta
Phylum Chromophyta
Phylum Rhodophyta
Phylum Euglenophyta
Phylum Dinophyta
Phylum Cryptophyta
Phylum Prymnesiophyta
Phylum Charophyta
Phylum Myxomycota
Phylum Dictyosteliomycota
Phylum Oomycota
Phylum Chlorophyta
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The Green Algae
 Includes about 7,500 species that occur in
a rich variety of forms and occur in diverse,
widespread habitats.
- Greatest variety found in freshwater
lakes, ponds, and streams.
- Most have a single nucleus.
- Most reproduce both sexually and
asexually.
Fig. 18.2
Green Algae:
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contain pigments (chl a & b) similar to higher
plants.
store food in the form of starch within their
chloroplasts.
Phylum Chlorophyta
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Chlamydomonas
 Common inhabitant of freshwater pools.
 Pair of whip-like flagella on one end pull
the cell through the water.
 Single, cup-shaped chloroplast with one or
two pyrenoids inside.
- Pyrenoids = Proteinaceous structures
thought to contain starch synthesis
enzymes.
Chlamydomonas
Chlamydomonas
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Asexual Reproduction
 Nucleus divides by mitosis, and cell
contents become two daughter cells within
the cellulose wall.
- Develop flagella and swim away.
Sexual Life Cycle of Chlamydomonas
Phylum Chlorophyta
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Ulothrix
 Thread-like alga.
- Single row of cylindrical cells forming a
filament.
 Basal cell functions as a holdfast.
Ulothrix Life Cycle
Phylum Chlorophyta
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Spirogyra (Watersilk)
 Common freshwater algae consisting of
unbranched filaments of cylindrical cells.
- Frequently float in masses at the surface
of quiet waters.
 Asexual Reproduction
- Fragmentation of existing filaments.
 Sexual Reproduction
- Papillae fuse and form conjugation
tubes.
Spirogyra Sexual Reproduction
Phylum Chlorophyta
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Oedogonium
 Epiphytic filamentous green alga.
- Each cell contains a large, netlike
chloroplast that rolls and forms a tube
around and toward the periphery of each
protoplast.
Phylum Chlorophyta
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Other Green Algae
 Chorella - Widespread green alga
composed of tiny spherical cells.
- Reproduce by forming either daughter
cells or autospores through mitosis.
 Desmids - Mostly free-floating and
unicellular.
- Reproduce by conjugation.
Fig. 18.8
Phylum Chlorophyta
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Other Green Algae
 Hydrodictyon (Water Nets) - Net-like, tubular
colonies with hexagonal or polygonal
meshes.
- Asexual reproduction as well as
isogamous sexual reproduction.
 Volvox - Colonial green algae held together
in a secretion of gelatinous material
- Reproduction asexual or sexual.
Fig. 18.9
Fig. 18.10
Phylum Chlorophyta
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Other Green Algae
 Ulva (Sea Lettuce) - Multicellular seaweed
with flattened green blades.
- Isomorphic reproductive structures.
 Cladophora - Branched, filamentous green
alga with species represented in both fresh
and marine waters.
- Mostly multinucleate.
Fig. 18.11
Phylum Chromophyta
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The Diatoms (Bacillariophyceae)
 Among best known and economically most
important members of this phylum.
- Mostly unicellular
 Occur in both fresh and salt water.
 Particularly abundant in colder
marine habitats.
Fig. 18.14
Reproduction in Diatoms
Phylum Chromophyta
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The Brown Algae (Phaeophyceae)
 Relatively Large
 Most Marine
 Non-Unicellular or Colonial
 Many have a thallus differentiated into a
holdfast, a stipe, and blades.
- Blades may have gas-filled bladders.
 Sargassum - Floating Brown Seaweed
 Fucus - Common Rockweed
Brown Alga Nereocystis
Fig. 18.16
Fig. 18.18
Phylum Rhodophyta
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The Red Algae
 Most species are seaweed.
- Tend to occur in warmer and deeper
waters than brown algae.
 Most are filamentous.
 Relatively complex life cycle involving
three types of thallus structures.
 Colors mostly due to phycobilins.
 Numbers of species produce agar.
Fig. 18.21
Phylum Euglenophyta
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The Euglenoids
 Spindle-shaped.
 No cell wall, thus changes shape as it
moves.
- Sub-membrane strips and membrane
form pellicle.
 Contains gullet.
 Contains red eyespot.
 Reproduction by cell division.
Fig. 18.23
Phylum Dinophyta
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The Dinoflagellates
 Unicellular
 Contain two flagella.
- One trails behind the cell.
- Other encircles the cell at right angles.
 Most have disc-shaped chloroplasts.
- Contain xanthophyll pigments.
 Many have tiny projectiles.
 Many types of toxins produced. (Red Tides)
Dinoflagellates
Human and Ecological Relevance of Algae
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Diatoms
 Oils are sources of vitamins.
 Diatomaceous Earth
- Filtration
- Polishes
- Reflectorized Paint
Other Algae
 Chlorella
- Potential human food source.
Human and Ecological Relevance Algae
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Algin
 Produced by giant kelp.
- Ice Cream, Salad Dressing
- Latex Paint, Textiles, Ceramics
Agar
 Produced by red alga Gelidium.
- Solidifier of nutrient culture media for
growth of bacteria.
Table 18.2
Phylum Myxomycota
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The Plasmodial Slime Molds
 Totally without chlorophyll and are
incapable of producing their own food.
- Distinctly animal-like during much of life
cycle, but fungus-like during
reproduction.
 Plasmodium converts into separate
small sporangia (each containing
spores) during times of significant
environmental changes.
Fig. 18.30
Fig. 18.31
Phylum Dictyosteliomycota
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The Cellular Slime Molds
 About two dozen species of cellular slime
molds are not closely related to the other
slime molds.
- Individual amoebalike cells feed
independently, dividing and producing
separate new cells periodically.
 Human and Ecological Relevance
- Break down organic particles to simpler
substances.
Fig. 18.33
Phylum Oomycota
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The Water Molds
 Often found on dead insects.
 Range in form from single spherical cells to
branching, threadlike, coenocytic hyphae.
- Coenocytic hyphae may form large
thread masses (mycelia).