Transcript Plant-Like” Protists: - Emerald Meadow Stables

“Plant-Like” Protists:
Unicellular Algae
Unicellular Algae
• Chlorophyll and accessory pigments allow
algae to harvest and use energy from
sunlight.
– Both give algae a wide range of colors
Phylum Euglenophyta - Euglena
• “Plant-like” protists that have two
flagella but no cell wall
• Red eye-spot – helps organism find
sunlight to power photosynthesis
• Phototrophic autotroph or
heterotroph (absorb nutrients in
decayed organic material)
• Pellicle – cell membrane
• Reproduce asexually by binary
fission
Euglena Anatomy
Chloroplast
Carbohydrate
storage bodies
Gullet
Pellicle
Flagella
Eyespot
Nucleus
Contractile
vacuole
Phylum Pyrrophyta Dinoflagellates
• Half are photosynthetic,
half are heterotrophs
• Two flagellas
• Reproduce asexually by
binary fission
• Some luminescent/give
off light
• Only eukaryote with no
histones to help store
DNA
Phylum Chrysophyta
• Mostly solitary
• Yellow-green and goldenbrown algae
• Gold-colored chloroplasts
• Cell walls contain pectin
rather than cellulose; others
can have both pectin and
cellulose
• Reproduce asexually and
sexually
• Store oil, not starch
Phylum Bacillariophyta – Diatoms
• Most abundant organisms on Earth
• Thin, silicon cell walls
Ecology of Unicellular Algae
• Helpful:
– Phytoplankton – diatoms and dinoflagellates
– 70% of photosynthesis occurs in ocean
– Symbiosis – corals and dinoflagellates –
Tridacha gigas (clam) and dinoflagellates
• In both cases, algae provide food to the animal
Ecology of Unicellular Algae
• Harmful:
– Algae “blooms” –
dangerous toxin
produced by algae –
shellfish eat the algae
and eat the toxin =
people can’t eat it
– Dinoflagellate Gonyaulx –
red tide
“Fungus-like” Protists
• Heterotrophs that absorb nutrients from
dead or decaying matter. Unlike true
fungi, “fungus-like” protists have centrioles
and lack chitin in cell walls
• Recyclers of dead organisms
Slime Molds
• Play key roles in recycling organic material
• 3 Phyla of slime molds
– Phylum Acrasiomycota
– Phylum Myxomycota
– Phylum Oomycota
Phylum Acrasiomycota
• Cellular slime molds
– Begin life as amoeba-like cells
– When food begins to run out, then form colonies and
produce a fruiting body which produces spores
– Spores “hatch” into amoeba-like cells
Phylum Myxomycota
• Acellular slime molds
– Begin life as amoeba-like
cell, called plasmodia, that
contain thousands of nuclei
but only one cell membrane
– Plasmodia may reach
several meters in diameter
– Form fruiting bodies
– Produce haploid spores
which germinate into
flagellate cells which fuse to
produce the diploid
“amoeba”
Phylum Oomycota
• Water molds
– Thrive on dead or decaying organic matter in water
and are plant parasites on land
– Hyphae – thin filaments
– A water mold caused the potato famine in Ireland in
1840s