Protists and Fungi
* 2
Diverse Kingdoms of Life
Domain Eukarya
* Eukaryotes
(review BIOL 1020 notes)
* Differ
from other domains by:
* 1)
multicellularity: body formed of cells which are in contact and coordinate
activities
* Note
some eukaryotes are unicellular or colonial (aggregation of cells with little
coordination of activities)
* 2)
sexual reproduction: absent from all bacteria known
* Note
some eukaryote groups rarely or never reproduce sexually (only asexual
reproduction has been observed)
* But,
evolution of eukaryotes involved endosymbiosis, incorporation of Eubacteria
cells into eukaryotes as mitochondria and chloroplasts.
Domain Eukarya
* The
mitochondria of all eukaryotes, and the chloroplasts of photosynthetic ones,
evolved from Eubacteria.
Domain Eukarya
* The
mitochondria of all eukaryotes, and the chloroplasts of photosynthetic ones,
evolved from Eubacteria.
Domain Eukarya
Kingdom Protista (protists)
* Most
diverse kingdom in Eukarya
* Unicellular
(single cells)
* Colonial
(loose confederations of cells which generally do not coordinate activities or
specialize to perform particular functions)
* Multicellular
(many cells that do coordinate activities and often become specialized to
divide up life functions)
Domain Eukarya
Kingdom Protista (protists)
* Artificial
group: not based on phylogeny
* Placed
together for convenience and because they are NOT fungi, animals, or plants
* Polyphyletic
group
* Note
that classifications
* vary:
text and lab use
* different
systems!
Kingdom Protista (protists)
* We
will cover them by grouping similar phyla together into 5 general groups:
* Heterotrophs
with no permanent locomotor apparatus
* Photosynthetic
ones
* Heterotrophs
with flagella
* Non-motile
spore-formers
* Heterotrophs
with restricted
* mobility.
1) Heterotrophs with no permanent locomotor apparatus
* Mostly
unicellular and ameoba-like:
* Phylum
Rhizopoda (amoebas)
* Phylum
Actinopoda (radiolarians)
* Phylum
Foraminifera (forams).
Phylum Rhizopoda (amoebas)
* Move
by pseudopods (flowing extensions of cytoplasm)
* Lack
sexual reproduction, cell walls, flagella
* Reproduce
asexually only
Phylum Rhizopoda (amoebas)
* Many
are predators (use pseudopods to engulf other cells).
* Exception:
Vampyrella, the "sucking amoeba"
* Sucks
contents of algal cell in matter of seconds.
Phylum Rhizopoda (amoebas)
* Hundreds
of species: freshwater, marine, soil
* Some
are parasites (feed on host tissues or cells but usually donšt kill host).
Phylum Rhizopoda (amoebas)
* Example:
Entamoeba histolytica (cause of amoebic
dysentery)
* Up to
10 million Americans may be infected by parasitic amoebas.
Phylum Actinopoda (radiolarians)
* Have
shells (external skeletons) made of silica (glass)
* Pseudopods
needle-like
* Marine
group. Part of plankton (microscopic floating marine organisms)
* Valuable
fossils for geological record.
Phylum Foraminifera (forams)
* Marine,
make skeleton (called test) of organic material plus sand, calcium carbonate
* Some
float in plankton, most live attached to bottom or other organisms
* Podia
(thin cytoplasmic projections) used for swimming, feeding.
Phylum Foraminifera (forams)
* Life
cycle: sporic meiosis (haploid and diploid generations formed)
* Important
fossil group (200 million years of geological record
* Limestones
often rich in forams (ex, Dover, England).
2) Photosynthetic protists
* Phylum
Phyrrhophyta (dinoflagellates)
* Phylum
Euglenophyta (euglenoids)
* Phylum
Chrysophyta (diatoms and golden algae)
* Phylum
Rhodophyta (red algae)
* Phylum
Phaeophyta (brown algae)
* Phylum
Chlorophyta (green algae)
Phylum Phyrrhophyta (dinoflagellates)
* Unicellular,
mostly marine: 2100 species
* Usually
2 flagella, skeleton of plates of cellulose
* Reproduce
mostly by asexual reproduction (sex rare)
* Chlorophylls
a + c
Phylum Phyrrhophyta (dinoflagellates)
* Important/interesting
roles:
zooxanthellae:
symbionts (live in mutually beneficial relationship) in other organisms
(jellyfish, sea anemones, mollusks, corals)
Zooxanthellae in
corals (up to 30,000 cells per cubic mm or coral tissue) do photosynthesis and
carbon products absorbed by corals, helping to make coral reefs one of most
productive habitats on Earth!.
Phylum Phyrrhophyta (dinoflagellates)
* Important/interesting
roles:
bioluminescent:
emit light when disturbed
creates sparkling
waves and wakes of ships at night
why do this?
Perhaps to attract predatory fish to eat the predators of the dinoflagellates!
Phylum Phyrrhophyta (dinoflagellates)
* Important/interesting
roles:
red tides:
population explosions ("blooms") that can color the water with pigmented
dinoflagellate cells
toxins in cells
can kill marine life
Example, Pfiesteria
piscicida: stuns fish with toxin and feeds
on body fluids.
Phylum Euglenophyta (euglenoids)
* Mostly
freshwater, unicellular. 1000 species
* Some
photosynthetic (chlorophylls a + b), some not
* Protein
coat called pellicle on outside of cell
* Important
members of food freshwater food chains
* Example,
Euglena.
Phylum Chrysophyta (diatoms and golden algae)
* Here
we emphasize the diatoms: 11,500 species
* Use
chlorophyll a + c, lack flagella
* Make
chrysolaminarin: unique energy storage chemical
* Cell
wall of silica
* (glass),
with intricate
* designs. Like petri
* plate,
with top and
* bottom
halves.
Phylum Chrysophyta
* Asexual
reproduction common, but do gametic meiosis.
* Importance:
1) "grass of the
sea." Abundant members of plankton. Do large % of ocean photosynthesis
2) fossil deposits
of cell walls called "diatomaceous earth." Mined and used for pest control
(applied to insects, gets in appendages and grinds them to death), reflective
paints, filters.
Phylum Rhodophyta (red algae)
* Mostly
marine (many tropical), multicellular. 4000 species.
* Lack
flagella
* Have
only chlorophyll a: similar to photosynthetic bacteria called cyanobacteria
* Reproduction:
mostly sporic meiosis (make gametophyte and sporophyte generations).
Phylum Rhodophyta (red algae)
* Importance:
Coral reefs: part
of reef made of coralline red algae, which have calcium carbonate forming part
of cell walls.
Phylum Rhodophyta (red algae)
* Importance:
Agar and
carrageenan (cell wall chemicals) are extracted from some red algae
Used as
emulsifiers and thickeners (chocolate milk, ice cream, cosmetics, jellies,
microbiology medium, etc.)
Phylum Phaeophyta (brown algae)
* Marine
(cold water), multicellular: 1500 species
* Chlorophylls
a + c
* Reproduction
often sexual: sporic meiosis (sporophyte and gametophyte generations)
Phylum Phaeophyta (brown algae)
* Large
species called kelps
* Form
"kelp forests": important shallow water habitats.
Phylum Phaeophyta (brown algae)
* Kelps
also harvested for cell wall materials called alginates: used as thickeners in
foods and other products.
Phylum Chlorophyta (green algae)
* Mostly
aquatic (some on most terrestrial surfaces), marine and freshwater: 7000
species
* Unicellular
to multicellular
* Chlorophylls
a + b
Phylum Chlorophyta (green algae)
* Unicellular
motile example: Chlamydomonas
* To be
seen in lab: note zygotic meiosis and asexual reproduction in haploid phase.
Phylum Chlorophyta (green algae)
* Motile
(swimming) colonial example: Volvox
* To be
seen in lab: note daughter colonies (made asexually inside main sphere).
Phylum Chlorophyta (green algae)
* Parenchymatous
(3-D body) form: Ulva (sea lettuce)
* To be
seen in lab: note life cycle is sporic meiosis where gametophyte and sporophyte
look identical (isomorphic alternation of generations)!
Phylum Chlorophyta (green algae)
* Importance:
producers in
aquatic ecosystems (base of food chains)
human/animal
nutritional supplement? Chlorella in the
news....
Phylum Chlorophyta (green algae)
* Evolutionary
Importance
* Land
plants (Kingdom Plantae) evolved from a line of green algae.
3) Heterotrophs with flagella
* Phylum
Sarcomastigophora (zoomastigotes)
* Phylum
Ciliophora (ciliates)
Phylum Sarcomastigophora (zoomastigotes)
* Mostly
unicellular, often with flagella
* Here
we emphasize Class Zoomastigophora, especially a group called the trypanosomes
* Most
reproduction is asexual.
Phylum Sarcomastigophora (zoomastigotes)
* Some
trypanosomes are parasites that cause serious human diseases:
African sleeping
sickness: Caused by Trypanosoma
Carried to new
host by biting fly (tsetse fly)
Affects cattle and
prevents livestock culture in large area of Africa.
Phylum Sarcomastigophora (zoomastigotes)
* Some
trypanosomes are parasites that cause serious human diseases:
Leishmaniasis
(caused by Leishmania)
Carried to new
host by biting fly (sand fly) in tropical areas
Causes sores and erosion of skin (4
million people/yr).
Phylum Sarcomastigophora (zoomastigotes)
* Some
trypanosomes are parasites that cause serious human diseases:
Giardiasis caused
by Giardia lamblia
Infects humans and
some other animals (dogs). Found across U.S.
Causes nausea,
cramps, diarrhea.
Phylum Sarcomastigophora (zoomastigotes)
* Some
trypanosomes are gut symbionts:
Trichonympha in guts of termites (Order of insects)
Digest cellulose
in wood for insect, receive home in gut.
Phylum Ciliophora (ciliates)
* Unicellular
(but some big and internally complex)
* 8000
species
* Most
with many cilia
* Also
have 2 types of nuclei: macronucleus (large) and micronucleus (small)
* Outer
covering (called pellicle) of tough protein material
Phylum Ciliophora (ciliates)
* Do
sexual reproduction by conjugation (exchange of micronuclei).
Phylum Ciliophora (ciliates)
* Examples,
Paramecium and Stentor
* Cilia
used for locomotion and for feeding.
4) Nonmotile spore-formers
* Phylum
Apicomplexa (sporozoans)
Phylum Apicomplexa (sporozoans)
* Unicellular,
do not make cilia/flagella: 3900 species
* All
are parasites of animals
* Spores
are infective bodies used to reach new hosts
* Cell
structure unique: on end (apex) of cell has concentration of organelles.
Phylum Apicomplexa (sporozoans)
* Example,
Plasmodium
* Cause
of malaria
* Complex
life cycle: uses mosquito and human as host
* One of
most serious diseases worldwide: 500 million cases/yr (2 million deaths).
* Attacked
by mosquito control (often insecticides) and antimalarial drugs
* Problem:
both mosquitoes and Plasmodium evolve
resistance to control chemicals
* Maybe
develop vaccine?.
5) Heterotrophs with restricted mobility
* Phylum
Oomycota (oomycetes)
* Phylum
Acrasiomycota (cellular slime molds)
* Phylum
Myxomycota (plasmodial slime molds)
Phylum Oomycota (oomycetes)
* All
are parasites or saprobes (feed on dead organic matter). About 600 species
* Cell
walls present (cellulose)
* Gametic
life cycles (like us!)
* Make
asexual spores by mitosis: called mitospores. As with all spores, one can form
new organism without joining with another cell. If swimming mitospore, called a
zoospore.
* May
form threadlike cells
One called hypha
(pl. hyphae).
Phylum Oomycota (oomycetes)
* Importance:
some cause diseases of plants or fish
* Example,
late blight of potato (Phytophthora).
Irish Potato Famine
* Irish
peasants depended on potatoes as staple food
* 1845-1847,
late blight of potato struck
* Destroyed
crops
* 1
million Irish starved to death, 1 million emigrated (many to U.S.).
Phylum Acrasiomycota
(cellular slime molds)
* Weird
group: 70 species.
* Amoeboid
cells
* Join
together for form mass called "slug"
* Makes
spores.
Phylum Myxomycota
(plasmodial slime molds)
* Another
weird group (700 species). Plasmodium is multinucleate mass of cytoplasm
* Flows
around in moist areas, ingesting unicells and organic matter
* Example,
Physarum.
Phylum Myxomycota
(plasmodial slime molds)
* Later
form meiospores with cellulose walls
* Note a
spore-containing structure often called a "sporangium" ("angios" from Greek for
"vessel")
* Plural
is sporangia.
Kingdom Fungi
* Unlike
Protista, are monophyletic group
* Large:
about 77,000 named species
* Many
more remain to be discovered.
General fungal traits
* Terrestrial
heterotrophs (digestion is external: enzymes secreted and food absorbed from
solution)
* Cell
walls of chitin
* Unique
type of mitosis (nuclear mitosis: where nucleus divides within nuclear
membrane)
* Do not
make swimming cells (lack cilia and flagella)
* Reproduce
by spores
sexual spores are
meiospores (formed by meiosis)
asexual spores are
mitospores (formed by mitosis).
General fungal traits
* Most
cells are threadlike and tubular (hyphae)
Mass of hyphae
called mycelium.
General fungal traits
* Some
hyphae lack crosswalls (coenocytic hyphae)
* Some
hyphae have crosswalls (septate hyphae)
General fungal traits
* Sexual
reproduction: zygotic meiosis
* Haploid
phase predominates
* BUT,
syngamy fertilization has 2 steps
Plasmogamy: union
of gamete cells
Karyogamy: union
of gamete nuclei
* Some
fungi do plasmogamy but delay karyogamy, forming cells that have separate
haploid nuclei. These hyphae called dikaryotic.
General fungal traits
* Example
of fungal life cycle with dikaryotic hyphae: mushroom
* Dikaryotic
mycelium is major phase
* Only
when mushroom is formed does karyogamy occur, followed by meiosis.
Fungal Phyla
* 3
phyla but 4 groups
* Phyla
separated mainly by how meiospores are formed (how sexual reproduction done)
* Phylum
Zygomycota (zygomycetes or bread molds): Meiospores made by zygosporangium
(resistant microscopic structure).
Fungal Phyla
* 3
phyla but 4 groups
* Phyla
separated mainly by how meiospores are formed (how sexual reproduction done)
* Phylum
Ascomycota (ascomycetes or sac fungi): Meiospores made in sac-like ascus. Asci
(plural) containing in fruiting body called ascoma (plural ascomata).
Fungal Phyla
* 3
phyla but 4 groups
* Phyla
separated mainly by how meiospores are formed (how sexual reproduction done)
* Phylum
Basidiomycota (basidiomycetes or club fungi): Meiospores made on club-like
basidium. Basidia (plural) contained in fruiting body called basidioma (plural
basidiomata).
Fungal Phyla
* 3
phyla but 4 groups
* 4th
group? Fungi that donšt make meiospores (to our knowledge)
* Reproduce
only asexually (by mitospores)
* Called
Imperfect Fungi
* Not a
true phylum but a temporary holding group.