Eukaryotic Microbes
3 Domains
www.emc.maricopa.edu
5 Kingdoms

Protista *
 Fungi *
 Animalia
 Plantae
 Bacteria
www2.bc.cc.ca.us/bio16/1_Lecture.htm
What are some
characteristics of eukaryotic
organisms?
Kingdom Protista

Any eukaryote that is not an animal, plant,
or fungus.
 60,000 protist species.
 Most are single-celled.
 Include algae and protozoa.
Marine Protists
Algae

Many produce energy by photosynthesis.
 Most algal cell walls contain cellulose (also
found in plants).
 May be:
– Unicellular
 Diatoms
 Dinoflagellates
 Desmids
– Multicellular
 Large, plantlike seaweeds
 Include Red and Brown algae
Euglena.
www.britannica.com
Unicellular Algae

Diatoms
– Freshwater and
marine
environments.
– Cell walls contain
silicon dioxide
(glass).
– Used in filtration
systems, insulation,
and abrasives (like
toothpaste).
www.rbgsyd.nsw.gov.au
Unicellular Algae
www.botany.hawaii.edu

Dinoflagellates
 Usually
photosynthetic.
 Some produce light
and are often called
fire algae.
 Responsible for
“red tides.”
www.botany.hawaii.edu
news.bbc.co.uk
Unicellular Algae

Desmids
– Group of green algae.
– Can photosynthesize.
– Ex. Euglena





Has algal and protozoan
characteristics.
Has a primitive mouth.
Does not have a cell wall.
Has an eyespot.
Has flagellum.
Spirogyra. www.marietta.edu
– Ex. Spirogyra

Filamentous algae.
Euglena. www.biologie.uni-erlangen.de
Multicellular Algae

Consists mainly of Brown
and Red algae.
 Brown Algae
Brown algae.
saltwater-aquariumguide.net
– Usually found in ocean
water.
– Are a source of algin,
which is a thickener in ice
cream.

Red Algae
– Found in deeper ocean
water than brown algae.
– One type of red algae
(Gelidium) is the source of
agar.
Red algae.
Gelidium spp.
www.canari.org
Protozoa

Most are
unicellular.
 Most are free-living
organisms that live
in soil and water.
 Ingest other
organisms or
organic material.
 Do not have a cell
wall.
www.marietta.edu
Protozoan Life Cycle

Usually have 2
stages to their life
cycle.
– Trophozoite
 Motile, feeding,
dividing stage.
– Cyst
 Dormant, survival
stage.
www.tulane.edu
Protozoa

Symbiotic
relationship
– Between termite and
A termite (top) next to a
gut from another termite
(middle). Contents
(bottom) include
spirochetes (arrows) and
protozoa (P).
animals.howstuffworks.com
protozoan.

Parasitic relationships
– Malaria
– Giardiasis
– African sleeping
sickness
– Amoebic dysentery
Tsetse flies in the genus Glossina
transmit the protozoan pathogens that
cause African sleeping sickness
(Trypanosoma gambiense and T.
rhodesiense). www.cals.ncsu.edu
Protozoan Reproduction

Asexual reproduction
– Binary fission
 produces 2 daughter cells.
– Schizogony
 Multiple nuclear divisions before cytoplasmic
divisions.
 Results in more than 2 daughter cells.

Sexual reproduction
– Gametocyte production
 2 haploid gametes which fuse to form a diploid
zygote.
Protozoan Classification

Based on method of
locomotion.
 Major groups
– Amoebae
Flagellate. Giardia
 Pseudopodia
lamblia.
– Flagellates
www.pathobio.sdu.edu.cn
 Possess flagella
– Ciliates
 Possess cilia
– Nonmotile protozoa
 Called sporozoa
Nonmotile. Plasmodium
vivax. www.dpd.cdc.gov
Amoeba. Naegleria
fowleri.
classes.midlandstech.edu
Cilate.
Balantidium coli.
www.tulane.edu
What is the world’s largest
organism?
Blue Whale
Giant Sequoia
Honey Mushroom,
Armillaria spp.
Fungi

Unicellular or multicellular eukaryotes.
 Reproduce asexually and sexually.
 5 phyla
– based on their mode of sexual reproduction.

Lack chlorophyll.
 Have a cell wall made of chitin.
 Are saprophytes
– “garbage disposers” of nature.
Unicellular Yeast






3-8 µm in diameter.
Found in soil and water and on skin of
many fruits and vegetables.
Reproduce by an asexual process called
budding.
Yeast cells
budding.
Results in the production of a type of
immunenhance.com
asexual spore called a blastospore.
Responsible for beer, wine, leavened bread.
Some species are human pathogens (i.e.
Candida albicans).
Multicellular Fungi

Possess hyphae
– A hypha is a tube-
like cell.

A mass of hyphae
forms a mycelium.
 Septate hyphae
have cross walls or
septations.
 Non-septate
hyphae lack cross
walls or septations.
Hyphal structure with septae.
www.fungionline.org.uk
Multicellular Fungi Reproduction

Sexual or asexual reproduction.
 Can produce sexual or asexual spores.
 Sexual spores form by the fusion of 2
gametes.
 Asexual spores form in many different
ways.
Molds





Consists of many types of
multicellular fungi.
Have great commercial
importance.
Consists of many antibiotic
producing molds like
Penicillium.
Used to make many
different kinds of cheese.
Potato blight mold caused
the famine in Ireland in the
mid-19th century.
Penicillium, a genus
of green mold, attacks
many fruits and is the
source of the antibiotic
drug penicillin.
www.britannica.com
Moldy bagel.
www.sciencedaily
.com
There are other types of fungi that are
multicellular and are not considered
microorganisms.
Fungi and Disease

Are responsible for
diseases in humans,
animals, and plants.
 In humans, infections
could be superficial
Ringworm. Tinea
corporis.
www.research.usf.edu
– affecting the skin, hair,
fingernails, toenails.

Some of these fungal
infections can be more
internal and thus be
more severe.
Madura foot.
Lichens

Mutualistic relationship
between an alga and a
fungus.
 Are tough and selfsufficient.
 Can inhabit inhospitable
habitats such as deserts,
newly formed volcanic
islands, the Arctic, bare
rock.
 Grow slowly
– Arctic colonies grow 1-2
inches every 1000 years.
– Some thought to be over 4000
years old.
Slime Molds

Have both fungal
and protozoal
characteristics.
 May be cellular or
acellular.
 Found in soil and on
rotting logs.
www.genome.gov
Slime Molds
www.treknature.com
Cellular Slime Molds





Begin life as ameba-like organisms.
If harsh conditions ensue, individual organisms
will fuse together to form a motile, multicellular
form that is called a slug.
Slug becomes a fruiting body which consists of a
stalk and spore cap.
Spores released and are airborne.
If suitable habitat is found, a spore becomes an
ameba.
Acellular Slime Molds

Also called plasmodial slime mold.
 Also produce a stalk and spores.
 Haploid cells fuse to form diploid cells.
– forms large masses of motile, multinucleated
protoplasm.
The End