eukaryotic microbes. 3 domains
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What are some What are some characteristics of eukaryotic characteristics of eukaryotic
organisms?organisms?
Kingdom ProtistaKingdom 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
AlgaeAlgaeMany 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 AlgaeUnicellular AlgaeDiatoms
– 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 AlgaeUnicellular AlgaeDinoflagellatesUsually
photosynthetic.Some produce light
and are often called fire algae.
Responsible for “red tides.”
www.botany.hawaii.edu
www.botany.hawaii.edu
news.bbc.co.uk
Unicellular AlgaeUnicellular 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.
– Ex. Spirogyra Filamentous algae.
Spirogyra. www.marietta.edu
Euglena. www.biologie.uni-erlangen.de
Multicellular AlgaeMulticellular Algae
Consists mainly of Brown and Red algae.
Brown Algae– 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
Brown algae. saltwater-aquarium-guide.net
ProtozoaProtozoaMost 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 CycleProtozoan Life Cycle
Usually have 2 stages to their life cycle.– Trophozoite
Motile, feeding, dividing stage.
– Cyst Dormant, survival
stage. www.tulane.edu
ProtozoaProtozoa
Symbiotic relationship– Between termite and
protozoan.
Parasitic relationships – Malaria– Giardiasis– African sleeping
sickness– Amoebic dysentery
A termite (top) next to a gut from another termite (middle). Contents (bottom) include spirochetes (arrows) and protozoa (P). animals.howstuffworks.com
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 ReproductionProtozoan ReproductionAsexual 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 ClassificationProtozoan Classification Based on method of
locomotion. Major groups
– AmoebaePseudopodia
– FlagellatesPossess flagella
– CiliatesPossess cilia
– Nonmotile protozoaCalled sporozoa
Amoeba. Naegleria
fowleri. classes.midlandstech.edu
Flagellate. Giardia
lamblia. www.pathobio.sdu.edu.cn
Cilate. Balantidium coli. www.tulane.edu Nonmotile. Plasmodium
vivax. www.dpd.cdc.gov
FungiFungi
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 YeastUnicellular 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. Results in the production of a type of
asexual spore called a blastospore. Responsible for beer, wine, leavened bread. Some species are human pathogens (i.e.
Candida albicans).
Yeast cells budding. immunenhance.com
Multicellular FungiMulticellular FungiPossess 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 ReproductionMulticellular 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 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 There are other types of fungi that are multicellular and are not considered multicellular and are not considered
microorganisms.microorganisms.
Fungi and DiseaseFungi and DiseaseAre responsible for
diseases in humans, animals, and plants.
In humans, infections could be superficial – affecting the skin, hair,
fingernails, toenails. Some of these fungal
infections can be more internal and thus be more severe.
Ringworm. Tinea corporis. www.research.usf.edu
Madura foot.
LichensLichens Mutualistic relationship
between an alga and a fungus. Are tough and self-sufficient. 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 MoldsSlime MoldsHave both fungal
and protozoal characteristics.
May be cellular or acellular.
Found in soil and on rotting logs.
www.genome.gov
Cellular Slime MoldsCellular 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 MoldsAcellular 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.
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