Protists

What is it?

• It is an organism that is not an animal, plant, fungus, or prokaryote

• Kingdom: Protista

• “The Very First” (the very first eukaryotes)

Evolution

• First eukaryotic organisms on earth

• 1.5 billion years ago (bya)

• Endosymbitotic Theory: Eukaryotic cells may have evolved when multiple cells joined together into one.

Classification(s)

• Animal-like

• Plant-like

• Fungus-like

Animal-like Protists (Unicellular):

Characteristics:

• All Heterotrophs

• 4 phyla: These are determined by movement

• Some are decomposers

• Base of some food chains

• Some cause disease

Types:

Zooflagellates:

• They’re apart of the Phylum: Zoomastigina

• They swim using flagella

  • Can either have 1 or 2

• Absorb food through their cell membrane

• Reproduce sexually (conjugation) or asexually

Sarcodines:

• Phylum: Sarcodina

• Moving cytoplasmic extensions called psuedopods

• Amoeboid movement

• Capture food with psuedopods: food vacuole

  • Food Vacuole: an organelle where food is stored after it’s captured

    • Can cause disease (Pathogenic)

      • Entomoeba

      • Giardia causes disease that causes diarrhea

        

Ciliates:

• Phylum: Ciliophora

• Move through the use of cilia: hair-like projections that allows ciliates to move and get food

• Ciliate Anatomy (Paramecium)

  • Trichocycts: structures used for defense

  • Macronucleus: “working library” of genetic info (used for reproduction)

  • Micronucleus: “reserve copy” of genetic info (used for reproduction)

  • Gullet (Oral Groove): where food is trapped

    • The food is collected here until it is stored in the food vacuoles

  • Anal pore: where waste product is emptied

Contractile vacuole (sun shaped): collects/disperses water; maintains homeostasis

Ciliates Conjugation:

• Usually reproduce asexually: Mitosis

• Can exchange DNA through conjugation

• No NEW organisms are creates; simply an exchange of genetic info

• Occurs under stress (environmental pressures)

Sporozoans:

• Phylum: Sporozoa

• Do not move on their own

• They are parasitic

• Have complex life cycles

• Malaria: caused by a type of protist called. . .

  • Plasmodium

Plant-like Protists: Unicellular Algae

Ecology:

• Phytoplankton: base of most aquatic food webs

• Algal blooms

  • “red tides”

Types:

Euglenophytes:

• Phylum: Euglenophyta

  • Phyta: “plant-like”

• Have two flagella

• No cell wall; instead they have Pellicle

• Have eyespot: helps organism find sunlight to aide in photosynthesis

• 

Chrysophytes:

• Phylum: Chrysophyta

• Gold-colored

• Cell walls have carbohydrate Pectin rather than cellulose

• 

Diatoms:

• Phylum: Bacillarophyta

• Cell walls of Silicon (Si)

• 

Dinoflagellates:

• Phylum: Pyrrophyta

• Usually luminescent

Plant-like Protists: Multicellular Algae

Red Algae:

• Phylum: Rhodophyta

  • “Red plants”

• Live at great depths

• Contain chlorophyll as well as Phycobillins (extra pigment) (absorb blue light, give off reddish color)

Brown Algae:

• Phylum: Pheophyta

  • “Dusty plants”

• Have chlorophyll and fucoxanthin

• Largest and most complex algae

• Marine

Green Algae:

• Phylum: Chlorophyta

  • “green plants”

• Share many characteristic with plants

  • Cell wall of cellulose

  • Chlorophyll a and b

  • Hypothesized to be the ancestor of modern plants

Human Use of Algae:

Medications:

• Treat ulcers, arthritis, and blood pressure

Food:

• Sushi wrap

• Algin (thickener) in candy bars, ice cream, pudding, salad dressing

Industry:

• Used to make plastics and waxes

Fungi-like Protists:

• Heterotrophs

• Decomposes

• Lack cell wall

• Have centrioles

• Plant diseases: potato famine

  • Two Groups

    • Slime Molds

      • Free-living cells in soil on the surface

    • Water Molds

      • Thrive on dead or decaying organic material in water, or plant

      • (parasite)(on land)

Fungi:

• Eukaryotic

• Heterotrophs

  • Digest food on the outside of their body (external digestion), then absorb it

  • All are multicellular, except yeasts

• Cell walls

  • Made of chitin

Structure:

• Hyphae: thin filaments that make up fungi

  • Each hypha are only one cell thick

  • Can form cross-walls

• Fungi bodies are composed of many hyphae tangled into a mass called:

  • Mycelium: where food is absorbed (buried underground)

• Fruiting Body: reproductive structure above the soil (“mushroom” part)

Reproduction:

• Asexually

  • Hyphae break off and grow on their own

  • Spores: a reproductive cell that scatters and grow new organisms

• Sexually

  • Fusion of (+) and (-) nuclei that happens inside the fruiting body

  • There are no males or females

Spreading:

• Spores are carried through wind or attached onto animals for them carry

Classification:

• Common

• Sac

• Club

• Imperfect

Common:

• Phylum: Zygomycetes

• Life cycle includes a Zygosporangium: resting spore that contains zygotes (until conditions become favorable to spread)

• Bread Mold:

  • Structure and Function of Bread Mold:

    • Rhizopus Stolonifer

    • Rhizoids (mycelium): rootlike hyphae that penetrate the bread’s surface

• Stolons: stem like hyphae that run along surface

• Sporangiophores: hyphae that push into air

  • Contain 40,000 spores; each able to grow new fungus

Sac Fungi:

• Phylum: Ascomycota

• Ascus: reproductive structure that contains spores

• Largest phylum of fungi

• Yeasts:

  • Unicellular fungi

  • Used for baking and brewing

  • Dry granules are ascospores

  • Budding: asexual reproduction

Club Fungi:

• Phylum: Basidiomycota

• Specialized reproductive structure that resembles a club

  • Basidium (spores): the whole cap itself

• Life Cycle:

  • Mushroom cap; has gills; lines with basidia

  • 2 haploid nuclei fuse creating diploid zygote

  • Undergoes meiosis, producing haploid basidiospores

  • Basidiospores are then scattered

• Edible and Inedible

  • Many wild mushrooms are poisonous

  • Can look identical to edible types

  • Don't eat the shrooms

  • 

Imperfect Fungi:

• Phylum: Deuteromycota

• Varied

• Placed in this phylum because a sexual phase has never been documented by researchers

• Majority of them resemble ascomycetes

• Penecillium

Fungi Ecology: Decomposers

• All Heterotrophs

• Most are saprobes: obtain food from dead or decaying organic matter

• Maintain equilibrium in every ecosystem

• Parasites:

  • Plant

    • Wheat rust

    • Corn smut

  • Human

    • Ringworm

    • Athlete’s Foot

  • Animal

    • Cordyceps in grasshoppers in Costa Rica