KINGDOM PROTISTA

Overview

Cell number: Unicellular/MulticellularCell type: EukaryoticNutrition: Autotrophs & HeterotrophsHabitat: Moist environmentsDivided into three categories:

– animal-like – plant-like– fungus-like

Animal-like Protists

Protozoa—single-celled microscopic organisms that can move independently

Heterotrophic Can be parasitic (live off other organisms,

cause disease) Live most anywhere that moisture is

available

Protozoa

Can have three types of locomotion (movement)

1. cilia—short, hair-like projections

2. flagella—long, whip-like “tails”

3. pseudopodia (“false feet”)—large, round cytoplasmic extensions that help move cell. They also surround and engulf food.

Protozoa in the News

Calvin and Hobbes (Bill Watterson)

Types of Protozoa: Amoebas

Ameobas (Sarcodines)

Use pseudopodia

Shape constantly changes

Live in fresh or salt water, soil

Amoeba engulfing a paramecium

Amoebas

Can cause disease: Amoebic dysentery --spread by contaminated food or water; causes severe intestinal problems; can be fatal

Types of Protozoa: Ciliates

Have cilia

Live in ponds, slow moving streams

Example: Paramecium

Ciliated protozoan

Types of Protozoa: Flagellates

Have 1 or more flagella

Live in lakes, ponds

Many are parasitic

Ex: Giardia lamblia (intestinal parasite)

Types of Protozoa: Sporozoans

Produce spores

Many adult forms have no locomotion

Many are parasitic, live in blood and tissue of host

Sporozoans

Ex: toxoplasmosis—why pregnant women should not change litterboxes

Plasmodium—causes malaria, spread by bite of female Anopheles mosquito

Plant-like Protists: Algae

Unicellular or multicellular ALGAE Can be very large OR microscopic Photoautotrophic, go through photosynthesis Reasons why algae is not a plant:

– Lack organs (don’t have leaves, roots, stems)

– Different type of reproduction than plants

Algae

Phytoplankton—microscopic protists that live in water– Major source of food for ocean life– Major producer for food chain

Diatomaceous earth —when diatoms die, they settle at the bottom of oceans. Build up over time into layers. Material used as abrasive in cleaning supplies and toothpaste

Unicellular Algae: Euglena

Have flagella

Live in fresh water

Contractile vacuole —gets rid of excess water (hypotonic environments)

Euglena

Very flexible (no cell wall)

Usually photosynthetic, but can be heterotrophic

Has an eyespot—helps cell find light

Unicellular Algae: Diatoms

Photosynthetic

Outer shells made of silica (glass-like material)

Release large amounts of oxygen

Large component of phytoplankton

Unicellular Algae: Dinoflagellates

Small, usually unicellular

Most photosyn., but can be heterotrophs

Tend to be yellow, green or red

Some are bioluminescent (glow)

Dinoflagellates

Some produce “red tides”– release a toxin that kills fish and

humans if we eat contaminated food

Multicellular Algae: Red Algae

Ocean seaweed

Live in deep waters

Used as a food (nori)

Multicellular Algae: Green Algae

Can be unicellular

Most diverse group of algae

Most live in fresh water, but can live in oceans, soil

Green Algae

Some are colonial (many cells living together)

Ex. Volvox

Multicellular Algae: Brown Algae

Usually in salt water

Large

Ex. Kelp

Fungus-like Protists

1st part of life cycle spent as an amoeba-like organisms

Later, they grow and look like a slimy, white/yellow mold

Can be seen without microscope

Dog Vomit Mold

Fungus-like Protists

Two types: – slime molds– water molds

Examples: – white “fuzz” on dead fish/leaves– Potato Blight that caused the Irish Potato

Famine

*THEY ARE ALL DECOMPOSERS*

Protists Reproduction

1. binary fission— asexual

2. conjugation— asexual

3. fragmentation—asexual; algae will break into pieces and each piece grows into a new individual

Reproduction: Alternation of Generations

Alternation of generation —life cycle that alternates between a haploid and diploid generation

haploid—gametes (gametophytes)

diploid—results from fusion of gametes (sporophytes)

KINGDOM FUNGI

Overview

Eukaryotic

Can be uni- or multicellular

Heterotrophic always (they absorb nutrients)

Cell walls made of chitin (a tough polysaccharide)

Structure

Hyphae—hair-like filaments of fungi that can group together to form larger structures

Mycelium—a cluster of hyphae

Structure

Uses of Fungi

Decomposers for environment

Make foods– Edible mushrooms, truffles– Bleu cheese– Breads and alcohols are made with yeast (a

single celled fungus) – Medicines (ex: antibiotic Penicillin)

Nutrition

Fungi release enzymes that break down food outside of cells. Then, the fungi absorbs the nutrients from their surroundings

Obtaining Nutrients

1. Saprophyte—lives on dead organic (carbon-containing) matter

2. Parasite—absorbs nutrients from living cells

Obtaining Nutrients

3. Mutualistic—lives in a symbiotic (mutually beneficial) relationship with another organism

ex: Lichens—organisms made of both an algae (protist) and a fungus.

– Algae - provides energy through photosynthesis

– Fungi - provides moisture/place to grow

Fungi Reproduction

Type of reproduction that a fungus has is important in classification into species

Fungus Reproduction

1. AsexuallyA. Fragmentation—part of hyphae breaks off and

grows into a new mycelium

B. Budding—cells replicate their DNA, split into two identical cells

Ex: yeast

C. Spores—reproductive cells that can develop into new organisms (are NOT true seeds, but they act in a similar way)

Fungus Reproduction

2. Sexually

Can happen occasionally

When hyphae from two different fungi meet, they can fuse together and make spores that combine genetic info from both hyphae

Fungal Infections

Human infections– Can cause allergies/severe respiratory

illnesses– Infect hair, skin, nails

Athlete's foot, jock itch, and ringworm are caused by the same fungus that can grow in various locations

Fungal Infections

Plants– Some “blights” are caused by fungi– Almost all chestnut trees have been

infected with a blight

More Examples

Unicellular:– Yeast (Sac fungus)

Colonies resemble bacteriaAre naturally occurring in humans, but when

growth gets “out of control” can cause yeast infections

Multicellular – Mushroom (Club fungus)

White Cliffs of Dover

Amoeba