Kingdom Protista

If you look at a drop of pond water under a microscope, all the "little creatures" you see swimming around are PROTISTS.

All protists have a nucleus and are therefore eukaryotic. Most protists are unicellular. Protists are either plant-like, animal-like or fungus-like.

Plant-like protists are autotrophs – they contain chloroplasts and make their own food. Animal-like and fungus-like protists and are heterotrophs.

Protozoans Animal-like protists are heterotrophs and are grouped according to how they move. The word protozoa means "little animal." They are so named because many species behave like tiny animals—specifically, they hunt and gather other microbes as food.

Watch this single-celled “animal” move and eat.

The stomach-like compartments that all protozoa digest their food in are called vacuoles <vac-you-ohls>.

Groups of PROTOZOANS Protozoa range in size from 1/5,000 to 1/50 of an inch (5 to 500 µm) in diameter. They can be classified into three general groups based on how they move.

Groups of PROTOZOANS SARCODINES move using pseudopods CILIATES move using cilia FLAGELLATES move using flagella SPOROZOANS move because they are parasites.

SARCODINES Some protists move by changing their shape and filling their cell membrane with cytoplasm. This “false foot” is called a pseudopod.

SARCODINES An amoebae is example of a sarcodine and moves using a pseudopod. They live in water or moist places. They have a cell membrane but no cell wall just like an animal.

This ciliate is called a paramecium. Ciliates Some protozoans move using tiny hairs on their cell membrane called cilia. The cilia also help sweep food into their mouth. This ciliate is called a paramecium.

Flagellates <flah-geh-lets> Flagellates are generally the smallest of the protozoa and have one or several long, whip-like projections called flagella poking out of their cells.

Giardia

Sporozoans These are parasitic and nonmotile. For example……

Plant-like protists are ALGAE. Algae are eukaryotic autotrophs. They, along with other eukaryotic autotrophs, form the foundation of Earth’s food chains. They produce much of Earth’s oxygen.

Some have shells of silica. They make up a large portion of the world’s phytoplankton which is Earth’s largest provider of oxygen and they live in our oceans.

DIATOMS

Algae contains many pigments so they come in many colors. Red, green, and brown, algaes can grow so abundant that they can form “blooms” and make entire sections of ocean look colored.

These algae blooms can damage other organisms.

Multicellular algae are classified by color.

Rhodophyta are red seaweeds. They are found in warm or cold marine environments along coast lines in deeper water. They absorb green, violet, and blue light waves. These light waves are able to penetrate below 100 meters.

Phylum Phaeophyta is made up of the brown algae. They are found in cool saltwater along rocky coasts. Giant Kelp are the largest and most complex brown algae. They have hold fasts and air bladders.

The last of the multicellular algae are the green algae from the Phylum chlorophyta. Most green algae are found in fresh water habitats.

A Volvox is a hollow boll composed of hundreds of flagellated cells in a single layer.

Chlamydomonas are actually unicellular and flagellated.

Fungus-like protists, Myxomycota and Oomycota are decomposers. Phylum Myxomycota are made up of plasmodial slime molds. Phylum Oomycota is made up of water molds and downy molds.

Slime Molds Slime molds have traits like both fungi and animals Slime Molds Slime molds have traits like both fungi and animals. During good times, they live as independent, amoeba-like cells, dining on fungi and bacteria. But if conditions become uncomfortable—not enough food available, the temperature isn't right, etc.—individual cells begin gathering together to form a single structure. The new communal structure produces a slimy covering and is called a slug because it so closely resembles the animal you sometimes see gliding across sidewalks. The slug oozes toward light. When the communal cells sense that they've come across more food or better conditions, the slug stops

Water molds from the Phylum Oomycota are classified as protists because they have flagellated reproductive cells. Downy mildews parasitize plants and are decomposers in freshwater ecosystems.