Kingdom Protista

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

What is a Protist? All protists have a nucleus and are therefore eukaryotic. Are either plant-like, animal-like or fungus-like.

Heterotrophs vs. Autotrophs Animal-like and fungus-like protists and are heterotrophs. They are organisms that cannot make its own food Plant-like protists are autotrophs – they contain chloroplasts and make their own food.

Animal Like Protists Protozoans are animal-like protists (heterotrophs) 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.

All protozoa digest their food in stomach-like compartments called vacuoles. As they chow down, they make and give off nitrogen, which is an element that plants and other higher creatures can use. Protozoa can be classified into three general groups based on how they move: Pseudopods Flagellum Cilia

Pseudopods Pseudopods: or “false foot” Cell membrane pushes in one direction & the cytoplasm flows into the bulge. This allows the protozoan to move, dragging the rest of the cell behind it engulfing food as they go

Amoebae Aquatic – lives in ponds, ditches, or slowly moving streams. Just visible to the naked eye Unicellular Obtain nutrition by feeding on other animals have a thin cell membrane but no cell wall. no definite shape

EXAMPLE OF HOW PSEUDOPODS MOVE FLOW PUSH DRAG

It can form 2 pseudopods to surround & trap food It can form 2 pseudopods to surround & trap food. Then form a food vacuole to break down food in the cytoplasm.

Flagellum The smallest of the protozoa Flagellates (FLAJ-uh-lits) use their flagella to move, whip-like projections poking out of their cells, providing a back and forth movement Can have one or several long flagella Unicelluar Has characteristics of both plants and animals

Euglena (yoo-glee-nuh) Move freely and feed on other organisms Makes its own food and also obtains nutrients by feeding as well. Has an eyespot (to see) When an eyespot detects light it uses flagellum to move toward the light so that its chloroplast can carry out photosynthesis

Cilia Generally the largest protozoa Unicellular, slipper shaped Cilia – hair-like structures - help organisms move, get food and sense environment

Paramecium Feeds with the help of a structure called an oral groove – where food is drawn in by external and internal cilia to form a food vacuole Will eat the other two types of protozoa as well as bacteria. Anal pore sends out waste Aquatic - common in ponds and slow moving streams

ORAL GROOVE

Plant-like protists 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. Found in ponds and ditches, and even in shallow rain puddles

Volvox Unicellular protists that has chloroplasts that can carry out photosynthesis Does not live alone Forms groups called colonies Two small flagella that are used to move them Cells near the surface are specialized to move the entire colony through water Food source – makes its nutrients.

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