What do these things have in common?

Mosquito

Metal polish

Insecticide

Fine china

Kitty litter

Sushi

Toothpaste

Ice cream

Think about the following scenario:You find an organism that has the following characteristics:• Is green and can create its own food• Has moving body parts• Can move around in its environment• Has a nucleus

How would you classify this organism?

A) Virus

B) Bacteria

C) Plant

D) Animal

E) Protist

The Kingdom ProtistaChapter 19

Protists are a group of living things that are eukaryotes, can move about, most are single-celled, and they have species that get energy in every way possible.

They live in moist habitats on land and in fresh and salt water.

Protists are difficult to classify. There are four Kingdoms in the Domain Eukarya and there are many phyla of protists that have very little in common with each other.

Protists do not fit into the kingdoms Fungi, Plantae or Animalia. Kingdom Protista can be considered the junk-drawer kingdom for eukaryotes.

Protists fill many important beneficial roles:• Photosynthesis• Oxygen production• Base of food webs• Decomposers• Predators of other microbes like

bacteria.• Human food production.

Kingdom Protista is the most diverse of the six kingdoms.

There are 200,000 species!

They vary in size from a single-celled amoeba to a 100-foot long seaweed.

Protists can be divided into 3 groups:

Animal-like Plant-like Fungus-like

Protozoa = “first animal”• They are heterotrophs. • They are further classified according to the

way they move.

1. Protozoa: Animal-Like Protists

Animal-like Protist:

a) Amoebas – Feed on small organisms such as bacteria. Move by forming pseudopodia and reproduce asexually.

Brain-eating amoeba

• Naegleria fowleri: enters the nose and invades the central nervous system. 99% of people who contract it die! Very rare! Contracted by swimming in warm muddy lakes.

b) Flagellates – Move by whipping one or more flagella side to side. Some are dangerous: African sleeping sicknesscaused by Trypanasoma through the bite of a Tse Tse Fly.

Some flagellates are helpful.

Example: Trichonympha

Living inside a termite’s gut digesting cellulose (cell walls of plants) for the termite.

c) Ciliates – Move by the rhythmic beating of cilia that cover their bodies. Ciliates are found in every kind of aquatic habitat. Reproduce by binary fission (asexual) or conjugation (sexual)

Example: Parameciumhttp://www.microscopyu.com/moviegallery/pondscum/

Ciliates – Reproduction: BINARY FISSION

Animal-like Protist:

Ciliates – Reproduction: CONJUGATION

Animal-like Protist:

d) Sporozoans – Parasitic non-motile protozoa that produces spores for reproduction.

http://www.youtube.com/watch?v=zqJIrhLCFgQ&list=FLWimFhMBb0md1aLNw53jAcw&index=1&feature=plpp_video&safety_mode=true&persist_safety_mode=1&safe=active

Example: Plasmodium which causes malaria.

• Vector = an organism (typically an insect) that transfers a pathogen.

2. Algae (Plant-Like Protists)

Photosynthesizing protists are called algae. Further classified into six types by their pigments or cell wall structure. Both unicellular and multicellular.

a) Euglenoids –

Swim using flagellum.

Unicellular and are both autotrophic and heterotrophic.

b) Diatoms – Unicellular with delicately patterned glass-like shells made of silica. These make up much of the phytoplankton. They are photosynthetic and found in both fresh and salt water. Have many interesting geometric shapes.

Plant-like Protist:

c) Dinoflagellates – Single-celled protists. 90% live in salt water. They have 2 flagella which cause them to spin when they swim. Some are bioluminescent. Some live symbiotically with coral.

Example: Red tide releases toxins into the water and causes major fish kills. People can be poisoned by eating contaminated seafood.

d) Red Algae – Multicellular marine algae attaches to rocks with structures called holdfasts.

• Red algae can live deeper in the ocean than any other algae because of the light absorbing pigments they use.

Red Algae• Is used in some types of sushi rolls.

Red Algae• Is used to produce agar, the substance in petri

dishes used to culture bacteria, fungi, protists.

Petri film: Bacteria

Petri dish

e) Brown Algae – Multicellular marine algae that lives along the rocky coast or floating on the surface of the water in large clumps.

Examples: Kelp & Sargasso seaweed

f) Green Algae – Very diverse, over 7,000 species. Some live on land and in salt water but most live in fresh water. Green algae have the same pigments as plants and both have cell walls made of cellulose. These similarities suggest that green algae were an early ancestor to plants.

• Examples: Volvox and Ulva

3. Slime Molds and Water Molds (Fungus-Like Protists)

• Most are decomposers, some are parasites• Produces spores• Can move during part of their life cycle so they cannot be classified as fungi

Slime Molds – Animal-like and fungus-like. Live in cool, moist, shady areas. Grow on damp organic matter, such as in soil, rotting leaves or underneath logs.

Fuligo septicaDog-vomit slime mold

• One of many slime molds that live as a large single cell with many nuclei. They can grow to be a meter or more in diameter. It moves like a giant amoeba creeping over the ground.

Water Molds – Live in water and moist places. Appear as fuzzy white growths on decaying matter.

Saprolegnia

Water Mold

Phytophthora infestans - a soil protist that destroyed the potatoes in Ireland (1845-1860) resulting in a famine that killed 1 million people, and also resulted in a mass immigration to America.