Protists are eukaryotic, unicellular organisms that simply ...

Protists are eukaryotic, unicellular

organisms that simply do not fit into

any other kingdom.

They can be categorized as:

1. Animal-like (Protozoans)

2. Fungus-like

3. Plant-like

• Animal-like protists, often called protozoans, are

heterotrophic.

• They commonly consume other organisms for

food and a number of them are parasites, taking

nutrients from the organism in which they reside.

• Protozoans can be broken down into 4 basic

groups:

1. Cercozoans

2. Ciliates

3. Flagellates

4. Sporozoans

The most common cercozoan is the amoeba, often times characterized by their pseudopods or “false feet” used to eat or move.

• Ciliates have many short, hair-like projections that cover the surface of the cell, that are used for sweeping food particles and for locomotion.

• The paramecia is the most common ciliate.

These protists have

long, hair-like

projections extending

from the cell

membrane known as

flagella.

The flagella are used in

a whip-like motion to

propel protists.

These protists are parasitic and take

nutrients away from their host.

Malaria is a deadly disease caused

by the sporozoan in the Plasmodium

genus living between two hosts:

humans and mosquitoes.

Heterotrophic organisms that feed by means of absorbing nutrients from other living things, dead organisms, and wastes.

They also produce spores (like fungi). Major groups include slime moulds

(plasmodial and cellular) and water moulds.

These organisms contain pigments

in their chloroplasts, enabling them

to carry out photosynthesis.

Unicellular plant-like protists

include: 1. Diatoms

2. Dinoflagellates

3. Euglenoids

Diatoms, such as

phytoplankton, are

single-celled, free-

floating aquatic

organisms usually

reproduce asexually,

but under certain

conditions can

reproduce sexually.

Most dinoflagelletes are also phytoplankton,

but they also have two flagella at right angles to

each other allowing these organisms to spin

through the water.

Under ideal conditions, they are responsible for

algal blooms (red tides).

These plant-like protists can

not only photosynthesize,

they also have flagella and

can absorb nutrients.

With both animal-like and

plant-like characteristics,

euglenoids tend to be

autotrophs in sunlight and

heterotrophs in the dark.