Protists

Kingdom: Protista

Learning Goal

We are learning about the Kingdom

Protista, how it is classified, its

anatomy, physiological

characteristics and its impact on

STSE.

Success Criteria

I can describe the basic characteristics of

protists.

I can identify the main differences between

animal-like, plant-like and fungi-like

protists.

I can explain the impact of protists on the

environment and on society and vice versa.

Intro to Protists

The Six Kingdoms

A phylogenetic tree is a diagram that represents evolutionary

relationships among organisms. Phylogenetic trees are hypotheses

not definitive facts.

Introduction to Protists

Characteristics of Protists

Appeared about 1.5

billion years ago

All are eukaryotic

Most are unicellular,

some are

multi-cellular

Some reproduce

asexually (binary

fission) and some

sexually (conjugation)

Most live in water

(fresh and salt water),

damp areas (moist

soil), animal fluids

(human blood)

Protists Classification

Protists are classified based

on:

How they obtain

nutrition

How they move

Protists are divided into 3

groups

Plant-like protists

Animal-like protists

Fungi-like protists

Methods of Obtaining Energy

Methods of Movement

Pseudopods: “false feet”

Temporary projections of a cell

Use for locomotion & phagocytosis

Ex. amoeba

Pseudopods

Methods of Movement

Cilia: short, hair-like projections

Provide movement in watery environments

Beating in waves to produce movement

Assists with food gathering

Creates a current or wave that helps to

draw in microorganisms which are

filtered out by protists

Ex. paramecium

Cilia

Methods of Movement

Flagella: long, hair-like projections

Generates feeding currents to encounter

prey or to enhance nutrient uptake

(can have 1, 2, or 100)

Ex. Euglena

Flagellum

Methods of Movement

Pseudopods: “false feet”

Ex. amoeba

Cilia: short, hair-like projections

Ex. paramecium

Flagella: long, hair-like projections

(can have 1, 2, or 100)

Ex. Leishmania

Passive movement: using wind and water

currents

Spores: using a host

Ex. plasmodium

Methods of Ingestion

Plant-like Protists

Also called “Algae”

Contain chlorophyll and carry out

photosynthesis

Dinoflagellates, along with

zooflagellates and many other

protists help to make up plankton

The foundation of most

aquatic food webs

Primary food in

aquatic food

chains

Supply 2/3 of

world’s oxygen

Used to make agar

(used in medical

facilities)

Plant-like Protists

Dinoflagellates such as red algae are

unicellular

have a cell wall made of cellulose, have two

flagella

A red tide off the

California coast in 2005.

Plant-like Protists

Euglenoids photosynthesize but can turn

into heterotrophs if kept in the dark

Plant-like Protists

Diatoms have cell walls of made of

silicon

They are important source of food for

marine organisms

Animal-like Protists

Also called “Protozoans”

Are heterotrophs that

capture and ingest their

food

4 Phyla are classified by

how they move:

Flagellates

Ciliates

Cercozoans

Sporozoans

Animal-like Protists

Flagellates use one or

more whip-like

appendages

Intestinal diseases such

as the widespread

giardiasis – caused by

intestinal parasite

Giardia lamblia

A parasite that causes

diarrhea (water and

nutrient loss) and

painful abdominal

cramps

Animal-like Protists

Ciliates capture prey by

using cilia to sweep

nutrients into an oral

groove

Balantidium coli is an

intestinal protozoan

parasite that can infect

humans with persistent

diarrhea, abdominal

pain, and perforated

colon.

Animal-like Protists

Cercozoans (amoeba) uses

pseudopods to capture and

ingest prey, form a food

vacuole to store the nutrients

can cause amoebic dysentery

Animal-like Protists

Sporozoans

reproduces using

spores

The Plasmodium

species live in

humans and causes

malaria

Malaria

Fungi-like Protists

Are heterotrophs – they feed on

bacteria and decaying organic

matter

Reproduce asexually

Prefer cool, shady and moist

places

Fungi-like Protists

Cellular slime moulds

Found on forest floors/rotting logs

Have unusual morphology

Ingest their food – not absorb

Fungi-like Protists

Plasmodial Slime Moulds

They appear large and multicellular but in fact is

a single mass of cytoplasm shared by many

nuclei called plasmodium (different from the

malaria one)

Begins life as amoeba-like cells

Dog Vomit Slime mold

Fungi-like Protists

Water moulds

Resembles white fuzz

growing on dead fish

Some are plant

parasites on land

Ex. Blight of potato and

sudden oak death

Why are Protists Important?

Pros

Algae

helps maintain healthy

aquatic ecosystem

can be used as food for

humans

can be used as fertilizers

help make petroleum

(brown algae)

provide 2/3 of the world’s

oxygen

Used to make agar (medical)

Symbiotic Relationships

Cons

Harmful Algae Bloom

Disease

Symbiotic Relationship

parasitic