Protists are organisms that:

Chapter 19- Protists and the Origin of Eukaryotic Cells

Algae are groups of protists that:

Algae are autotrophic which means they can produce their own organic food.

Protozoa is an informal name for various groups of protists that lack plastids

(not photosynthetic).

Protozoa are:

Heterotrophic- must obtain organic food from outside their bodies

How can protists be distinguished from plants, fungi, and animals?

-not included in the land plant, fungal or animal

kingdoms

-often microscopic in size

-occur most commonly in aquatic habitats

Protists are eukaryotic organisms that are not included in the land plant, fungi, and animal kingdoms, because they lack

characteristics that typify these other kingdoms.

-contain one or more plastids

-usually photosynthetic

-single-celled

-mobile organisms

-heterotrophic

Protists are common and numerous in aquatic and moist habitats.

Most protists reproduce and grow best in moist habitats:

Some protists live cooperatively within hosts

Ex: Dinoflagellate living within the tissues of corals

and other marine animals.

Endosymbiont

Microscopic protists move in several ways:

Many protists have immobile or multicellular bodies

for much of their life cycle, but produce flagellate

reproductive cells.

Many protists bear one or more flagella, a long

propelling extension from the cells

-freshwater ponds, streams, and lakes

-ocean waters

-soil water

-moist tissues and cells of animals or plant bodies

Cilia are structures that are internally similar to flagella,

but shorter and more abundant on cells.

Ciliates are often larger than flagellates.

Ciliates have cilia that extend from part or all surfaces

of nonalgal protists.

Protists include diverse groups whose relationships

are not completely known.

These data indicate that eukaryotes (protists,

fungi, animals, and plants) may have a common

ancestor.

Protists do not form a single monophyletic clade (a group of organisms descended from a common ancestor).

Biologists examine protist diversity and relationships

by comparing cell structure and DNA sequences.

Major groups of algae and distinguishing features.

Algae are grouped with the protists based on:

Algae morphology may be:

Mallamonas

-unicellular

-aggregates of cells (colonies)

-cells joined end-to-end to form filaments

-composed of tissues whose cells communicate

and are specialized (multicellularity)

Seaweeds are examples of macroscopic protists.

Euglenoids (in Discicristates)

-the kinetoplastids include trypanosomes, a group of non-photosynthetic

parasites that infect mammals, fish, and plants

Trypanosoma

-in a group of flagellates that includes the kinetoplastids

Euglenoids

-many relatives have green plastids

http://www.jochemnet.de/fiu/bot4404/BOT4404_14.html

- typically flagellated

http://www.photomacrography.net/f

orum/viewtopic.php?t=3193&highli

ght=euglena

http://www.biologie.uni-

hamburg.de/b-online/e25/14.htm

Cryptomonads (“hidden single cells”)

Cryptomonads are important members of the planktonic

food web:

Dinoflagellates (in Alveolates)

The dinoflagellates, together with ciliate protozoa and a group of parasites known

as the apicomplexans make up the Alveolates.

Plasmodium

(d) An apicomplexan:

Plasmodium

Plasmodium is the agent of malaria and infects 40%

of the world’s population, with up to 500 million cases,

and 2.7 million deaths per year.

Some euglenoids have a distinct motion called metaboly, that allows movement through moist soil.

Euglenoids

-mostly single-celled flagellates

-red, blue-green, olive, or colorless plastids

-commonly occur in marine and freshwater

-readily consumed by other protists and zooplankton

Dinoflagellates (in Alveolates)

These organisms are grouped together because they

all have membranous sacs known as alveoli at the

edges of their cells.

These are known as the armored dinoflagellates.

Although many dinoflagellates have plastids and

are autotrophic, many dinoflagellates are heterotrophic

and feed by ingesting food particles.

Some photosynthetic marine dinoflagellates generate

harmful ocean blooms or red tides.

These blooms are responsible for:

Pfiesteria

Dinoflagellate poisons occur through production of

various toxins that cause:

Harmful blooms result from eutrophic conditions

(excess nutrients in the water) which arise from:

http://www.epa.gov/owow/estuaries/pfiesteria/

Dinoflagellates with little or no cellulose are unarmored

or “naked” dinoflagellates.

Dinoflagellate plastids originated from a variety of

eukaryotic algae that were originally digested as food.

Haptophytes

Some of the haptophytes have a modified flagellum called a

haptonema for which the group is named.

Some members of this group have a covering of detailed

calcium carbonate scales known as coccoliths.

Stramenopiles

Highly diverse algal lineage that includes both tiny flagellates and giant seaweeds.

Because the two flagella are structured differently, members of this group are also called the heterokonts.

Stramenopiles include:

Some oomycetes are parasites that cause widespread diseases in

seaweeds, molluscs, fish, and terrestrial crop plants.

Mallamonas

Along with carbonate-shelled protozoa, haptophytes

produce huge chalk deposits about 100 million years

ago (White Cliffs of Dover)

-many types of algae with golden-brown colored plastids

-flagellates or colonies of floating cells

-some have golden-colored plastids

-occur in mostly marine systems

Stramenopiles are named for the distinctive straw-like hairs on one of the two flagella.

The oomycete Phytophthora caused the historic Irish potato crop failure.

http://pinkava.asu.e

du/starcentral/micro

scope/portal.php?p

agetitle=assetfactsh

eet&imageid=27292

Dinobryon

Chyrsophyceae

Synurophyceae

Stramenopiles include:

Stramenopiles include:

Red algae (Rhodophyta)

Many large brown algae known as kelps form extensive

forests in cold and temperate coastal oceans

Gelidium Corallina

Porphyra

Batrachospermum

Porphyridium

The simplest red algae are microscopic single cells,

some of which occur in hot, acidic freshwater.

-usually occur in marine waters

Commercial use of red algae

Annual harvest of red algae approximately 1 million tons, both cultivated and natural populations.

1)

2)

Many red algae are used for food, but the most

important are species of Porphyra.

Nori is widely

cultivated in Japan,

Korea, and China.

http://nhm.ac.uk/nature-online/british-

natural-history/seaweeds-

survey/importance-of-

seaweeds/index.html

Cell walls- Red algae (Rhodophyta)

Cellulose forms the microfibrillar framework in most rhodophycean cell walls.

In all other red algae, amorphous polysaccharides or mucilages occur between the cellulose microfibrils.

Fine structural study of the red

seaweed Gymnogongrus

torulosus (Phyllophoraceae,

Rhodophyta)

José M. Estevez1 and Eduardo J.

Cáceres2

The two largest groups of amorphous mucilages are:

Agar

Cellulose

Agarose

Agar is obtained commercially from only a few red algae, know collectively as agarophytes.

Gelidium

Carrageenan is obtained from the Irish moss, Chondrus crispus.

Chondrus crispus

Green algae (Chlorophyta)

One subgroup of the green algae, the charophyceans (Charophyta), are ancestral to land plants.

Red algae (Rhodophyta)

Red algae are noted for their inability to produce flagella in any life stage.

-flagellated or have flagellated reproductive stages

-freshwater, marine, and terrestrial

-chlorophyll a and b (green in color)

Green algae (Charophyceans)

Comparative studies of charophycean green algae and modern relatives of the earliest land plants help us

to understand how plants first colonized land.

Green algae (Charophyceans)

http://blog.opentreeoflife.org/tag/chlorophyta/

VIRIDIPLANTAE

Because mitochondria (and structures derived from them)

occur in most eukaryotes, these organelles may have

been present in early protists.

Algae and other protists have been useful in the discovery of how and

in what order eukaryotic cells acquired structural features that

distinguish them from prokaryotes.

Chapter 19-Protists and the Origin of Eukaryotic Cells

The eukaryotic nucleus and endomembrane system are thought to have

originated by in-folding of the cell membrane in an ancestor of modern

eukaryotic cells.

Modern protist lineages, fungi,animals, and plants inherited

mitochondria from early protists.

Molecular evidence supports the idea that mitochondria

originated from endosymbiotic protobacterial cells.

Primary plastids originated from endosymbiotic

cyanobacteria.

Because all modern eukaryotic organisms known to

contain plastids also possess mitochondria, it is thought

that algae acquired plastids after mitochondria through

endosymbiosis.

The process by which an endosymbiotic cyanobacterium

is engulfed and transformed into a plastid is known as

primary endosymbiosis.

Some protists have acquired plastids from eukaryotic algal cells, a process known as secondary or tertiary

endosymbiosis.

All protists are able to reproduce by asexual reproduction

that involve mitotic divisions.

Reproductive cycles in protists

Examples of the three main types of sexual life cycles

are found among algal protists.

Study questions for Chapter 19-Protists and the Origin of Eukaryotic Cells

What are 3 characteristics of protists?

What are the general characteristics of algae?

Define autotrophic. Give an example.

Define protozoa.

What are 3 characteristics of protozoa?

Define heterotrophic. Give an example.

How can protists be distinguished from plants, fungi and animals?

Define plankton.

Define phytoplankton.

Define zooplankton.

List the habitats where you would find protists.

Define endosymbiont. Give an example.

Distinguish between flagella and cilia.

Name an alga with a flagellum/or flagella.

Name a group of protozoa with cilia.

Define monophyletic.

Protists include diverse groups whose relationships are not completely known. Do protists form a

single monophyletic group?

Algal morphology is diverse. Label the images below with following terms:

-unicellular

-colonies

-filaments

-multicellular

-large macroscopic cells

Study questions for Chapter 19-Protists and the Origin of Eukaryotic Cells

Euglenoids

Define kinetoplastids.

What is a pellicle?

What is paramylon?

What is metaboly in euglenoids?

Cryptomonads

What does the word cryptomonad mean?

Dinoflagellates

Define alveolates.

What are alveoli in dinoflagellates?

Distinguish between a naked and an armored dinoflagellate?

What is a bloom or “red tide?”

What are some of the consequences of toxic algal blooms?

Define eutrophic.

Why do some harmful algal blooms occur?

Haptophytes

What is a haptonema?

What are coccoliths?

Why are haptophytes associated with the White Cliffs of Dover?

Stramenopiles/Heterokonts

What does stramenopile mean?

What does heterokont mean?

What algae are included in the Stramenopiles?

Which member of the Oomycota caused the historic Irish potato famine?

What is a diatom?

What is a frustule?

What are diatom cell walls made of?

Which class included in the Stramenopiles includes brown kelps?

What does phaeo mean?

Rhodophyta

What does rhodo mean?

Name two freshwater genera in the Rhodophyta?

What are the 2 largest groups of amorphous mucilages?

Agar is obtained from which algal genus?

Carrageenan is obtained from which algal species?

What is agar used for?

What is carrageenan used for?

What is the triphasic life cycle in red algae?

Green Algae

Chlorophyta

Charophyta

Why are members of the Charophyta important in the evolutionary history of plants?

The Origin of Eukaryotic Cells

Where did the nucleus and endomembrane system originate?

Where did modern protist lineages, fungi, animals and plants inherit mitochondria?

Define primary plastid.

Define secondary plastic.

Define primary endosymbiosis.

Define secondary or tertiary endosymbiosis.

Chyrsophyceae

Dinobryon

Gelidium Corallina Porphyra

Euglenoids Cryptomonads

Dinoflagellates Haptophytes Stramenopiles/Heterokonts

Volvox

Matching-Stramenopiles/Heterokonts

___ Bacillariophyceae (diatoms)

___ Phaeophyceae (brown algae)

___ Chrysophyceae

___ Oomycota

A. B. C. D.

Rhodophyta (Red algae) Chlorophyta (green algae)

Charophyta (green algae most closely related to land plants)

Study questions for Chapter 19-Protists and the Origin of Eukaryotic Cells

Three characteristics for each algal group.