Chapter 23:Protistans

http://www.ucmp.berkeley.edu/alllife/eukaryota.map

dinoflagellates

charophytes

green algae

red algae

Stramenopiles

brown algae

chrysophytes

oomycotes

slime molds

parabsalids(e.g., Trichomonas)

diplomonads(e.g., Giardia)

endosymbiotic originsfrom prokarytic

ancestors

protists

amoeboidprotozoans

branch leading to fungi

branch leading to animals

Alveolates

ciliates

apicomplexans

euglenoids

kinetoplastids(e.g., Trypanosoma)

“crown” of eukaryotes(rapid divergence)

branch leading to plants

Fig. 20-2, p.316

I. Traditional Protista Organization

A. Fungi-like protists: MoldsB. Animal-like protists: Protozoans a. Amoeboids b. Ciliates c. Flagellated ProtozoansC. Plant-like Protists: Algae a. Dinoflaggelates b. Red Algae c. Brown Algae e. Green Algae

II. More Recent Organization

A. Flagellated Protozoans (animal-like protists with flagella)

1. Human importance: Giardia, African Sleeping Sickness, Chargas Disease.

2. Example: Euglenoids, such as euglena. Single cell, free-living organism. About 30% are autotrophic. Contain contractile vacuole.

Fig. 23.15, p. 383pelliclemitochondrionGolgi body

ER

nucleus

eyespot shielding a light-sensitive receptor

long flagellum

contractile vacuole chloroplast

Euglena: ‘Plant-like’ ?

Some are photosynthetic, other heterotrophs. No cell wall but flexible cell coat. Motile and eukarytoic.

II. More Recent Organization

3. Variety in Euglena due to primary

endosymbiosis (engulf bacteria).

II. More Recent Organization

B. Alveolates: Broad group with small sacs under their plasma membrane.

1. Ciliates: Move with cilia (many small extensions). Example: Paramecium. Most are heterotrophs.

Fig. 23.6b-d, p. 378

food vacuole

food residues being ejected

gullet cilia

trichocysts (“harpoons”)

contractile vacuole filled

micronucleusmacronucleus

contractile vacuole emptied

pellicle

cillium

intact trichocyst

basal body of cilium

Fig. 20-6b, p.318

II. More Recent Organization

B. Alveolates: Broad group with small sacs under their plasma membrane.

2. Dinoflagellates: ‘Algae’ and/or predators.

a. Algae inside corals.

b. Red tide algae (video clip).

Fig. 20-9b, p.319

II. More Recent Organization

B. Alveolates:

3. Malaria: Caused by Plasmodium.

Sporozite (liver), Merozoites (liver

and blood), gametes (blood, passed

to mosquitoes)

Fig. 23.14, p. 382

sporozites

3 Sporozites reproduce asexually in liver cells.

merozoite

4 Progeny (merozoites) enter bloodstream, invade red blood cells, and reproduce asexually. They may do so many times over a prolonged period. Disease symptoms (fever, chills, shaking) become more and more severe.

5 Some merozoites return to liver and are basis for more episodes of malaria.

6 Other merozoites develop into male and female gametocytes, which are released into bloodstream.

male gametocyte in red blood cell

sporozoite

2 Mosquito bites a human, sporozoites enter bloodstream and reach liver.

1 In the gut of a female mosquito carrying the malarial parasite Plasmodium, zygotes of the parasite develop into sporozoites, which migrate to her salivary gland.

7 A biting female mosquito sucks blood from infected human. Gametocytes in the blood reach her gut, mature into gametes used in sexual reproduction. Gametes fuse to form zygotes.

II. More Recent Organization

C. Stramenopiles

1. Some fungi-like organism: potato

blights and water molds.

2. Diatoms: algae with silicate shells.

3. Other algae: Golden algae and

coccolithophores.

4. Brown Algae: Include Kelp.

Fig. 20-12, p.321

Fig. 20-13b, p.321

holdfast

bladder

blade

stipe

Fig. 20-13c, p.321

II. More Recent Organization

D. Green Algae

1. Many biologist consider these plants,

use similar photosynthesis pigments,

cell wall w/ cellulose, make starch…

2. Chlorophyta: largest group

Fig. 20-16c, p.323

Fig. 20-16b, p.323

II. More Recent Organization

E. Red Algae: Often found at depths in saltwater environments.

Fig. 23.19, p. 386

sporophyte (2n)

germinating spore (n)

10 cmgametophyte (n)

female gametes

male gametes

zygote

MeiosisDiploid Stage

Haploid StageFertilization

II. More Recent Organization

F. Ameoboids: Move with pseudopods (false foot) and often involve complex cell communication.

p.314b

Fig. 20-18a, p.325