Alberts, Bray, Hopkins, Johnson Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Professor: Dr. Barjis Room: P313 Phone: (718) General Biology Sylvia S Mader Lecture 3: Chapter 22 The Protists

Outline General Biology Evolution Diversity – Green Algae – Red Algae – Brown Algae – Diatoms – Dinoflagellates Diversity – Euglenoids – Zooflagellates – Pseudopods – Ciliates – Sporozoans – Slime Molds – Water Molds

General Biology of the Protists Most are unicellular, but have achieved a high level of complexity. Asexual reproduction is common, but sexual reproduction can occur when the environment becomes stressful. – Spores – Cysts

Diversity of Protists Protista include: – Protozoas, – Algae, – Water molds, – Slime molds

Protists Reproduction Protist reproduction: – asexual fission. – sexual with the adult haploid. – sexual with the adult diploid. – sexual with alternation of haploid and diploid generations. Type of movement in some Protists – amoeboids – pseudopodia – ciliates – cilia – zooflagellates – flagella

Protozoan A protozoan is – heterotrophic – usually motile

Algae Algae can be green, red, brown or golden- brown. They can photosynthesize like plants. Algae are NOT considered plants because they lack modifications that protect the gametes and zygote from drying out.

Green Algae – Spirogyra is a filamentous green algae  found in masses on the surfaces of standing water.

Red Algae Multicellular, and live mostly in warmer seawater.  Economic Importance  Agar

Brown Algae Have chlorophylls in their chloroplasts. Often observed on rocky coasts in north temperate zone.

Brown Algae

The Euglenoids Euglenoids are small freshwater unicellular organisms. Euglenoid has both plantlike photosynthesis and animal ‑ like motility

Euglena

Protists with Pseudopods Pseudopods form when cytoplasm streams forward in a particular direction. – Amoeboids are protists that move and ingest their food with pseudopods.

Protists with Pseudopods

The Ciliates A member of the ciliate group of protists is Paramecium.

Ciliates

The Sporozoans Sporozoans are nonmotile parasites. – Most widespread human parasite is Plasmodium vivax, the cause of one form of malaria.

Plasmodium vivax Life Cycle

Slime Molds Plasmodial Slime Molds – Can have cellular and plasmodium form with multiple nucli.

Plasmodial Slime Molds

Water Molds – Have filamentous body with cell walls largely composed of cellulose. – Water molds may live in water or on land