Protozoa

• Protist- general term that does not distinguish between plant-like and animal-like unicells.

• Protozoan- term used for a subset of animal-like unicellular organisms.

• Plants-like- typically autotrophs– Ex: Algae

• Animal-like- typically heterotrophic– Phagocytosis: food is engulfed

Characteristics of Protozoa

• Unicellular– Since Protozoa are single celled they often rely on other

organisms for some necessities

• Eukaryotic– Has nucleus and other membrane bound organelles.

Locomotion

• Cilia – short “hair-like” structures• Flagella- long “tail-like” stuctures• Pseudopodia- extention of cell body

LOCOMOTION

Locomotion

Amoeba- pseudopodia

Reproduction

– Asexual: 1. binary fission: cytoplasmic division

follows mitosis, producing two organisms

2. budding3. multiple fission or schizogeny: cell or

organism is split into many new cells or organisms

Reproduction

Fission - asexual

Fussion – sexual or conjugation

Conjugation

Habitats

1.Aquatic Habitats: fresh and saltwater-Zooplankton-hetertrophic protozoa that live in

the ocean

2.Moist soil: upper layer of soil can include 40,000 species

3.Body tissue, plants, and animals

Nutrients• Obtain nutrients directly from environment

• Oxygen, potassium, and other dissolved substances pass through cell membrane by diffusion-moving from greater concentration to lesser concentration

• Also expel waste such as carbon dioxide, ammonia, and other molecular wastes through diffusion

• Some protozoa can engulf large food particles through phagocytosis

Relationships•Protozoa can live independently or in symbiosis •Protozoa can live parasitism, mutualism, commensalism

Relationships: an intimate association between two organisms

Three types of symbiosis:1. Parasitism: one organism lives in or on a second organism,

called the host. – the host is harmed, but usually survives

2. Commensalism: one organism benefits and the other neither benefits nor is harmed

3. Mutualism: both organisms benefit from the relationship

Habitats•1. Aquatic Habitats: fresh and saltwater•Zooplankton-hetertrophic protozoa that live in the ocean•2. Moist soil: upper layer of soil can include 40,000 species•3. Body tissue, plants, and animals

Protozoan Evolution

Classification

• Protozoa are motile organisms-use energy to move freely

• Nonmotile protozoa are parasites that live in rich food supplies such as the bloodstream

• Protozoa are classified according to their method of movement

Protozoan Taxonomy

Phylum Sarcomastigophora Subphylum

Mastigophora Subphylum Sarcodina

Phylum Apicomplexa Phylum Ciliophora

SARCOMASTIGOPHORA

Phylum Sarcomastigophora: 18,000 species, largest protozoan phylum

Characteristics:1. Unicellular or Colonial

2. Locomotion by flagella, pseudopodia, or both

3. Autotrophic, saprozoic, or heterotrophic

4. Single type of Nucleus

5. Sexual Reproduction (usually)

•2,500 species of Mastigophora•Move by use of flagella•Least complex of protozoa because movement requires limited coordination•Most are parasites

• Two subphyla:– Subphylum Mastigophora– Subphylum Sarcodina

Subphylum Mastigophora: locomotion by one or more flagella

Volvox - colonial

Subphylum Mastigophora

• 2,500 species of Mastigophora• Move by use of flagella• Least complex of protozoa because

movement requires limited coordination• Most are parasites

Subphylum Sarcodina: locomotion and food gathered by pseudopodia (false foot)

- includes the Amoeba

Subphylum Sarcodina

• Sarcodines-move by extended parts of their cytoplasm and cell membrane called pseudopodia

• Some Sarcodines have hard outer shells of calcium carbonate

• Pseudopodia extend through holes in shell

• Other Sacrcodines are soft, jellylike organisms: Family: Amoebas

The AMOEBA

• Phylum Apicomplexa

APICOMPLEXA

Phylum Apicomplexa:

Characterisitics:

1. All are parasites

2. Apical Complex for penetrating host cells

3. Single type of Nucleus

4. Usually No Cilia and Flagella

5. Life cycles that typically include asexual and sexual phases

Malaria

Malaria caused by Plasmodium

• Phylum Ciliophora

Phylum Ciliophora:

Characteristics:1. Cilia for locomotion and for the

generation of feeding currents of water.2. Relatively rigid pellicle and more or less

fixed shape3. Distinct cytostome (mouth) Structure4. Dimorphic nuclei, typically larger

macronuclei and one more smaller micronuclei

Ciliophora

Body types

Genetic Control and Reproduction:

Ciliate have two kinds of Nuclei

1. Macronuclei: large polyploid nucleus that regulates daily metabolic activities

2. Micronuclei: one or more small nucleus which are genetic reserve of the cell