CH21: Protists - The Simplest Eukaryotes

protists

 Eukaryotes that are not fungi, plants, or animals

How many supergroups are protists dived into?

6

colonial organisms

 Live in groups and behave in an integrated fashion, but remain self-sufficient. Capable of living and reproducing on it own

hydrogenosomes

 **allow protists to live in the anaerobic environment and reproduce**

pellicle

 outer layer of plasma membrane with elastic proteins that protects and gives shaped to many unwalled, single-celled protists. Allows the organism to squeeze through narrow openings

contractile vacuoles

organelle that expels excess water from the cytoplasm

cyanobacteria

**evolved into chloroplasts in the common ancestor of red and green algae**

primary endosymbiosis

evolution of a bacteria that entered a host cell and live inside it.

secondary endosymbiosis

 evolution of chloroplast from a protist that itself contains chloroplasts

autotrophs

Carry out photosynthesis

heterotrophs

Absorb organic molecules from the environment or ingest smaller organisms

mixotrophs

Can be photosynthetic or heterotrophic depending on conditions. **Ex. Euglenoids** 

phytoplankton

 aquatic autotrophic (photosynthetic) organisms

zooplankton

aquatic heterotrophic organisms

alternation of generations

life cycle in which both haploid and (diploid multi-celled) bodies form. Ex: all plants, some multicellular algae

excavates

are unwalled cells with one or more flagella

excavation

a groove that functions in feeding

metamonads

Lack mitochondria (not using oxygen - b/c lack of mitochondria) and have multiple flagella

diplomonads

Two identical nuclei and several freely beating flagella, live in animals; example: parasite Giardia lamblia aka Beaver Fever

parabasalids

Have an undulating membrane, which is a finlike membrane enclosed flagellum.  They also have modified mitochondria (hydrogenosomes) that produce ATP and hydrogen

euglenids

 Free-living flagellated protists that have multiple mitochondria

kinetoplastids

have a singular large mitochondrion

**Trypanosomes**

the most diverse kinetoplast subgroup, **parasitizes plants or animals**

SAR

is the most diverse protistan supergroup: includes stramenopiles, alveolates, and rhizarians

stramenophiles

Two flagella, one short shaggy one and a longer smooth one

diatoms

Diploid, photosynthetic, secrete a protective silica shell. Many are cylinder shaped, but other are triangular, square, or needlelike.

brown algae

Multicelled, some appear plantlike.  1,500 different species range from microscopic filaments to kelp 30 meters tall; **kelp life cycle is alternation of generations**

water molds

 Heterotrophs, form a mesh of nutrient-absorbing filaments

alveolates

Defined by sacs beneath their plasma membrane

ciliates

 Have cilia (short motile structures)

dinoflagellates

have two flagella that cause rotation