Protists and Their Classification

This set of flashcards covers the key concepts related to the classification and characteristics of protists, their evolutionary significance, and specific examples.

Protists

Eukaryotes that are not plants, fungi, or animals; can be unicellular, colonial, or multicellular.

Supergroups of Protists

5 supergroups: Excavata, SAR, Archaeplastida, Amoebozoa, Opisthokonta.

Excavata

A supergroup characterized by unique cytoskeletal features, including flagella and specific DNA sequences.

Diplomonads

A group within Excavata that has 2 haploid nuclei and no functional mitochondria.

Parabasalids

Excavata group with an undulating membrane, semi-functional mitochondria, and a single nucleus.

Euglenozoans

Excavata group known for having a pellicle and including free-living euglenids and parasitic kinetoplastids.

Kinetoplastids

Euglenozoans with a unique mitochondrion containing complex mitochondrial DNA, many are parasites.

Trypanosoma

A genus of kinetoplastids that includes species causing human diseases such as sleeping sickness.

Alveolata

A part of the SAR supergroup characterized by flattened vesicles called alveoli.

Red Tide

A harmful algal bloom caused by dinoflagellates that can affect aquatic ecosystems and cause biomagnification.

Apicomplexans

Spore-forming parasites within Alveolata, characterized by an apical complex for invading hosts.

Plasmodium

The parasite that causes malaria in humans, requiring both human and mosquito hosts for its lifecycle.

Intermediate Host

A host in which a parasite undergoes asexual reproduction; in Toxoplasma, typically a mouse.

Definitive Host

A host in which a parasite undergoes sexual reproduction; for Toxoplasma, the cat is the definitive host.

Ciliates

A group in Alveolata characterized by cilia for locomotion and two types of nuclei for different reproductive functions.

Conjugation

A sexual reproduction process in which two cells exchange micronuclei.

Rhizaria

Supergroup of ameboid organisms that use pseudopods for locomotion, including Radiolaria and Foraminifera.

Plasmodial Slime Molds

Molds that stream as a multinucleate mass of cytoplasm and form spores in unfavourable conditions.

Cellular Slime Molds

Molds that behave as separate amoebas and aggregate into a slug under food scarcity.

Choanoflagellates

Unicellular or colonial organisms in Opisthokonta; closest relatives of animals, resembling sponge cells.