Protist

Protists

Eukaryotic organisms that are not classified as plants, animals, or fungi.

Why are protists paraphyletic?

Some protists are more closely related to plants, animals, or fungi than to one another.

Diagnostic features of eukaryotes

Nucleus with pores, mitochondria, cytoskeleton, histone-organized DNA, and division via mitosis/meiosis.

Endosymbiotic theory

Explains the evolutionary origins of mitochondria and chloroplasts from engulfed prokaryotic cells.

Primary vs secondary endosymbiosis

Primary involves engulfing a prokaryote; secondary involves a eukaryote engulfing another eukaryote with a primary plastid.

Tertiary endosymbiosis

Occurs when a eukaryotic cell engulfs another eukaryotic cell containing a secondary plastid.

Protist metabolic strategies

Includes photoautotrophy, heterotrophy (phagocytosis and saprotrophy), and mixotrophy.

Protist motility structures

Includes flagella, cilia, and streaming pseudopodia, often used in taxis.

Protist reproduction

Includes asexual fission/budding, sexual reproduction, cyst stages, and alternation of generations.