ProtistsChapter 28 Key Points

Protists are Highly Varied

Simplest EukaryotesMost diverse kingdomCan be unicellular or multicellular

ParaphyleticUnder reorganization

Evolutionary History

Evolved from cyanobacteria

Serial endosymbiosis Evidence:▪Separate DNA▪Multiple membranes▪Similar reproduction

Endosymbiosis

Three Primary Groups

Animal-like Protists Ex: ciliates, euglenids,

diplomonadsPlant-like Protists

Ex: algaeFungus-like Protists

Ex: slime molds, water molds

Animal-Like Protists

HeterotrophsMobileOften cause disease

Sleeping sickness Malaria Chagas disease Dysentery

Malaria

Plant-Like Protists

AutotrophsInclude largest protists (kelp)

Closest relatives of land plants

Used in food processingCan cause “red tide”

Fungus-Like Protists

Some produce fruiting bodies like fungi

Model for evolution of multicellularity

Often act as decomposers

Plasmodium

Fruiting Bodies