Chapter 27 - Eukaryotes: Two Domains United

Contractile Vacuoles

a specialized cytoplasmic organelle that pumps fluid in a cyclical manner from within the cell to the outside by alternately filling and then contracting to release its contents at various points on the surface of the cell

Food Vacuoles

a membrane-bound sac used for digestion

Pellicle

a layer of supportive protein fibers located inside the cell, just under the plasma membrane, providing strength and flexibility instead of a cell wall

Colonies

multiple individual organisms of the same species living in a group

Pseudopodia

a temporary cytoplasmic extension of a cell

Phytoplankton

microscopic, free-floating photosynthetic organisms

Zooplankton

small, usually microscopic, animals that float in aquatic habitats

Supergroups

a level of evolutionary classification below domain but above kingdom. In the current classification of eukaryotes, there are four supergroups: Amorphea, Archaeplastida, SAR, and Excavat

Secondary Endosymbiosis

in the model for the origin of plastids in eukaryotes, the second event, in which a nonphotosynthetic eukaryote engulfed a photosynthetic eukaryote

Primary Endosymbiosis

in the model for the origin of plastids in eukaryotes, the first event in which a eukaryotic cell engulfed a photosynthetic cyanobacterium

Amorphea

a eukaryotic supergroup, comprising organisms in which a single posterior flagellum is found at some stage in the life cycle. Animals, fungi, and related protists are amorphea

Amoeba

a descriptive term for a single-celled eukaryote that moves by means of temporary cellular projections called pseudopods

Amoebozoa

a group within the Amorphea supergroup of eukaryotes that includes most of the amoebas as well as the cellular and plasmodial slime molds; characterized by the use of pseudopods for locomotion and feeding for all or part of their life cycles

Slime Molds

members of the Amoebozoa; heterotrophic eukaryotes that, at some stage of their life cycle, exist as individuals that move by amoeboid motion but that exist in more complex forms the remainder of the time

Fruiting Body

in some fungi, a stalked, sporeproducing structure such as a mushroom

Cellular Slime Molds

any of a variety of primitive organisms of the phylum Acrasiomycota, especially of the genus Dictyostelium; the life cycle is characterized by a slimelike amoeboid stage and a multicellular reproductive stage

Plasmodial Slime Molds

a slime mold of the class Myxomycetes

Plasmodium

the composite mass of plasmodial slime molds consisting of individual nuclei suspended in a common cytoplasm surrounded by a single plasma membrane

Nucleariidae (nucleariids)

a eukaryotic group consisting of heterotrophic, predominantly spherical amoebas with radiating, fine pseudopods that are not supported by microtubules. Nucleariids are a subgroup of the Amorphea and are more closely related to fungi than to animals

Choanoflagellata (choanoflagellates)

a group of minute, single-celled eukaryotes found in water; the flask-shaped body has a collar of closely packed microvilli that surrounds the single flagellum by which it moves and takes in food. Choanoflagellates are a subgroup of the Amorphea

Archaeplastida

a supergroup of eukaryotes, consisting of the Rhodophyta and Chlorophyta protists, and the land plants; all are photosynthesizers

Rhodophyta (red algae)

a lineage of the Archaeplastida supergroup of eukaryotes; mostly freeliving autotrophic marine seaweeds

Agar

a gelatinous product extracted from certain red algae or seaweed used as a culture medium in the laboratory and as a gelling or stabilizing agent in foods

Carrageenan

a chemical extracted from the red alga Eucheuma that is used to thicken and stabilize paints, dairy products such as pudding and ice cream, and many other creams and emulsions

Chlorophyta (green algae)

a lineage within the Archaeplastida supergroup of eukaryotes; autotrophs that carry out photosynthesis using the same pigments as plants

Charophytes

a member of the group of green algae most similar to the algal ancestors of land plants

Biofuel

a fuel produced from a living organism