Excavates and SAR

biological carbon pump

process by which inorganic carbon is fixed by photosynthetic species that then die and fall to the sea floor where they cannot be reached by saprobes and their carbon dioxide consumption cannot be returned to the atmosphere

bioluminescence

generation and emission of light by an organism, as in dinoflagellates

contractile vacuole

vesicle that fills with water (as it enters the cell by osmosis) and then contracts to squeeze water from the cell; an osmoregulatory vesicle

cytoplasmic streaming

movement of cytoplasm into an extended pseudopod such that the entire cell is transported to the site of the pseudopod

endosymbiosis

engulfment of one cell within another such that the engulfed cell survives, and both cells benefit; the process responsible for the evolution of mitochondria and chloroplasts in eukaryotes

mitosome

nonfunctional organelle carried in the cells of diplomonads (Excavata) that likely evolved from a mitochondrion

mixotroph

organism that can obtain nutrition by autotrophic or heterotrophic means, usually facultatively

plankton

diverse group of mostly microscopic organisms that drift in marine and freshwater systems and serve as a food source for larger aquatic organisms

plastid

one of a group of related organelles in plant cells that are involved in the storage of starches, fats, proteins, and pigments

test

porous shell of a foram that is built from various organic materials and typically hardened with calcium carbonate

main traits that eukarya share

1. membrane-bound chromosomes
3. nuclei with nuclear envelope
6. linear chromosomes
8. sexual reproduction

Lynn Margulis

suggested that the endosymbiotic theory described the origin of the mitochondria

mitochondria

generate ATP, and clusters of iron and sulfur that are important for enzyme activity

alpha-proteobacterium

evidence (such as the cristae within mitochondria) suggests that mitochondria started as this before becoming what they are today

secondary endosymbiosis

-engulfment of one cell within another, and then engulfment of that cell within a new cell
-this creates four membranes
- the theory that explains the origin of eukaryotic chloroplasts (a protist engulfed a cyanobacterium)

protist

-term used for Eukarya that are not land plants, fungi, or animals
-not particularly useful as a term because it does not reflect evolutionary history
-not a phylogenetic group

alveolus

flattened, membrane-bound vesicles packed into a continuous layer supporting the cell plasma membrane, provide support for the cell

amoeboid motion

-the extending of part of a cell, pushing down on something, and dragging the rest of the cell behind it
(movement without cilia)
-seen in rhizaria
-uses pseudopodia, which are long and hair-like

ecosystem service

benefits that humans derive, directly or indirectly, from ecosystem functions