Ch 20 The Protists
protist
eukaryote that is not a fungus, animal, or plant
flagellated protozoan
protist belonging to an entirely or mostly heterotrophic lineage with no cell wall and one or more flagella
plasmodial slime mold
protist that feeds as a multinucleated mass; forms a spore-bearing structure when environmental conditions become unfavorable
water mold
protist that grows as nutrient-absorbing filaments
sporophyte
spore-forming diploid body that forms in the life cycle of land plants and some protists
what are protists?
-a collection of eukaryotic lineages. most are single-celled but there are some multi-celled species -some are autotrophs, others are heterotrophs, some can switch between modes -most reproduce sexually and asexually
what are amoebozoans?
-heterotrophic protists with cells that lack a cell with wall or pellicle, and so can constantly change shape -amoebas live as single cells, usually in fresh water -slime molds live on forest floors, plasmodial slime molds feed as a big multinucleated mass. cellular slime molds feed as single cells, but come together as a multi-celled mass when conditions are unfavorable. both types of slime molds form fruiting bodies that release spores
what are stramenopiles?
-include diverse lineages that are united on the basis of their genetic similarity rather than any visible traits -water molds are filamentous decomposers and parasites -diatoms are silica-shelled cells, brown algae are multi-cellular. Both groups have a brown accessory pigment in chloroplasts that evolved from a red alga
what are flagellated protozoans?
-parabasalids and diplomonads are heterotrophs that lack mitochondria, some are important human pathogens -trypanosomes are parasites with a large mitochondrion, biting insects transmit some that cause human disease -euglenoids include heterotrophs and photoautotrophs with chloroplasts that evolved from green algae
what are red algae and green algae?
-red and green algae are protists that belong to the same clade as the land plants. all members of this clade deposit cellulose in their cell wall and store excess sugars as starch -red algae mostly multicellular and marine, have red accessory pigments that allow them to live at greater depths than other algae -green algae include single-celled, colonial, and multi-celled species. one subgroup, the charophyte algae, includes closest living relatives of land plants
what are alveolates?
-single cells with an array of membrane-bound sacs (alveoli) beneath the plasma membrane -Dinoflagellates are common in plankton, flagellated heterotrophs of photoautotrophs have cellulose plates and move with a whirling motion -the ciliates are heterotrophs. cilia cover all or part of the cell surface and function in locomotion and feeding -apicomplexans are intracellular parasites with a special host-piercing device
cellular slime mold
amoeba-like protist that feeds as a single predatory cell; joins with others to form a multicellular spore-bearing structure when conditions are unfavorable
toxin
chemical that is made by one organism and harms another
euglenoid
flagellated protozoan with multiple mitochondria; may be heterophic or have chloroplast descended from algae
gametophyte
gamete-producing haploid body that forms in the life cycle of land plants and some protists
contractile vacuole
in freshwater protists, an organelle that collects and expels excess water
pellicle
layer of proteins that gives shape to many unwalled, single-celled protists
alveolate
member of protist lineage having small sacs beneath the plasma membrane; dinoflagellate, ciliate, or apicomplexan.
brown alga
multi-celled marine protist with a brown accessory pigment in its chloroplasts
alternation of generations
of land plants and some protists, a life cycle in which haploid and diploid multi-celled bodies form
trypanosome
parasitic flagellate with a single mitochondrion and a membrane-encased flagellum
green alga
photosynthetic protist that deposits cellulose in its cell wall, stores sugars as starch, and has chloroplast containing chlorophylls a and b
red alga
photosynthetic protist that deposits cellulose in its cell wall, stores sugars as starch, and has chloroplast containing chlorophylls a and red pigments called phycobilins
algal bloom
population explosion of tiny aquatic producers
amoebozoan
shape-shifting heterotrophic protist with no pellicle or cell wall; and amoeba or slime mold
dinoflagellate
single-celled aquatic protist with cellulose plates and two flagella; may be heterotrophic or photosynthetic
diatom
single-celled photosynthetic protist with brown accessory pigments in its chloroplasts and a two-part silica shell
amoeba
single-celled protist that extends pseudopods to move and to capture prey
apicomplexan
single-celled protist that lives as a parasite inside animal cells
ciliate
single-celled, heterotrophic protist with many cilia