chap 28 Flashcards
(27 cards)
characteristics of protists
- abundant in moist env.
- most are microscopic in size
- eukaryotes
evolutionary relationships between protists groups
some protists are more closely related to animals/plants/fungi than to other protists.
importance of endosymbiosis in the evolution of photosynthetic eukaryotic groups
- phosynthetic cyanobacterium was consumed by a heterotrophic eukaryote –> first plastid.
created the first two photosynthetic protist lineages (algae)
2 membrane layers around the plastid
secondary endosymbiosis gave protists 3 membrane layers around the plastid.
zygotic life cycle
haploid stage is multicellular
meiosis occurs after zygote is formed
gametes 2 n’s –> fertilization –> 2n (zygote) –> meiosis 1 n’s –> mitosis n (haploid organism)
sporic (alternation of generations)
alters from multicellular haploid and diploid stage.
gametes 2 n’s –> fertilization –> 2n (zygote) –> mitosis –> 2n diploid organism –> meiosis 1 n’s –> mitosis n (haploid organism)
Gametic life cycle
only diploid stage is multicellular (animals)
gametes 2 n’s –> fertilization –> 2n (zygote) –> mitosis –> 2n diploid organism –> meiosis 1 n’s
classification of protists is based on
3
ecological role (photoautotrophic..), habitat (photosynthetic, heterotrophic..), and motility
SAR clade – stramenopiles
range of algae (NOT PLANTS), protozoa, and fungus
there photosynthetic stramenopiles
ex. diatoms, brown algae, kelp (largest protists), seaweeds (NOT PLANTS)
SAR clade – alveolates
have membranous vesicles in cell periphery, alveoli, have pore-like instrusions through cell surface.
ex. dinoflagellates (2 flagellas), ciliates, and apicomplexans
SAR clade – rhizarians
thin, hair-like extensions of the cytoplasm (filose pseudopodia). many amoebas
(may also look like shells/cool things)
ex. forams, cercozoans, and radiolarians
supergroup archaeplastida
includes land plant as well as algal phyla related organisms
ex. phylum chlorophyta (green algae) and phylum rhodophyta (red)
red algae
lack flagella, complex life cycles, and are multicellular
secondary endosymbiosis
a primary endosymbiot (symbiotic relationship with one cell living inside the other) is consumed and becomes an endosymbiot themselves.
plastid
organelle that allows for photosynthesis
protists reproduction
ALL asexually and some sexually
asexual rep on protists
most will rep ase.
allows for rapid pop growth
mitosis
sexual rep in protists
someee can
when conditions aren’t favorable
meiosis
increases gen. variability
pseudopodia
extensions that may bulge from anywhere from the cell surface.
temporary – emerged in the direction of movement and a tool to capture prey.
protozoa
lack of cell wall
heterotrophic
membrane-bound nucleus
single celled
mixotroph
org with different modes of nutrition,
flagella
long hair-like appendanges – movement
moves entire cells
cilia
short hair like organalles
provides locomotion
meiosis
diploid cells divide 2 times to produce a genetically diversed organism. it has crossing over
for sexual rep.
mitosis
a haploid or diploid cell separates into 2.
used for regular cell division.
