Week 2 Flashcards
do unicellular eukaryotes have tissues or organs?
no
what do unicellular eukaryotes have?
specialized organelles to perform different functions
what can special features of unicellular eukaryotes organelles be defining characteristics for?
different unicellular eukaryote clades
what do some of these unicellular eukaryote organelles resemble?
prokaryotic organisms (membranes DNA)
are cells basic units of life?
yes
does having larger organisms without cellular differentiation work ?
no
example of large organisms without cellular differentiation that work
some marine algae
what does multicellularity allow
larger size and other advantages
protoplasmic
single celled eukaryotes
what can colonials have
not specialized, multicellular organisms have some specialization, such as for reproduction
cell-tissue
similar cells collect into tissues that perfrom specific function
tissue- organ
organs usually multiple kinds of tissue and have more specialized function than tissues
organ system
organs working together to perform functions
levels of organization
cytoplasmic cellular cell-tissue tissue-organ organ-system
example of cytoplasmic
unicellular eukaryotes
example of cellular
colonial protists, sponges
example of cell-tissue
Cnidarians (jellies, corals, anemones)
example of tissue-organ
Platyhelminthes (flatworms)
example of organ-system
most other animal groups
types of body symmetry
none, radial, bilateral, spherical, asymmetry
metazoa
“along with/ among animals”
eukaryotic multicellular heterotrophs with differentiated cells, generally synonymous with “animals”
Kingdom Animalia
metazoans
4 characteristics of animals
1- heterotrophic
2- motile (at some point)
3- multicellular eukaryotes
4- any organism that develops from a blastula
when do fossil records indicate first appearance of metozoa?
700 MYA
what did metazoa likely evolve from?
colonial protist choanoflagellate
choanoflagellates
1- single- celled and some colonial, flagellates, protozoa
2- often spherical with long flagellum surrounded by a collar of microvilli, very similar to a layer of flagellated cells found in sponge body
3- over time, teamed up to more efficiently filter water and get food
4- many gene families in common with animals
protozoa-
“first animal”
unicellular
are protozoa technically animals?
no
what does studying protozoa help us understand?
origins of animals
does protozoa have a huge or small diversity?
huge
what are the three domains?
Bacteria, Archaea, Eukarya
what do protists make up several of?
groups, mostly unicellualr, mostly microscopic eukaryotes
how many protozoa named?
64,000 species
are protozoa a monophyletic group?
no
is “protozoa” formal or informal?
informal
what are protists
any eukaryote that is not an animal, fungus, or plant
protoplasmic
complex, semifluid, translucent substance that constitutes the interior matter of a living cell and is composed of proteins, fats, and other molecules suspended in water. It includes the cytoplasm, the nucleus in eukaryotes, and organelles such as mitochondria
what do characteristics do protists specialized organelles have?
no germ layer present, no organs or tissues
are protozoa one group?
no, divided up into many different groups
are choanoflagellates aniamals?
no, they are a sister group to metazoa (animals)
how did eukarya evolve?
primary due to endosymbiosis
mitochondria
proteobacterium able to derive energy from carbon compounds using oxygen produced by cyanobacteria
anaerobic bacterium that engulfed this proteobacterium developed ability to survive in oxygen-rich environment produced as cynaobacterium multiplied
plastid
cynobacterium, primary endosymbiosis of photosynthetic cyanobacterium led to plants
what evidence do we have that eukarya evolved from endosymbosis?
mitochondria have their own cell membranes, have their own DNA, and reproduce via fission
is archaea more closely related to eukaryotes or bacteria?
to eukaryotes
endosymbosis
organism living inside another
protozoa form and function
defense locomotion nutrition osmoregulation reproduction
what do protozoa use for defense?
extrusomes such as trichocysts
test, pellicle,
what do predatory protists use?
toxicysts in capturing prey
extrusomes
membrane-bound organelles that extrude something from cell
test
hard shell of calcium carbonate or silica
protection from predators, potentially, but in some cases can also protect from dry habitats
pellicle
actin microfilaments reinforce cell membrane,
not so much to help keep them from being eaten but makes the cell a bit more resilient to damage
defense mechanisms of protozoa
extrusomes
test
pellicle
is flagella and cilia structurally the same?
yes
how does cilia propel water?
parallel to cell surface
how does flagella propel water?
parallel to axis of flagellum
are cilia and flagella “unidulipodia”?
yes
sliding tubule hypothesis
small arms of periphral tubule pairs powered by ATP, walk along adjacent microtubules bending of flagellum/cilium due to resistance of “spokes”
what does cytoplasmic streaming do to pseudopodia?
pushes it forward through gel/sol transitioning
endoplasm flows into ectoplams cap, crosslinks to form gel-liek ectoplasm, at back end transitions back to sol. requires substrate to pull body forward
what is the chief means of locomotion in ameboid cells
pseudopodia
different forms of pseudopodia
lobopodia
filopodia
reticulopodia
axopodia
lobopodia
large, blunt extensions
filopodia
thin extenstions
teticulopodia
repeatedly rejoinn to form net-like mesh
axopodia
contain rod of microtubules
how do protozoa get food
some have plastids obtained from endosymbiosis and are autotrophs, some need to get thieir food and are heterotrophs
are protozoa exclusively autotrophs or herterotrophs
no
2 basic modes of heterotrophy
1- phagotrophs
2- osmotrophs
phagotrophs (halozoic feeders)
ingest “visibble” particles
osmotrophs (saprozoic feeders)
ingest food in soluble form
what does holozoic nutrition use?
phagocytosis
phagocytosis
membrane invaginates around a food particle
cytosome
“cell mouth”
what happens during phagocytosis?
food is enclosed in a food vacuole, lysosomes fuse and dump enzymes in to digest contests
osmoregulation
in freshwater, concentration of solutes inside of cell is higher than outside, water enters the cell and causes swelling and possible burst
what do contractile vacuoles do?
pump ions in, water follows, release to outside of cells
what do unicellular organisms use diffusion for?
exchange materials with environment
can diffusion be a problem?
yes, depending on the environment
how do protozoa reproduce?
asexual or sexual
protozoa asexual reproduction
via fission- (binary fission, budding, schizogeny, sporogeny)
protozoa sexual reproduction
via syngamy (autogamy or conjugation)
sporogeny
forming spores
syngamy
fertilization of one gamete by another to form a zygote
what is standard fertilization for protozoa?
syngamy
autogamy
gametic nuclei arise and fuse to form zygote inside parent organisms
conjugation
exchange of gametic nuclei between paired organisms
can protozoa have complex life cycles?
yes, they can have alternating sexual and asexual stages
7 important “protozoan” groups
1- metamonada 2- euglenozoa 3- stramenopiles/heterokonta 4- alveolata 5- plantae/archaeplastida 6- amoebozoa 7- opsithokonta
is metamonada a settled group?
no
what unites Retortomonada, Diplomonada, and Parabasalids?
lack of mitochondria,
does Retortomonada, Diplomonada, and Parabasalids make up a monophyletic group?
no
Fornicata group
Retortomonada and Diplomonada appear to be closely related and probably make up a monophyletic group
what are ameobas?
recurrent body form, showing up in several different groups
examples of metamonada group
Trichonympha and Mixotricha
what is Trichonympha and Mixotricha?
Parablasids, which are common endosymbionts found in termite and cockroach guts
what is metamonda similar to?
rumen ciliates in that they help termites and cockroaches break down cellulose in wood
what does Trichonympha have?
its own endosymbiotic bacteria that produce cellulase to break down wood fibers, and other symbiotic bacteria that help them move around and produce energy in place of mitochondria
Euglenozoa (protozoa group)
microtubules beneath plasma membrane stiffen membrane into a pellicle
what variety of organisms are included in
parasites, autotrophs, heterotrophs, and mixotrophs
what in euglenids are secondarily derived?
chloroplasts when present
what are chloroplasts in euglenis most closely related to?
green algae
what do many euglenids have?
stigma, or eyespot
what is Euglena
mixotroph
what is a mixotroph?
can use photosynthesis when light is present but in dark the plastids shrink up and they can take up nutrients from environment
kinetoplast
many copies of mitochondrial DNA in single oversized mitochondrion
what is kinetoplast possible involved in?
changing metabolism associated with parasite life cycle stages
stramenopiles
heterokonts
“staw-like”
what is the most important producer in marine photosyntheis?
diatoms
heterokonts
two different flagella
what is considered to be in Stramenopiles group?
diatoms, brown and yellow algae
examples of brown algae
kelp, wakame, and kombu
what are yellow algae generally?
unicellular part of plankton community
is brown algae multicellular or unicellular?
multicellular
diatoms
unicellular, photosynthetic microalgae with cell wall of silica
how much do diatoms contribute to oceanic primary production of organic material
up to 45%
are diatoms a crucial component of carbon cycle?
yes, they reduce atmospheric CO2, produce 20% of oxygen on the planet
what is kelp?
a large macroalgae
what brown algae is edible?
wakame and kombu
alveoli
membrane-bound vesicles supporting membrane and forming a stiff but flexible pellicle
three major groups of alveolata
ciliophora
dinoflagellata
apicomplexa
ciliophora
posses cilia at some state
examples of ciliophora
Paramecium, Stentor, Vorticella
Dinoflagellata
“red tides”
example of Dinoflagellata
zooxanthellae
Apicomplexa
endoparastic, have apical complex
examples of Apicomplexa
Plasmodium, Toxoplasma
where is ciliophora common?
almost anywhere water is
how many species of ciliophora
3,500 described, 30,000 total
what is ciliophora to protozoa?
one of the largest and most complex
ciliophora
presence of cilia, which beat synchronously and aid in locomotion and obtaining food
how is cilia on ciliophora
in rows, tufts, spirals, or sheets
what makes up a large percentage of the endosymboints of ruminants and help to digest cellulose fibers
certain ciliates
what does increased nutrient loading from human activity lead to in Dinoflagellata
blooms or “red tides”
what can dinoflagellata blooms produce?
toxins which can adversely effect fish, shellfish industry, and poison humans
what can happen when dinoflagellata blooms die off?
deplete oxygen in environment and suffocate marine life
are dinoflagellatea that is bioluminescent toxic
no
what is bioluminescent blooms used for?
defense mechanism,
used to startle or ward off predators, kind of like a “burglar alarm” attracts attention to predator which may then be subject to predation by higher trophic levels
where can Dinoflagellata live as mutualists?
protozoa, anemones, corals, and clams
what does rise in water temperature lead to?
loss of zooxanthellae and coral bleaching
plantae (Archaeplastida)
plants and their relatives,
vascular plants, bryophytes, green algae, red algae, glaucophytes
where is chloroplasts in Plantae derived?
from primary endosymboisis and cynobacterium
Viridiplantae (green plants)
green algae, bryophytes, vascular plants
what is plantae in broad sense
Archaeplastida- green plants, plus red algae and glaucophytes
what is plantae in strict sense
Viridiplantae- green plants( green algae and land plants)
bryophytes
non-vascular plants (mosses, hornworts, liverworts)
glaucophytes
small group of rare freshwater microscopic algae, may be basal than rest of Archaeplastida
basal
similar to common anscestor
examples of unicellular, colonial, and multicellular forms of green algae
Chlamydomonas, Gonium, and Volvox
characteristics of Amoebas
pseudopodia
phagocytosis
may have a “test”
what makes up many limestone and chalk deposits?
Foraminiferans with their tests
heterolobosea
includes “brain-eating” ameba Naegleria fowleri
Naegleria fowleri
Lives in warm water and causes amebic meningoencephalitis when water is inhaled. Migrates along olfactory nerve to brain and causes hemorrhage and necrosis, nearly always resulting in death.
Amoebozoa are?
unikonts (when flagella present), sister group to opsithokonta
opisthokonta
pole/flagellum
what are considered opsithokonta?
fungi, choanoflagellates, aimals
characteristics of opisthokonta?
one posterior flagellum (when present)
choanoflagellates
sister group to animals, very similar to cells in sponges
what does a collar of microvilli surrounding a flagellum do?
beating of flagellum moves water through collar where food particles are filtered and collected
trichocyst
any of numerous minute rodlike structures, each containing a protrusible filament, found near the surface of ciliates and dinoflagellates
what helps to keep water out of a protozoa when there is too much
contractile vacuole
if a unicellular eukaryote is in a well suited environment will it sexually or asexually reproduce
asexually
if a unicellular eukaryote is in a an environment it is not well suited for what type of sexual reproduction will it use?
sexual
