Ch 18 Protists Flashcards
1
Q
what are protists
A
- Protists are the first order of Eukaryotes
- They are unicellular, Eukaryotes for the most part
- They appear in fossil record around 1.5 billion years ago
2
Q
how are protists classified
A
- there are more than 115 000 species
- protists can have characteristics similar to plants, fungi, and animals
- they can be difficult to classify and were once classified as eukaryotes not meeting the criteria to be plants, animals, or fungi
3
Q
what is thought about protists evolution
A
- Lynn Margulis formed the Endosymbiont Hypothesis that stipulates that some Prokaryotes absorbed others and then lived in mutually beneficial symbiosis. These smaller prokaryotes would evolved into various organelles like mitochondria and chloroplasts
- This same endosymbiont process can be show by Cyanophora Paradoxa which contains blue-green bacteria inside it
4
Q
what are the four phyla of animal like protists
A
Ciliophora, Zoomastigina, Sporozoa, Sarcodina
5
Q
what are ciliophora
A
Ciliophora: Cilia-bearing Protists
- ciliates possess cilia (little hair like projections)
- 7000+ species
- can be solitary or colonial and live in the water
- most are free living (non parasitic)
Ex: Paramecium:
- 350 micrometers long
- have a complex folded outer layer that gives the surface a quilt like appearance (called a pellicle)
- The pellicle contains little flask like structure that hold spikes Called trichocysts. Dislodging the spikes is used for defence
- Most ciliates have a micronucleus and a macronucleus
- the cilia force water into an indentation called a gullet, from which it forces food bits into food vacuoles
- the food vacuoles connect with lysosomes before the waste exits through an anal pore
- contractile vacuoles pump water in and out of cell
- normally they use binary fission, but they can use conjugation
6
Q
what are zoomastigina
A
Zoomastigina: Animal like protists with flagella
- have flagella, and so are called flagellates
- no shells or cell walls, absorbed food
- mainly use binary fission but can use meiosis to very genetics
7
Q
what are sporozoa
A
Sporozoa: Spore producing parasitic protists
- don’t move
- parasites
- generally complex life cycles
- plasmodium causes malaria (carried by anopheles mosquito)
- reproduce with spores
- Plasmodium infects a human, grows in its liver then blood cells, is picked up by a mosquito where it multiples further than goes into the saliva, and back into a human or other animal
8
Q
what are sarcodina
A
Sarcodina: protists with false feet
- a pseudopod is a temporary projection of cytoplasm used to eat and move
- the pseudopods vary a lot
- amoebas are one group
- they are flexible cells without walls, flagella, cillia, or defined shapes
- amoeboid movement is when they push out a pseudopod then move along it
- they use binary fission
- other groups include heliozoans, radiolarians, foraminiferans
- these ones can make shells
- foraminiferans can make CaCO3 shells that cover the ocean floor
9
Q
how do animal like protists fit into our world
A
How Animal like protists fit into the world
- very common
Harmful relations
- many parasites or pathogenic species (groups)
- Trypanosomes live in blood and cause diseases like African sleeping sickness (transmitted by Tsetse fly)
- Entamoeba looks like an amoeba but can cause amoebic dysentery. lives and attacks the intestines, bread through faces
Helpful relationships
- Trichonympha helps termites digest wood
- many protists make up plankton and form the base of the marine food chain
10
Q
what are plant like protists like
A
- 5 phyla
- Photosynthesize
- 3 phyla make up algae
- 2 phyla are called fungi like protists or slime molds
11
Q
what are the 5 phyla of plant like protists
A
Euglenophyla, Pyrrophyta, Chrysophyta, Acrasiomycota, myxomycota
12
Q
what are euglenophyla
A
Euglenophyla: flagella with chloroplasts
- closely related to zoomastiginans
- Euglena is the prime examples: they have 2 flagella or can crawl, they have a red eye spot that shows light, they have 10-20 chloroplasts
- they can also eat food (heterotrophic) when sunlight isn’t abundant
- Euglena have small ridge like sacs in their pellicle that maintain shape and help them to crawl
- very adaptable
- binary fission
13
Q
what are Pyrrophyta
A
Pyrrophyta: Fire Protists
- know as dinoflagellates
- most are autotrophic, some have become heterotrophic
- one flagella wraps around the “body” they other tail hangs behind
- can have thick shell plates
- most are bioluminescent
- the only only eukaryotes without histones
14
Q
what are chrysophyta
A
Chrysophyta: Golden Protists
- contain green, brown algae and diatoms
- have gold and green protists
- have proteins walls not cellulose
- very diverse
- 2000 are diatoms and have silicon or glass like walls, photosynthetic
15
Q
what are the slime molds
A
The Slime Molds: Unusual protists
- found near rich food sources like rotting wod
- amoeba like at one point, then become mold like
- 2 phyla ( Acrasiomycota , Myxomycota )
