2. Protists
• Over 38,000 species of protists!
• Members of the original life forms on earth!
About 1.5 billion years ago!
• Some protists are plant like, some are animal
like
– Protozoa: animal like protists
• Many have symbiotic relationships:
– Parasitism
• Scientists who study only protists:
protozoologists
3. Protozoa
• Protozoa
– Unicellular, plasmic organization
– BUT THAT DOES NOT MEAN THEY ARE
SIMPLE
– Individuals or colonies
4. Phylum Sarcomastigophors
• Largest protozoan phylum.
• All protozoa in this phylum:
– Unicellular or colonial
– Locomotion by flagella, pseudopodia, or
both
– Autotrophic, saprozoic, heterotrophic
– Single type of nucleus
– Sexual or asexual reproduction
5. Ever wonder about that green
gunk?
• Its Euglena!
– Possess
chlorophyll, 1 or 2
flagella
6. Euglena
• Salt or fresh water
• Digestion- perform
photosynthesis or
absorb nutrients
– stigma at base of flagella
allows euglena to orient
themselves towards a
light source
• Reproduce using
binary fission
– Split into two new
organisms
13. Dinoflagellates: food/digestion
• Many are mixotrophic
• They have
Chloroplasts:
– Photosynthesis
• But also absorb food
– Osmotrophy
– Eat other plankton:
copepods, diatoms, other
dinoflagellates
15. Dinoflagellates: ecological
Role
• Red Tides
– Release toxins
– Digestion of toxins
can cause:
numbness, slurred
speech, nausea, par
alysis, death
– Paralytic shellfish
poisoning
17. Foraminiferans
• Amoeboid
protozoans
– Branch like
psuedopods
– Form elaborate net
like structures: Tests
• Help catch prey
• Most are benthic
– Use psuedopod to
crawl around
18. Forams: digestion/energy
• Consume a lot of
diatoms and
dinoflagellates
• Some host
green/red algae
– Symbiotic
relationship
• Forams get nutrients
• Coral reefs get
calcium carbonate
19. Forams: Structure
• Produce Elaborate
Tests
– Multichamber
– Grow as the foram
grows
• Geometric
– Resembles
microscopic snail
shell
22. Phylum Apicomplexa
• All Parasites!
• Apical complex for
penetrating host cells
• Single type of nucleus
• No cilia and
flagella, except in
certain reproductive
states
• Life cycle includes
asexual and sexual
phases
23. Phylum Apicomplexa
• Feed off nutrients
from the host
• Cause serious
diseases: Malaria
– 5th largest cause of
death world wide
– 2008: 708,000 and
1,300,00 people died
24. Reproduction
• 3 stages
– Schizogony:
asexual fission in
host cell
– Gametogony:
begins sexual phase
: produces zygote
– Sporogony: zygote
divides by mitosis
creating sporozoites.
Sporozoites go on to
infect other hosts
26. Phylum Ciliophora
• Have cilia for locomotion
• Rigid pellicle and more or less fixed
shape
• Distinct (cytostome) mouth structure
• Dimorphic nuclei: macronucleus and
micronucleus
27. Cilia
• Similar to flagella
– Much shorter
– More of them
– Move in coordinated
waves
– Many ciliates can
reverse
• Some cilia are
specialized
– Sweep food into
mouth
28. Digestion and Food
• Heterotrophic
• Prey on other protists or small animals
• Example: Suctorians
– Attach to a prey
– Secrete mucus to paralyze prey
– Cut opening in cell wall and suck out cytoplasm
1. Attack and 2. Maneuver and
3. Gulp !
secure line up
31. Often have symbiotic
relationships
• Digestion
• Parasitic: Live in
digestive system of
humans
– Secretes enzyme
that causes ulcers
• Mutualistic: live in
the digestive system
and help digest food
– Hoofed animals
