Lecture 2: Protistan Phyla

What kind of group are protists?

Paraphyletic

What does amoeboza mean?

Amoeba with blunt pseudopods

What kind of habitats can you find amoebas?

A variety of aquatic habitats, and moist terrestrial, but they are typically benthic

Do amoebas perform asexual or sexual reproduction?

Both

How do amoebas reproduce asexually?

Binary fission or mitosis

Where can you find the endoplasm?

within the ectoplasm

What organelles are found within the endoplasm?

• contractile and food vacuole

• nucleus

Where can you find the ectoplasm?

The outer layer of the cytoplasm and its under the cell membrane

Which is also known as sol?

Liquid endoplasm

Which is known as gel?

Solid ectoplasm

What is the function of ectoplasm?

Gives the amoeba its shape and elastic support

What is the function of actin filaments?

Tiny structural protein fibers that make up the cytoskeleton

What part of the amoeba is responsible for changing the shape of the cytoplasm?

actin filaments

What is the purpose of the food vacuole?

acts as a temporary stomach

How does the amoeba obtain food?

phagocytosis

What is phagocytosis?

the primary feeding process where an amoeba engulfs solid food particles like bacteria or algae using its cell membrane

What is the purpose of the contractile vacuole?

To act as a biliary pump to keep the amoeba from swelling and bursting

are amoebas made up of salts, sugars, and proteins??

yes

What process that occurs in the contractile vacuole that prevents the amoeba from bursting?

osmosis

What type of feeders are amoebas?

Omnivores

What is the hyaline cap?

a clear, transparent layer of cytoplasm found at the leading edge of an advancing pseudopodium in a moving Amoeba

How does nutrients cross the cellular membrane?

either both types of diffusion or pinocytosis

What is pinocytosis?

a cellular process known as "cell drinking," where the organism takes in extracellular fluids and dissolved nutrients by forming tiny channels or pockets in its cell membrane

What are 2 examples of amoebozoan groups?

Tubulinea and Arcellinida

What does the phylum Tubulinea mean?

Naked amoeba

What does naked amoeba mean?

It lacks a shell

what does the Phylum Tubulinea eat?

primarily eat bacteria, green algae, small yeasts, and other microscopic protozoans.

What does the Phylum Arcellinida mean?

Testate amoeba

What does testate amoeba mean?

Amoeba possesses a shell

What is the Phylum Arcellinida shell made up of?

Sand grains, carbonate bits, and other foreign particles cemented onto the base secreted by the amoeba

What is an example of an amoeba from the phylum Arcellinida?

Difflugia

How do both phylums Arcellinida and Tubulinea move?

Lobopods

What is an example of an amoeba from the phylum Archamoeba?

Entamoeba (histolytica)

What does the supergroup Rhizaria mean?

amoeba with fine pseudopod

What is an example of a phylum from the supergroup Rhizaria?

Foraminifera (Granuloreticulosa)

Is the phylum Foraminifera posses a shell?

Yes they do

Can you find Foraminifera in marine enviornments?

yes for the most part you can

Where can you find Foraminifera in the enivonrment?

Open water (planktonic) or benthic

What are the two types of shells in the phylum Foraminifera?

cellular secretions or materials from surrounding environment

What kind of pseudopods do Foraminifera possess?

Reticulopods

What are reticulopods?

• a type of pseudopods that are thin, sticky

• Sometimes there branches may connect with each other

• food can stick to them

What are lobopods?

• thick, blunt, finger-like pseudopods

Why are Foraminifera important in the environment?

• Their dead shells make up most of the ocean floor

• Geologists can examine their shells to date rock layers, reconstruct ancient climates, and locate oil and gas reserves

Where else in the world can you find Foraminifera?

Cliffs of Dover or the pyramids

What phylum do Radiolarians and Heliozoans belong to?

Acantharia

What kind of environment can you find Radiolarians?

Marine only

What kind of skeleton do Radiolarians posses?

Delicate skeletons made often of silica

Do Radiolarians have a shell?

They have a shell

What kind of environment can you find Heliozoans?

Freshwater only

Do Heliozoans posses a shell?

They do not

What do Heliozoans look like?

They are often stalked and lack a mineral skeleton

What are heliozoans sometimes referred to as?

Sun Animals

What kind of pseudopods does the Phylum and its two groups possess?

Actinopods (axopodia)

In the phylum Acantharia, what is the purpose of the spine?

To provide protection and creates buoyancy

In the phylum Acantharia, What is the purpose of the internal skeleton?

To provide support and act as an anchor point for the radiating spines

In the phylum Acantharia, what is the purpose of the actinopods?

• Trap food by acting like a stiff, sticky underwater spiderweb

• Traps food as prey float by

• They dont fuse together

• Supported by rigid microtubules

In the phylum Acantharia, what is the purpose of the ectoplasm?

• Flexible, less dense cytoplasm used for buoyancy and prey capture

In the phylum Acantharia, what is the purpose of the endoplasm?

• Granular cytoplasm that makes up the bulk of the internal cell mass

In the phylum Acantharia, what is the purpose vesicular ectoplasm?

Can control the depth ranges

• Sink = compress

• Float = expands

How does members of the phylum Acantharia reproduce sexually?

Reabsorbs its skeleton, transforms it into a reproductive cyst, and sinks; the cyst wall ruptures, releasing biflagellate swarmers

How does members of the phylum Acantharia reproduce asexually?

Gametogensis occurs in adult cell and floats, multiple nuclei divide, the cells’ outer layer bursts, and swarmers are released towards the surface

Where can you find the Phylum ciliata?

marine and freshwater habitats, sometimes terrestrial

How many nuclei do memebe’s of the phylum ciliata possess?

Macro and micronucleus

What does the macronucleus do in Ciliata?

Cellular metabolism

Are macronucleus diploid of hyperpolyploid?

hyperpolyploid

Are micronucleus diploid of hyperpolyploid?

Diploid

What does the micronucleus do?

Reproduction

What is the main function of the cytosome in Ciliata?

To act as a mouth, where food enters

What is an example of a synapomorphy of the Phylum Ciliata?

Infraciliature

What does the term Infraciliature mean?

• Internal anchoring beneath the cell membrane

• Ensures the cilia are in sync

• Acts as the cell's under-root system

What is the purpose of trichocysts?

Defensive in structure beneath each cilia

How do Ciliata feed?

• Filter feeding or suspension feeding

• Raptorial feeding

• Diffusion feeding

What does filter feeding/suspension feeding?

Cilia create a whirlpool, food attaches to cilia, food gets pushed down to its throat, traps food into a food vacuole by using its cell membrane

What does raptorial/Holozoic feeding?

Active predators, actively hunt down their prey (either through chemical scent trails or smell) swallow them whole

What does diffusion feeding mean?

No movement occurs, relies on natural movement within its environment

• Cilia attaches to substrate

• Cilia doesnt move and waits for food to bump into it

• Prey is presently glued and exposed to toxins

• Prey is sucked into the cilias body, creating a food vacuole

How do cilia reproduce sexually?

conjugation

How does conjugation occur?

• Two cells line up side by side and fuse cell membranes temporarily

• Macronuclues in both cells dissolve and disappear

• Micronuclei undergo meiosis to create fresh haploid genetic packages, each cell keeps one package and sends the other copy to the neighborhood cell

• Cells separate new DNA fuses with the retained old DNA, each cell uses the new genetic material to build a new macronuclei

How do cilia reproduce asexually?

Binary fission via mitosis

What are some common characteristics of the phylum Chaonflagellata?

• Single

• Live on the ocean floor

• Creates its own current and filter feeds