Laboratory Exercise 1 – Excavata & SAR Protists

• This document serves as a self-guided tour of the laboratory exercise focused on Excavata and SAR Protists.

• The content is structured to link labeled images to the respective details in the lab manual.

• Students are expected to recognize specific taxonomic groups for an upcoming quiz.

Key Groups to Know for Quiz

• Phylum Diplomonads

• Phylum Parabasalids

• Phylum Kinetoplastida

• Phylum Euglenophyta (also known as eugleniids)

• Phylum Bacillariophyta (also known as diatoms)

• Phylum Phaeophyta (also known as brown algae)

• Phylum Oomycota (also known as water molds)

• Phylum Dinophyta (also known as dinoflagellates)

• Phylum Apicomplexans

• Phylum Ciliates

• Clade Rhizarians

Important Note

• Students do not need to know the genus or species for quizzes this semester.

Excavata

• Excavata comprises a large, monophyletic group that includes 4 phyla.

Phyla in Excavata

1. Diplomonads

   • Example: Giardia cysts

     • Description: Thick-walled infective stage observed under 1000x magnification.

     • Key Characteristics: Presence of 2 nuclei of equal size.

   • Example: Giardia trophozoites

     • Description: Swimming, feeding stage seen under 1000x magnification.

     • Key Characteristics: Presence of flagella, 2 nuclei.

2. Parabasalids

   • Example: Trichomonas vaginalis trophozoites

     • Description: Features undulating membrane observed under 1000x magnification and flagella.

3. Kinetoplastida

   • Example: Trypanosoma

     • Description: Notable for presence of kineticoplast near the nucleus.

     • Observed inside red blood cells under 1000x magnification.

4. Euglenophyta

   • Example: Euglena stained slide

     • Observations include flagellum and evidence of metaboly in action under 400x magnification.

   • Example: Live Euglena individuals

     • Observations include green chloroplasts and eyespot noted at 400x magnification.

SAR Clade

• The SAR clade is a larger, monophyletic group composed of 7 phyla divided into 3 subclades:

  • S = Stramenopiles

  • A = Alveolates

  • R = Rhizarians

Phyla Required for Knowledge in Labs

• Students need to know the phylum names for Stramenopiles and Alveolates; however, recognition of the clade Rhizarians is required without needing to know the specific phylum names.

Stramenopiles (Includes 3 Phyla)

1. Diatoms

   • Types of Diatoms:

     • Pennate (left) and Centric (right) diatoms represented as their glass cell walls under 400x magnification.

   • Observations:

     • Live diatoms found in filamentous colonies (multiple individuals connected), one individual diatom noted under 400x.

     • Question discussed: "If diatoms are photosynthetic, why aren't they green?"

   • Diatomaceous Earth:

     • Definition: Fossilized, marine diatoms with significant economic utility observed under 400x magnification.

2. Brown Algae

   • Example: Ectocarpus (dried herbarium specimen)

   • Example: Laminaria

     • Observed attributes: Stipe, blade, holdfast

     • Specific specimen: Laminaria agardhii Kjellman (common name: Blade Kelp) collected on May 10, 1989.

   • Example: Macrocystis (dried herbarium specimens)

     • Key feature: Pneumatocyst noted.

   • Example: Nereocystis

     • Observed attributes include blade, pneumatocyst, and stipe; specific specimen noted as Nereocystis luetka.

   • Example: Sargassum

     • Key features: Pneumatocyst

     • Specific specimen: Sargassum fluitans.

3. Water Molds

   • Example: Saprolegnia

     • Observations include asexual sporangia (stained and live) under 400x magnification.

   • Example: Saprolegnia

     • Observations include sexual gametangia with detailed parts: antheridium, oogonium, hyphae, antheridial hypha, oogonial stalk, and oospore.

Alveolates (Also Includes 3 Phyla)

1. Dinoflagellates

   • Example: Peridinium

     • Features include a groove for flagellum and chloroplast, observed under 400x magnification.

     • Question discussed: "If dinoflagellates are photosynthetic, why aren’t they green?"

   • Example: Peridinium (stained slide) under 400x magnification.

2. Apicomplexans

   • Example: Plasmodium

     • Description: Merozoites (dark pink) inside human red blood cells (light pink) noted under 1000x magnification.

3. Ciliates

   • Example: Paramecium (live) observed under 100x magnification.

   • Example: Paramecium (detailed stained slide) showcases subcellular structures including cilia, macronucleus, and micronuclei, observed under 100x magnification.

   • Example: Paramecium conjugation (sexual process) noted in stained slides under 100x magnification.

   • Example: Paramecium binary fission (asexual process) is depicted (circled) in stained slides also showcasing cilia on cells under 100x magnification.

Clade Rhizarians

• Contains 3 phyla: radiolarians, foraminiferans, and cercozoans.

• For quiz purposes, only recognition of this clade is required, not the phyla names.

Features of Rhizarians

1. Radiolarians

   • Observations of the structure include holes through which thread-like pseudopodia extend in living individuals; noted under 400x magnification.

   • Radiolarian shells are predominantly composed of glass, observed under 100x magnification.

2. Foraminifera

   • Shells composed of calcium carbonate; similar observations to radiolarians regarding thread-like pseudopodia extensions in living individuals, noted under 100x magnification.