Lab Write Up

Jacqueline Shapiro
Dr. Gerin

Lab Write-Up #2 – Protist Diversity

Background: Protists are diverse unicellular organisms that vary in morphology, ecology, metabolism, and reproduction, including the four "supergroups" known as Excavata, the SAR Clade, the Archaeplastida, and the Unikonta. Since most Eukaryotic lineages are protists and most protists are single-celled, the keys to a more accurate tree of Eukaryotic life lies within the single-celled protists.
Purpose: The purpose of this lab was to observe protist diversity in the Excavate group known as the Euglenozoans by identifying the distinguishing features present in the kinetoplastids and the euglenids.
Hypothesis: If the evolutionary history of various protists shows evidence of similar needs for adaptation, then these needs affect the presence or absence of certain distinguishing features contributing to diversity among protist organisms  
Procedure: Place a drop of live Euglena on a slide with a coverslip under a microscope, noting the movement of the Euglena under the microscope and any visible internal "organs". Look for the stigma, or eyespot, flagellum, nucleolus, nucleus, chloroplast, photoreceptor, and contractile vacuole. Observe the canal, emergent flagellum, emergent flagellum with paraflagellar swelling, non-emergent flagellum, and reservoir. Next, examine a prepared slide of Trypanosoma in blood smear. Look for the large mitochondrion, the kinetoplast, and the nucleus under a microscope. Note other structures including the flagellar pocket, undulating membrane, flagellum, basal body, subpellicular microtubules, and other structures that may be visible.
Results: The distinguishing features of euglenids include a pocket where flagella come out, a light-sensitive swelling at the base of the long flagellum, and the stigma, or eyespot. Chloroplasts are found in some autotrophic or heterotrophic euglenids and absent in other heterotrophic euglenids. The bands of protein beneatht he plasma...