Rev 7/15
Name ___________________________________
Organisms Once Protista Species!
Today we examine the structure and function of organisms at least once considered part of the
admittedly-polyphyletic Kingdom Protista. In recent years Protista (sensu lato) is being refined into
separate lineages (hopefully monophyletic) based on cladistic analysis of genetic sequences as well as
morphology and biochemistry. Some of these groups are more clearly and widely refined into newlyproposed Kingdoms (as presented in your textbook). Other groups of organisms are not so clearly
refined at present and the groupings are controversial. Many modern phylogenetic analyses are
abandoning the Linnean taxonomic hierarchy (Kingdom, Phylum, Class, etc.) and consider these
groupings to be (or at least have been) artificial and thus are invalid and/or irrelevant. The revised
monophyletic groupings are given new names, which we might consider lineages rather than
taxonomic levels; but admittedly some of these lineages are more deeply rooted than the others. Given
the fluent state of these organisms, the instructors of this course are not necessarily in agreement on a
“correct” taxonomic nomenclature to present to you. Please be warned that the nomenclature in this
exercise includes language that is likely not finalized, and we are providing synonyms for some of the
organismal groupings that you will find in literature.
Homework Before and After Class:
Prior to class, find the required organisms on Google Image™. As homework, make a preliminary
sketch of each organism as described below. Rotate your worksheet to avoid crossing lines and get
your sketch fully labeled. Knowing what you are looking for will save you a lot of “searching time” in
class! It is important to get to the experiments in class! Much time is wasted if you believe that an air
bubble, detritus, etc. is the organism! More time is wasted if you are sketching the organisms provided
as food for the subject organism or contaminating organisms rather than the subject organism!
After class, if you missed something, YouTube™ can be a great resource for observing organisms.
You are a generation with access to resources way beyond what your instructors had available to them
back in their organismal biology courses! It will be easy for your instructor to determine who has
prepared a little bit for this lab exercise and who has done the follow-up verification of their
observations at home after class.
In Laboratory Tips:
The organisms will be present in the laboratory in various jars and/or tubes. Be sure to use only
the pipette for the particular culture as we do want to keep the organisms separate. Releasing a
predator into one of our stock cultures of prey might be a disaster for those observing after you. Some
of our organisms are marine and others are freshwater so mixing up the pipettes might execute
everything in it! So only use the species-specific pipette to remove organisms for observation.
It is important to note that these eukaryotic organisms are small but visible with the naked eye!
They hang out on the bottom and sides of the jars; they are NOT found in the middle of the water in the
jar. Placing a sheet of paper under the jar/tube may provide contrast to help reveal the organisms. You
have to be the hunter and have skill with the pipette to suck up an organism in just a couple of drops
and put it on a microscope slide for observation!
For most of these organisms you will need to make a wet mount (slide, drop(s) of medium with
specimen, cover slip). The pressure generated between two pieces of flat glass and the surface tension
of an evaporating film of water is not to be underestimated! Therefore some larger or motile organisms
will need to be mounted in a depression slide. The depression ground into only one side (!) of the glass
Document © Ross E. Koning 1994. Permission granted for non-commercial instruction.
Koning, Ross E. 1994. Organisms Once Protista Species! Plant Information Website.
http://plantphys.info/organismal/labdoc/protista.doc
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is a place to hold a few drops of medium with the specimen under the coverslip but with space enough
for the organism to survive the observation! So be sure you use the depression slide and add enough
medium to avoid air pockets under the cover slip as indicated for larger organisms. And, then you will
need to constantly focus as the specimens move about in the depth of this depression slide mount.
As you look for the organism on your slide, be careful to note that some of the material in the
culture may be present as food (prey) for the organism in the same tube or jar. So making sketches of
whatever is the "food" or other “contaminant” organisms will not win any points! One organism that is
a contaminant in almost all the cultures is rotifers; ignore them (maybe before class, look them up in
Google Image™ so you know what to ignore!).
Please do not pile huge amounts of our precious organisms onto your one slide…don't be piggish!
You only need to observe a few organisms. Also, there is nothing wrong with sharing your good slides
with someone else in the room. This way we can learn cooperatively much more than we might learn
alone.
In homework, and then also in class, examine each organism first to learn about its size, its
structure, and what you can learn of function. Make a LARGE sketch of each organism showing the
details of the structures it has. Label each structure as fully and clearly as possible! Use the labels
provided, but before you start sketching, notice the printed sequence of these labels; rotate your paper
or your mental image of what you see on-line or in the microscope to avoid crossing lines. In
connecting the printed labels to your sketch, be sure the lines end by touching the structure you are
identifying in the sketch. Shade organelles or parts to reflect colorations and differences between the
organelles; write a color word next to any labeled structure having a distinctive coloration. Remember
that one color word indicates a lack of color: colorless; this should not be confused with the word,
clear, which means a lack of turbidity (cloudiness) rather than lack of color. A very colorful organelle
could also be very clear; so choose your terms carefully! In the case of multicellular organisms, please
show the organelles together in ONE cell, so you are not communicating the false idea that each
organelle is found in a separate cell. Be sure your sketch shows the biological reality of how many of a
particular organelle are found in each cell.
Experiments:
After sketching and labeling each organism, you will be directed to apply some kind of treatment
and observe the organismal response to it. Obviously you need to be looking at the organism as you
apply the treatment to see the changes as they happen! Having a partner apply the chemical treatment
to the edge of the cover slip as you watch is a reasonable approach. You can add to your sketch
something to indicate color changes with shading and words. An “after treatment” sketch might also be
helpful.
Today you are exercising the scientific method. Observe each organism thoroughly. Think of
questions you might like to answer about the organism's structure and function. Based on your
experience and perhaps pre-lab reading, pose an educated guess about the answer to the question…
posing a falsifiable hypothesis. Make a prediction about what you should observe when you provide a
treatment if the hypothesis is true. Carry that prediction through the experiment with the treatment and
remember your untreated control. Observe carefully over some time to note multiple occurrences on
your slide to be sure your results are not just chance events. Analyze your observations. Decide
whether to reject your hypothesis or not.
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Kingdom Amoebozoa
Pelomyxa palustris (be sure to mount this large organism in a depression slide)
In sketching, draw the whole organism, not its labels! If there is more than one of a structure in the cell, be sure your
sketch shows that; if there is ONLY one, then be sure you only show that one.
-cell membrane
-nucleus
-food vacuole
-contractile vacuole
-endosymbiont
-pseudopodium
-uroid
Pelomyxa is a freshwater organism.
Add some NaCl to the mount. What happens to cyclosis? faster slower
What happens to the cell? enlarges
stops
shrinks
no change
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Kingdom Excavata
Euglena gracilis (a flat slide is suitable; the three blanks are for color words)
-cell membrane
-pellicle
-nucleus
-chloroplast ___________
-contractile vacuole _______
-eyespot ___________
-flagellum
Turn off the lamp and observe the rate of motility: faster slower no change
Turn the lamp back on and observe the rate of motility: faster slower
no change
What process do you conclude provides energy for motility? _________________________
Turn the lamp on and off 10 cycles while looking...the response: ______________________
Cover half of the lamp in the base with a notecard for 20 seconds.
What does the distribution of the euglena cells in the field of view tell you?
The organisms are + phototactic
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– phototactic
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Kingdom Chromalveolata/Alveolata
Stentor coeruleus (be sure to mount this large organism in a depression slide)
-cilia
-cytostomium
-contractile vacuole
-cell membrane
-macronucleus
-myoneme (color__________)
-holdfast
Are cilia used for motility? yes
no
Are cilia used for feeding? yes
no
http://youtu.be/jAWp8TtOpKE
What is the evidence? _________________________________________________________
Hint: a moustache is near a mouth, but this is not evidence that it assists in eating!
Add Methylene Blue to the mount.
What is its impact on motility of Stentor? faster
slower no change
Methylene Blue is thought to trap electrons and protons normally used for ATP synthesis.
What conclusions do you draw from your observation?
ATP synthesis is
Methylene Blue does
is not required for motility.
does not trap electrons and protons, slowing or blocking ATP synthesis.
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Kingdom Chromalveolata/Heterokonta/Stramenopila
Ectocarpus-Use needles to tease out a few fuzzy filaments for mounting on a flat slide.
http://university.uog.edu/botany/474/images/hinck_cells.jpg
Vegetative Cells (sketch part of a filament 3-5 cells long, large enough to show these details in one cell!)
- cell wall
-cell membrane
-chloroplast
-nucleus
-vacuole
The branching in this organism is true false .
Hint: “seriate” = “cells-wide”
Ignoring any reproductive structures, the filaments are mostly uniseriate
multiseriate .
What is the natural color of the vacuole? white colorless
What is the natural color of the chloroplast? _______________________________________
Based on color, name the major non-chlorophyll accessory pigment: __________________ .
Does laminarin give a positive iodine test? yes
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no
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Kingdom Archaeplastida/Rhodophyta (disputedly Protista/Plantae)
Polysiphonia-Use needles to tease out a few fuzzy filaments for mounting on a flat slide
Vegetative Cells (sketch part of a filament 3-5 cells long, large enough to show these details in one cell!)
-cell wall
-cell membrane
-chloroplast
-nucleus
The branching in this organism is true false .
Ignoring any reproductive structures, the filaments are mostly uniseriate
multiseriate .
Does this observation lead you to believe that the supplier sent the right genus? yes
no
What is the natural color of the chloroplast? _______________________________________
Based on color, name the major non-chlorophyll accessory pigment: ___________________
Given the color of this organism and its major pigment,
what color of light should be maximally absorbed by this pigment? ____________________
You may check your answer using a Google search using the pigment name and “absorbance spectrum” as a keyword.
If you were to provide more photons of this color of light to the pigment than it can use in photosynthesis, the excess
energy will be absorbed (not transferred to chlorophyll) and re-emitted (fluorescence) as photons of a longer
wavelength. Use the flashlight provided to test this by shining it down through the jar of
Polysiphonia.
What color of light is re-emitted during fluorescence in this organism? __________________
Is this emitted light of longer wavelength (less energy) than the excitation light used? yes
Does floridean starch give a positive iodine test? yes
no
no
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