Miss. AF
10/28/09
Unicellular Algae
A. Purpose:
The purpose of this experiment is to examine the features of a
specific member of Kingdom Protista, the dinoflagellate. Its name comes from "dino", which means two, and "flagellate",
which has to do with having flagella. As the name implies, then, it has
two flagella, one encompassing its middle and the other attached to its end
like a tail. At first glance, the dinoflagellate
looks simple, but actually, it is a complex creature and has several intricate
features that will be observed in the experiment.
Dinoflagellates are phytoplankton. They
"are unicellular protists which exhibit a great
diversity of form" (Introduction). Their one cell has a cellulose cell
wall that it uses as a protective covering for itself. Many dinoflagellates can use photosynthesis to make their own
food which makes them plant-like. Interestingly enough, however, many of
them also can engulf food particles, making them animal-like.
Additionally, some dinoflagellates have an eye-spot
that is sensitive to light, and it can guide them to light sources.
In terms of reproduction, dinoflagellates use an
asexual method called cell division to reproduce. The cell divides into
two daughter cells, each of which then constructs a new dinoflagellate.
Mass amounts of this kind of reproduction can create a bloom
or red tide where many of the dinoflagellates
congregate together, turning the water red, brown, or green. Red
tides are dangerous because of the toxins emitted by certain types of dinoflagellates. Interestingly enough, "About
75-80% of toxic phytoplankton species are dinoflagellates"
(Dinoflagellates). These toxins kill marine life, and
they can even affect people through the sea food that they consume.
Also, some dinoflagellates can light up. A
procedure called bioluminescence allows them glow. These creatures are
very adept at surviving since they are microscopic. They get everything
they need (food, water, and waste removal) from their surrounding environment,
the water. If that was not amazing enough, the dinoflagellates
also have certain structures on their bodies that help them remain near the
surface so they can do photosynthesis.
This experiment hopes to show how intricate and amazing the dinoflagellates
are. At first glance, the dinoflagellates may
appear boring since they are just a single-celled organism. However, they
have many interesting features. Thus, through this experiment, students
should clearly see dinoflagellates' incredible
design.
This experiment is of interest because it helps students understand that there
is an incredible amount of design, even in the smallest organisms.
Evolution would teach that the earth and all its creatures came into being on
accident. However, by simply observing the dinoflagellates
and their amazing complexity, students can easily see that Someone
had to create them in order for them to be that complex. Therefore, this
experiment is important and interesting.
Hypothesis: If the dinoflagellates
are observed, then at least one dinoflagellate with
an eyespot will be seen.
B. Equipment:
1. Microscope
2. Prepared slide of diatoms (This slide was included in the kit for the
first year biology course. If the student does not have that kit, the
slide can be ordered individually from Nature's Workshop Plus.)
3. Prepared slide of dinoflagellates
C. Procedure:
1. Observe the prepared slide of diatoms on all three
magnifications. Notice that there are many different types.
2. Make a sketch of a few diatoms and note the tiny perforations and
spines on the frustules. Tiny circular spots inside the frustules may be
seen. These are oil spots. Diatoms store excess food in the form of
oil, so when an oil spot is seen, this is stored food.
3. Now observe the prepared slide of dinoflagellates
on all three magnifications.
4. On the highest magnification, try to use the fine focus and observe a
transverse groove like a "belt" as drawn in Figure 3.4. This is
where the transverse flagellum is located.
5. Make a sketch of what is seen.
6. Clean the microscope lenses with lens paper and put everything away.
D. Observations:
1. The diatoms slide was viewed at 40x magnification.
Many different types of diatoms were seen. They all had different colors,
shapes, and size.
2. A pink diatom was centered on. Magnification was increased to 100x. At this magnification, the diatom was slightly
bigger and more features were visible. There were a few small dark spots
on the diatom as well.
3. Magnification was increased to 400x. At
this magnification, the dark spots were clearly visible within the
diatom. Some tiny spines on the frustules were visible too.
4. A sketch was made.
5. The slide of dinoflagellates was placed on
the microscope stand. Magnification was placed at 40x.
6. At 40x magnification, not much was seen other than the dinoflagellates themselves. Two of them had a pinkish
color, and the other two had a green color. All of them looked slightly oblong
in shape.
7. Magnification was increased to 100x, and more
structures were visible. It was noticed that two of the dinoflagellates had small flagella at the end of them.
8. Magnification was increased again to 400x.
At this magnification, the transverse flagellum was clearly visible on each dinoflagellate. Only two of the dinoflagellates
had a second flagellum, however.
9. A sketch was made.
10. Everything was put away.
E. Conclusions:
When the diatom was observed, dark spots were seen inside it.
It was remembered that diatoms can engulf their food, so it was assumed that
this must be what the dark spots were. This was confirmed by the
textbook. When the dinoflagellates were
observed, only two of them had flagella. It was then concluded that the
other two must either have extremely tiny flagella, or the flagella were
damaged when the dinoflagellates were preserved.
Additionally, no eye spots were seen when the dinoflagellates
were observed. The dinoflagellates were scanned
several times in an attempt to find one. However, no irregular spots were
seen. Thus, the hypothesis made at the beginning of this experiment is
incorrect.
A way to improve this experiment would be to clean the microscope before
performing the experiment. Cleaning the
microscope can be accomplished with lens paper.
A gentle circular motion with the lens paper across the ocular and objective
should be sufficient to clean the glass.
By doing this, a more accurate view of the organisms will be obtained.
An idea of further research would be to collect a drop of ocean
water, stain it, and place it on a slide.
The best stain for dinoflagellates is Safranin-O, which can be obtained through Nature’s Workshop
Plus. Diatoms can be stained with iodine
liquid, which can be obtained at the drug store. The sample could be scanned for diatoms and dinoflagellates, and the two samples of each (the ones from
this experiment, and the one collected) could be compared.
F. Bibliography:
Hoppernrath, Mona and Juan F. Saldarriaga. "Dinoflagellates."
September 16, 2008. October 26, 2009.
Domain: http://tolweb.org
Document: Dinoflagellates/2445
Rosenoff, Steven. Class
Lecture. October 9, 2009.
Seligson, Sherri. Exploring
Creation with Marine Biology. Apologia
Educational Ministries, Inc. 2005
Waggoner, Ben. "Introduction to the Dinoflagellata." October 26, 2009.
Domain: www.ucmp.berkeley.edu
Document: /protista/dinoflagellata.html