The first part of this lab is a computer simulation based on one of the most famous ecology experiments,
which is described in pages 201 – 202 in your text. You should read the text to better understand this
experiment before you actually go to the website. Once you have read and understood these pages in your
text, go to this website: http://virtualbiologylab.org/community-ecology/ click on “Launch model” under
“Barnacle competition” and read the “Background Information” on the webpage about this computer
simulation before starting the simulation. This will give you even more information about the ecology
relevant to this lab. Finally, read about the three organisms of this lab on the lab sheet below also. Once
you have done this all this reading, click on “Run Experiments”, and answer the questions below. The
second part of this lab is a computer simulation of population growth, exploring exponential and logistic
growth. The first part of the lab is worth lab is worth 21 points, the second part is worth 6 points. You
should type out your answers to the questions (in blue font) and turn in both parts of this lab sheet
(electronically via email) to.
Here are the organisms in the simulation for the first part of the lab:
Chthamalus stellatus which is a barnacle. Barnacles are crustaceans (like shrimps and crabs) that attach to
hard substrates (rocks in this case) and filter-feed on plankton in the ocean. This species lives in the
intertidal zone, so they are covered with water (and they can be active feeding) when the tide is high, and
they are exposed to air (and they shut themselves inside their shell or “tests”) at low tide.
Balanus balanoides another species of barnacle that lives in the intertidal zone, similar to C. stellatus
above.
, Thais lapillus (actually Nucella lapillus) A dog whelk, which is a predatory gastropod (snail) that can
feed upon barnacles. It has a modified radula (sort of like teeth) to drill through the barnacle shells. These
live on rocky shores.
Run the simulation for about 1 minutes at 1X speed, then you can speed it up to 3X speed and let it run
for an additional 3 minutes. Then pause it. After this time, describe what is in the upper (intertidal) zone
(including density), describe what is in the middle (intertidal) zone (including density), and describe what
is in the lower (subtidal) zone (including density). Upper and lower intertidal zones are sometimes
submerged by seawater and sometimes exposed to air, whereas subtidal zones are never exposed to air
and are always submerged. I will refer to this as the “normal state”. When I refer to the upper, middle and
lower intertidal zone in questions below, I’m referring to the zones in this “normal state”. (3)
Answer:
Upper intertidal: The upper intertidal region as mainly Chthamalus stellatus. in high density and in high
tide. barnacle species open up to feed while they are submerged, and close up when the tides go on the
ebb. As for their density, it is comparatively lower than the Balanusbalanoides species that remain
submerged in most instances.
Lower intertidal: This zone is primarily inhabited by the Balanus balanoides species of the barnacle and a
few instances of the smaller-sized white Chthamalus stellatus barnacle species. The density is quite high
which is described in pages 201 – 202 in your text. You should read the text to better understand this
experiment before you actually go to the website. Once you have read and understood these pages in your
text, go to this website: http://virtualbiologylab.org/community-ecology/ click on “Launch model” under
“Barnacle competition” and read the “Background Information” on the webpage about this computer
simulation before starting the simulation. This will give you even more information about the ecology
relevant to this lab. Finally, read about the three organisms of this lab on the lab sheet below also. Once
you have done this all this reading, click on “Run Experiments”, and answer the questions below. The
second part of this lab is a computer simulation of population growth, exploring exponential and logistic
growth. The first part of the lab is worth lab is worth 21 points, the second part is worth 6 points. You
should type out your answers to the questions (in blue font) and turn in both parts of this lab sheet
(electronically via email) to.
Here are the organisms in the simulation for the first part of the lab:
Chthamalus stellatus which is a barnacle. Barnacles are crustaceans (like shrimps and crabs) that attach to
hard substrates (rocks in this case) and filter-feed on plankton in the ocean. This species lives in the
intertidal zone, so they are covered with water (and they can be active feeding) when the tide is high, and
they are exposed to air (and they shut themselves inside their shell or “tests”) at low tide.
Balanus balanoides another species of barnacle that lives in the intertidal zone, similar to C. stellatus
above.
, Thais lapillus (actually Nucella lapillus) A dog whelk, which is a predatory gastropod (snail) that can
feed upon barnacles. It has a modified radula (sort of like teeth) to drill through the barnacle shells. These
live on rocky shores.
Run the simulation for about 1 minutes at 1X speed, then you can speed it up to 3X speed and let it run
for an additional 3 minutes. Then pause it. After this time, describe what is in the upper (intertidal) zone
(including density), describe what is in the middle (intertidal) zone (including density), and describe what
is in the lower (subtidal) zone (including density). Upper and lower intertidal zones are sometimes
submerged by seawater and sometimes exposed to air, whereas subtidal zones are never exposed to air
and are always submerged. I will refer to this as the “normal state”. When I refer to the upper, middle and
lower intertidal zone in questions below, I’m referring to the zones in this “normal state”. (3)
Answer:
Upper intertidal: The upper intertidal region as mainly Chthamalus stellatus. in high density and in high
tide. barnacle species open up to feed while they are submerged, and close up when the tides go on the
ebb. As for their density, it is comparatively lower than the Balanusbalanoides species that remain
submerged in most instances.
Lower intertidal: This zone is primarily inhabited by the Balanus balanoides species of the barnacle and a
few instances of the smaller-sized white Chthamalus stellatus barnacle species. The density is quite high
