Very Basic Copepod Introduction
(Skip this if you already know what a copepod is.)
Copepods are a type of crustacean, the class of animals that also
includes shrimps, lobsters, and crabs. Copepods are one of the most
abundant animals on the planet. Most are saltwater plankton, living
their entire lives in the open ocean without ever touching the bottom
or surface. Copepods also live on the sea bottom, in fresh water, as
parasites on fish, in caves...
Euchaeta Biological Introduction
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 Copepods in the genus Euchaeta are
planktonic and predatory. Congeners of Euchaeta (Kingdom
Animalia, Phylum Crustacea, Class Copepoda, Order Calanoida,
Superfamily Clausocalanoidea, Family Euchaetidae, Genus
Euchaeta) live in seas from the Antarctic to the tropics,
within the fjords of Norway and Puget Sound, and in deep lochs of
Scotland. In their respective open-ocean planktonic communities,
these copepods are often biomass dominants because of their high
abundance, large size, and high lipid content (up to 70% their body
weight). The image to the right was taken by Yen and Strickler and
shows a typical Euchaeta. The long antennules are lined with
sensitive setal receptors to detect fluid motion and odors. This photo
of the live subarctic species, shows its natural coloration with blue
oocytes within the oviducts and iridescence imparted by the thin
caudal setae. The robust capture appendages, the paired maxillipeds,
are shown extended away from anterior section of body.
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Euchaeta are gigantic (for copepods), with the adult
subtropical females growing to 2.4 millimeters in length and the polar
species reaching up to 1 cm. Males are somewhat smaller. Their
maxillipeds are used to capture and eat other copepods. These photos
depict the structure of the capture appendages, the maxillipeds and
maxillae. The left photo is a drawing from Wickstead(1959). The
right is a scanning electron micrograph by J. Yen(1985).
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Computer Visualization Introduction
We created and animated our model using 3D Studio Max from Discrete
Logic. This high-end animation package is widely used by movie
special effects artists.
To create our models and animations, we first looked at
illustrations in the literature. Rose 1933
gave us a good starting point. To create the prosome, we scanned 2D
images from Rose into the computer and traced them using Bezier curves
to create the outline of the prosome as seen from the left-hand side.
We then made an estimate of curves representing the outline of the
prosome as seen from the rear. Using these two sets of curves, we
were able to create a Bezier patch surface approximating the prosome.
We then checked our results by rendering images from several
viewpoints and comparing them against preserved specimens. We also
showed the images to Annie Townsend, curator of the SIO Planktonic
Invertebrates Collection. She was able to suggest many important
improvements.
The other segments of the prosome and urosome were constructed in a
similar fashion, as were the appendages. We found that NURBS surfaces
generally gave better results with less effort than other techniques
for modelling curved surfaces.
Setae provided a special animation challenge, as there are so many
of them. After exploring several techniques we used loft surfaces
created from circles and Bezier splines. The tip of each seta was
attached to a controller, so that each seta could be individually
positioned if necessary. We generally avoided this by attaching the
tips of each set of setae to a master controller. To give a more
natural appearance, the setae on the maxillae are translated and
rotated using a random noise function.
To animate our model, we first determined the range of motion of
the joints by examining preserved specimens. We then looked at video
of live animals. Using key frame animation, we were able to
approximate the motion of the living animals. Once the computer model
had been animated, it could be examined from any angle and at any
speed.
All images, animations, models, and scripts are copyright 2000
Scripps Institution of Oceanography and may not be published or
re-used without permission.
Copepods in the genus Euchaeta are
planktonic and predatory. Congeners of Euchaeta (Kingdom
Animalia, Phylum Crustacea, Class Copepoda, Order Calanoida,
Superfamily Clausocalanoidea, Family Euchaetidae, Genus
Euchaeta) live in seas from the Antarctic to the tropics,
within the fjords of Norway and Puget Sound, and in deep lochs of
Scotland. In their respective open-ocean planktonic communities,
these copepods are often biomass dominants because of their high
abundance, large size, and high lipid content (up to 70% their body
weight). The image to the right was taken by Yen and Strickler and
shows a typical Euchaeta. The long antennules are lined with
sensitive setal receptors to detect fluid motion and odors. This photo
of the live subarctic species, shows its natural coloration with blue
oocytes within the oviducts and iridescence imparted by the thin
caudal setae. The robust capture appendages, the paired maxillipeds,
are shown extended away from anterior section of body.
