Morphoanatomy Laboratory

1. Organism: TILAPIA (Oreochromis niloticus)
 How this animal obtains food?
Tilapia obtains ingest a wide variety of natural food organisms, including
plankton, some aquatic macrophytes, planktonic and benthic aquatic
invertebrates , larval fish, detritus , and decomposing organic matter . With
heavy supplemental feeding , natural food organisms typically account for 30
to 50 percnt of tilapia growth can be traced to ingestion of natural food
organisms. Tilapia are often considered filter feeders because they can
efficiently harvest plankton from the water.
 How it reproduced?
 In all Oreochromis species the male excavates a nest in the pond bottom
(generally in water swallower than 3 feet ) and mates with several females. After
a short mating rituals the females spawn on the nest (about 2 or 4 eggs per gram
of brood female ) the male fertilizes the eggs in her mouth (bucal cavity) until
they hatch . Fry remains in the females mouth trough yolk sac absorption and
often seek refuge in her mouth for several days after they begin to feed.
 Body plan
 It is laterally compressed, and it has a deep body with long dorsal fins, the front
part that of which have spines. Native coloration is dull greenish or yellowish,
and there may be weak bonding. Adult reach approximately 35 centimetres (14
in) in length up to 1.3 kg (2.5 lb) size and coloration may vary in captive and
naturalized populations due to environmental and breeding pressures.It lives up
to 11 years.
 Stages of development
 The first stage of embryo development is the stage of cleavage, which is when
a zygote undergoes meiotic cell divisions and in embryonic stem cells called
blastomeres. The period of blastula is the second stage of embryonic
development, presenting the blasts, whose blastomeres are formed by more than
64 cells and in the present study occurred after fertilization 6 hours.
ORGANISM: Bangus or Milkfish (Chanos chanos)

2.  How this animal obtain food?
 Milkfish take food mainly on the substrate. They ingest the surface layer of the
substrate together with the associated micro and meio-fauna (Blaber 1980) the
kind of food ingested vary by habitat and by fish size. Juvenilles from natural
habitats commonly take in bluegreen algae, diatoms, detritus, filamentous green
algae copepods and nematodes. The food items in milkfish grown in culture
ponds are similar to those of natural nursery grounds. Pond reared milkfish feed
mainly on either lablab (a complex mat of bluegreen algae, diatoms and
associated invertebrates) or lumut (mainly filamentous green algae). Milkfish
grow better in lablab than on lumot.
 How it reproduce?
 Milk fish breed near shore in clean , clear, saline, warm, and shallow waters
over sand or coral reefs. These spawning locations are closed as 6 km off shore
but are no more than 30 km off shore. Milkfish may spawn more than once a
year and spawning usually takes place during the night. Spawning is highly
seasonal and may be influenced by the lunar cycle.
 Body plan
 Elongated, moderate compressed; head pointed; eye large; mouth small, opens
at front, without teeth; 1 dorsal fin, at midbody; pelvics under dorsal fin; anal
fin small, well behind dorsal; large forked tail fin; scales small, smooth; lateral
line present, straight, entire length of body.
 Stages of development
 Adult occur in small to large schools near the coasts or around islands where
reefs are well developed. Eggs and larvae are pelagic up to 2-3 weeks. Older
larvae migrate onshore and settle in coastal wetlands (mangroves, estuaries)
during the juvenile stage, or occasionally enter freshwater lakes. Juveniles and
subadults return to sea where they mature sexually. Spawns only in fully saline
water. Larvae eat zooplankton ; juveniles and adult eat cyanobacteria.
ORGANISM: Clam (Venerupis philippinarum)

3.  How this animal obtains food?
 They lack head but most can react to changes in light and some, such as scallops,
have rudimentary eyes. Through a common food item, many are too small to be
useful as food, and not all species are considered palatable. All clams have two
calcareous shells or valves joined near a hinged structure with a flexible
ligament, and all are filter feeder.
 How it reproduce
 Eggs and sperm are release into the water seasonally, generally in mid-summer
when water is warm and planktonic food is abundant. After fertilization of an
egg, cellular division produces larvae and eventually tiny clams that settle to the
bottom. In a few species, the final stages is completed within the mantle cavity
of the parent.
 Body plan
 A clam`s shells consist of two (usually equal)valves, which are connected by a
hinge joint and a ligament that can be external or internal. The ligament provides
tension to bring the valves apart, while one or two adductor muscles can contract
to close the valves. Clams also have kidney, a heart, a mouth, a stomach, a
nervous system and an anus. Many have a siphon.
 Stage of development
 Certain kinds of clams, in early stages of life possesses a gland that produces a
threadlike material (byssus) that serves the anchor them to grains of sand or
rocks. Other types of clam lacks a byssal gland and use the foot to burrow into
the seabed as the clam grows, its wedge –shaped foot, which expanded and
contracts as it moves, becomes more important as a burrowing tool.
ORGANISM: Crabs (Liocarcinus vernalis)

4.  How this organism obtains food?
 Crabs are omnivores, feeing primarily on algae, and taking any other food,
including molluscs, worms, other crustaceans, fungi, bacteria and detritus,
depending on their availability and the crab species . for many crabs a mixed
diet of plant and animal matter result in the fastest growth and greatest fitness.
However some species are more specialized in their diets. Some eat plankton,
some eat primarily shellfish like clams, and some even catch fish.
 How it reproduce?
 Crabs attract a mate through chemical (pheromones), visual, acoustic, or
vibratory means. Pheromones are used by most fully aquatic crabs, while
terrestrial and semiterrestial crabs often used visual signals, such as fiddler crab
males waving their large claws to attract females. The vast number of
brachyuran crabs have internal fertilization and mate belly-to-belly. For many
aquatic species, mating takes place just after the female has moulted and is still
soft. Female can store the sperm for a long time before using it to fertilize their
eggs. When fertilization has taken place, the are release onto the female`s
abdomen, below the tail flap, secured with a sticky material . in this location,
they are protected during embryonic development. Females carrying eggs are
called “beried” since the eggs resembles round berries.
 Body plan
 Typically have a very short projecting tail (abdomen) , usually entirely hidden
under the thorax. Crabs are generally covered with a thick exoskeleton,
composed primarily of calcium carbonate, and armed with a single pair of
chelae (claws).
 Stages of development
 When development is complete, the male releases the newly hatched larvae into
the water, where they are part of the plankton. The release is often timed with
the tides. The free swimming tiny zoea larvae can float and take advantage of
water currents . They have a spines , which probably reduces the rate of
predation by larger animals. The zoea if most species must find food , but some
crabs provide enough yolk in the egg that the larval stages can continue to live
off the yolk. Each species has a particular number of zoeal stages, separated by
moults, before they change into a megalopa stage, which resembles an adult
crab, except for having the abdomen (tail) sticking out behind.
ORGANISM: Snail (Neptunea angulata)
 How this organism obtain its food?

5.  Snails tend to feed on a variety of items found in their natural habitat. What they
will actually consume depend on where they live and the species of snail that
they are. Some common items for their diet include plants, fruits, vegetables,
and algae plants that are decaying are often a good meal for them. Seeking for
calcium to get a thicker shell, snails usually will eat the dirt. Most snail species
are hervibors, which means they have only a plant diet, but some species are
carnivors or omnivors. You will like find snails around your garden as this
offers them plenty of fresh plants and leaves to eat. If you use herbicides or
pesbicides on your plants you many be causing the death of many snails without
even realizing it.
 How it reproduce?
 Snails will be able to reproduce differently than almost any other type of
creature. This begins with the build that all snails have. Snails are considered to
be a hermaphrodites. This means that every snails will have both male and
female reproductive organs. Most terrestrial gastropods are hermaphrodites.
The only snails that have not adapted this attribute are some freshwater and
marine species, specifically including apple snails and periwinkle. These two
types of snails still have separate male and female individuals.
 Body plan
 Head, foot, visceral mass, mantle,
 Head foot- continuous muscular mass with sensory and feeding structures
associated with head and foot and locomotion. Visceral mass contains organs of
digestion, reproduction, circulation, excretion. Mantle covers visceral mass and
secretes shell, mantle cavity contains ducts for reproduction and excretion. Head
possess paired tentacles that may have terminal eyes.
 Stage of development
 Visceral mass asymmetrical because of torsion (twisting) during development
120o twist result in loss of right gill and positioning of anus to the right of the
head. Coiling of shell due to one side of snail growing faster than other not due
to torsion.

6. TILAPIA (Oreochromis niloticus)

7. Clam (Venerupis philippinarum)

8. Snail (Neptunea angulata)

9. Crabs (Liocarcinus vernalis)

10. Bangus or Milkfish (Chanos chanos)

11. Field study
in
Animal Morpho-Anatomy
(lab)