Pre-Lab 13 Assessment: Kingdom Animalia
Name:
Section:
Please read the lab in its entirety and answer the following questions to the best of your
ability.
1. What characteristics are shared by all animals?
2. Compare radial symmetry and bilateral symmetry.
3. What is an example of an organism that exhibits radial symmetry?
4. What is an example of an organism that exhibits bilateral symmetry?
5. What event led to a huge diversification in animal evolution?
6. Name the four key features of the Phylum Chordata.
7. Frogs are ectotherms, what does this mean?
8. Why do you think frogs have webbed-feet?
9. What are two advantages of being an amphibian?
10. What are some functions of the skin of a frog?
Laboratory Thirteen
Kingdom Animalia
Purpose
This lab will enable the student to understand the characteristics that define an animal and
compare the anatomy of several different phyla through the process of dissection. Note that this
lab is divided between two days: day one students will perform the invertebrate dissections and
on day two students will perform the vertebrate dissection.
Introduction
The kingdom Animalia is made up of a diverse group of organisms that comprise 37 different
phyla. Despite this diversity, all animals share some features and are classified based on their
similarities and evolutionary relationships. All animals share the following characteristics:
1. Eukaryotic
2. Obtain nutrients by ingesting food (heterotrophic)
3. Display some type of movement
4. Multicellular
Most animals reproduce through sexual reproduction. Adults produce haploid gametes in the
form of eggs and sperm. Eggs and sperm come together to form a zygote that then develops into
an adult (diploid) through the process of mitotic division.
Through this laboratory exercise, you will study the characteristics that help separate animals
into the major groups. Biologists use several criteria to classify animals and help establish their
evolutionary relationship.
It is hypothesized that early animals evolved from a colonial, flagellated protist and the oldest
animal fossils date back to 550-575 million years ago. The Cambrian explosion resulted in a
huge diversification of animals with many body plans and new phyla appearing. The second
major evolutionary split in animal evolution is based on body symmetry. Animals exhibit radial
symmetry, bilateral symmetry, or none at all. The simplest of animals are the sponges and
they are asymmetrical.
An animal that exhibits radial symmetry can be divided into
identically all around a central axis. It is similar to a pie in which all slices through the middle
can be made into identical parts. Bilateral symmetry means that an animal can only be split in
one way to make 2 equal halves. A bilateral animal will have mirror image left and right sides.
Most bilateral animals have a “head” end and a concentration of nerves and sensory organs. This
is advantageous since it aids in movement.
Another phylogenic feature amongst the animal kingdom is whether or not a body cavity is
present in an organism. There are two major types of body cavities, pseudocoelom and coelom.
A pseudocoelom is a body cavity that is not completely lined with tissue (from the mesoderm).
The intestinal parasite Ascaris has a pseudocoelom that is easily viewable via a dissection
microscope. A coelom is a body cavity that is completely lined with tissue (from the mesoderm).
Coeloms (or true coeloms) are found in many organisms; one in particular that might be quite
familiar is the earthworm. There are also organisms, such as planaria, that have no body cavity
(acoelomate).
The absence or presence of tissue is also a major phylogenic characteristic that is used to classify
animals. Organisms, such as jellyfish (Phylum Cnidaria), are animals with stinging cells that
contain true tissue. Sponges (Phylum Porifera), ancient organisms that are found in many aquatic
habitats, lack true tissue. Finally, a field of biology that is gaining great attention in the scientific
community, molecular diagnostics, has allowed biologists to classify animals based on their
genetic data. This genetic data is known as deoxyribonucleic acid (DNA), and is found in every
living organism (and unique to each). DNA analysis is a useful tool because it not only allows
genetic comparison (using DNA sequencing) but it also allows biologists to study mutations and
other clinical abnormalities.
Laboratory 13 Part A: Invertebrate
Dissection (Day One)
Flatworms (Phylum Platyhelminthes)
Flatworms are the simplest organisms that display bilateral symmetry. They may be either freeliving in marine or freshwater habitats or parasitic. All flatworms are hermaphroditic.
Free-living flatworms
Figure 13.1 shows the major organs of Planaria. The concentration of neural structures are
located at the anterior end. This condition is called cephalization and begins in flatworms and
continues through evolution of animals to the end point of humans. The auricles contain touch
and chemical receptors and the eyespots are photoreceptors. These features aid the worm in
their free-living lifestyle
Parasitic flatworms
Tapeworms are parasitic flatworms that survive off humans and other carnivorous animals.
Adults live attached to their host’s small intestine by suckers or hooks of the scolex. Through
this association, it absorbs nutrients through the body wall.
[Insert 66L02011 (Planaria) from Pearson Library]
Figure 13.1 Anatomy of Planaria.
Roundworms (Phylum Nematoda)
Roundworms are characterized by a cylindrical body that is tapered at both ends. They are the
most numerous and widespread of all the animals. Most are free-living, but some are parasitic in
nature.
Ascaris is a large roundworm parasite that lives in the small intestine of humans and pigs and
feeds on partially digested food. Humans can be infected by accidentally eating eggs and the
larvae then enter the blood vessels and are carried to the lungs. Females can be distinguished
from males because they are larger and they lack a curl at their posterior end.
The structure of a female Ascaris is shown in Figure 13.2. The body wall is covered by a
cuticle that is secreted by the epidermis. The cuticle protects the worm from the enzymes in the
host’s small intestine. Between the intestine and the body wall lies a space called the
pseudocoelom, which is incompletely lined with mesodermal tissue. Most of the pseudocoelom
is filled with the female reproductive system and the intestine.
Figure 13.2 Anatomy of Ascaris. (70L04011) from Pearson Library
Materials for the lab group of 2 students:
1 preserved Ascaris
gloves
Ascaris female, x.s.
biology photo atlas
blunt probe
dissecting pins
scissors
Compound microscope
dissecting pan
blunt probe
Procedure
1. Obtain a preserved female Ascaris. Notice the external characteristics.
2. Carefully slit the body wall from one end to the other using scissors. Use the dissecting
pins to pin out the body wall and expose the internal organs.
3. Use a probe to separate the parts of the female reproductive organs. Use Figure 13.2 and
the photo atlas to help locate the structures.
4. Examine a prepared slide of Ascaris and locate the same structures of Figure 13.2.
Segmented Worms (Phylum Annelida)
The major characteristic that distinguishes these worms from others is their segmented body. It
is formed out of repeating units called somites. Earthworms, sandworms or polychaetes, and
leeches represent the three major classes of segmented worms. The specimen you will be
dissecting today is an earthworm that lives in moist soil. Earthworms eat any dead or living
organic matter that is in the soil.
Materials for the lab group of 2 students:
preserved earthworm
dissecting pins
scalpel
gloves
blunt probe
dissecting microscope
dissecting pan
photo atlas
Procedure
External Examination
1. Make observations of the external anatomy of your worm.
2. The first observation you should see is the segmented body, which is characteristic of all
annelids. Refer to Figure 13.3 to see the location of each external feature. Starting at the
anterior end of the worm is the prostomium, which is a small projection over the mouth.
Moving down the worm’s body, you will next notice the clitellum.
It appears as a
smooth band around the worm. It secretes mucus that later becomes the cocoon for the
fertile eggs. Earthworms are hermaphroditic and exchange sperm during copulation.
3. Using the blade of the scalpel gently scrape the thin layer of epidermis. This layer is
called the cuticle and functions for protection.
Figure 13.4
(Earthworm Anatomy) (Ms. Deb O’Connell stated Pearson can supply this
illustration).
Figur 13.4 (74L.12001) and (74L16001)
Internal Examination
The internal structure of the earthworm is shown in Figure 13.4. The characteristic segmentation
of annelids is also carried out internally. Notice the septa that separate the segments. On the
ventral side, you will also notice four pairs of setae on each body segment. At the anterior end
you will first see paired cerebral ganglia that form a simple “brain” that is dorsal to the pharynx.
It is connected to the ventral nerve cord, which runs the length of the body. Seminal vesicles
contain sperm that are formed by two pairs of testes. Seminal receptacles release the sperm to
fertilize eggs that are created by a pair of ovaries and released via oviducts. The digestive tract
is separated into specialized segments. The muscular pharynx aids in the ingestion of food,
which passes through the esophagus to the crop and then leads to the gizzard. The gizzard
grinds the food into smaller pieces before it moves on to the intestines. In the intestines,
nutrients are absorbed into the blood and carried to all parts of the body. Annelids have a closed
circulatory system, meaning that their blood is contained in blood vessels. The nephridia are
excretory structures that filter fluid, collect, and concentrate waste to be excreted.
4. Differentiate between the ventral and dorsal sides. Place the earthworm dorsal side up.
The dorsal side is usually darker in color. Gently make an incision starting mid way up
the worm and work up towards the prostomium. Be careful to cut through only the body
wall and not the underlying organs.
5. Using your pins, you can spread the body wall apart and pin the worm to the pan.
6. Locate the structures shown in Figure 13.4. The dissecting microscope can aid you in
viewing smaller structures.
7. Remove the crop, gizzard, and part of the intestine to expose the underlying nerve cord.
Cut open the crop and gizzard to compare their wall structure related to their function.
8. Dispose of your earthworm in the appropriate container. Disinfect your area.
Phylum Echinodermata: Sea Star Dissection
Phylum Echinodermata includes thousands of species, all of which are adapted to a marine life.
Examples of echinoderms are sea stars, sea urchins, sand dollars, and sea cucumbers. Animals
of this phylum possess distinctive characteristics which include: a calcified internal skeleton
(endoskeleton), a water vascular system that helps to circulate nutrients and remove waste, tube-
feet that provide locomotion and adherence for feeding, collagen containing ligaments, some
sensory neurons (no brain or cephalization). Most adults possess radial symmetry (body parts
arranged in fives around a oral axis) following the metamorphosis from a bilateral larval stage.
Many researchers study Echinoderms because they play an important role in marine ecology,
possess an extensive fossil record, exhibit embryonic development similar to our own, and are
able to regenerate lost limbs and body parts, this characteristic may be useful in biomedical
research. For some commercial fishing industries, starfish or sea stars are viewed as pests,
because they consume clams and oysters in commercial beds. Sea stars can live up to thirty five
years. In addition to the spiny calcified skin which provides many functions including protection,
sea stars possess colors that help to either camouflage it or scare off its predators.
Materials for the lab group of 2 students:
preserved sea star specimen
dissecting pan
scissors
forceps
blunt probe
dissecting pins
scalpel
goggles
disposable gloves
Procedure: Before you begin, be sure to obtain a sea star dissection guide.
1) Put on the gloves, then place a sea star in dissecting pan with the spiny surface face up
(aboral surface) and observe the madreporite located between two of the five arms or
rays of the adult (pentaradial symmetry). The madreporite helps to regulate the seawater
as it enters the water vascular system. Under the dissecting microscope you can closely
view the madreporite and the skin (dermis) that perform important functions such as
protection and respiration, the dermis contains numerous spines surrounded by pincer like
structures called pedicellariae that remove debris, to protect the animal and to sometimes
utilize nutrients on its surface.
Gas exchange occurs on out-pockets of the body wall
called (papullae or dermal gills). In order to maximize gas exchange these structures
are ciliated.
Please Insert Sea Star Illustrations from Pearson Library: 82L.20051 and
82L.20061
2) Turn the sea star over to examine the tube-feet and oral surface. The mouth can be
found in the center. When a sea star is hungry it will seek out a clam or mollusk, wrap
its limbs around it, pull open the shell, protrude its stomach inside out through the mouth,
then release enzymes to digest the yummy body of the clam or mussel. When able to do
so, the stomach retracts back into the body along with the semi-digested mollusk to
complete digestion. View the ambulacral groove flanked by numerous tube-feet. The
vascular system supplies water and hydraulic pressure to operate the tube-feet which in
turn provides movement, temporary attachment, hold prey while feeding, and are highly
sensitive to touch. At the tip of each limb there is an eye spot that does not see images
but is sensitive to light.
3) Return the sea star to the dissection surface aboral side facing up. Using scissors cut the
tips of three arms. Starting with this incision cut up the sides of the three arms without
disturbing the center of the animal and Madreporite. Using forceps peel back the thick
top layer and observe the endoskeleton of calcified plates called ossicles embedded
within the dermal surface. Under the dermis a yellowish spongy mass or pyloric cecum
is revealed. The cecum helps to store some food and produces enzymes needed to digest
food. Carefully remove the top layer of the center region (disc) of the organism. With a
probe follow the pyloric cecum along the pyloric duct to the center to locate an
enlargement which is the double chambered stomach. The cardiac chamber is attached
to the mouth (oral surface) and is located below the pyloric stomach. The intestine is
connected to the stomach, where nutrients are absorbed and waste is formed.
Waste
exits by a rectal gland tube to the anus, located on the aboral surface.
4) Using forceps remove the pyloric cecum of the second arm to expose round structures
that are found below and that extend about a quarter of the way down the arm. These
round structures are gonads where gametes are formed for reproduction. Gametes either
female or male are released for external fertilization.
5) Using the third arm (the starfish’s!), remove both the pyloric cecum as well as the gonads
to expose part of the vascular system.
Transport of nutrients in Echinoderms is
accomplished by fluids that circulate within canals of the perivascular coelom, water
vascular system, and hemal system. Fluids are moved through these systems largely by
cilia and sometimes by muscle pumping.
Phagocytic amoeboid cells called
coelomocytes travel within the vascular systems. Observe the canals in the middle of
each ray including the radial canal a part of the water vascular system that extends the
length of the arm and is surrounded by tiny sac like structures called ampullae. Water
entering the madreporite flows into the radial canal and into the small sac-like ampullae.
When squeezed by muscles the ampullae provide water pressure to operate the tube-feet.
Using a probe, trace the ampullae from the radial canal back to the center where the ring
canal is located; note how it connects with the radial canals of each limb. See if you can
trace the ring canal to the Stone canal which connects to the Madreporite. Retractor
muscles and skeletal plates are adjacent to the radial canal. Before discarding your
dissection, be sure to show your lab instructor your dissected sea star.
Laboratory 13 Part B: Vertebrate
Dissection (Day Two)
Phylum Chordata
Animals located within the Phylum Chordata include mostly vertebrate organisms and a few
invertebrates. Examples of vertebrates include fish, reptiles, mammals, and amphibians. The
invertebrate chordates include tunicates, lancelets, and hagfish. Among all of these animals, there
are four key characteristics that can be observed at some point of their embryonic development.
The four key characteristics include:
1. Dorsal, tubular nerve cord.
2. Pharyngeal gill slits.
3. Notochord.
4. Post-anal tail.
Class Amphibia (The Frog)
The frog dissection illustrates to students the organization of the vertebrate body and how it
functions. The frog is an amphibian (lives on land and in the water) that begins life as an aquatic
tadpole and eventually develops into a terrestrial adult frog (Figure 13. 5). Frogs are ancient
organisms that have been around millions of years. They are carnivores that hunt for food on
both land and water. While studying their external anatomy, one can notice that frogs have
webbed feet, which serves them well when swimming in ponds and lakes. They have saltation
locomotion that allows them to roam on land and escape predators. Frogs are ectotherms (i.e.
cold-blooded), which means the environment dictates their internal temperature. There are many
species of frogs that have unique attributes, including some that inhabit trees and others that
contain poisons to deter predators.
Eggs
Adult
frog
Tadpole
Developing
Tadpole
Figure 13.5 A typical frog lifecycle. Courtesy of Vincent E. Piscitelli, MHS, M(ASCP)CM
During this dissection, you will be examining various organ systems and physical attributes of
the frog while studying both external and internal anatomy.
You will begin by making
observations of the external anatomy of the frog, then start dissection and study the various
organs systems. While conducting this dissection, try to identify the various organs and their
associated structures that are presented in the following illustrations. Also, ponder why each
organ system is organized and constructed the way it is, and why this may have occurred via
evolution.
External Anatomy
When observing the frog, you will notice a slimy skin that covers the entire organism. This skin
functions in respiration, camouflage, and protection. Through evolution, different frog species
have adapted different skin-characteristics. The body of the frog is divided into two parts, the
head (anterior) and trunk (posterior). The head of the frog contains the eyes, mouth, external
nares, and tympanic membrane. The eyes contain a nictitating membrane, which acts as a third
eyelid which aides to protect the vision of the frog on land. The external nares (nostrils) are
located toward the tip of the head. Just behind the eyes, there is a medium sized circular
structure known as the tympanic membrane. The tympanic membrane allows the frog to hear
sounds. As you move down the body of the frog, you will notice short forelimbs and longer,
more muscular hind limbs. The hind limbs contain webbed feet, which allow the frog to swim
in water. While observing the frog’s external anatomy, please see Figure 13.6.
88L02001
(via Pearson Photo
library)
Figure 13.6 External anatomy of the frog.
Internal Anatomy:
Mouth
Toward the upper most region of the frog’s mouth, you will notice two tiny circular holes located
on each side of the mouth known as internal nares (figure 13.7). Between the internal nares are
two pit-like indentations known as vomerine teeth. Vomerine teeth allow the frog to hold on to
the prey for consumption. Surrounding the edge of the mouth are maxillary teeth. The
esophagus is located in the center of the mouth. Just above the esophagus, on either side, you
will notice two holes, which are the openings of the eustachian tubes. The Eustachian tubes
equalize the pressure between the external environment and the frog’s ears. Just below the
esophagus, is a vertical slit known as the glottis (airway). In male frogs, when observing both
sides of the lower mouth, you will notice two holes known as the openings to vocal sacs. Lastly,
the tongue is a massive structure that tends to be long. The tongue allows the frog to catch prey
for consumption.
88L04031
(via Pearson
Photo Library)
Figure 13.7 The frog mouth.
Muscular System
The muscle system of the frog is quite extensive and consists of many different parts (see figure
13.8). You will notice immediately that the hind legs are very large and muscular, allowing the
frog to hop to catch prey and escape danger. The hind legs help the frog move both in water and
on land. In order to properly examine the frog’s muscular system, the frog must be skinned very
carefully to avoid gouging the specimen. Once the skin is removed, position the frog so the
dorsal side is facing toward you. Toward the middle of the frog you will notice the latissimus
dorsi and longissimus dorsi muscles. As you move down the length of the frog, you can see the
external oblique muscles, located on both sides of the frog. Toward the upper portion of the
frog’s hind legs (the thigh region), you will notice a large triceps femoris muscle. As you head
toward the posterior portion of the hind leg, you will see the gastrocnemius muscle (calf
region).
Now, please flip the frog over to reveal the ventral muscular anatomy. The muscle covering the
frog’s throat is known as the mylohyoid. As you observe the frog’s chest region, you will see the
deltoid muscles. Directly below are the pectoralis major muscles. The cutaneous pectoris
muscles are located toward the center of the frog’s body in the pectoral region. On both sides of
the frog, you will notice the external oblique muscles. The rectus abdominus muscle is located
in the lower region of the frog’s body, in the abdominal region. When observing the hind legs of
the frog, locate the following muscles, abductor magnus (thigh region), gracilis major (inner
portion), and gracilis minor (outer portion) muscles. When the entire muscular system has been
observed, you may continue on to examine the internal anatomy of the frog.
88L50001
88L52001
(via Pearson
Photo Library)
(via Pearson
Photo Library)
Figure 13. 8 The frog muscular system. From left to right, dorsal muscular anatomy;
ventral muscular anatomy
Digestive System
When opening the ventral side of the frog, you will notice a large dark mass that contains three
lobes. This is known as the liver. The liver acts as a filter for the blood; it also secretes bile for
digestion. Behind the liver, you will notice a smaller greenish circular mass known as the
gallbladder. The gallbladder acts as a storage unit for the bile that was secreted by the liver. Bile
aids in digestion of fats. Coming off the side of the liver is the stomach. The stomach is shaped
as a half-circle and functions in digestion. The stomach is connected to the mouth via the
esophagus. When a frog eats an insect, the food travels from the mouth, through the esophagus,
into the stomach. The food is then passed through the small intestine, where the food is then
completely digested and the nutrients are absorbed. The small intestine is held in place by a
transparent connective tissue known as the mesentery. Within the mesentery, you will notice a
thin structure located between the stomach and upper portion of the small intestine. This is
known as the pancreas, which secretes digestive enzymes into the small intestine. The
undigested food is then passed through the large intestine, which is then defecated out via the
anus. Just above the small intestine, you will notice a circular mass known as the spleen. The
spleen acts as a filter that removes damaged red blood cells from circulation. Along both sides
of the abdomen you will notice yellow finger-like projections, these are fat bodies (figure 13.9).
88L10011
(via Pearson
Photo
Library)
Figure 13.9 The frog digestive system
Respiratory System
Once the chest cavity of the frog is pinned open, you will notice two blackish structures on both
sides of the frog known as lungs (Figure 13.10). The lungs provide the frog with oxygen for
survival. Looking just above the lungs, you will notice a “forked” structure known as the
bronchi (use the blunt probe to observe the bronchi). The bronchi are connected to the larynx,
which connects to the glottis.
88L04041
(via Pearson
Photo Library)
Figure 13.10 The frog respiratory system.
Circulatory System
Toward the center of the frog, just under the throat, you should be able to observe the heart.
Surrounding the heart is a clear membrane known as the pericardium. The heart consists of
three-chambers, the left atrium, right atrium, and ventricle (see Figure 13.11). The left atrium
receives oxygenated blood returning from the lungs via pulmonary veins. The right atrium
receives deoxygenated blood returning from the rest of the frog’s body via the sinus venosus.
The two anterior venae cavae and one posterior vena cava receives the blood supply and a
mixing of the deoxygenated and oxygenated blood occurs as soon as the blood travels into the
ventricle. The job of the ventricle is to pump blood to both lungs and the entire body at the same
time. Blood passes through the ventricle and exits into the conus arteriosus, which divides into
right and left branches (truncus arteriosus) that branch out into other arteries.
The arteries provide a blood supply to all of the frog’s body. Branching upward, from the left
and right truncus arteriosus, are the carotid arch and internal and external carotid arteries that
provide a blood supply to the frog’s head. Branching down is the pulmocutaneous arch, which
connects to the pulmonary arties that provides blood to the lungs and the cutaneous artery,
which provides blood to the skin. The aortic arch is attached to the truncus arteriosus and
expands down the frog’s body, giving rise to the dorsal aorta. The subclavian artery provides
blood to the upper appendages of the frog (forelegs). The celiacomesenteric artery branches out
and provides blood supply to the spleen, pancreas, stomach, and small intestine. Branching off
the dorsal aorta is the urogenital artery that supplies blood flow to the kidney and the frog’s
gonads. Further down the dorsal aorta is a branching artery known as the posterior mesenteric
artery that provides a blood supply to the large intestine. The dorsal aorta eventually “forks”
producing a common iliac artery that branches further into the femoral and sciatic arteries.
These arteries provide blood to the frog’s muscular hind legs.
Returning blood travels via the veins. Located on the heart’s dorsal surface is the sinus venosus.
The sinus venosus forks upwards into the anterior vena cava and downwards into the posterior
vena cava. Coming off the anterior vena cava is the brachiocephalic vein that returns blood
from the shoulders and deeper sections of the head. Another branch that comes off the anterior
vena cava is the external jugular vein that returns blood from the superficial sections of the
head. The pulmonary veins return oxygenated blood from the lungs to the left atrium. The
posterior vena cava is located just below the sinus venosus and returns blood from the two
hepatic veins, which are connected to the liver. As you go down, you will see a hepatic portal
vein that carries blood from the digestive tract to the liver, which then exits via the hepatic veins.
Moving toward the frog’s hind legs, you will notice the femoral and sciatic veins. These veins
carry blood from the frog’s hind legs, to the renal portal veins, which in return send the blood to
the frog’s kidneys. The kidneys are then connected to the renal veins. Blood also flows from the
ventral abdominal veins and travels up into each of the liver lobes (note there are three liver
lobes).
The frog
circulatory system
(Ms. Deb O’Connell stated
Pearson can supply this
illustration).
Figure 13.11 The frog circulatory system
Urogenital System
Just above the hind legs, toward the center of the frog’s body are two reddish structures known
as kidneys (see figure 13.12). Toward the center of the kidneys, you will notice a crescentshaped structure known as the adrenal body. Right above the kidneys you will see stringy,
finger-like projections known as fat bodies (provide nutrition during hibernation). Attached to
the kidneys are renal veins that send blood to the posterior vena cava. Connecting to the frog’s
gonads is a slender gonadal vein. If the frog is a male, it connects to the testis. If the frog is a
female, it connects to the ovary. Below the kidneys is an attached tube structure known as the
ureter. The ureter receives urine from the kidneys and sends it to the cloaca. Attached to the
cloaca is the urinary bladder.
88L12001 (via
Pearson
Photo
Library)
Figure 13.12 The frog urogenital system
Materials for the lab group of 2 students:
frog specimen
dissecting pan
probe
dissecting pins
scissors
scalpel (with new blade)
gloves
goggles
Procedures
1. Place the frog on a dissection tray on its ventral surface. Using the information above, observe
the frog’s external anatomy.
2. Flip the frog over and observe the frog’s external anatomy of the frog’s ventral surface.
3. Cut the hinges of the frog’s mouth (on the left and right sides) using the scissors. Keep the
frog’s mouth open using the dissection pins. Using the information above, observe the frog’s
mouth.
4. Proceed to carefully skin the frog, revealing the muscular system. The scalpel can be used to
make small incisions in the skin and then the skin can be peeled back while cutting along with
the scissors. Observe the frog’s muscular system.
5. With the frog positioned on its dorsal surface, use the scalpel to make a vertical incision from
just under the frog’s jaw to the frog’s cloaca-region. Be careful to not cut too deep and damage
the internal organ systems. Open the incision and makes cuts accordingly to form “door-like”
flaps. Pin these flaps to the dissection pan.
6. Using the information above, observe the internal anatomy of the frog.
7. When your observations are complete, return all instruments to their designated areas, dispose
of the frog in the correct container, and clean/sanitize your laboratory bench.
*Goggles are required in order to prevent preservative from splashing into your face.
**It is useful to use the blunt probe to aid in observation of arteries, veins, and many other small
internal structures.
***Ensure your scalpel blade is new. A new blade provides a cleaner cut.
Post-Lab 13 Assessment: Kingdom Animalia
Name:
Section:
After completing the laboratory assignment, please re-read the lab in its entirety and
answer the following questions to the best of your ability.
1. Where does the adult Ascaris live in the host?
2. What is the function of the cuticle?
3. What are possible ways to prevent human infection with Ascaris?
4. What is the primary characteristic of annelids?
5. Which structure matches the description? (Use your text for assistance.)
a. membranes that divide segments internally
____________________
b. secretes the egg case
____________________
c. grinds food into small pieces
____________________
d. transports nutrients to body cells
____________________
e. receives sperm during copulation
____________________
6. Following your examination of the crop and gizzard, which had a thicker wall? How does
this observation relate to their function in the earthworm?
7. Explain the function of the three-chambered heart.
8. What is the difference in function between arteries and veins?
9. How does a frog survive during hibernation?
10. List some unique observations you noticed when dissecting the frog.
11. What is the purpose of the frog’s nictitating membrane?
12. When comparing the dissected sea star and frog, what did you find that was similar?
What did you find that was different?(try to use scientific terminology in your answer)
13. How is the Sea star vascular system different from that of the Human?
14. Why does the aboral surface of the starfish look clean when compared with dermal surfaces
of other marine organisms?
15. What characteristics of the Starfish cause it to be a threat to commercial mollusk farmers?
16. When comparing the dissections of the Sea star and frog, what did you find that was similar?
What did you find that was different?(try to use scientific terminology in your answer)
References
Brusca, R.C. & Brusca G.J. (2003). Invertebrates. (2nd ed.). Sinauer Associates, Inc.,
Sunderland, MA
Gunstream, S. (2012). Explorations in Basic Biology. (12th Ed.).San Francisco, CA: Pearson
Education
Merriam-Webster Visual Dictionary online. Web. Accessed 11-10-2013.
http://visual.merriam-webster.com/index.ph
National Geographic Society online, Sea Star, Web. Accessed 11-12-2013
http://animals.nationalgeographic.com/amimals/invertebrates/starfish
Rydene, H. (2010). Introduction to Biology Lab Procedures (and other important information).
(5th ed) . New York, NY: Freeman Custom Publishing
Simon, E., Dickey, J., & Reece, J. (2013). Campbell Essential Biology with Physiology. (4th
Ed.). Pearson Education.
Wray, Gregory A. 1999. Echinodermata .Spiny-skinned animals: sea urchins, starfish, and their
allies. Version 14 December 1999 (under construction).
http://tolweb.org/Echinodermata/2497/1999.12.14 in The Tree of Life Web Project.
*Sea Star Dissection update by L. M. Breuninger-Tenney 11-12-2013