“I like some animals more than some people, some people more than some animals” – Jane Goodall
OBJECTIVE
S
1. Provide examples and
descriptions of animals
from several different
phyla.
2. Understand taxonomy
and hierarchal
classification.
3. Use a dichotomous
key.
4. Dissect a frog and
identify external and
internal structures.
5. Dissect a perch and
identify external and
internal structures.
Kingdom Animalia
Kingdom Animalia consists of multicellular eukaryotes that are heterotrophs (must
ingest other organisms to maintain life). Below you will find a brief description of
some of the most known phyla, subphyla and classes found in Kingdom Animalia.
Phylum Porifera – Phylum Porifera includes approximately 10,000 species of sponges
that vary in size from a few millimeters to 2 meters across. Sponges have bodies
that are organized around a system of water canals and chambers.
Phylum Cnidaria – Phylum Cnidaria includes nearly 10,000 species of mainly marine
invertebrates including sea anemones, jellyfish, Portuguese man-of-war, coral and
freshwater Hydras. Cnidarians exhibit radial symmetry and are diploblastic (having
only 2 germs layers during development).
Phylum Platyhelminthes – A flattened, ribbon-like body is a common characteristic
of members of phylum Platyhelminthes. Planarians, liver flukes and tapeworms are
all member of this phylum that lack specialized respiratory and circulatory systems.
Phylum Nematoda – Phylum Nematoda consists of round worms. Common
examples of Phylum Nematoda are ascaris, hookworms, pinworms, Guinea worms,
eye worms, heartworms and whipworms. Member of this phylum range from
microscopic to 30cm in length. Their bodies are generally cylindrical and tapered on
both ends.
Phylum Arthropoda – Common examples of Phylum Arthropoda are butterflies, fleas, lobsters, spiders, ticks
and barnacles. More than 1,000,000 species have been identified and this number continues to grow.
Arthropods are distinguished by their chitinous exoskeleton that provides support and protection to the
arthropods.
Phylum Mollusca – Phylum Mollusca exhibits great diversity, but they share a body plan that is bilaterally
symmetrical. Members of phylum Mollusca include cuttlefish, octopi, snails, clams, mussels, scallops and
squid.
Phylum Echinodermata – Echinoderms, members of Phylum Enchinodermata, have five-pointed
(pentamerous) symmetry. Some examples include sea lilies, starfish, brittle stars, sea urchins, sand dollars
and sea cucumbers.
Phylum Chordata – fundamental characteristics of chordates area notochord, dorsal nerve cord, pharyngeal
pouches and a postanal tail.
Subphylum Urochordata – This subphylum is composed of nearly 3,000 species of marine tunicates
(sea squirts), salps and larvaceans.
Subphylum Cephalochordata – Members of this subphylum are often referred to as sea lancelets
because of their slender bodies.
Subphylum Vertebrata (Craniata) - This subphylum is made up of more than 55,000 species that follow
the general body plan of chordates. In the majority of vertebrates, the vertebral column surrounds or
replaces the notochord.
Superclass Agnatha – This superclass consists of about 70 species of jawless fish that lack scales,
internal ossification and paired fins while possessing eel-like bodies. Hagfish and lampreys are
members of Superclass Agnatha.
Class Chondrichthyes – Member of this class are cartilaginous fishes that include sharks, rays,
skates and sawfish. The entire skeleton of members of Class Chrondrichthyes is made of
cartilage. This class was the first set of vertebrates to have jaws and paired appendages. Their
jaws, paired appendages, more efficient respiration and better nervous system allowed them to
attack and eat larger prey.
Class Osteichthyes – Class Osteichthyes includes nearly 27,000 species of bony fish and is the
largest group of all vertebrates. Their gills are covered by a bony operculum, they have flat and
bony scales and most have a swim bladder that acts as a floatation device.
Class Amphibian – Class Amphibian includes nearly 6,000 species including frogs, toads,
salamanders and newts. Amphibians evolved from fish and developed a protective integument
(skin) that allows them to breathe on land. They still, however, require water for their
reproduction.
INSERT FIGURE 30.1 (Pg. 602) from Pendarvis HERE
Class Reptilia – Approximately 7,500 species of reptiles make up Class Reptilia and they are the
oldest group of vertebrates living exclusively on land. Common examples includes turtles,
lizards, snakes and crocodiles. These animals are ectothermic and therefore rely on the
environment for their temperature regulation. Additionally, they produce amniotic eggs.
Class Aves – Birds (Class Aves) evolved from the dinosaur lineage and consists of nearly 9,700
species. Their most distinguishing characteristic is the presence of feathers. They are
endothermic with a four chambered heart and have hollow bones.
Class Mammalia – Class Mammalia consists of approximately 5,000 species that live in marine,
freshwater, aerial and terrestrial habitats. Humans are a member of Class Mammalia. One of
the most obvious characteristics of mammals is the presence of hair and mammary glands.
Additionally, mammals have specialized teeth and in-folding of the brain that generally make
the brain larger in mammals than in any other group of animals.
Anatomical and Morphological Terms
Animals come in an enormous variety of shapes and sizes and have varying degrees of complexity and
similarity. Below is a list of terms used to describe animals:
Appendages: These are extensions from the animal’s body. The purposes are for movement, feeding,
or other purposes. Examples include legs and arms.
Asymmetric: Irregular organization, not the same on any side.
Bilateral symmetry: The body parts are arranged so that they are a mirror image on the left and right
sides. Humans are bilaterally symmetrical.
Radial symmetry: The animal looks the same from all sides. The body is arranged like a circle around a
central axis. Examples include sea stars and jellies.
Exoskeleton: The animal has a hard, external skeleton that protects it and provides points of
attachment for muscles. Animals with exoskeletons do not have internal bones. Examples include
shrimp and crabs.
Endoskeleton: The animal has a hard skeleton composed of cartilage and/or bone within the soft
tissues. Cats and fish have internal skeletons.
Hydrostatic skeleton: The animal is supported by a fluid filled coelom (inner cavity). Sea urchins,
earthworms, and jellies have hydrostatic skeletons.
Segmentation: The animal body is subdivided into a series of repeated parts called segments. An
earthworm is segmented because it is divided into many compartments. An example of internal
segmentation is the vertebral column (backbone).
Microscopic: Animals too small to be seen without a microscope.
Macroscopic: Animals large enough to be seen without a microscope.
Larva: Distinctive juvenile form.
Pores: Small openings for passage of water. The porifera (sponges) contain many incurrent (waterentering) pores and one main excurrent (water exiting) pore.
Procedure 1 – Observing and understanding animal morphology
Observe the different animal groups on the display table. As you observe them, note their distinctions and
sketch them. These can be done in any order.
List two animals with radial symmetry
Common Name
Scientific name
1.
2.
Sketch one of these animals.
Common name_____________________________________________
Phylum
List two animals with bilateral symmetry
Common Name
Scientific name
Phylum
1.
2.
Sketch one of these animals.
Common name_____________________________________________
List two adult animals or larva that are microscopic
Common Name
Scientific name
1.
2.
Sketch one of these animals.
Common name_____________________________________________
Phylum
List two animals that are segmented
Common Name
Scientific name
Phylum
1.
2.
Sketch one of these animals.
Common name_____________________________________________
List two animals with an endoskeleton
Common Name
Scientific name
1.
2.
Sketch one of these animals.
Common name_____________________________________________
Phylum
List two animals with a hydrostatic skeleton
Common Name
Scientific name
Phylum
1.
2.
Sketch one of these animals.
Common name_____________________________________________
Check Your Understanding
How many appendages are on an alligator? ______________________________________________________________
Why is a human considered “segmented”? _______________________________________________________________
__________________________________________________________________________________________________
What are the differences between an endoskeleton, an exoskeleton, and a hydrostatic skeleton?
__________________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Procedure 2 – Animal Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Taxonomy is the classification of organisms based on shared characteristics. Organisms can be
classified using different systems. Classical taxonomy groups organisms primarily based on
morphology. During the mid-1800s Carolus Linnaeus developed a scheme where he assigned
each organism a two part scientific name, genus and species. All organisms are divided into a
taxonomic hierarchy. As you go down the hierarchy, the members are increasingly similar to
one another.
Phylogenetic systematics is the classification of organisms based on DNA sequence information.
Increasingly, taxonomists are regrouping organisms based on DNA.
One way to identify organisms is by using a dichotomous key, formatted as a series of paired
choices. For each choice, only one will describe the specimen. Each selection will direct the
user to find a reference to the next set of choices. The choices will guide the user to identify the
organism.
KEY TO ANIMAL PHYLA
Characteristics
1. Radially symmetric or asymmetric adult
1b. Bilaterally symmetric
Next Step
2
4
2. Body contains pores
2b. Body does NOT have pores
Porifera
4
3. Radial symmetry, with soft body and stinging cells
3b. Radial symmetry in adult, but bilateral symmetry in larva;
Adults have tube feet, body plan usually pentamerous (5 parted)
4. Body unsegmented
4b. Body segmented
5. Body thin & flat; usually parasitic or aquatic; mouth & anus
are a single opening
5b. Body not flat
Phylum
Cnidaria
Enchinodermata
5
7
Platyhelminthes
6
6. Body is pencil or spindle-shaped
6b. Body is soft; most have shells over body and move with a large
muscular “foot”; others have tentacles modified from the ancestral
foot
Nematoda
Mollusca
7. Body is worm-like in adult without a distinct head, but with a separate
mouth and anus; paired appendages which are NOT jointed
7b. Body is NOT worm-like & has a distinct head
8
Annelida
8. Skeleton is external (exoskeleton); 1 or 2 pairs of jointed
appendages per body segment
8b. Skeleton is internal (endoskeleton); only 2 pars of jointed appendages
Arthropoda
Chordata
Procedure 3 – Classification of Unknowns
Classify the unknown animal specimens provided into their correct phylum by using the dichotomous key
given on the previous page.
Number
A
1
2
3
4
5
6
7
8
9
10
Steps
1b, 4b, 7b, 8
Description
5 pairs of jointed appendages,
pinchers, exoskeleton
Phylum
Arthropoda
Common
Name
Crab
Procedure 4 – Frog Dissection
1. Follow all of your instructor’s directions carefully.
2. Obtain a set of protective goggles and gloves.
3. Put your gloves and googles on properly. Goggles should NEVER be worn on your forehead or around
your neck. They aren’t protecting your eyes unless you look a little goofy…better to look goofy than
never be able to see yourself again.
4. Obtain a doubly injected bullfrog and place it in a dissecting tray.
5. Locate the dorsal and ventral external anatomical features shown in the figure below.
6. Using a probe, carefully pry open the mouth and observe the structures shown in the figure below.
INSERT FIGURE 30.42 External anatomy of a bullfrog Pg. 639 Pendarvis
7. Using sharp scissors, cut through the skin and muscle with a shallow incision where the legs meet the
body. Lift the tissue as much as possible to avoid damaging the organs underneath.
8. Continue this incision up to the jaw. It is easiest to cut a couple of millimeters to the left or right of the
midline (also known as linea alba). You will have to carefully cut through the pectoral girdle.
9. Make 2 sets of lateral cuts through the body wall to each side; one set is immediately behind the
pectoral girdle and the other at the other end of the trunk incision.
10. Fold and pin down the muscles flaps you have created.
11. Identify the internal organs and sex of the bullfrog using the figures on the next page.
12. Be sure to observe a frog of the opposite sex from another lab group.
13. Discard of the bullfrog in the labeled bucket as indicated by your instructor.
14. Thoroughly clean all instruments, your dissecting tray and your lab bench.
15. Return all equipment (including goggles) to the proper locations.
INSERT FIGURE 30.47, 30.48, 30.49 Pg. 641 and 642 Pendarvis
Procedure 5 – Perch Dissection
1. Follow all of your instructor’s directions carefully.
2. Obtain a set of protective goggles and gloves.
3. Put gloves and googles on properly. Goggles should NEVER be worn on your forehead or around your
neck. They aren’t protecting your eyes unless you look a little goofy…better to look goofy than never
be able to see yourself again.
4. Obtain a perch from your instructor.
5. Identify the external anatomical structures shown in the figure and listed below.
1. Spiny dorsal fin
8. Pelvic fin
2. Eye
9. Lateral line
3. External nares
10. Soft dorsal fine
4. Upper jaw (maxilla)
11. Caudal fin
5. Lower jaw (mandible)
12. Anal fin
6. Operculum
13. Anus
7. Pectoral fin
INSERT FIGURE External Anatomy of a perch with callouts
6. Use a probe to lift the operculum and observe the gills.
7. Locate the anus (in front of the anal fin). A male perch has only one pore (urogenital pore) behind the
anus. A female has a genital pore and a urinary pore behind the anus. Determine the sex of your fish.
Be sure to look for the opposite sex perch at another lab bench.
8. Use dissecting pins to secure the fish to the dissecting tray.
9. Use scissors to make the cuts shown in the figure from Carolina Biological Supply
10. Using the figure below, identify the viscera of the perch.
INSERT FIGURE Anatomy of a female perch AND viscera of a perch with callouts
11. Discard of the perch in the labeled bucket as indicated by your instructor.
12. Thoroughly clean all instruments, your dissecting tray and your lab bench.
13. Return all equipment (including goggles) to the proper locations.
Animal Diversity Review
1. Label the internal organs in this ventral view of the bullfrog
1. _____________________________ INSERT FIGURE Ventral view of frog viscera with callouts
2. _____________________________
3. _____________________________
4. _____________________________
5. _____________________________
6. _____________________________
7. _____________________________
8. _____________________________
9. _____________________________
10. _____________________________
11. _____________________________
12. _____________________________
2. Label the internal organs in the perch
1. _____________________________ INSERT FIGURE Viscera of a perch with callouts
2. _____________________________
3. _____________________________
4. _____________________________
5. _____________________________
6. _____________________________
7. _____________________________
8. _____________________________
9. _____________________________
10. _____________________________
11. _____________________________
12. _____________________________
3. Who created the binomial system for naming organism in the 18 th century? ______________________
____________________________________________________________________________________
4. Why are scientific names important in biology? _____________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
5. List the 7 levels of the taxonomic hierarchy from largest to smallest.
1. _____________________________
2. _____________________________
3. _____________________________
4. _____________________________
5. _____________________________
6. _____________________________
7. _____________________________
6. Complete the following chart:
Phylum
Porifera
Cnidaria
Enchinodermata
Platyhelminthes
Nematoda
Mollusca
Annelida
Arthropoda
Chordata
Characteristics
List 1 animal found in this
phylum