The Diversity of Animals
Objectives
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Know the difference between
invertebrate and vertebrate animals
Show animals are classified
taxonomically using Kingdom, Phylum,
and Class levels
Describe 3-4 unique features of Sponges,
Cnidarians, Worms, Molluscs,
Arthropods, Echinoderms, Fish,
Amphibians, Reptiles, and Mammals
Specifically name at least one animal
that belongs in each of the major groups
What is an Animal?
An animal is a member of Kingdom
Animalia. Members of this kingdom are all
eukaryotic and multicellular, being made
of many cells having nuclei. They lack cell
walls, having only a plasma membrane.
Finally, they are all heterotrophic, meaning
that they get their energy by eating other
organisms (alive or dead). These four
features distinguish animals from the
monerans, protists, plants and fungi.
Most animals have distinct tissue and
organs that have different functions in
keeping the animal alive. The organs often
include a brain for coordination, a heart for
circulating nutrients and gases, lungs or
gills for gas exchange, a stomach and gut
(intestine) for digestion, and kidneys for
cleaning the blood and producing urine.
Nearly all animals perform sexual
reproduction by making and releasing eggs
and sperm. Some animals can also
reproduce asexually, which they do during
times when the environment is stable and
food is plentiful. The development of an
animal after fertilization (the meeting of egg
and sperm) is also distinctive. Animals
develop through a series of embryonic
stages called the blastula and the gastrula.
After the gastrula stage, many animals
develop into adults, while others move
through a series of larval stages, like insects
(think of a caterpillar larva as opposed to its
adult form, the butterfly).
Although you are probably most
familiar with animals with backbones
(vertebrates), most of the 2 million
members of Kingdom Animalia (97%) are
invertebrates. Of all the animals, the insects
(Phylum Arthropoda) are the most diverse,
having thousands of different species.
Animals are thought to have evolved
from unicellular protists that starting living
together in groups or colonies. Then, simple
animals like placoderms and sponges
evolved from them. As you look through
the different groups of animals today, keep
in mind that biologists try to order the
animals in a sequence according to their
development in evolutionary time. The
more complex the animal, the more recently
this animal is thought to have evolved.
The animal groups we will look at today are:
INVERTEBRATES
 Sponges (Phylum Porifera)
 Cnidarians (Phylum Cnidaria)
 Worms (Phylum Platyheminthes,
Nematoda, and Annelida)
 Molluscs (Phylum Mollusca)
 Arthropods (Phylum Arthropoda)
 Echinoderms (Phylum Echinodermata)
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Procedure
VERTEBRATES (Phylum Chordata)
 Fish (Class Agnatha, Chondrichthyes,
and Osteichthyes)
 Amphibians (Class Amphibia)
 Reptiles (Class Reptilia)
 Birds (Class Aves)
 Mammals (Class Mammalia)
Differences Between Animals
As you look through the animal groups
today, pay special attention to the following
characteristics:
Symmetry –does the animal have radial,
bilateral, or no symmetry?
Gut – does the animal have a mouth? Is the
gut complete (with an mouth and an anus or
exit?)
With the members of your lab team,
work around the room and visit each of the
stations showing animals from each group.
You do not need to visit the stations in
order, especially if there is a traffic jam of
too many students at any station. If you do
visit the stations out of order, make sure you
stand back and look at the animals from
simplest to most complex to see the course
of evolution from the “big picture”.
At each station, read the information
supplied at the station and examine the
specimens carefully. You may work
together as a team in discussing answers tot
he questions, but each student should write
his/her own answers. You may also use any
textbook to help you get your answers in the
laboratory.
Coelom – does the animal have a body
cavity or space between its organs and the
body wall?
Head – does the animal have a distinct head?
Does it have a center of nervous activity?
Segmentation – is the animal divided into
parts? Are these parts specialized to
perform different functions?
Regulation of Body Temperature – does the
organism maintain a constant internal body
temperature (endothermic) or does it
fluctuate with environmental temperature
(exothermic)?
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Lab Report
Diversity of Animals
Name
Sponges (Phylum Porifera)
1. How many different kinds of cells does a sponge have? What are they?
2. What type of symmetry does a sponge have?
3. Describe the how a sponge gets and digests food. Does it have a digestive tract?
5. Describe the "skeleton" of a sponge and what types of things it can be made of.
Cnidarians or Stinging-Cell Animals (Phylum Cnidaria)
1. What are the “feeding structures” that surround the mouth of a cnidarian? What special type
of cells are found in these feeding structures?
2. What are the two body plans that a cnidarian can have?
4. Name three kinds of cnidarians.
5. What type of symmetry do cnidarians have?
6. Describe how a cnidarian catches and digests “food”. What type of digestive tract do these
organisms have?
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The Worms (Phyla Platyhelminthes, Nematoda, and Annelida)
1. The flatworms are the simplest of the worms. What type of symmetry is seen in this worm
that was absent in the sponges and cnidarians?
2. Write down the names of two of the flatworms you see at this station.
3. Describe the digestive tract of a flatworm.
4. Does the flatworm have a body cavity?
5. Which type of worm(s) are circular in cross-section?
6. What is unique about the digestive tract in roundworms?
7. Draw a picture of the cross-section of a roundworm,
indicating the pseudocoelom. This body cavity is not
a true coelom because it is missing a layer of tissue
around the digestive tract. What type of tissue is missing?
9. Annelid worms have a complete digestive tract. What type of body cavity do they have, if
any?
10. Name at least two kinds of annelid worms, according to what you see at this station.
11. What important new evolutionary developments are seen in the annelid worm body plan that
was absent in the other worms?
Molluscs (Phylum Mollusca)
1. Name three unique features of most molluscs.
2. Name at least three different kinds of molluscs.
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3. Describe the molluscan symmetry, presence of a coelom, and digestive tract.
4. What is a radula, and what is it used for?
5. Which mollusc group has members that usually do not have a shell?
Arthropods (Phylum Arthropoda)
1. Describe the body plan of an arthropod. Are they segmented? Into what parts?
2. What makes the arthropod body stiff, and gives it protection? What is this structure made of?
3. How do arthropods grow bigger and larger, given the restrictions of the structure you
mentioned in question 2?
4. Name three unique features of arthropods.
5. Which arthropod group has more species than any other group of living things?
6. Name at least two kinds of animals in this very diverse arthropod group (in question 5.)
7. Which arthropod group contains members that virtually all live in the ocean?
8. Which group(s) of arthropods have many legs?
9. Name two special sensory structures that many arthropods have.
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Echinoderms (Phylum Echinodermata)
1. Name three features of an echinoderm
2. Name three kinds of echinoderms.
3. How do echinoderms move?
4. What type of symmetry is seen in echinoderms?
5. Describe the digestive tract of echinoderms.
1. Which echinoderms have very long spines?
The Fish (Class Agnatha, Chondrichthyes, and Osteichthyes)
1. The fish are the first animals you have seen today that are vertebrates. Name four
characteristics of all vertebrate animals.
1.
2.
3.
4.
2. Name at least two features of Jawless Fish (Agnathans).
3. Name a species of Jawless Fish.
4. Name at least two features of Cartilaginous Fish (Chondrichthyans)
5. Name a species of Cartilaginous Fish.
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6. Name three features of Bony Fish (Osteichthyans).
7. Write the name of a species of Bony Fish.
8. Name and describe the organs that fish use to get oxygen into their bodies and remove carbon
dioxide from their bodies. What do these structures look like close up?
Amphibians (Class Amphibia)
1. Name three unique features of an amphibian.
2. What special adaptation(s) allow amphibians to live on land?
3. Write the name of two different kinds of amphibians.
4. Describe how amphibians move on land (when they’re not jumping). How strong are they in
holding themselves up off the ground?
5. Where do amphibians lay their eggs? Why do they have to lay them there?
Reptiles (Class Reptilia)
1. Name three unique or new features of a reptile.
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2. What is unique about reptile eggs? Where are they usually laid (on land or in water)? How is
the reptilian egg adapted for this environment where they are laid?
3. Name three kinds of reptiles
4. What is unique about the way in which reptiles fertilize their eggs? Why are eggs fertilized in
this fashion (hint: it’s related to where reptiles live).
5. Summarize the adaptations that allow reptiles to live on land as opposed to being attached to
water, like the amphibians.
The Birds (Class Aves)
1. From what group of animals are birds thought to have evolved?
2. Name at least three differences between birds and the group from which they evolved.
3. Birds are very active animals and have high metabolic rates. To do this, birds must keep a
constant high body temperature. With regards to regulating body temperature, birds are
while the group from which they evolved are all
.
4. Feathers are thought to have evolved from what structures (belonging to their ancestors)?
5. How are bird eggs different from reptilian eggs or amphibian eggs?
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Mammals (Class Mammalia)
1. Name four unique characteristics of mammals.
1.
2.
3.
4.
2. What is unusual about the eggs of most mammals? What is different about the way mammals
are born and the way birds and reptiles are born?
3. Name the three groups of mammals.
4. What is a placenta, and what does it do?
5. To what placental mammalian group do humans belong?
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