Download File - Biology by Napier

Name: _____________________________________
Invertebrate Diversity
Invertebrates are animals that do not have a backbone. For example, an earthworm is an
invertebrate.
Today, you will observe four types of invertebrates: earthworms, mealworms, crickets and
darkling beetles. You will handle all the animals except for the cricket. Please be careful
and don’t handle them roughly.
PRE-LAB Question:
Look at your 4 specimens. These specimens belong in two Phyla, Phylum Annelida
(segmented worms) and Phylum Arthropoda (jointed appendages). Place the names of the
specimens in the table below where you believe they belong.
P. Annelida
P. Arthropoda
Comparing Invertebrate Anatomy
Observe the external appearance of the earthworms and mealworms. You are encouraged
to handle them, but please be careful and handle gently. Turn the earthworm and
mealworm over and check out what's underneath. Look at them with a dissecting microscope
or hand lens.
1. Complete the table.
Name
Type of
Symmetry
Other aspects of body form
Eyes/
Soft or hard
Legs?
antennae?
covering?
Other
Observations
Earthworm
Mealworm
2. Place the earthworm and mealworm on a moist paper towel in a tray. Observe the
organisms as they move. The leading end is the anterior end, the opposite is the posterior
end. Roll the organisms over and observe what happens. The side that the organisms prefer
UP is the dorsal side. The side preferred down is the ventral side. Draw a picture of your
earthworm and mealworm and label the anterior, posterior, dorsal, and ventral side of each.
Earthworm
Mealworm
3. Notice how the earthworm moves. What body system must this earthworm have in order
to move?
4. What does the meal worm use to move?
5. On the ventral side of the earthworm are small bristles called SETAE. They are too tiny to
see, but you can feel them by running your fingers along the ventral side of the worm.
What do you think these setae help the worm do?
6. Measure the length of the SAME earthworm three times in centimeters.
______ cm
______ cm
______cm
a. Is the length of an earthworm always the same or does it change? ____________
b. Why or why not?
7. Measure the length of the SAME mealworm three times in centimeters.
______ cm
______ cm
______cm
a. Is the length of an earthworm always the same or does it change? ____________
b. Why or why not?
8. Use your book, notes or the internet to look at the characteristics of Annelids and
Arthropods. Which one of these organisms is NOT a “true” worm? ____________________
How do you know this?
Study the diagrams below of the systems in the mealworm and the earthworm. Notice
the location of each system.
Circulatory system
Digestive tract
Ganglia and nerve cord
mealworm
earthworm
9. How do all three systems compare between the two?
2
Mealworms and Darkling Beetles
Observe the external appearance and behavior of the Darkling beetle and the mealworm.
You can handle the Darkling beetle but be CAREFUL, do NOT drop or crush your specimens.
1. Complete the table.
Name
Symmetry
Other aspects of body form
Eyes/
Soft or hard
Legs?
antennae?
covering?
Other
Observations
Mealworm
Darkling
Beetle
2. What do the mealworm and beetle have in common?
3. What are the main differences between the mealworm and the beetle?
4. The mealworm and the Darling Beetle are actually the same species! Explain how this
can be.
Darkling Beetle and Cricket
Due to the quick movements of the cricket you may not remove them from the containers.
You will have to observe them in the container.
1. Complete the table.
Name
Symmetry
Other aspects of body form
Eyes/
Soft or hard
Legs?
antennae?
covering?
Other
Observations
Darkling
Beetle
Cricket
2. What do the cricket and beetle have in common?
3. What are the main differences between the cricket and the beetle?
4. The cricket and the Darkling Beetle are both arthropods. What are common characteristics
of Phylum Arthropoda?
3
5. Look at the cricket in the container. DO NOT OPEN IT.
Examine the posterior end to determine if the cricket is
a male or female. Males have two abdominal
protrusions and a female will have three abdominal
protrusions. Is your cricket a male or female?
Female
Male
3. The cricket has a hard outer covering. Would this be considered an endoskeleton or
exoskeleton?
4. What is the function of the hard outer surfaces of crickets and beetles?
5. What type of symmetry do all of the organisms you looked at today have?
6. You looked at 4 specimens today. After performing the lab and studying these organisms,
fill in the table below with mealworm, earthworm, beetle and cricket where you believe
they belong.
P. Annelida
P. Arthropoda
7. Did you make any changes on this table from the table you filled in on page 1 in the
PreLab? _________ If so, what change did you make and why?
Make sure all your specimens are safely back in the original containers
and lids are secure (but not too tight). Clean up your work station. You
may not leave until I have checked your table.
4