Laboratory Exercise 9: Animal Diversity II
Phyla Arthropoda, Mollusca, and Annelida
Biology II Laboratory BSC1011L Version: BJ AG RE SF AN JR BE 18Oct2020
Material from this lab exercise is also covered in Chapter 33 of the textbook Campbell Biology, 11th Edition. This handout is a
supplement to Chapter 7 in your lab manual (A Photographic Atlas for the Biology Laboratory 8th Edition).
KEY CONCEPTS:
1. The Bilateria are Eukaryotes and include most animals. They are an ancient lineage and are distinguished by:
• Bilateral symmetry. They have a left and a right side (at least at the larval stage).
• The kind of coelom (either a pseudocoelom or a “true” coelom). All Bilateria are triploblastic (three layers of
embryonic tissue) and coelomate (they have a true coelom or body cavity derived from the mesoderm). The
coelom was lost in the groups we examined last week but is present in those we will examine today.
• The development as a protostome or deuterostome. The Bilateria that we examined last week (Nematoda and
Platyhelminthes) and will examine today are protostomes, or animals for which the blastopore develops into
the mouth.
2. There are three main groups of Bilateria: the Ecdysozoa, Lophotrochozoa, and the Deuterostomia.
• The Ecdysozoa secrete external skeletons and include the Nematoda (we examined roundworms last week) and
the Arthropoda. Shedding of the exoskeleton is called ecdysis.
• The Lophotrochozoa are organisms that develop a lophophore (ciliated tentacles involved in feeding) or have
trochophore larva (a stage of larval development). It is difficult to see either of these structures. This group
includes the molluscs and annelids as well as the flatworms (we examined flatworms last week).
• The Deuterostomia (deuterostomes) will be examined next week (the echinoderms and chordates).
3. Dissection is one method to identify internal animal anatomy (morphology). Dissection requires specific techniques
and careful work to identify, but not destroy, anatomical structures.
4. The key groups of animals we will today examine are:
Clade, phylum, subphylum, group Clade, class, subclass or common name Material you will examine
Clade Bilateria
Clade Ecdysozoa (protostomes)
Phylum Nematoda (roundworms) - Pseudocoelomates were examined last week. This is also a clade.
Coelomates we will examine today include:
1.Phylum Arthropoda
(pgs 179-93)
Chelicerates (clade) Class Merostomata (sea spiders and horseshoe crab) Specimens
Subphylum Chelicerata Class Arachnida (spiders, mites and ticks, scorpions) Specimens
Group Crustaceans Class Malacostraca (lobsters, crayfish, crabs, shrimp) Specimens, Dissection
Lab 9: Arthropoda, Mollusca, and Annelida
Subphylum Crustacea Class Maxillopoda (copepods and barnacles) Specimens
Group Insects Class Insecta- (beetles, bees, flies, fleas, Specimens
Subphylum Hexapoda grasshoppers, butterflies, termites, true bugs, others)
Myriapods (clade) Class Chilopoda (Centipedes) Specimens
Subphylum Myriapoda Class Diplopoda (Millipedes) Specimens
Clade Lophotrochozoa (protostomes)
Phylum Platyhelminthes (flatworms)- Acoelomates were examined last week. This is also a clade.
2.Phylum Mollusca (clade) Class Polyplacophora (chitons) (a clade) Specimens
(pgs 166-171) Class Gastropoda (snails and slugs) (a clade) Specimens
Class Bivalveia (clams, oysters, and mussels) (clade) Specimens, Dissection
Class Cephalopoda (squids, octopi, and nautilus)(clade) Specimens, Dissection
3.Phylum Annelida (clade) Class Polychaeta (tubeworms and sandworms) Specimen
(pgs 173-5) Earthworms (Subclass Oligochaeta) Specimens, Dissection
Leeches (Subclass Hirudinea) Specimen
Clade Deuterostomia (dueterostomes) We will examine these next week. These are all coelomates.
1
, The taxonomic classifications used in this lab are based on both the textbook (Campbell Biology 11th edition) as well as
the Photographic Atlas for the Biology Laboratory. All phyla recognized above are clades, but not all historically
recognized groups and classes are clades (all that are known to be clades are indicated as such). Even though they are not
clades, class, subclass and common names are critical to know to be able to navigate most literature, including the
Photographic Atlas.
By the end of this lab you should have an understanding of the evolutionary diversity of form among protostomes of
the Bilateria. You should be able to:
1. Recognize the kind of symmetry, kind of coelom, and development as a protostome or deuterostome of the
various Bilateria.
2. Distinguish between the Ecdysozoa and Lophotrochozoa. You should be able to recognize the clades, phyla, and
major groups (identified in bold on the first page of the lab) of the various specimens you will examine today.
3. Know basic dissection techniques, especially the use of a blunt probe, to tease apart tissues and identify internal
anatomical structures.
4. Recognize both the external and internal anatomy of the crayfish, squid, clam, and earthworm.
You are already familiar with many of the animals we will examine today. Can you identify the organisms?
Phylum: ________________
Subphylum: ____________ Monarch butterfly
Common name: ____________
Phylum: ___________________
Subphylum: ________________
Phylum: _________________________
Class: _____________________
Subphylum: ______________________ http://en.wikipedia.org/wiki/File:Monarch_In_May.jp
Common name: ___________________
http://en.wikipedia.org/wiki/Horshoe_Crab
Phylum: _______________
Lab 9: Arthropoda, Mollusca, and Annelida
Subphylum: ____________
Common name: ____________
http://en.wikipedia.org/wiki/Myriapoda
Brown Dog tick
Phylum____________
Common Atlantic Octopus Subphylum: ________
Phylum: ________________ Class: _____________
Love Bugs mating. Class: __________________ http://en.wikipedia.org/wiki/Brown_Dog_Tick
http://en.wikipedia.org/wiki/Octopus
Phylum: _______________
Introduction
Subphylum:____________
Class: _________________
http://en.wikipedia.org/wiki/File:Lovebugs.jpg
2
Phyla Arthropoda, Mollusca, and Annelida
Biology II Laboratory BSC1011L Version: BJ AG RE SF AN JR BE 18Oct2020
Material from this lab exercise is also covered in Chapter 33 of the textbook Campbell Biology, 11th Edition. This handout is a
supplement to Chapter 7 in your lab manual (A Photographic Atlas for the Biology Laboratory 8th Edition).
KEY CONCEPTS:
1. The Bilateria are Eukaryotes and include most animals. They are an ancient lineage and are distinguished by:
• Bilateral symmetry. They have a left and a right side (at least at the larval stage).
• The kind of coelom (either a pseudocoelom or a “true” coelom). All Bilateria are triploblastic (three layers of
embryonic tissue) and coelomate (they have a true coelom or body cavity derived from the mesoderm). The
coelom was lost in the groups we examined last week but is present in those we will examine today.
• The development as a protostome or deuterostome. The Bilateria that we examined last week (Nematoda and
Platyhelminthes) and will examine today are protostomes, or animals for which the blastopore develops into
the mouth.
2. There are three main groups of Bilateria: the Ecdysozoa, Lophotrochozoa, and the Deuterostomia.
• The Ecdysozoa secrete external skeletons and include the Nematoda (we examined roundworms last week) and
the Arthropoda. Shedding of the exoskeleton is called ecdysis.
• The Lophotrochozoa are organisms that develop a lophophore (ciliated tentacles involved in feeding) or have
trochophore larva (a stage of larval development). It is difficult to see either of these structures. This group
includes the molluscs and annelids as well as the flatworms (we examined flatworms last week).
• The Deuterostomia (deuterostomes) will be examined next week (the echinoderms and chordates).
3. Dissection is one method to identify internal animal anatomy (morphology). Dissection requires specific techniques
and careful work to identify, but not destroy, anatomical structures.
4. The key groups of animals we will today examine are:
Clade, phylum, subphylum, group Clade, class, subclass or common name Material you will examine
Clade Bilateria
Clade Ecdysozoa (protostomes)
Phylum Nematoda (roundworms) - Pseudocoelomates were examined last week. This is also a clade.
Coelomates we will examine today include:
1.Phylum Arthropoda
(pgs 179-93)
Chelicerates (clade) Class Merostomata (sea spiders and horseshoe crab) Specimens
Subphylum Chelicerata Class Arachnida (spiders, mites and ticks, scorpions) Specimens
Group Crustaceans Class Malacostraca (lobsters, crayfish, crabs, shrimp) Specimens, Dissection
Lab 9: Arthropoda, Mollusca, and Annelida
Subphylum Crustacea Class Maxillopoda (copepods and barnacles) Specimens
Group Insects Class Insecta- (beetles, bees, flies, fleas, Specimens
Subphylum Hexapoda grasshoppers, butterflies, termites, true bugs, others)
Myriapods (clade) Class Chilopoda (Centipedes) Specimens
Subphylum Myriapoda Class Diplopoda (Millipedes) Specimens
Clade Lophotrochozoa (protostomes)
Phylum Platyhelminthes (flatworms)- Acoelomates were examined last week. This is also a clade.
2.Phylum Mollusca (clade) Class Polyplacophora (chitons) (a clade) Specimens
(pgs 166-171) Class Gastropoda (snails and slugs) (a clade) Specimens
Class Bivalveia (clams, oysters, and mussels) (clade) Specimens, Dissection
Class Cephalopoda (squids, octopi, and nautilus)(clade) Specimens, Dissection
3.Phylum Annelida (clade) Class Polychaeta (tubeworms and sandworms) Specimen
(pgs 173-5) Earthworms (Subclass Oligochaeta) Specimens, Dissection
Leeches (Subclass Hirudinea) Specimen
Clade Deuterostomia (dueterostomes) We will examine these next week. These are all coelomates.
1
, The taxonomic classifications used in this lab are based on both the textbook (Campbell Biology 11th edition) as well as
the Photographic Atlas for the Biology Laboratory. All phyla recognized above are clades, but not all historically
recognized groups and classes are clades (all that are known to be clades are indicated as such). Even though they are not
clades, class, subclass and common names are critical to know to be able to navigate most literature, including the
Photographic Atlas.
By the end of this lab you should have an understanding of the evolutionary diversity of form among protostomes of
the Bilateria. You should be able to:
1. Recognize the kind of symmetry, kind of coelom, and development as a protostome or deuterostome of the
various Bilateria.
2. Distinguish between the Ecdysozoa and Lophotrochozoa. You should be able to recognize the clades, phyla, and
major groups (identified in bold on the first page of the lab) of the various specimens you will examine today.
3. Know basic dissection techniques, especially the use of a blunt probe, to tease apart tissues and identify internal
anatomical structures.
4. Recognize both the external and internal anatomy of the crayfish, squid, clam, and earthworm.
You are already familiar with many of the animals we will examine today. Can you identify the organisms?
Phylum: ________________
Subphylum: ____________ Monarch butterfly
Common name: ____________
Phylum: ___________________
Subphylum: ________________
Phylum: _________________________
Class: _____________________
Subphylum: ______________________ http://en.wikipedia.org/wiki/File:Monarch_In_May.jp
Common name: ___________________
http://en.wikipedia.org/wiki/Horshoe_Crab
Phylum: _______________
Lab 9: Arthropoda, Mollusca, and Annelida
Subphylum: ____________
Common name: ____________
http://en.wikipedia.org/wiki/Myriapoda
Brown Dog tick
Phylum____________
Common Atlantic Octopus Subphylum: ________
Phylum: ________________ Class: _____________
Love Bugs mating. Class: __________________ http://en.wikipedia.org/wiki/Brown_Dog_Tick
http://en.wikipedia.org/wiki/Octopus
Phylum: _______________
Introduction
Subphylum:____________
Class: _________________
http://en.wikipedia.org/wiki/File:Lovebugs.jpg
2
