exploring life exercise 10: arthropodsbio.wayne.edu/bio1500/ex10wkbk.pdf · exercise 10: arthropods...

EXPLORING LIFE

EXERCISE 10: ARTHROPODS

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Exercise 10: Arthropods Workbook Contents Corresponding Section on CD Vocabulary Key Concepts Introduction 1. Introduction Common Patterns Across the Arthropods 1A. Common Patterns Across the Arthropods Common Patterns and Taxonomy 1B. Common Patterns and Taxonomy Subphylum Chelicerata 2. Subphylum Chelicerata Class Merostomata: Horseshoe Crabs 2A. Class Merostomata: Horseshoe Crabs Class Arachnida: Scorpions and Spiders 2B. Class Arachnida: Scorpions and Spiders Class Arachnida: Ticks and Mites 2C. Class Arachnida: Ticks and Mites Subphylum Crustacea 3. Subphylum Crustacea Survey of Crustacea 3A. Survey of Crustacea Class Malacostraca: Crabs, Shrimps, 3B. Class Malacostraca: Crabs, Shrimps, Lobsters and Crayfish Lobsters and Crayfish Subphylum Uniramia 4. Subphylum Uniramia Survey of the Uniramia 4A. Survey of Uniramia Class Insecta 4B. Class Insecta Summary & Review Vocabulary Biramous - Describes one form of arthropod appendage, which is branched into two 'arms'. The other form of

arthropod appendage is called uniramous, and is unbranched. Book gills/lungs - Folded lamellae of thin exoskeleton through which oxygen is exchanged. In aquatic species

like horseshoe crabs, book gills are directly exposed to the outside environment. In terrestrial arachnids, the book lungs are enclosed in sacs within the exoskeleton.

Carapace - A shield-like plate covering the dorsal surface of the cephalothorax of crustaceans and trilobites Chelicerae - The first pair of appendages in horseshoe crabs, sea spiders and arachnids. In most cases they are in

the form of pincers, fangs, or claws. Cheliped - In the decapod crustaceans (shrimp, crabs, lobsters), this is the enlarged appendage commonly called

a claw. Chitin - A tough fibrous molecule, made of a long polysaccharide chain with amino groups appended to each

sugar unit. It is further strengthened by depositing calcium carbonate along the fibers. It forms the exoskeleton of the arthropods.

Cyclomorphosis - A change in morphology observed particularly in the Cladocera, usually in response to the threat of predation. Tail portions become elongated and head shape changes from rounded to 'helmeted', making it harder for possible predators to ingest the modified form.

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Dioecious - Having the male and female sex organs on separate individuals Ecdysone/ecdysis - Ecdysone is the steroid hormone that triggers molting in arthropods. Ecdysis is the process

of shedding the old outer cuticular layers that is commonly called molting. Elytra - The hardened forewings of some insects, e.g. beetles, that cover and protect the hindwings of those

insects Endo-/exo-/epicuticle - The three layers of chitinous exoskeleton. The deepest layer is the endocuticle; above

that lies the exocuticle; and the layer closest to the surface is the epicuticle. Ephippium - The resistant, resting 'egg' of cladocera, made when environmental conditions deteriorate, and

from which new females develop the following spring Green gland - The excretory organs of decapod crustaceans. They lie at the base of the antennae, and resorb

nutrients and salts, excreting waste products Halteres - The small, reduced hindwings of diptera. Their chief function is in orientation, providing information

to correct pitch, yaw, and roll during flight. Hemocoel - A collective name for the sinuses that surround tissues and organs of the arthropod body. Blood

flows from vessels into the sinuses, while the coelom has been severely reduced in size. Hypodermis - The deepest layer of an arthropod's surface tissues. Enzymes secreted by the hypodermis

dissolve the old endo- and exocuticle when molting begins, then the hypodermis makes a new epicuticle beneath the old one.

Instar - Each of the distinct stages of development through which arthropods go. Usually stages are separated by molting events.

Malpighian tubules - Tubes with closed off ends opening into the hindgut of terrestrial arthropods. They are the excretory organs of those arthropods.

Metamerism - A scheme for the animal body plan that is organized into segments, evident in some species, but frequently disguised by fusion of segments in the adult bodies of many arthropods

Nauplia - The name for the larval stage of many crustacea. It characteristically has a single 'eye' consisting of one to four cups with a few photoreceptors in each.

Ocelli (singular - ocellus) - The simple light receptors present on many invertebrates. Arthropods such as spiders have multiple pairs of ocelli along with pairs of compound eyes.

Ommatidia (singular - ommatidium) - The individual units from which an arthropod compound eye is constructed. Each one has a ring of light sensitive cells and a crystalline lens to focus light on the receptive surfaces of those cells.

Ostia - The slit-like openings through which blood returns to the hearts of arthropods Pedipalps - A pair of appendages attached to the heads of arachnids. Their functions vary, but in many spiders

they act as poison glands, either paralyzing or poisoning prey. Pericardium - The largest of the sinuses collectively forming the hemocoel. This one surrounds the heart. Pheromone - A chemical substance released by one animal that affects the behavior or physiology of another

animal in the same species. Pheromones thus act as externalized hormones. Rhabdome - The translucent cylinder that forms the core around which the light sensitive cells of an

ommatidium are arranged. Spermatophore - A packet of sperm cells left by a male to be collected by a female he is or has courted,

particularly in the arachnids Spinneret - The organ of arachnids from which silk is exuded. There may be multiple spigots comprising a

single spinneret, with the strands from the individual spigots twisted together as they are exuded.

Spiracles - The external opening leading to the system of trachea and tracheoles that bring oxygen to the cells and tissues of insects and other terrestrial arthropods

Statocyst - An organ permitting orientation with respect to gravity. In decapods, they are located at the base of the antennules. Sand grains within fall to the 'bottom' of the statocyst, exciting sensory hairs that line the interior surface.

Tapetum - A reflective layer at the 'back' of the eye, behind the receptor cells. Reflection of light by the tapetum makes the eyes of animals having this layer look bright, as are many of the eyes of arachnids and numerous others like cats.

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Telson - The last abdominal segment of crustaceans and arachnids (or, in some cases, an appendage of that segment). In decapods, the telson is the flattened 'tail' of the animal; in scorpions, the telson is the 'stinger.'

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KEY CONCEPTS This section of the workbook is set up to help you note important information relating to the key concepts of this exercise and then organize and summarize the information in order to develop a synthesis and prepare for a review. As you complete this exercise, you will focus on the structural and life cycle characteristics of the animals, particularly the simple ones, so that you will be able to distinguish: How these animals are classified 1. What structural and life cycle characteristics distinguish the arthropods from every other group of animals? 2. What structural and life cycle characteristics distinguish each group within a subphylum from every other group within that subphylum? The evolutionary trends demonstrated in these animals 3. What are the evolutionary trends in development in the structural and life cycle characteristics of the arthropods? The first sixteen pages are questions that can be answered by following the progression of slides and paying careful attention to the information, both visual and audio. These questions should be read in advance of each section so that you can be better prepared to answer them by knowing what you are looking for. The underlined subheadings correspond to the sections of the exercise as outlined in the main menu. The subsequent pages are designed to help you summarize and synthesize the pertinent information to answer the questions posed above.

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KEY CONCEPTS Introduction

Common Patterns Across the Arthropods

1. By the end of this exercise, you should be able to:

a.

b.

c.

d.

e.

f. 2. Arthropods are the least / most diverse phylum of animals; the nearly one billion / million species

named represent one / three quarters of all animal species. They are also the least / most

abundant phylum on earth, living in virtually all / no habitats where life can be found.

As the images appear on the screen, list some of these organisms and the habitats in which they are found:

3. Circle the characteristic in each group that is common to all members of the arthropod phylum.

a. All arthropods are segmented / unsegmented, though segmentation of the abdomen / head

/ thorax may be lost.

b. Arthropods in the advanced / primitive condition bear one / two / three appendages on

each segment, very much like the oligochaetes / polychaetes.

c. All arthropods have an endoskeleton / exoskeleton made of cellulose / chitin into which

calcium carbonate / sodium carbonate is deposited for additional / less strength.

EC: Describe the process of molting. You may include one or more labeled diagrams:

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THE ARTHROPODS Question 3 continued:

d. The nervous systems of arthropods and annelids / mollusks show a basic structural similarity -

a dorsal / ventral “brain” and a dorsal / ventral nerve cord with ganglia in each segment.

The senses and behaviors are relatively limited in the annelids / arthropods, but can be very

diverse, complex and sophisticated in the annelids / arthropods. What are the major sense

organs of the head?

The antennae / chemoreceptors / eyes are the most interesting and complex. They are

described as compound / singular, made up of many segments called eyespots / ommatidia.

EC: Describe the structure and function of the arthropod eye. You may include a labeled diagram:

e. Arthropods have closed / open circulatory systems. The blood is called hemoglobin /

hemolymph. This fluid is pumped through a(n) aortic arch / heart.

EC: Describe the structure and function of the circulatory system. You may include a labeled diagram:

f. During arthropod development, the coelom is enlarged / reduced in size and importance.

Arthropods are deuterstomes / protostomes. The cleavage pattern is radial / spiral.

The first opening that appears in the embryo becomes the anus / mouth. A splitting of the

ectoderm / endoderm / mesoderm forms the animals’ body cavities. Development is

indeterminate / determinate.

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KEY CONCEPTS Common Patterns and Taxonomy 4. The diversity of structures for what function distinguish many arthropods? 5. Match the gas exchange structure(s) with the correct arthropod(s) and habitat(s):

Gas Exchange Structures Arthropods Habitats

book gills arachnids

book lungs centipedes strictly aquatic

trachea & spiracles horseshoe crab

tracheal walls lung-like insects terrestrial

tracheoles

6. Match the excretory structure(s) with the correct waste elimination structure(s) and arthropod(s):

Excretory Structures Wastes Eliminated from Arthropods

coxal glands ducts opening to outside arachnids, centipedes, insects

Malpighian tubules gut horseshoe crab 7. Fill in the tree with the following terms: annelid-like progenitor, has antenna, no antenna, biramous appendages, uniramous appendages, Chelicerata, Mandibulata, Uniramia, Crustacea. Also, list the classes beneath each subphylum and an example organism in each class.

Subphylum: Characteristic: Classes:



Grouped together as:

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THE ARTHROPODS In the remainder of this exercise, you may go as in-depth as you choose. Most of the questions will focus on key characteristics for each subphylum and class. This will include some, but not all of the specialized vocabulary that is used to define these characteristics, particularly anatomical structures. Also, details regarding the lifestyles and habits of many organisms will not be explored here, though they do appear on the CD.

Subphylum Chelicerata

Class Merostomata: Horseshoe Crabs 8. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle features of this class.

Diversity (# of species) a. not very diverse (less than 200) or diverse (200 to 25,000)

Habitats b. marine or freshwater or terrestrial

Locomotion c. walking or swimming or burrowing or none (sessile as adults)

Internal Anatomy d. gas exchange: book gills or book lungs or gills or trachea

External Anatomy e. # of legs: 6 or 8 or 10 or 12 or more than 12

f. head and thorax: separate head and thorax or fused cephalothorax

g. sensory organs: eyes or ocelli

h. number of eyes: 2 or 4 or 8

i. type of eyes: naupliar or compound or single or stalked

Label the structures on this horseshoe crab diagram:

Feeding j. scavenging/detritus or predatory/carnivorous or herbivorous

k. digestion: in midgut or outside of body

l. diffusion of nutrient: through circulation or directly to tissues

Label the structures on this horseshoe crab cross-section:

Reproduction m. sexes: separate (dioecious) or together (hermaphroditic)

n. fertilization: internal or external

o. eggs: brooded internally or laid externally

p. care of eggs/young: none or minimal or extensive

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KEY CONCEPTS Class Arachnida: Scorpions and Spiders 9. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle features of this class.


External Anatomy m. surface: cuticle or epicuticle or no cuticle

Internal Anatomy p. gas exchange: book gills or book lungs or gills or trachea

External Anatomy f. number of body segments: 1 or 2 or 3 or more than 3

g. head and thorax: separate head and thorax or fused cephalothorax

i. # of legs: 6 or 8 or 10 or 12 or more than 12

k. other appendages: chelicerae or pedipalps or chelipeds or pleopods

Feeding e. scavenging or predatory/carnivorous or herbivorous or parasitic

r. digestion: in midgut or outside of body

s. diffusion of nutrient: through circulation or directly to tissues

t. excretion: coxal glands or Malpighian tubules or gills or other glands

External Anatomy n. sensory organs: eyes or ocelli or sensory hairs or slit or antenna

o. type of eyes: naupliar or compound or single or stalked

Reproduction p. sexes: separate (dioecious) or together (hermaphroditic)

q. fertilization: internal or external; with or without spermatophore

10. Label as many structures as you can on this example arachnid:

11. List at least five of the minor orders of arachnids and a representative, with a short description, of each:

a.

b.

c.

d.

e.

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THE ARTHROPODS Order Scorpiones (the scorpions)

12. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle features of this class.

Diversity (# of species) a. diverse (200 to 25,000) or very diverse (more than 25,000)

External Anatomy b. abdomen: segmented or unsegmented or fused with other regions

Specialties c. poison: in oral structures or in abdominal segment structure

Reproduction d. eggs: brooded internally (young born alive) or laid externally

e. courtship: none or minimal or elaborate

f. fertilization: internal or external; with or without spermatophore Order Aranae (true spiders)



Locomotion b. walking or swimming or burrowing or none (sessile as adults)

c. by muscular contraction or by blood pressure

Specialties d. silk or luminescence or repugnatorial glands

EC: Describe some of the functions of silk:

Specialties e. poison: in oral structures or in abdominal segment structure

External Anatomy f. sensory organs: eyes or ocelli or sensory hairs or slit

g. type of eyes: naupliar or compound or single or stalked

h. number of eyes: 2 or 4 or 8

Feeding i. predatory/carnivorous or herbivorous or omnivorous

Reproduction j. sexes: separate (dioecious) or together (hermaphroditic)

k. courtship: none or minimal or elaborate

l. fertilization: internal or external; with or without spermatophore

m. eggs: brooded internally or laid externally

EC: Describe some of the ways in which a male spider may find and court a mate:

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KEY CONCEPTS Class Arachnida: Ticks and Mites The Acari (ticks and mites)



Feeding b. scavenging/detritus or predatory or herbivorous or parasitic

EC: Describe, using example organisms, the economic importance of this group:

Internal Anatomy c. circulation: heart or no heart; vessels or no vessels

External Anatomy d. number of body segments: 1 or 2 or 3 or more than 3

e. head and thorax: separate head and thorax or fused cephalothorax

f. abdomen: segmented or unsegmented or fused with other regions

g. # of legs: 6 or 8 or 10 or 12 or more than 12

h. other appendages: chelicerae or pedipalps or chelipeds or pleopods

i. exoskeleton: highly sclerotized or not highly sclerotized

Reproduction j. sexes: separate (dioecious) or together (hermaphroditic)

k. fertilization: internal or external

l. eggs: brooded internally or laid externally

Subphylum Crustacea

Survey of Crustacea 15. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle features of this group.


Feeding b. scavenging or predatory or herbivorous or suspension or filter


Habitats d. marine or freshwater or terrestrial

External Anatomy e. exoskeleton: highly calcified or not highly calcified or 2 distinct valves

f. type of legs: uniramous or biramous


h. sensory appendages: antenna or antennules; antenna: 1 pair or 2 pairs

i. other appendages: mandibles or maxillae or chelipeds or pleopods

Internal Anatomy j. excretion: coxal glands or Malpighian tubules or gills or other glands

External Anatomy k. sensory organs: eyes or sensory hairs or statocysts or proprioceptors

l. type of eyes: naupliar or compound or single or stalked

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THE ARTHROPODS Question #15 continued:

Reproduction m. sexes: separate (dioecious) or together (hermaphroditic)

n. fertilization: internal or external

o. eggs: brooded internally or laid externally

Label as many structures as you can on this typical crustacean:

Class Branchiopoda




EC: List some example organisms from this class. What is their ecological importance?

Internal Anatomy c. gas exchange: gills or trachea or surface of body

Feeding d. scavenging or predatory/carnivorous or herbivorous or suspension

Internal Anatomy e. circulation: heart or no heart; vessels or no vessels; hemocyanin or

hemoglobin

Reproduction f. eggs: brooded internally or laid externally

g. sexes: separate (dioecious) or missing one (parthenogenic)

Class Ostracoda (seed shrimp)


Diversity (# of species) a. not very diverse (less than 200) or diverse (200 to 25,000

External Anatomy b. exoskeleton: highly calcified or not highly calcified or 2 distinct valves

Habitats c. marine or freshwater or terrestrial

Feeding d. predatory/carnivorous or herbivorous or filter or parasitic

Internal Anatomy e. gas exchange: gills or trachea or surface of body

Specialties f. silk or poison or luminescence or repugnatorial glands

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KEY CONCEPTS Class Copepoda




Feeding c. predatory/carnivorous or herbivorous or suspension or parasitic

Locomotion d. walking or swimming or burrowing or none (sessile as adults)

External Anatomy e. type of eyes: naupliar or compound or single or stalked

Internal Anatomy f. gas exchange: gills or trachea or surface of body

g. circulation: heart or no heart; vessels or no vessels

Reproduction h. sexes: separate (dioecious) or together (hermaphroditic)

i. courtship: none or minimal or elaborate

j. fertilization: internal or external

k. eggs: brooded internally or laid externally

Class Cirripedia (barnacles)


Locomotion a. walking or swimming or burrowing or none (sessile as adults)


Feeding c. scavenging or predatory/carnivorous or suspension or parasitic

EC: Describe the unique anatomical features of this class. Label the diagram as part of your discussion.

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THE ARTHROPODS

Class Malacostraca: Crabs, Shrimps, Lobsters and Crayfish 20. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle features of this class. You may have to return to some of these features as you proceed through this class on the CD exercise.


External Anatomy b. number of body segments: 1 or 2 or 3 or more than 3

c. head and thorax: separate head and thorax or fused cephalothorax

d. abdomen: segmented or unsegmented or fused with other regions

e. other appendages: chelicerae or pedipalps or chelipeds or pleopods

Locomotion f. walking or swimming or burrowing or none (sessile as adults)

Internal Anatomy g. gas exchange: gills or trachea or surface of body

Reproduction h. sexes: separate (dioecious) or together (hermaphroditic)

i. fertilization: internal or external

EC: The gonopores (reproductive openings) are found on the thoracic segment of the female and

the thoracic segment of the male.

Feeding j. scavenging/detritus or predatory or herbivorous or omnivorous or

suspension or filter or parasitic

EC: Give an example of an isopod, , and an amphipod, .

How are these two groups similar? How are they specially adapted to their particular environments?

Habitats k. marine or freshwater or terrestrial

EC: What do the decapods and krill have in common?

What is the ecological importance of krill?

EC: List some well-known decapods:

(decapods only) l. # of legs: 6 or 8 or 10 or 12 or more than 12

Internal Anatomy m. gas exchange: gills or trachea or surface of body

n. circulation: heart or no heart; vessels or no vessels; hemocyanin or

hemoglobin

o. excretion: coxal glands or Malpighian tubules or gills or other glands

Reproduction p. sexes: separate (dioecious) or together (hermaphroditic)

q. courtship: none or minimal or elaborate

r. fertilization: internal or external

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KEY CONCEPTS Subphylum Uniramia

Survey of the Uniramia

The Myriapods (centipedes and millipedes)


External Anatomy k. other appendages: mandibles or maxillae or chelipeds or pleopods

o. type of eyes: naupliar or compound or single or stalked

i. # of legs: 6 or 8 or 10 or 12 or more than 12

j. type of legs: uniramous or biramous

n. sensory appendages: antenna or antennules; antenna: 1 pair or 2 pairs


Internal Anatomy p. gas exchange: gills or trachea or surface of body

t. excretion: coxal glands or Malpighian tubules or gills or other glands


EC: Along what evolutionary path did the myriapods theoretically develop? Describe an onychophoran as a part of your discussion:



h. abdomen: segmented or unsegmented or fused with other regions

m. surface: cuticle or epicuticle or no cuticle The Chilopoda (centipedes)




Specialties c. silk or poison or luminescence or repugnatorial glands

d. other appendages: forcipules or chelipeds or pleopods

Internal Anatomy e. circulation: hemocyanin or hemoglobin

f. by muscular contraction or by blood pressure

Feeding g. scavenging/detritus or predatory/carnivorous or herbivorous

External Anatomy h. sensory organs: eyes or ocelli or sensory hairs or slit or antenna

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THE ARTHROPODS The Diplopoda (millipedes)




i. # of legs per body segment: 1 or 2 or 3 or more than 3

EC: What is interesting and unique about the body segmentation of the millipedes?

Specialties z. silk or poison or luminescence or repugnatorial glands

Feeding e. scavenging/detritus or predatory/carnivorous or herbivorous

n. sensory organs: eyes or ocelli or sensory hairs or slit or antenna


Reproduction u. sexes: separate (dioecious) or together (hermaphroditic)

x. eggs: brooded internally or laid externally

y. care of eggs/young: none or minimal or extensive

EC: Label as many structures as you can on these myriapods:

Centipede Millipede

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KEY CONCEPTS Class Insecta 24. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle features of this class.

Diversity (# of species) a. very diverse (> 25,000) or extremely diverse (> 500,000)

External Anatomy b. number of body segments: 1 or 2 or 3 or more than 3

c. # of legs: 6 or 8 or 10 or 12 or more than 12

d. # of wings: none or 1 pair or 2 pair

e. type of legs: uniramous or biramous

f. sensory organs: eyes or ocelli or antenna or antennules

g. sensory appendages: antenna or antennules; antenna: 1 pair or 2 pairs

h. type of eyes: naupliar or compound or single or stalked

Internal Anatomy i. gas exchange: book gills or book lungs or trachea or surface of body

Habitats j. marine or freshwater or terrestrial

Locomotion k. walking or swimming or flying

EC: Discuss the various structures, function and possible evolutionary path of wings:

Feeding l. scavenging/detritus or predatory/carnivorous or herbivorous or

omnivorous or suspension or filter or parasitic

Discuss the ecological and economic importance of insects. Use specific examples in your discussion:

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THE ARTHROPODS External Anatomy m. other appendages: chelicerae or pedipalps or mandibles or maxillae

EC: Describe some of the various mouthparts of insects and their uses. Use specific examples:

Internal Anatomy n. digestion: in midgut or outside of body

EC: What is unique about the digestive structures and capabilities of insects?

o. circulation: heart or no heart; vessels or no vessels

p. excretion: coxal glands or Malpighian tubules or gills or other glands

Reproduction q. sexes: separate (dioecious) or missing one (parthenogenic)

r. fertilization: internal or external; with or without spermatophore

s. eggs: brooded internally or laid externally

Describe, using specific examples, some important plant and insect relationships:

Describe, using specific examples, some of the complex social structures of insects. In which two groups

have these societies evolved? and

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KEY CONCEPTS 25. Review the section on the class Insecta and label as many structures as you can in the diagram below:

26. Using the dichotomous key on the next page, identify the order for each of these insects. To use the key: a) ask yourself the first question (both the prime and non-prime versions) with regard to the organism you are trying to identify; b) select the version that most closely matches your organism; c) follow the instructions at the end of the line or identify the organism as belonging to the order at the end of the line.

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THE ARTHROPODS 1. With well developed wings

1'. Wingless, or with vestigial or rudimentary wings

2. Front wings horny, leathery, or parchmentlike, at least at the base; hind wings, if present, membranous

2'. Wings entirely membranous

3. Front wings minute and club-shaped, hind wings fanlike; antennae with at least one segment bearing a long lateral process; minute insects

3'. Not exactly fitting the above description

4. Mouth parts haustellate (a tube), the beak (tube) elongate and usually segmented

4'. Mouth parts mandibulate (designed for chewing)

5. Abdomen with forceps-like cerci, the elytra short, leaving most of the abdomen exposed, tarsi (the last segments on leg) 3-segmented

5'. Abdomen without forceps-like cerci, wings cover most of the abdomen, tarsi variable

6. Front wings without veins, and usually meeting in a straight line down the middle of the back; antennae generally with 11 or fewer segments; hind wings narrow usually longer than front wings

6'. Front wings with veins, and either held roof-like over abdomen or overlapping over abdomen when at rest; antennae generally with more than 12 segments; hind wings broad

7. With 2 wings

7'. With 4 wings

8. Wings largely or entirely covered with scales; mouthparts usually in the form of a coiled proboscis; antennae many-segmented

8'. Wings not covered with scales, though the body may be hairy; mouthparts not in the form of a coiled proboscis; antennae variable

9. Beak arising from the front of head; front wings usually leathery at base and membranous at tip, the tips generally overlapping when at rest

9'. Beak arising from the hind part of head, often appearing to arise at the base of front legs; front wings of uniform texture throughout, the tips not, or but slightly, overlapping when at rest

10. Body insectlike, with a more or less distinct head and segmented legs

10'. Body not insectlike, without a distinct head or legs, and usually incapable of locomotion

11. Front wings present, but rudimentary; hind wings absent or represented by halteres; tarsi nearly always 5-segmented

11'. Wings entirely absent, or with 4 rudimentary wings and no halteres; tarsi variable

12. Antennae present; size variable

12'. Antennae absent; length 1.5mm or less

13. Ectoparasites of birds, mammals, or honeybees, and usually found on the host; body more or less leathery, and usually flattened dorso-ventrally or laterally

13'. Free-living, not ectoparasites; terrestrial or aquatic

14. Abdomen distinctly constricted at base; antennae usually elbowed; hard-bodied, ant-like insects

14'. Abdomen not constricted at base; antennae not elbowed

1. Go to 2

1'. Go to 10

2. Go to 3

2'. Go to 7

3. Strepsiptera

3'. Go to 4

4. Go to 9

4'. Go to 5

5. Dermaptera

5'. Go to 6

6. Coleoptera

6'. Orthoptera

7. Diptera

7'. Go to 8

8. Lepidoptera

8'. Odonata; Hymenoptera

9. Hemiptera

9'. Homoptera

10. Go to 11

10'. Homoptera

11. Diptera

11'. Go to 12

12. Go to 13

12'. Protura

13. Mallophaga; Siphonaptera

13'. Go to 14

14. Hymenoptera

14'. Isoptera

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SUMMARY & REVIEW 1. List and describe the six characteristics that unite the arthropods:

a.

b.

c.

d.

e.

f. Evolutionary Trends 2. Without looking at your Key Concepts, fill in the following taxonomic tree. Then list these classes under their correct subphylum: Arachnida, Branchiopoda, Chilopoda, Cirripedia, Copepoda, Diplopoda, Insecta, Malacostraca, Merostomata, Ostracoda, Pauropoda, Pycnogonida, Symphyla

3. Complete the chart on the next page. Then, in each group, list the characteristics of the arthropods in order from most primitive to most derived. The first one has been done for you as an example:

a. habitats: restricted; usually marine to not restricted; found in many or all habitats

b. body structure: to to

c. “eyes”: to to

d. gas exchange: to to

e. excretion: to

f. circulation: to




Grouped together as:

10-22

THE ARTHROPODS Mark an "X" next to each characteristic that is found in all or some of the members of each of these groups.

Che

licer

ata

Mer

osto

mat

a

Ara

chni

da

Cru

stac

ea

Mal

acos

trac

a

oth

er C

rust

acea

Uni

ram

ia

Inse

cta

oth

er U

nira

mia

Che

licer

ata

Mer

osto

mat

a

Ara

chni

da

Cru

stac

ea

Mal

acos

trac

a

oth

er C

rust

acea

Uni

ram

ia

Inse

cta

oth

er U

nira

mia

Diversity Excretionnot very coxal glandsdiverse Malpighian tubulesvery gillsextremely other glands

Habitats Circulationmarine no heartfreshwater heartterrestrial no vessels

Body Structure vesselsdistinct head hemocyanincephalothorax hemoglobinsegmented abdomen Digested Nutrientsunsegmented abdomen direct to tissuesbiramous appendages through circulationuniramous appendages Reproduction

Sensory Organs dioeciousocelli hermaphroditicnaupliar eyes parthenogenicsingle eyes no courtshipcompound eyes some courtship

Gas Exchange internal fertilizationbook gills external fertilizationbook lungs eggs broodedgills eggs laid externallyacross body surface no care of youngtrachea & spiracles some care of youngtracheal walls lung-liketracheoles

10-23

SUMMARY & REVIEW 5. Write the letter of the group next to the appropriate common name and organism:

A. Merostomata barnacles

B. Scorpiones centipedes

C. Aranae horseshoe crab

D. Acari insects

E. Ostracoda lobsters, crabs, shrimps

F. Cirripedia millipedes

G. Malacostraca scorpions

H. Chilopoda seed shrimp

I. Diplopoda ticks and mites

J. Insecta true spiders

Fill out the chart on the next page. Then, using that chart and the one on the previous page, answer the following questions.

6. What characteristics are unique to each subphylum?

a. Chelicerata:

b. Crustacea:

c. Uniramia: 7. What characteristics are unique to each class?

a. Merostomata:

b. Arachnida:

c. Branchiopoda:

d. Ostracoda:

e. Copepoda:

f. Cirripedia:

g. Malacostraca:

h. Chilopoda:

i. Diplopoda:

j. Insecta:

10-24

THE ARTHROPODS Mark an "X" next to each characteristic that is found in all or some of the members of each of these groups.

Che

licer

ata

Mer

osto

mat

a

Ara

chni

da

Sco

rpio

nes

Ara

nae

Aca

ri

Man

dibu

lata

Cru

stac

ea

Bra

nchi

opod

a

Ost

raco

da

Cop

epod

a

Cir

ripe

dia

Mal

acos

trac

a

Uni

ram

ia

Chi

lopo

da

Dip

lopo

da

Inse

cta

Locomotionwalkingswimmingburrowingsessile

External Anatomyexoskeleton calcifiedexoskeleton sclerotizedtwo valvesexoskeleton none of abovecuticleepicuticleno cuticle6 legs8 legs10 legs12 legsmore than 12 legs2 eyes4 eyes8 eyesno wingswings

Appendageschelideraepedipalpsmandiblesmaxillaechelipedspleopods1 pair antenna2 pair antennaantennules

Other Sensory Organssensory hairsslit organs

Specialitiespoison in oral structurespoison in abdominal structuressilkrepugnatorial glandsluminescence

10-25

SUMMARY & REVIEW 8. What characteristics were necessary for successful colonization of terrestrial habitats?

a.

b.

c.

d. 9. Which class of Arthropods is considered the most successful, based on its diversity and habitats? What anatomical and behavioral features have facilitated that success?

10. Describe, using specific examples, some of the ecologically and economically important arthropods:

EC On a separate sheet of paper, develop your own dichotomous key(s) for: a. Distinguishing the subphyla and classes from one another b. Distinguishing the orders within each class from one another for: 1) Arachnida 2) Insecta

exploring life exercise 10: arthropodsbio.wayne.edu/bio1500/ex10wkbk.pdf · exercise 10: arthropods...

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