Podcast
Questions and Answers
What is one distinguishing feature of members in the Class Insecta?
What is one distinguishing feature of members in the Class Insecta?
Which characteristic is NOT typical of Class Arachnida?
Which characteristic is NOT typical of Class Arachnida?
In Class Crustacea, which of the following appendages are typical?
In Class Crustacea, which of the following appendages are typical?
Which statement about Class Chilopoda is true?
Which statement about Class Chilopoda is true?
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How is the gonopore positioned in Class Diplopoda?
How is the gonopore positioned in Class Diplopoda?
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What distinguishes the tagmata of Class Arachnida from those of Class Insecta?
What distinguishes the tagmata of Class Arachnida from those of Class Insecta?
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What type of eyes do insects possess?
What type of eyes do insects possess?
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Which of the following statements about Class Crustacea is correct?
Which of the following statements about Class Crustacea is correct?
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Study Notes
Class Insecta
- Distinguishing characteristics:
- Three distinct body regions (tagmata): head, thorax, and abdomen
- Three pairs of legs in adult stage
- Typically one or two pairs of wings, if present
- Single pair of segmented antennae on the head
- Two types of eyes: compound and simple
Relatives of Insects
Class Arachnida
- Little evidence of external segmentation
- Two body regions (tagmata): prosoma (cephalothorax) and opisthosoma
- Prosoma:
- Chelicerae, pedipalps, and four pairs of legs
- Simple eyes; no antennae
- Opisthosoma:
- Without locomotor appendages
- Gonopore hidden on the ventral surface of the opisthosoma (embryologically segment 2)
Class Crustacea
- Varied tagmata: head and thorax covered by an unsegmented carapace (shield-like plate) and distinctly segmented abdomen
- Appendages: biramous (composed of two branches)
- Compound eyes on long stalks
- Head appendages:
- Two pairs of antennae
- One pair of mandibles
- Two pairs of maxillae
- Gonopores (external openings of reproductive tract): one pair located on the base of posterior appendages of the thorax
Class Chilopoda or Symphyla (Centipede)
- Distinct external segmentation
- Two body regions (tagmata): head and trunk
- Head:
- One pair of antennae
- Mandibles
- Two pairs of maxillae
- Trunk:
- 12 pairs of legs
- Most segments with one pair of legs, some without legs
- Gonopore: unpaired, on segment 4 of the trunk in front of the legs
Class Diplopoda (Millipede)
- Plainly evident external segmentation
- Tagmosis (body division) not pronounced: distinct head followed by an enlarged dorsal segment (collum) resembling those of the trunk
- Trunk:
- Composed of thorax and abdomen
- Thorax poorly differentiated from the collum and abdomen
- Thorax distinguished by having only one pair of legs on each of the three segments
- Legs moved forward on segments 1 and 2
- Abdomen: almost all apparent segments have two pairs of legs
- Gonopore: paired, at the base of the legs or segment 2 of the thorax
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Description
Test your knowledge on the distinct characteristics of Insecta and its relatives, including Arachnida and Crustacea. This quiz covers their body structures, adaptations, and key similarities and differences. Perfect for biology students looking to enhance their understanding of these important classes.
