Questions and Answers
What are insects?
phylum arthropoda, superclass/subphylum Hexapoda, class insecta
What is subclass hexapoda?
Six-legs, body segments organised into three groups: head, thorax and abdomen
What is class insecta?
Simple eyes (ocelli) and compound eyes usually present, legs with at least 6 segments, exposed mouthparts (ectognathus) consisting of mandibles, maxillae and labium
What is the evolution of six-legged arthropods (Hexapoda)?
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What are non-insect hexapods?
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Before which period were all the major groups of modern insects established?
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What do insects in amber provide?
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What are Pterygotes unusual for?
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What does the EXITE-ENDITE HYPOTHESIS suggest?
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What are the routes to flight from small winglets?
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What characterizes Collembola, or springtails?
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What are Proturans?
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What characterizes STREPSIPTERA?
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What are the classifications of mouthparts?
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What are mandibulate mouthparts?
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What are suctorial mouthparts?
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What characterizes Coleopteran species?
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What does Siphonaptera have?
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What are wings in insects?
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Study Notes
General Overview of Insects
- Insects belong to the phylum Arthropoda, specifically the superclass/subphylum Hexapoda and class Insecta.
- Characterized by three body segments: head, thorax, and abdomen; the presence of six legs.
Morphological Features
- Class Insecta features simple eyes (ocelli) and compound eyes; legs contain a minimum of six segments.
- Mouthparts are ectognathous, meaning they are externally visible, consisting of mandibles, maxillae, and labium.
Evolutionary Background
- The earliest known hexapods, Collembola (springtails), date back to the Devonian period, approximately 394-401 million years ago.
- Most modern insect groups emerged before the Triassic period (245 million years ago), with Hymenoptera and Lepidoptera being exceptions.
Fossils and Historical Insights
- Insects preserved in amber date from 45 to 15 million years ago, offering valuable insights into their history.
Flight Adaptations
- Pterygotes uniquely retain all limbs while developing wings, which might have evolved from gill structures in aquatic ancestors.
- Multiple theories suggest that pathways to flight may have included floating, paragliding, running-jumping, and surface sailing.
Non-Insect Hexapods
- Include groups such as Protura, Collembola, and Diplura, which present distinct anatomical features like a lack of antennae in Proturans.
Specific Insect Groups
- Collembola (Springtail): possess a ventral tube for jumping, lack cerci, and are primarily detritivores.
- Proturans: characterized by a lack of antennae, exist in soil and leaf litter environments, with mouthparts hidden in the head.
- Strepsiptera: exhibit bulbous eyes and have both parasitic males and wingless females, primarily targeting Hemiptera and Hymenoptera.
Mouthpart Classifications
- Mouthparts can be categorized as entognathous (hidden) or ectognathous (visible).
- Mandibulate mouthparts are adapted for gripping or chewing, while suctorial mouthparts are specialized for liquid feeding, with variations found across different insect orders.
Insect Wing Structure
- Wings develop only in adult life stages, sharing a basic structure characterized by three zones and eight wing veins across all winged insects.
Families and Orders
- Further exploration of specific orders such as Blattodea (cockroaches), Coleoptera (beetles), Hymenoptera (bees, ants, wasps), Lepidoptera (butterflies, moths), Odonata (dragonflies, damselflies), and Orthoptera (grasshoppers, crickets) can provide additional insights into diversity and adaptations within the class Insecta.
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Description
Explore the fascinating world of insects with this quiz on their classifications. Learn about their biological definitions, subclasses, and physical characteristics. Perfect for biology students or anyone interested in entomology!