External Morphology
Study of the external features, body segmentation (head, thorax, abdomen), exoskeleton, and various appendages like antennae, mouthparts, legs, wings, and anal cerci.
What is External Morphology?
A rigid external covering for the body in some invertebrate animals, providing support and protection.
Key points
- Identify and describe the three main body parts of a cockroach.
- Explain the composition and function of the exoskeleton.
- List and describe the appendages found on the head, thorax, and abdomen.
- Differentiate between the forewings (tegmina) and hindwings.
Common exam trap
Confusing the number of thoracic segments.
Definitions
- Term
Exoskeleton
- Meaning
A rigid external covering for the body in some invertebrate animals, providing support and protection.
- Term
Tegmina
- Meaning
The hardened, leathery forewings of cockroaches and some other insects, which protect the membranous hindwings.
- Term
Anal Cerci
- Meaning
A pair of sensory appendages located at the posterior end of the abdomen in cockroaches and other insects, used to detect air currents and vibrations.
- Term
Compound Eye
- Meaning
An eye consisting of numerous small visual units (ommatidia), typically found in insects and crustaceans.
Learning objectives
Identify and describe the three main body parts of a cockroach.
Explain the composition and function of the exoskeleton.
List and describe the appendages found on the head, thorax, and abdomen.
Differentiate between the forewings (tegmina) and hindwings.
Recognize the sensory role of antennae and anal cerci.
Prerequisites
Basic understanding of animal body plans.
Familiarity with insect anatomy basics.
Knowledge of arthropod characteristics.
Common mistakes
Confusing the number of thoracic segments.
Misidentifying the function of tegmina (forewings).
Forgetting the presence and function of anal cerci.
Incorrectly stating the body is radially symmetrical.
Keywords
Cockroach
External Morphology
Head
Thorax
Abdomen
Exoskeleton
Antennae
Compound Eye
Mouthparts
Legs
Wings
Tegmina
Anal Cerci
Arthropoda
Insecta
Practice preview
The mouthparts of a cockroach are described as:…
medium
Which of the following statements about the cockroach's abdomen is INCORRECT?…
medium
Which part of the cockroach's body is responsible for locomotion?…
easy