- Human: Develops distinct head, limbs, and facial features; tail regresses; body proportions change to upright posture.
- Chicken: Forms beak, wings, and legs; tail shortens; feathers begin to develop; body becomes compact for flight.
- Rabbit: Limbs elongate; ears grow large; fur develops; tail shortens; body shape adapts for hopping.
- Tortoise: Shell begins to form over spine; limbs become sturdy with claws; head and neck elongate; tail remains small.
- Salamander: Gills regress as lungs develop; limbs grow longer; tail remains prominent; skin becomes moist and smooth.
- Fish: Fins develop fully; gills become functional; tail fin grows for propulsion; body streamlines for swimming.
1. In their earliest stages, all six embryos show a similar basic body plan: a curved body, a prominent head, pharyngeal arches (gill slits), a tail, and limb buds. They share the presence of a notochord, dorsal nerve cord, and segmented muscle blocks (somites).
2. Yes, this suggests an evolutionary relationship. The shared embryonic structures indicate these organisms inherited developmental patterns from a common ancestor. As development progresses, species-specific adaptations emerge, but the early similarities reflect conserved genetic and developmental pathways, supporting the theory of descent with modification.
Parent Tip: Review the logic above to help your child master the concept of comparative embryology worksheet.
