How has the appendages of arthropods changed over evolution?

Answer 1

The modifications of arthropod appendages has shaped the formation of different groups, such as centi/millipedes, crustaceans, arachnids and insects. The most primitive arthropods are centipedes and millipedes, using all their legs as walking legs. More advanced groups, differing from this ancestral state, modified their walking legs into mouthparts, antennae, pedipalps (arachnids) or flippers (crustaceans, look at a lobster tail).

Look carefully at an insect face and you'll see it's a fused mess of segments with the legs still attached! Stick insects and beetles are a good example, other groups have modified their palps (mouth-legs) into unrecognizable structures such as mosquito or butterfly probosci.

Answer 2

1. Fewer body segments

2. More specialized appendages for feeding, movement, and other functions