Evolution Quotes

“But if they’re all rigid and stiff, then how do they move at all? Ahhh, that’s where the joints come in. The stiff shells and tubes are jointed, and the muscles that move their bodies are attached to the insides of them. This gives them rigid bodies, but flexible, movable legs. The arthropod’s body is built in sections or segments, and pairs of limbs stick out from the side or the bottom of certain body segments. The typical insect, like an ant or beetle, has a head, thorax and abdomen, along with three pairs of leg segments, giving them six legs altogether. To move, each leg moves (from the ‘hip’ joint where it contacts the body) up, forward, back, then down in an alternating pattern, driving the insect forward.”
― Glenn Murphy, Evolution: The Whole Life on Earth Story: The Whole Life-On-Earth Story