LCMartin's Thoughts

Rhineura (Worm Lizards), Lizards, and Earthworms                     Rhineura (worm lizards) and common lizards share a similarly shaped skull. They also share a common lizard ancestor, explaining the similarity in their skull shape. Worm lizards, however, have evolved using their skull to burrow underground and to spend most of its time moving and living underground. This has caused its skull to change slightly in structure to be harder.   Its life underground also accounts for the fact that the worm lizard is limbless and nearly blind.   Spending most of its time burrowing through the ground caused it to lose its limbs because they hindered its ability to burrow and caused it to lose its eyesight because it is not necessary to see when burrowing through dirt constantly.   A common lizard may use its skull to help it burrow but will also use its limbs to dig out a burrow and use it as a home.   It doesn’t live...

      I would argue that Thomas Malthus had the most influence over Darwin’s development of his theory of natural selection.  Malthus’ Essay on the Principle of Population pointed out that the increase in human population was growing despite not having sufficient resources available to support growth.  This concept inspired Darwin and he, along with Wallace, extended the concept to include all organisms which set up the basis of Darwin’s future theory of natural selection, the competition for resources.  The traits that allowed certain species to survive and thrive in an environment of limited resources would be passed on to future generations, whereas the less advantageous traits in a species that limited certain organism's ability to survive, ultimately ending in its demise, would hence naturally eradicate that trait from future generations.  Thomas Malthus’ idea of competition for resources provided the necessary groundwork for the theory of natur...