Final answer:
The color and weight variations in German Shepherds over generations are due to sexual reproduction, which creates genetic diversity. Starfish often reproduce asexually through fragmentation, resulting in less genetic variation since the offspring are clones of the parent.
Step-by-step explanation:
The variation in color and weight among German Shepherds over four generations is more noticeable than in starfish due to different modes of reproduction. German Shepherds reproduce sexually, resulting in genetic diversity because of the combination of genes from both parents. In contrast, starfish often reproduce asexually through fragmentation, where each fragment can regenerate into a new individual starfish. This type of reproduction leads to offspring that are genetically identical to the parent, resulting in less variation over generations.
As explained in LibreTexts™, fragmentation allows a whole new individual to grow from a part of the parent organism. If starfish are cut into pieces, each piece can regenerate into a complete organism, provided the pieces include part of the central disc. This is why the practice of cutting starfish to reduce their numbers can backfire; instead of reducing the population, it doubles because of regeneration abilities. German Shepherds do not have this capability, and with sexual reproduction in play, genetic recombination and potential mutations influence the variation in physical traits.