[Campbell Biology P.586] The 405-million-year-old fossil of Aglaophyton major Figure 25.13 p... | Practice Question

The 405-million-year-old fossil of Aglaophyton major Figure 25.13 provides significant insight into early life. What is its primary significance as described in the text and figure?

  • A: It represents the earliest known terrestrial vertebrate, demonstrating early land colonization by animals.
  • B: It documents the existence of mycorrhizae in early plants, suggesting an ancient plant-fungal symbiosis crucial for land plant evolution.
  • C: It shows the first evidence of eukaryotic cells with both mitochondria and plastids, supporting the endosymbiotic theory.
  • D: It illustrates the diversification of lobe-finned fishes, which later gave rise to tetrapods.

Explanation

Figure 25.13 and its accompanying text specifically describe Aglaophyton major as documenting 'mycorrhizae in the early plant' and showing 'a branched fungal structure called an arbuscule; the fossil arbuscule resembles those seen in plant cells today.' This highlights its significance in providing evidence for ancient plant-fungal symbiosis, which was crucial for plants colonizing land.