A change in the timing and location of gene activity did the trick:
The team discovered that around 450-million years ago a switch enabled plants to delay reproduction and displace new cells downwards from the shoot tips, paving the way to plant diversification. Using cutting-edge developmental and genetic techniques, the team studied the swollen reproductive structures at the tips of the small stems of mosses. These plants, which represent a starting point for plant evolution, are raised upwards by new cells generated in the middle of the stem. Despite their different patterns of growth, similar genes are responsible for elongating the stems of mosses and plants with more elaborate shoots.
Contrary to prior work, the results demonstrate a nascent mechanism for shoot development as plants first emerged on land and suggest that a change in the timing and location of gene activity triggered the radiation of shooting forms.
Dr. Jill Harrison, the study’s lead author and Senior Lecturer from Bristol’s School of Biological Sciences, explains: “By comparing our new findings from a moss with previous findings, we can see that a pre-existing genetic network was remodelled to allow shoot systems to arise in plant evolution.”University of Bristol, “Genes that first enabled plants to grow leaves identified by scientists” at Phys.org
It looks very much like a plan rather than an accident.
See also: Researchers: Photosynthesis May Be A Billion Years Older Than Thought … But WAIT!
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