Lichens `much younger than scientists 以前 thought´
Most people have seen lichen, whether they know it or not.
For those not in the know, it is that crusty, mouldy looking stuff often seen on trees or 激しく揺するs.
And to those in the know, it’s a combination of algae and fungi living together almost as if they were one organism.
Either way, lichens are something scientists have long believed to be some of the first organisms to make their way の上に land from water ? until now.
A new 熟考する／考慮する upends the idea that lichen changed the 惑星’s atmosphere and 覆うd the way for modern 工場／植物s.
Crustose Porpidia lichen growing on a 激しく揺する (Matthew P Nelsen, Field Museum/PA)
Published in the Geobiology 定期刊行物, it delves 深い into the デオキシリボ核酸 of the algae and fungi that form lichens, showing they likely 発展させるd millions of years after 工場／植物s.
Matthew Nelsen, lead author of the paper and a 研究 scientist at the Field Museum in America, said: “When we look at modern ecosystems, and we see a 明らかにする surface like a 激しく揺する, oftentimes lichens are the first thing to grow there, and 結局 you’ll get 工場／植物s growing on there too.
“People have thought that maybe that’s the way 古代の colonisation of land worked, but we’re s eeing that these lichens 現実に （機の）カム later in the game than 工場／植物s.”
Four hundred and eighty-five million years ago, hardly anything lived on land.
But lichens can live in extreme 条件s, grow on 明らかにする 激しく揺するs and break them 負かす／撃墜する, helping to create the 国／地域 needed by コンビナート／複合体 工場／植物s with roots.
Scientists thought they must have arrived on land before such 工場／植物s, making the 環境 more hospitable.
However, the new 熟考する／考慮する ? which was 目的（とする）d at how the algae-fungi 関係 （機の）カム to be ? calls the timeline into question.
To 正確に 決定する when lichens 発展させるd, scientists 診察するd the evolutionary history of both the fungi and algae that make them up.
But the 早期に lichen 化石 記録，記録的な／記録する isn’t very （疑いを）晴らす, and all the 化石s that scientists know for sure are lichens are younger than the oldest コンビナート／複合体 工場／植物 化石s.
Therefore, the 研究員s used the 化石s that were 利用できる to extrapolate the ages of family trees of lichen-forming fungi and algae.
They compared these with ages of 化石 工場／植物s, and 設立する lichens probably 発展させるd long after コンビナート／複合体 工場／植物s.
Dr Nelson said: “Lichens aren’t as old as we thought they were.
“They’re a younger, newer sort of symbiosis and 港／避難所’t been around forever, covering the earth long before there were 工場／植物s and animals running around.”
He 追加するd that the 発見 reshapes the understanding of the 早期に 進化 of コンビナート／複合体 ecosystems on earth.
