Conifers for Christmas: Evolution above the level of species

Post provided by  Aelys Humphreys

Conifers for Christmas

It’s somehow fitting that the centre piece of an ancient midwinter tradition in Europe – that of decorating and worshipping an evergreen tree – is an ancient seed plant, a conifer. In Europe, we tend to think of conifers as “Christmas trees” – evergreen trees with needles and dry cones, restricted to cold and dry environments – but conifers are much more diverse and widespread than that. There are broad-leaved, tropical conifers with fleshy cones and even a parasitic species that is thought to parasitise on members of its own family!

Conifer diversity. Classic Christmas tree style conifers in the snow; a broadleaved, tropical podocarp (© Ming-I Weng); the only parasitic gymnosperm, Parasitaxus usta (©W. Baker).

Conifer diversity. Classic Christmas tree style conifers in the snow; a broadleaved, tropical podocarp (© Ming-I Weng); the only parasitic gymnosperm, Parasitaxus usta (©W. Baker).

However, while today’s distribution of conifers is global – spanning tropical, temperate and boreal zones – it is fragmented. The conifer fossil record extends well into the Carboniferous and bears witness to a lineage that was once much more abundant, widespread and diverse. So we can tell that today’s diversity and distribution have been shaped by hundreds of millions of years of speciation, extinction and migration. Continue reading

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