Posted on Friday May 24, 2019
Mention fossils and you’re sure to grab public interest. This was evident in the age range of the crowd in the theatre for Professor James Crampton’s lecture on “The give and take of biodiversity.” Families, students of all ages, and people interested in science, geology and fossils – like me (and probably you) were eager to get started.
Prof. Crampton’s talk is part of Victoria University’s “Blood from a Stone” series. The series culminates in a field trip fossil hunt which is guaranteed to be a crowd pleaser if the murmur of excitement that rippled through the audience is anything to go by.
One memorable concept Prof. Crampton introduced was how life on Earth is sustained. He presented a graph with gas concentrations necessary for life. Then what that graph would look like without life – vastly different. Apparently, Earth’s mean temperatures of 15C today would be -18C without the effect that life has in regulating conditions.
Another fascinating concept was that Earth is essential a microbial soup. The complex life we all recognise (plants, animals – and us) is outweighed by the microbes abundant on our ball of dirt and water. It’s not really ours at all – it belongs to the microbes.
Prof. Crampton veered into mathematical territory highlighting the amazing discovery that the periods of rapid explosions of species diversity evident in Earth’s past align with features of Mars’ orbit.
The peaks and troughs of population estimates across vast lengths of geological time are produced by two underlying wave patterns. These waves align with wobbles in Mars’ orbit (much like a spinning top) in its journey around the Sun. This produces small variations in Earth’s orbit, tweaking the conditions for life. In effect, Mars is a “celestial species pump“ – driving global growth conditions on Earth.
Sometimes the changes are favourable and there’s an explosion of life – other times the Earth becomes a giant slushy and population diversity declines.
Prof. Crampton then got into the subject matter that excites him – fossilised snails and clams. In question time he confessed that his favourite fossils are giant 2-metre-long clams. His analysis shows that local populations seem to have an in-built regulator and go through periodic explosions and drops in diversity and numbers through geologic time.
It was a fascinating and well delivered presentation – keep your eye out for the next ones in the series.
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