Darwin's Garden

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Presentation to Royal Botanic Gardens Foundation (Sydney) on 10 March 2009

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  • Darwin's Garden

    1. 1. Down House, Downe Darwin’s Garden Travel.webshots.com (magpearlst, london)
    2. 2. Isabela Island, Galapagos Islands (www.animalpicturesarchive.com ) South Plaza Island (Phil’s Public Gallery, Picasa Web Albums)
    3. 3. “ A traveller should be a botanist, for in all views plants form the chief embellishment” Charles Darwin 1831-1836
    4. 4. “ The same eye for detail, and integrative ability that Darwin showed…while aboard the Beagle were in use in the garden, greenhouse, and study in the last 40 years of his life” Patrick Armstrong (2009) Australian Garden History 20(3): 5-8 .
    5. 5. “ It was in the garden that Darwin conducted his botanical experiments on orchids, primroses and cowslips… It must have been the most charming laboratory in the world! And down the gravel path is a kitchen garden and greenhouses which are really the HQ of Darwin’s botanical investigations.”
    6. 6. “ He was an inveterate collector and hoarder – shells, postal franks, birds’ eggs, and minerals” Adrian Desmond & James Moore (1991) Darwin
    7. 7. Andy Muirhead and Donna Osland, 4 December 2008
    8. 8. Confidants, correspondents and colleagues Sir Joseph Dalton Hooker Director Royal Botanic Gardens Kew 1865–1885
    9. 9. He served them roast beef, vegetables, hard-boiled eggs… Adrian Desmond & James Moore (1991) Darwin
    10. 10. Carnivorous plants
    11. 11. They took their food like animals, secreting similar digestive juices, itself “a new and wonderful fact” Charles Darwin
    12. 12. “ I care more about Drosera than the origin of all the species in the world” Charles Darwin
    13. 13. Stylidium Trigger Plant
    14. 14. “ I never was more interested in any subject in my life than this of Orchids” Charles Darwin
    15. 15. “ It is hardly an exaggeration to say that Nature tells us, in the most emphatic manner, that she abhors perpetual self-fertilisation.” Charles Darwin
    16. 17. ***Add flying duck orchid from ?Nelson trip? Flying Duck Orchid Caleana major
    17. 19. “ It may be worth while to give another a more complex illustration of the action of natural selection” Charles Darwin [after discussing wolves and sea-birds]
    18. 20. Schotia brachypetala www.toof.org.uk/identify/birdcherry/ birdcherry.html
    19. 21. Some plants excrete sweet juice (to eliminate something injurious from the sap) Insects eat this sweet product, to no obvious benefit to the plant [although they can attract beneficial insects to eat pests…] If the juice was excreted inside the flower of some individuals, the visiting insects would get dusted with pollen, transporting it from one flower to another These individuals would be ‘crossed’, giving rise to more vigorous seedlings with the ability to adapt to change The plants with the largest ‘juice excreting systems inside their flower’ (nectaries) would be visited by more insects and be crossed more often – in the long-run they would ‘gain the upper hand and form a local variety’ Similarly, plants producing flowers with their reproductive parts arranged or shaped to attract insects and/or maximise the amount of pollen dusted on to them, would ‘likewise be favoured’ Even if the insect devours pollen, as long as there is a net gain to the plant in its chances of reproducing, and crossing, it is likely to be ‘favoured’
    20. 22. Red Clover (www.panoramio.com/photo/10625768)
    21. 23. The tubes at the base of a clover flower vary in length, and hold nectar. The hive-bee can get nectar from the Incarnate Clover ( Trifolium incarnatum ) but not the Red Clover ( Trifolium pratense ). The humble-bee, however, has a ‘proboscis’ long enough to reach into the tube of the Red Clover to get the nectar. Hive-bees like the Red Clover nectar, and in autumn they will bite holes in the base of the tube to get at it. The difference in tube length is very small – in fact, anecdotally, if the red clover is mown, the second crop sometimes has slightly smaller flowers and the nectar in these flowers can be reached by the hive-bees! Red clover is very common in England and it would seem to be a great advantage for the hive-bee to have a longer, or different shaped, proboscis, to get at its nectar. From the plant’s point of view, it depends upon bees for fertilisation so if humble-bees became rare, those individual plants with shorter tubes allowing the hive-bee to get the nectar, would be more likely to reproduce and be ‘favoured’ Darwin thus said that he could understand how such a system could adapt and change over time.
    22. 24. Angraecum sesquipedale Star of Bethlehem Xanthopan morganii praedicta
    23. 25. Where’s Wallace?
    24. 26. “ I never saw a more striking coincidence. If Wallace had my M.S. sketch written out in 1842 he could not have made a better short abstract! Even his terms now stand as Heads of my Chapters.” Charles Darwin
    25. 27. ‘ Wanted Poster’ published by Alfred Russel Wallace (1867) “ The proboscis of a hawkmoth from tropical Africa ( Xanthopan morganii ) is seven inches and a half. A species having a proboscis two or three inches longer could reach the nectar in the largest flowers of Angræcum… That such a moth exists in Madagascar may be safely predicted, and naturalists who visit that island should search for it with as much confidence as astronomers searched for the planet Neptune – and they will be equally successful."
    26. 28. “… in over 200 years only about 172,000 species have been described from an estimated 580,000-680,000 species that actually live here [in Australia].” Proceedings of the National Taxonomy Forum 2007 surface of Mars, 2008
    27. 29. The ‘tree of life’ a phylogeny http:// stri.discoverlife.org ] brown algae blue-green algae red algae euglenids Chlorarachniophytes green plants land plants fungi flowering plants, conifers, cycads, ferns, mosses green algae
    28. 30. “ If I met Darwin today, I’d tell him that we have worked out his ‘abominable mystery’ – that is, the origins and the family tree for flowering plants.” Peter Weston
    29. 31. “ The theory of evolution…is the only theory we know of that is in principle capable of explaining the existence of organised complexity ” Richard Dawkins “ Nothing in biology makes sense except in the light of evolution ” Theodosius Dobzhansky
    30. 32. Royal Botanic Gardens 2009 – our ‘thinking path’ The Sand Walk, Darwin’s ‘thinking path’

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