Geoscience Reference
In-Depth Information
For example,
Austrobaileya scandens
, a perennial flowering vine that com-
poses part of the shady undergrowth in the rainforest, is the only species repres-
enting its clade worldwide. To see any of its relatives, you would have to look at
the fossil record; its pollen closely resembles that of the oldest known flowering-
plant pollen in Australia, dating from the Early Cretaceous at about 120 million
yearsold.Unlikemanyfloweringplants,flies—notbutterfliesorbees—pollinateits
flowers,whichisbetter understoodwhenyousniffitsbroad,light-green flowerand
recoil from the rotten-meat smell. From these flowers, it produces plum-sized fruits
with about a dozen large seeds in its middle covered by only a thin layer of fleshy
goodness. Nonetheless, this fruit is on the extensive menu of cassowaries, hence
this plant probably depends on them to carry its seeds farther away from where
theymightjustfalloffthevines.Nodoubtotherlocalbirds—includingbowerbirds,
fairy-wrens,honeyeaters, andriflebirds—also helpwithseeddispersal intheforest,
but none had the voluminous guts of cassowaries. Even on a dare, I wouldn't swal-
low some of these fruits whole, yet cassowaries were doing it every day, transport-
ing the seeds far and wide through the forest, while also helpfully depositing them
with warm nitrogen- and phosphorus-rich fertilizer on top.
Earlier in the day, Chris and I explained to the students some of this basic in-
formation about the ecological importance of cassowaries, but also how these huge
birds are endangered owing to a lethal combination of habitat degradation and pre-
mature deaths. With regard to the latter, while driving into the area that morning
we saw many large yellow cautionary road signs saying “Cassowary Crossing” that
also graphically depicted a car striking a cassowary. Young cassowaries are also
vulnerable to predation by dogs, not being big enough to take on an aggressive can-
ine, let alone a ferocious pack.
We were thus becoming filled with this academic knowledge that was being
reinforced by reality, a most satisfying way to learn. So after walking another kilo-
meter down the trail past more tracks and scat, everyone had relaxed, including me.
Patches of sunlight reaching the forest floor surely contributed to our sense of ease.
