lpetrich
03-20-2009, 11:11 AM
An interesting category of design deficiency is limited scaling; designs that do not scale all the way to whatever absolute physical limits may exist. Some examples:
Palm-tree heights
Palm trees are monocot plants; following the typical monocot pattern, they have one stem (the trunk) which goes straight up with constant or tapering thickness, with leaves being continually sprouted from the end as the stem grows. Like other monocots, they do not have outward-growing trunks (secondary growth), and like most other monocots, they do not have side branching.
A problem with this "design" is that the trees eventually get tall enough to become top-heavy. However, conifers and dicot plants avoid this problem by growing outward as well as upward, producing more bulk in their lower trunks, and thus more strength where it is needed. This helps explain why conifers and dicots have been more successful at achieving greater gigantism.
The tallest monocot is the wax palm (Ceroxylon quindiuense) of Colombia, which grows up to 60 m with a trunk diameter of 30 - 40 cm that tapers off to 10 cm at full height. The tallest dicot is the mountain ash (Eucalyptus regnans) of Tasmania, which grows up to 120 m with a trunk diameter up to 6 m. The tallest conifer is the coast redwood (Sequoia sempervirens), which grows up to 115 m with a trunk diameter up to 8 m. The bulkiest plant is a close relative of the giant redwood, the giant sequoia (Sequoiadendron giganteum), which grows up to 95 m with a trunk diameter up to 17 m.
Arthropod skeletons
Arthropods use their outer skins as their skeletons, and they molt their skins as they grow. Having to survive between molts can be awkward, especially on land, where one will not be buoyed by surrounding water.
By contrast, vertebrate skeletons are internal, and are not molted; vertebrates have been much more successful at achieving gigantism. The largest known arthropod is the Middle Devonian eurypterid (sea scorpion) Jaekelopterus rhenaniae, which grew to as much as 2.5 m long.
However, that is far short of what vertebrates have been able to achieve. The longest present-day one on record is a 33-m-long blue whale (Balaenoptera musculus), and the longest present-day cold-blooded-one on record is a 12-m-long whale shark (Rhincodon typus). Some extinct sharks and bony fish, like the late-Cenozoic shark Carcharodon megalodon and the mid-Jurassic bony fish Leedsichthys problematicus, grew to whale-shark sizes or larger.
Palm-tree heights
Palm trees are monocot plants; following the typical monocot pattern, they have one stem (the trunk) which goes straight up with constant or tapering thickness, with leaves being continually sprouted from the end as the stem grows. Like other monocots, they do not have outward-growing trunks (secondary growth), and like most other monocots, they do not have side branching.
A problem with this "design" is that the trees eventually get tall enough to become top-heavy. However, conifers and dicot plants avoid this problem by growing outward as well as upward, producing more bulk in their lower trunks, and thus more strength where it is needed. This helps explain why conifers and dicots have been more successful at achieving greater gigantism.
The tallest monocot is the wax palm (Ceroxylon quindiuense) of Colombia, which grows up to 60 m with a trunk diameter of 30 - 40 cm that tapers off to 10 cm at full height. The tallest dicot is the mountain ash (Eucalyptus regnans) of Tasmania, which grows up to 120 m with a trunk diameter up to 6 m. The tallest conifer is the coast redwood (Sequoia sempervirens), which grows up to 115 m with a trunk diameter up to 8 m. The bulkiest plant is a close relative of the giant redwood, the giant sequoia (Sequoiadendron giganteum), which grows up to 95 m with a trunk diameter up to 17 m.
Arthropod skeletons
Arthropods use their outer skins as their skeletons, and they molt their skins as they grow. Having to survive between molts can be awkward, especially on land, where one will not be buoyed by surrounding water.
By contrast, vertebrate skeletons are internal, and are not molted; vertebrates have been much more successful at achieving gigantism. The largest known arthropod is the Middle Devonian eurypterid (sea scorpion) Jaekelopterus rhenaniae, which grew to as much as 2.5 m long.
However, that is far short of what vertebrates have been able to achieve. The longest present-day one on record is a 33-m-long blue whale (Balaenoptera musculus), and the longest present-day cold-blooded-one on record is a 12-m-long whale shark (Rhincodon typus). Some extinct sharks and bony fish, like the late-Cenozoic shark Carcharodon megalodon and the mid-Jurassic bony fish Leedsichthys problematicus, grew to whale-shark sizes or larger.