Adaptations: Survival of the fittest

Morphological Adaptations:
    In order to withstand the elements and interactions between other regional organisms, the Macadamia tetraphylla has developed some important physical adaptations.  Here, natural selection has chosen the best qualities to thrive, and therefore give rise to more organisms with these desired aspects.  The two most distinct qualities within the Macadamia tetraphylla are found in the nut and the root system.
    Nut:
        The nut of the Macadamia tetraphylla is roughly 2-3 cm think.  For those of you that don't know, that's very dense!  There are many reasons for this thickness in nut coating.  One of many reasons is to aid in dispersal of the nut.  Many birds and and small rodents will pick up fallen Macadamia nuts in order to eat them.  The problem, however, is that many of these birds or small rodents cannot break through the shell!  So, after transporting it a distance from the parental tree, the animal tries- and generally fails- to open the shell to get to the kernel.  After a certain period of unsuccessful attempts, the organism gives up and leaves the seed.  Then, the seed just lies there and waits for the proper conditions until it can grow.  Another reason for the shell thickness is to aid in seed viability.  Due to the environment that they live in, Macadamia trees sometimes encounter droughts.  Here, the thickness of the shell, and just vast size, allow for the food and water within the nut to continue to feed the seed.  The thickness helps to prevent desiccation. 
    Root system:
        Similar to the nut, the root system aids in times of drought.  The vast system of roots allows for the uptake of the majority of the water around the organism.  This is important because during times of drought, the tree may not receive water from rainfall for a long period of time.  Therefore, the massive root system aids the tree in taking up as much water as possible while it is available.  In addition, it may also be able to obtain water through underground streams or any form of ground water.  Another reason for the large root system is to support the tree.  The Macadamia tree has broad leaves that will catch wind very easily.  In order to support the tree and avoid wind damage, the roots need to be vast and have a firm hold onto the substrate.

Hybridization:
    The genus Macadamia includes more than 10 different species of plants.  The two most common are the Macadamia tetraphylla and the Macadamia integrifolia.  In the wild, these species have been known to reproduce together to create a hybrid that is generally know as Macadamia ternifolia.  This hybrid of plant tends to have a thinner shell than the other two species of Macadamia; however, their kernel is larger.  This is very useful in the commercial world.  The hybrid Macadamia ternifolia is used as a commercial crop to grow the majority of the macadamia nuts that are produced, and are especially prevalent in Hawaii's commercial growing business. 
    Nutritionally, the kernel in the hybrid's nut is full of many beneficial fatty acids.  In fact, macadamia seed nut oil that was produced from a hybrid has a similar composition to olive oil.  Except, they say it's even healthier!

Cultivation:
    When cultivating the Macadamia tetraphylla, these plants are able to adapt to their changed environments.  Although they might not grow in their natural habitats, the plants are still able to prosper through some very basic adaptations.  For example, if grown in an environment with more rainfall or less soil drainage, the plants will leave the stomata open longer to allow for transpiration of the water out of the leaves.  This then allows the roots to take in the extra water in the soil without taking in too much and drowning the plant. 
    For more information on adaptations due to cultivation, click here.

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