the properties of life emerge from complex organization. biology

1 ANSWERS

1. amomipais82
   

   Hi There,
   The two KEY ones are #2 (Reproduction ... or more correctly, replication with inheritance) and #4 (Energy Utilization ... or more correctly, metabolism).
   
   I highly recommend the cover-story in the current (June '07) issue of Scientific American, which specifically addresses how, and in what order, replication and metabolism first arose in the earliest pre-life structures.
   
   All the others emerge as a consequence of these two (#2 and #4). Or more correctly, #2 and 4 lead to #1, 2, 5, and 6, which together are enough to support #7, which itself supports increases in 1-6. (I said this is complex.)
   
   As to how the others emerge as a consequence of #2 and #4:
   
   #1 Order is maintained (homeostasis) and increased through the expenditure of energy. E.g. the sodium-potassium pump in cellular membranes is just a structure that converts energy into maintaining homeostasis within the membrane, which is the same as maintaining the thermodynamic imbalance (order) between the inside and outside of the membrane. Order is increased through the process of growth and development (see #3).
   
   #3, Growth and Development is both energy expenditure and the execution of the structure of inheritance. E.g., specific sequences of nucleotides determine not only the order of amino acids of proteins, but how much of each protein to make, the order in which to make them, the assembly of these proteins into structures (membranes -> organelles -> cells and the cells -> tissues -> structures -> organs -> organism). All traceable to hierachies of instructions in the inheritance molecule (DNA or RNA) ... instructions whose job it is to turn other instructions on or off.
   
   #5, Response to Environment is precisely a conversion of energy. E.g., photopigments in the eye are simply proteins that change shape when they absorb photons of certain wavelengths, which begins a chain reaction of energy-driven events that eventually leads to muscles moving.
   
   #6, Homeostasis is just maintained order (see #1), so again, it is also maintained through expediture of energy.
   
   #7, Evolutionary Adaptation is explained by mutation + natural selection, which itself is explained by replication (but not completely error-free replication) + energy utilization occurring in environments with limited energy resources. I.e. competition for those energy resources means that those structures more efficient at getting those resources will, through inheritance, produce more structures just like them (but occasionally not exactly like them).

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