Tuesday 1 March 2016

evolution - What is meant in biology by the term "evolved"?

It is a phrase in common parlance without scientific meaning, fitting in the same category as devolved or devolution. It is as @terdon said:




There is no such thing as more or less evolved.




In a scientific context you should always find the evolutionary measure in question and the methods for quantifying that measure.



In a biological context the phrase would fail to find meaning, when evolution is a function of fitness. In such context fitness is inevitably tied to environmental parameters. The more complex these parameters, the more niches may be available for potential species, with temperature being one of the strongest factors (See: Effective evolutionary time Hypothesis ). Take this assertion with the necessary caution, as it is far outside my expertise.



Mostly I have come across the phrase more evolved in reference to large, tangible species, and also in science fiction.



Tell your student, to always be aware that in the end the unicellular species make life for us on this planet viable - we coevolved. But they also eventually consume/recycle us in one way or another, and surely will outlast us. It takes extreme effort and finesse for a large, energetic multicellular host to obtain, maintain and retain its niche on this planet. In all of the field of molecular biology there is nothing quite like Immunology.



For a mind experiment, let the student imagine soil with different pH, of the same plant species which equal seeding-times.



The outcome may be something as shown below. The phrase "more evolved" clearly fails to describe such a scenario of one generation of plant species, and hence is not suitable in an objective description of evolution.



Sidenote: Al3+-ions are toxic to plants, stuning root growth and phosphate intake. With increased pH, more aluminum dissolves.
enter image description here

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