On 9/24/2021 10:20 AM, Glenn wrote:
> "As a final example, fish residing in cave environments display distinctive traits such as reduced eyes and pigmentation. The standard evolutionary story is that these traits gradually developed through natural selection. But experiments over the past decade on the effects of exposing fish to cave-like conditions are changing the narrative."
OK, tell us how these are not just normal gene duplication events and
recombination of DNA? How were these events directed? What is the
result of such events, and do they occur when they are needed or are
they just occurring all the time?
Rohner et al. in a 2013 study raised A. mexicanus embryos in water with
low conductivity mimicking cave conditions. The embryos developed into
adults with significantly smaller eyes. Corral and Aguirre in a 2019
study raised A. mexicanus in different temperatures and different levels
of water turbulence. The variant conditions resulted in adult fish
differing in vertebral number and body shape. For instance, fish raised
in more turbulent water displayed more streamlined bodies and extended
dorsal and anal fin bases that improved their mobility in that
environmental condition. And Bilandžija et al. in a 2020 study raised
the same species in darkness, and the fish developed many cave-related
traits such as resistance to starvation and altered metabolism and
hormone levels. Future research will likely uncover even more examples
where cave-specific adaptations result not from random mutations but
from internal mechanisms.
How long have we known that development is affected by environmental
conditions, and that developmental programs were plastic and could
produce an array of phenotypes dependent on environment. Mutations do
not have to happen to get this to work, it just happens with the
existing program. Look up the vast literature on environment and
genetic expression. The new synthesis geneticists put it into their
equations around 90 years ago.
Phenotypic variance = genotypic variances + environmental variances +
genotype-environment interaction + experimental "error" variance
i.e., σ²P = σ²G + σ²E + σ²GE + σ²
or σ²P = σ²A + σ²D + σ²I + σ²E + σ²GE + σ²
Wow the ID perps have rediscovered environmental effects on genetics,
just about a century too late.