Evolutionary history shows in opossum ears, according to a study in ScienceDaily 16 February 2017. Scientists from University of Illinois, King’s College London and University of Chicago have studied the process for forming the jaw and two of the middle ear bones in the opossum, in order to find evidence for the evolutionary theory that mammal ear bones evolved from reptile jaw bones. This theory is based on the fact that reptiles have one bone in their middle ear and many bones in their jaw, while mammals have three middle ear bones and one jaw bone. Daniel Urban, who led the study, explained: "We came at this project through the approach of evolutionary developmental biology (evo-devo), which looks at the development of an organism…to help understand its evolutionary history." (words in brackets in original)

The American opossum was chosen for the study as it is born in a very immature stage with its jaw and ears not yet fully formed, so scientists can easily study the development as the baby continues to grow.

First they carefully studied the formation of the jaw and ear bones. Their study confirmed that in the early development of the opossum an elongated bar of cartilage named Meckel’s cartilage grows and then splits up. Two of these split off pieces develop into the malleus and incus bones as the ear is formed, and they link up to the third middle ear bone, the stapes to form a chain of bones between the eardrum and the inner ear.  The rest of Meckel’s cartilage is incorporated into the jaw.

They then studied the cellular processes and gene expression involved in splitting the ear bone precursors from Meckel’s cartilage, and found a gene named TGF-β made a protein that caused some cells in Meckel’s cartilage to die off, thus causing the cartilage to split at that point. When they blocked the activity of the protein the split did not occur and the developing ear bones remained attached to the developing jaw. ScienceDaily summarised the results as: “With one tweak of gene activity, this one detail of anatomy appeared to have slid backward through evolutionary time.”

ScienceDaily

Editorial Comment:  Did you also catch their starting point: "We came at this project through the approach of evolutionary developmental biology (evo-devo), which looks at the development of an organism…to help understand its evolutionary history." In other words they approached this study with the results already in their minds. They interpreted the way jaw and ear bones develop according to a previously held belief that reptiles evolved into mammals, and that the mammal ear bones used to be reptile jaw bones.

This concept that embryonic development is a re-enactment of evolution, is based on the totally discredited theory put forward by Ernst Haeckel, and summarised as “ontogeny (development) recapitulates phylogeny (evolution)”. In spite of the fact that Haeckel’s original diagrams used to support this theory have been proven fakes, the belief has been firmly embedded in the minds of evolutionists. How self-condemning when they accuse Christians of starting with a belief system when we share the truth of God as Creator.

Let us also suggest a more objective summary: ‘with one tweak of gene activity they messed up the opossum’s jaw and ears’. They don’t say what happened if they allowed the developing opossums to continue to grow, but we suspect they would have died anyway as meddling with the TGF-β signalling would have ruined other developmental processes.  Furthermore, survival without hearing ears or chewing jaws means being deaf and starving, and then soon dead – no help to evolution. (Ref. Mammals, embryology, embryogenesis)

Evidence News vol. 17, No. 2
7 March 2017
Creation Research Australia

 

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