Saturday Science Links: December 6, 2014
Many of this week's science links happen at the wondrous intersection of mystery and discovery.
Evolution Basics: Darwin’s Early Observations on Biogeography
For Darwin, both of these observations (that oceanic islands lacked terrestrial mammals, and that endemic species on islands were most similar to a species on the closest mainland) had the same explanation: his hypothesis that endemic, oceanic species were the modified descendants of a colonizing species from the nearest continent.
Where are the Transitional Fossils?
A common argument leveled against the theory of evolution is that scientists have not been able to produce transitional fossils that show the change of one species into another. In this podcast, we address a common misconception about what transitional fossils actually are.
What evidence do we have for evolution besides fossils and genes?
Scientists have found multiple lines of evidence for evolution, not just one or two. These types of evidence are independent of each other, coming from sources as different as ancient fossils and modern genetics labs. Evidence also comes from comparing the anatomy of creatures living today. All creatures with four limbs (whether mammals, birds, or reptiles) have the same bone structure in each limb, pointing to their descent from a common ancestor. More evidence comes from biogeography. Isolated islands are missing common species found on the mainland, but are filled with many unique species that can be related by a common ancestor. Finally, evidence comes from embryonic development. As an embryo of a mammal grows, its heart develops through stages similar to fish, amphibians, and reptiles. God’s creation declares the history of life in many different ways. All these ways are pointing to a consistent picture of God creating through evolution.
The Fossil Record
There are two opposite errors which need to be countered about the fossil record: 1) that it is so incomplete as to be of no value in interpreting patterns and trends in the history of life, and 2) that it is so good that we should expect a relatively complete record of the details of evolutionary transitions within all or most lineages.
Theory, Prediction and Converging Lines of Evidence, Part 3
One aspect of Christian anti-evolutionary materials that I find frustrating is that the broad sweep of evidence for evolution is avoided in favor of focusing in on specific, isolated details in an attempt to refute them individually.
Series: Evidences for Evolution (7 entries)
This technical series, co-written by Darrel Falk and David Kerk, looks into the evidence for evolution in order to dispel doubts that people may have about this well-supported theory. They look at three things specifically: the separate methods which reveal of the age of the earth, the unfolding history of whale evolution, and finally the common trends of heart development in vertebrates.
Series: Misconceptions About Evolution (2 entries)
This two-part series highlights some of the most common misconceptions about evolution and some helpful responses to them.
Series: New Limbs from Old Fins (7 entries)
Stephen Matheson presents common descent by evolution as the best explanation for the universal pattern found in tetrapod limbs. He discusses initially the evolution and development of limbs in specifically vertebrate tetrapods. He looks at the question of origins and further digs into amazing fossil discoveries. He then gives evidence of evolution from fish to tetrapods by discussing the similarities in the anatomy, development, and genetic systems associated with this amazingly common pattern in vertebrate appendages.
Series: The Cambrian "Explosion", Transitional Forms, and the Tree of Life (8 entries)
Many evolutionary critics have identified the Cambrian Explosion as a stumbling block to the theory of evolution, arguing that the “expected transitions between major invertebrate phyla are absent, and that the suddenness of their appearance in the fossil record demonstrates that evolutionary explanations are not viable.” Keith Miller argues that the Cambrian Explosion is not so problematic as these opponents claim after all.
Songs and Speciation
How many times have you heard someone ask the question: "Have scientists ever actually observed the formation of a new species?" In this PNAS article, Peter and Rosemary Grant actually demonstrate the key events in the formation of a new species as it occurred before their very eyes.
A Tale of Two Papers
Kenneth Miller tells a story of catching two students plagiarizing. It seemed quite clear that the two students had submitted the same papers, but the two argued it was merely by chance and that the fact that they were roommates explained why the papers seemed similar.
In The Bones
I am a fan of the blog "Jesus Creed." Recently it published an interesting post about the transition from fins to limbs as evidenced by fossils of an organism trapped in sediment 375 million years ago.
What does the fossil record show?
Fossils provide a unique view into the history of life by showing the forms and features of life in the past. Fossils tell us how species have changed across long periods of the Earth’s history. For instance, in 1998, scientists found a fossil showing an animal at the transition from sea creature to land creature. This tetrapod had a hand-like fin, confirming a prediction of evolutionary biology. Though the fossil record does not include every plant and animal that ever lived, it provides substantial evidence for the common descent of life via evolution. The fossil record is a remarkable gift for the study of nature.