However, religious creation stories and the idea of "intelligent design" can be taught in philosophy, religion, or history courses. Religion and Science provide different approaches to knowledge. It is important to understand both.
What Is Evolution? Biological evolution is genetic change in a population from one generation to another. The speed and direction of change is variable with different species lines and at different times. Continuous evolution over many generations can result in the development of new varieties and species. Likewise, failure to evolve in response to environmental changes can, and often does, lead to extinction. When scientists speak of evolution as a theory they do not mean that it is a mere speculation.
It is a theory in the same sense as the propositions that the earth is round rather than flat or that our bodies are made of atoms are theories. Most people would consider such fundamental theories to be sufficiently tested by empirical evidence to conclude that they are indeed facts.
As a result of the massive amount of evidence for biological evolution accumulated over the last two centuries, we can safely conclude that evolution has occurred and continues to occur. All life forms, including humans, evolved from earlier species, and all still living species of organisms continue to evolve today. They are not unchanging end-products. For those who have difficulty in accepting evolution because of what they perceive as contradictions with their fundamental religious beliefs, it may be useful to distinguish the ultimate origin of life from its later evolution.
Many, if not most, biological scientists accept that primordial life on earth began as a result of chance natural occurrences 3. However, it is not necessary to believe in that view in order to accept that living creatures evolved by natural means after the origin of the first life. Charles Darwin modified his religious beliefs, as did many others, as a result of the discovery of convincing proof of evolution. Darwin's religious faith was also severely challenged by the death of his 10 year old daughter Annie in Apparently, he came to believe that his God created the order of the universe including the rules of nature that result in biological evolution.
His famous book, On the Origin of Species , was not a denial of his God's existence. However, he did reject a literal interpretation of the Judeo-Christian Bible. His religious beliefs were probably very similar to those who advocate "theistic evolution" today.
We now understand that there are a number of different natural processes that can cause evolution to occur. These are presented in a later tutorial of this series Modern Theories of Evolution. The evidence for evolution has primarily come from four sources:. The Fossil Record. Remains of animals and plants found in sedimentary rock deposits give us an indisputable record of past changes through vast periods of time. This evidence attests to the fact that there has been a tremendous variety of living things.
Some extinct species had traits that were transitional between major groups of organisms. Their existence confirms that species are not fixed but can evolve into other species over time. The evidence also shows that what have appeared to be gaps in the fossil record are due to incomplete data collection. The more that we learn about the evolution of specific species lines, the more that these so-called gaps or "missing links in the chain of evolution" are filled with transitional fossil specimens.
One of the first of these gaps to be filled was between small bipedal dinosaurs and birds. Just two years after Darwin published On the Origin of Species , a million year old fossil of Archaeopteryx was found in southern Germany. It had jaws with teeth and a long bony tail like dinosaurs, broad wings and feathers like birds, and skeletal features of both.
This discovery verified the assumption that birds had reptilian ancestors. Since the discovery of Archaeopteryx , there have been many other crucial evolutionary gaps filled in the fossil record. Evidence of a common ancestor for all of life is reflected in the universality of DNA as the genetic material and of the near universality of the genetic code and the machinery of DNA replication and expression.
Fundamental divisions in life between the three domains are reflected in major structural differences in otherwise conservative structures such as the components of ribosomes and the structures of membranes.
In general, the relatedness of groups of organisms is reflected in the similarity of their DNA sequences—exactly the pattern that would be expected from descent and diversification from a common ancestor.
DNA sequences have also shed light on some of the mechanisms of evolution. For example, it is clear that the evolution of new functions for proteins commonly occurs after gene duplication events. These duplications are a kind of mutation in which an entire gene is added as an extra copy or many copies in the genome. These duplications allow the free modification of one copy by mutation, selection, and drift, while the second copy continues to produce a functional protein. This allows the original function for the protein to be kept, while evolutionary forces tweak the copy until it functions in a new way.
The evidence for evolution is found at all levels of organization in living things and in the extinct species we know about through fossils. Fossils provide evidence for the evolutionary change through now extinct forms that led to modern species.
For example, there is a rich fossil record that shows the evolutionary transitions from horse ancestors to modern horses that document intermediate forms and a gradual adaptation o changing ecosystems. The anatomy of species and the embryological development of that anatomy reveal common structures in divergent lineages that have been modified over time by evolution. The geographical distribution of living species reflects the origins of species in particular geographic locations and the history of continental movements.
The structures of molecules, like anatomical structures, reflect the relationships of living species and match patterns of similarity expected from descent with modification. The fact that DNA sequences are more similar in more closely related organisms is evidence of what? Fundamental divisions in life between the three domains are reflected in major structural differences in otherwise conservative structures such as the components of ribosomes and the structures of membranes.
In general, the relatedness of groups of organisms is reflected in the similarity of their DNA sequences—exactly the pattern that would be expected from descent and diversification from a common ancestor. DNA sequences have also shed light on some of the mechanisms of evolution. This video defines evolution and discusses several varieties of evidence that support the Theory of Evolution:.
Although the theory of evolution generated some controversy when it was first proposed, it was almost universally accepted by biologists, particularly younger biologists, within 20 years after publication of On the Origin of Species.
Nevertheless, the theory of evolution is a difficult concept and misconceptions about how it works abound. Scientists have a theory of the atom, a theory of gravity, and the theory of relativity, each of which describes understood facts about the world. In the same way, the theory of evolution describes facts about the living world. As such, a theory in science has survived significant efforts to discredit it by scientists. This is a mischaracterization.
Evolution is the change in genetic composition of a population over time, specifically over generations, resulting from differential reproduction of individuals with certain alleles.
When thinking about the evolution of a characteristic, it is probably best to think about the change of the average value of the characteristic in the population over time. If one measures the average bill size among all individuals in the population at one time and then measures the average bill size in the population several years later, this average value will be different as a result of evolution. Although some individuals may survive from the first time to the second, they will still have the same bill size; however, there will be many new individuals that contribute to the shift in average bill size.
First, the statement must not be understood to mean that individual organisms evolve. A changed environment results in some individuals in the population, those with particular phenotypes, benefiting and therefore producing proportionately more offspring than other phenotypes. This results in change in the population if the characteristics are genetically determined.
It is also important to understand that the variation that natural selection works on is already in a population and does not arise in response to an environmental change. For example, applying antibiotics to a population of bacteria will, over time, select a population of bacteria that are resistant to antibiotics. The resistance, which is caused by a gene, did not arise by mutation because of the application of the antibiotic. The gene for resistance was already present in the gene pool of the bacteria, likely at a low frequency.
The antibiotic, which kills the bacterial cells without the resistance gene, strongly selects individuals that are resistant, since these would be the only ones that survived and divided. Experiments have demonstrated that mutations for antibiotic resistance do not arise as a result of antibiotic. In a larger sense, evolution is not goal directed. Evolution has no goal of making faster, bigger, more complex, or even smarter species, despite the commonness of this kind of language in popular discourse.
What characteristics evolve in a species are a function of the variation present and the environment, both of which are constantly changing in a non-directional way. What trait is fit in one environment at one time may well be fatal at some point in the future.
People on all sides of the creation debate are convinced the other sides are doing it all wrong. After taking part in many conversations where people talk past one another, BioLogos forum moderator Christy has noticed a few recurring themes. Part Three in the Uniquely unique mini-series. We look to morality, language, and culture, and start to see that our species is quite an outlier. Author of "Thriving with Stone Age Minds," Justin Barrett responds to the reaction some people have to the idea of evolutionary psychology.
Biogeography predicted by evolution The theory of evolution predicts patterns of species not just over time in the fossil record, but also in the distribution of species today around Earth—the study of which is called biogeography. Genetics removes all reasonable doubt The relationships between species inferred from biogeography, the fossil record, and the shapes and structures of animals today now have their most impressive confirmation from the recently developed field of genetics.
What is BioLogos? Subscribe Now What is BioLogos? Common Question. How could humans have evolved and still be in the "Image of God"? What is the genetic evidence for human evolution? What is evolution? What is Evolutionary Creation? Is Evolutionary Creation compatible with biblical inerrancy?
Podcast Episode. Article Advanced. By Stephen Schaffner. Blog Post. By Christy Hemphill. By Justin Barrett. Guest Cart. It looks like your cart is empty!
0コメント