Stages in the evolution of the eye a A pigment spot b A simple pigment cup c The simple optic cup found in abalone d The complex lensed eye of the marine snail and the octopus The eye is an example of a supposedly irreducibly complex structure, due to its many elaborate and interlocking parts, seemingly all dependent upon one another. It is frequently cited by intelligent design and creationism advocates as an example of irreducible complexity. Behe used the "development of the eye problem" as evidence for intelligent design in Darwin's Black Box. Although Behe acknowledged that the evolution of the larger anatomical features of the eye have been well-explained, he pointed out that the complexity of the minute biochemical reactions required at a molecular level for light sensitivity still defies explanation.
What is natural selection, and how is it central to the theory of evolution? Natural selection is how species evolve by adapting to their environment. Natural selection explains design in nature. Charles Darwin studied beak variation of finches on the Galapagos Islands as evidence of natural selection.
Molecules to Man, Natural selection is the process by which species adapt to their environment. Natural selection leads to evolutionary change when individuals with certain characteristics have a greater survival or reproductive rate than other individuals in a population and pass on these inheritable genetic characteristics to their offspring.
Simply put, natural selection is a consistent difference in survival and reproduction between different genotypes, or even different genes, in what we could call reproductive success.
It is the one process that is responsible for the evolution of adaptations of organisms to their environment. Evidence to support evolution and natural selection, of course, has accumulated over time, and now science accepts that evolution is a fact and that natural selection explains very well how adaptive evolution takes place.
Is natural selection the only mechanism of evolution? Evolution has several mechanisms. Genetic drift involves random changes. There cannot be evolution without genetic variation in the first place. So there must be mutation and often recombination to generate the different genotypes or the different versions of the genes, known as alleles, which then may or may not make a difference in the ability of an organism to survive and reproduce.
But once you have genetic variation, there are basically two major possibilities: Natural selection is more consistent, adaptive change.
First, there is simply no difference between the different genotypes or different genes in their impact on survival or reproduction, and in that case, you can have random changes of one versus the other type in a population or a species until eventually one replaces the other. That is an evolutionary change.
It happens entirely by chance, by random fluctuations. That is what we call the process of genetic drift. Genetic drift is very different from possibility number two, natural selection, which is a much more consistent, predictable, dependable change in the proportion of one gene vs.
Simply because there is some consistent superiority, shall we way, of one genotype vs. Does natural selection lead to new species, and if so, how? Natural selection plays a role in the origin of new species.
It sometimes does but not always. A great deal of evolution by natural selection can happen without the formation of new species.
Natural selection is only the process of adaptation within species, and we see many examples of that. The process of splitting and becoming reproductively isolated, that is, incapable of breeding with one another, can often involve natural selection but perhaps not always.
Some take natural selection to mean survival of the fittest. How does this slogan sometimes lead to misconceptions? There may be several different types that are equally fit for different reasons. One is not going to replace the other because each has its proper place in the environment.
Natural selection is a difference in reproductive success that involves both the ability to survive until reproductive age and then the capacity to reproduce.
That is simply false. Evolution involves unpredictable chance. Chance means essentially that you cannot predict the outcome of a particular event. For example, you cannot predict whether your next child will be a son or a daughter, even though you can specify the probability or likelihood.
Evolution certainly does involve randomness; it does involve unpredictable chance. For example, the origin of new genetic variation by mutation is a process that involves a great deal of chance.Summary.
This lesson is aligned with the NGSS science practices of engaging in argument from evidence using mathematical and computational thinking and analyzing and interpreting data. Darwin's theory of evolution by natural selection provided the first, and only, causal-mechanistic account of the existence of adaptations in nature.
As such, it provided the first, and only, scientific alternative to the “argument from design”. That alone would account for its philosophical. The arguments for God's existence are variously classified and entitled by different writers, but all agree in recognizing the distinction between a priori, or deductive, and a .
If anything natural selection would be an argument FOR vegetarianism and veganism since most people in the world traditionally ate a plant based diet. Meat is added during the seasons when vegetables are in short supply, or to augment essentially vegetable meals. 54 Views.
A Summary of the Logic of Natural Selection Three inductions from observation and two nec essary deductive conclusion If Inductions (derived directly from observation) are true t hen the Deductions (A & B) necessarily follow.
Irreducible complexity (IC) is the idea that certain biological systems cannot evolve by successive small modifications to pre-existing functional systems through natural selection. Irreducible complexity is central to the creationist concept of intelligent design, but it is rejected by the scientific community,  which regards intelligent.