Natural Selection And The Evolution Of Populations
Though each has been tested and shown to be accurate, none of the observations and inferences that underlies natural selection is sufficient individually to provide a mechanism for evolutionary change. Overproduction alone will have no evolutionary consequences if all individuals are identical. Differences among organisms are not relevant unless they can be inherited. Genetic variation by itself will not result in natural selection unless it exerts some impact on organism survival and reproduction. However, any time all of Darwin’s postulates hold simultaneouslyas they do in most populationsnatural selection will occur. The net result in this case is that certain traits will, on average, be passed on from one generation to the next at a higher rate than existing alternatives in the population. Put another way, when one considers who the parents of the current generation were, it will be seen that a disproportionate number of them possessed traits beneficial for survival and reproduction in the particular environment in which they lived.
Study : What Proportion Of College Biology Students Think That Evolution Is Atheistic
In study 2, we wanted to explore atheistic perceptions of evolution in a large number of biology classes across the nation using a closed-ended survey. The decision to use a closed-ended survey in study 2 was a natural progression of the research aims in study 1, we were able to identify students who thought to write about an atheistic perception of evolution, but there may have been a greater number of students who had this perception but just did not choose to write about it. A closed-ended survey allowed us to determine the prevalence of atheistic perceptions of evolution among students in college biology courses, because each student had to choose whether they had an atheistic perception of evolution. Further, a closed-ended survey allowed us to give students the option to choose between an atheistic perception of evolution and an agnostic perception of evolution, something they were not able to do with the open-ended question in study 1. For study 2, we hypothesized that a significant proportion of students would have an atheistic perception of evolution.
No Increase In Genetic Information
There is no known observable process by which new genetic information can be added to an organisms genetic code, let alone how that information could arise from random chemicals in the first place. Information requires an intelligent source, since it requires not only data but also the ability to decode that data. This alone is enough to refute evolution because theres no way for a fish to become an amphibian without new information.
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Study : What Religious Ideas Do Students Think One Has To Reject In Order To Accept Evolution If Students Write That Evolution Has To Be Atheistic Is This Associated With Lower Evolution Acceptance
Although prior qualitative research has shown that students can have concerns about their ability to maintain their religious beliefs and accept evolution , we do not know exactly what religious ideas college biology students think someone would have to reject to accept evolution. Students could have a wide variety of perceptions, including that someone has to completely reject a belief in God in order to accept evolution, which could negatively affect religious students acceptance of evolution. Thus, in study 1, we asked students to answer an open-ended question about the religious ideas that would have to be rejected for someone to accept evolution. We hypothesized that some students would say that it is necessary to reject a belief in God in order to accept evolution, and we also hypothesized that highly religious students who wrote that evolution is atheistic would accept evolution less than highly religious students who did not. This exploratory study allowed us to investigate potential student perceptions and their association with student levels of evolution acceptance.
Typological Essentialist And Transformationist Thinking
Misunderstandings about how variation arises are problematic, but a common failure to recognize that it plays a role at all represents an even a deeper concern. Since Darwin , evolutionary theory has been based strongly on population thinking that emphasizes differences among individuals. By contrast, many naïve interpretations of evolution remain rooted in the typological or essentialist thinking that has existed since the ancient Greeks . In this case, species are conceived of as exhibiting a single type or a common essence, with variation among individuals representing anomalous and largely unimportant deviations from the type or essence. As Shtulman notes, human beings tend to essentialize biological kinds and essentialism is incompatible with natural selection. As with many other conceptual biases, the tendency to essentialize seems to arise early in childhood and remains the default for most individuals .
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Evolution Defined: Macro Vs Micro Evolution
Evolution is a word that is used a lot but is poorly defined. Evolutionists themselves frequently equivocate on the term, using it to mean multiple things, sometimes even within the same sentence.
Macroevolution is used to describe the large-scale changes believed to be able to turn a blob of protoplasm into a person. By contrast, microevolution is intended to describe the small-scale changes in populations, such as those exhibited by the finch populations change beak sizes regularly in response to environmental pressures. However, they remain finches. No new traits or major changes take place.
Since the term evolution is so strongly associated with the particles-to-people myth, we tend to use the word speciation to explain adaptation and variation within the created kinds, such as that exhibited by the finches.Because the small-scale changes generally lead to a loss of genetic information rather than a gain of new information needed to create new traits like arms and eyes, microevolution can never lead to macroevolution. Evolutionists tend to use these ideas interchangeably. For this reason, we avoid those terms, preferring to speak of speciation within created kinds and molecules-to-man evolution .
Evolution Is A Theory Not Just A Hypothesis
Darwin published his theory of evolution in the Origin of Species , with carefully reasoned evidence to support this theory that all life on earth evolved from a common ancestor. This theory has been tested in numerous ways by the work of many thousands of scientists. Every test has produced results that are consistent with the theory. Evolutionary biologists conduct research to elaborate or refine the theory and understand the mechanisms at work in specific populations. Evolutionary theory now forms a framework for biological thinking, so that one famous evolutionary biologist wrote that Nothing in Biology Makes Sense Except in the Light of Evolution .The scientific use of the word theory is very different from the casual, every-day use. A scientific theory is an overarching, unifying explanation of phenomena that is well supported by multiple, independent lines of evidence i.e., composed of hundreds or thousands of independent, well-supported hypotheses. For example, germ theory is the theory that explains how microorganisms cause disease, and cell theory explains how cells function as the basic unit of life.
Title page of Darwins The Origin of Species, 1859 from Wikipedia
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The Evolution Of Primates
All of the primates on Earth evolved from a single common ancestor, most likely a primate-like, insectivore mammal, which lived around 65 million years ago in the Mesozoic Era. At that time, the worlds continents were mostly connected. Fossil evidence suggests that these primitive animals lived an arboreal life, with good eyesight and hands and feet adapted to climbing through trees.
Around 55 million years ago, the first true primates evolved, diverging into the prosimians and simians.
Ancestral prosimians mostly resembled modern prosimians, which include the lemurs , lorises, tarsiers and bush babies. These are small-brained and relatively small-bodied, with a wet nose similar to that of a dog. They are often nocturnal, with body features that are considered primitive, compared to other primates.
The next big divergence occurred around 35 million years ago in the other phylogenetic branch of primates, the simians. This event resulted in the divergence of the common ancestor of all New World monkeys and Old World monkeys.
It is speculated that the two groups underwent divergent evolution as a consequence of allopatric speciation. As the continents of America and Eurasia had by this point separated, the split could have been caused by a chance migration across the Atlantic Ocean.
What Have Genes Got To Do With It
- The mechanisms of evolution operate at the genomic level. Changes in sequences affect the composition and of our genes, the basic units of .
- To understand how different species have evolved we have to look at the DNA sequences in their genomes.
- Our evolutionary history is written into our genome. The human genome looks the way it does because of all the genetic changes that affected our ancestors.
- When DNA and genes in different species look very similar, this is usually taken as evidence of them sharing ancestors.
- For example, humans and the fruit fly, Drosophila melanogaster, share much of their DNA. 75 per cent of genes that cause diseases in humans are also found in the fruit fly.
- DNA accumulates changes over time. Some of these changes can be beneficial, and provide a selective advantage for an organism.
- Other changes may be harmful if they affect an important, everyday function. As a result some genes do not change much. They are said to be conserved.
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How Does Genetic Variation Occur
Genetic variation occurs mainly through DNA mutation, gene flow and sexual reproduction. Since environments are unstable, populations that are genetically variable will be able to adapt to changing situations better than those that do not contain genetic variations.
Sexual reproduction allows for genetic variations to occur through genetic recombination. Recombination occurs during meiosis and provides a way for producing new combinations of alleles on a single chromosome. Independent assortment during meiosis allows for an indefinite number of combinations of genes.
Sexual reproduction makes it possible to assemble favorable gene combinations in a population or to remove unfavorable gene combinations from a population. Populations with more favorable genetic combinations will survive in their environment and reproduce more offspring than those with less favorable genetic combinations.
Evolutionary Thought Since Darwin
Since Darwins time, evolution has become the dominant dogma in the sciences, even in seemingly unrelated areas. It is impossible to go to a secular school and not get overdosed with evolutionary teaching. The base model of the dogma has changed very little since Darwin.
Evolutionists still teach that man evolved from apelike creatures over millions of years. Other aspects of the idea have been filled in so that the evolutionary skeleton looks a little more complete, at least for public consumption. However, digging beneath the surface reveals things are not well in the evolutionary dogma.
Evolution became permanently immortalized in American culture in 1925 in what was termed the Scopes Monkey Trial in Tennessee. Attempting to challenge a Tennessee state law that forbade teaching human evolution, the ACLU prompted a substitute teacher named John Scopes to admit to breaking the law, even though he later acknowledged he had never done so. The trial took on monumental proportions when two of the most famous lawyers in America, Clarence Darrow and William Jennings Bryan, took opposite positions. The trial ended with Scopes being convicted, but not before Darrow tricked Bryan into testifying and used him as a pincushion to mock the Bible.
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Evodevo Plus Endless Prefixes/suffixes
The past decade has seen the addition of modifiers to evodevo to reflect its embracing of other fields. Thus:
Eco-evodevo brings ecology into evodevo .
Evodevoniche construction links development to the evolutionary role of organisms constructing essential elements of their niche such as nests or tunnels .
Behavevodevo is the use of evolutionary developmental mechanisms to explain the origins of behaviors, learning, and language .
Evodevomedicine is the application of evodevo to medical practice .
The future of evodevo may be a continuation of this trend: evodevophysiology evodevolife history evolution.
Cells And Their Constituents
Biologists once depended on the light microscope to study the morphology of cells found in higher plants and animals. The functioning of cells in unicellular and in multicellular organisms was then postulated from observation of the structure the discovery of the chloroplastids in the cell, for example, led to the investigation of the process of . With the invention of the electron microscope, the fine organization of the plastids could be used for further quantitative studies of the different parts of that process.
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The Extent Of The Problem
In its most basic form, natural selection is an elegant theory that effectively explains the obviously good fit of living things to their environments. As a mechanism, it is remarkably simple in principle yet incredibly powerful in application. However, the fact that it eluded description until 150 years ago suggests that grasping its workings and implications is far more challenging than is usually assumed.
Three decades of research have produced unambiguous data revealing a strikingly high prevalence of misconceptions about natural selection among members of the public and in students at all levels, from elementary school pupils to university science majors . A finding that less than 10% of those surveyed possess a functional understanding of natural selection is not atypical. It is particularly disconcerting and undoubtedly exacerbating that confusions about natural selection are common even among those responsible for teaching it. As Nehm and Schonfeld recently concluded, one cannot assume that biology teachers with extensive backgrounds in biology have an accurate working knowledge of evolution, natural selection, or the nature of science.
Table 2 Summary of studies showing the high degree of misunderstanding of natural selection and adaptation among various groups of subjects
Evolution Adaptation And Model Organisms
Biological evolution is the change in inherited traits over successive generations in populations of organisms. Adaptation is a key evolutionary process in which variation in the fitness of traits and species are adjusted by natural selection to become better suited for survival in specific ecological habitats. The environment acts to promote evolution through changes in development. Therefore, determining how developmental changes are mediated is critical for understanding the mechanisms of evolution.
Biological processes are often studied in model organisms. A model organism is a species that is studied extensively in the laboratory with anticipation that the results can be applied to biological phenomena in general. Cave animals can serve as excellent models to study the relationships between the environment, evolution, adaptation, and development. Troglomorphic traits, including elongated appendages, lowered metabolism, specialized sensory systems, and loss of eyes and pigmentation have evolved as a response to the effects of perpetual darkness. In this article, we describe the characid fish Astyanax mexicanus, as a vertebrate model system for studying the developmental basis of evolution and adaptation to the cave environment.
William R. Jeffery, in, 2012
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Evolutions Effects On Christian Theology
Unfortunately, as in Darwins day, much of the church has accepted millions of years and evolution as fact, without ever considering the underlying assumptions or how the acceptance of these assumptions undermines the biblical text and the gospel.
For example, consider what happens when you attempt to add evolution into the Bible. Adam and Eve are no longer the first humans, and original sin goes out the window. This does irreparable damage to the biblical redemption narrative. The Bible says that death came into the world because of mans sin and that all of creation labors under a curse because of sin . Scripture also says that Christ is the last Adam, come to redeem us from the sin brought into the world through the first man, Adam . If Adam were a mythical figure, which is what evolution demands, even in a Christianized form, the entire parallel between the two Adams and the kinsman redeemer concept is destroyed. By advocating evolution, theistic evolutionists are undermining the very tenets of Christianity.
God tells us in Genesis exactly how he created the world, and even the order of events doesnt match the evolutionary tale. In addition, one of the things that drives evolution is death. But the Bible teaches that death was introduced into the perfect world as a result of Adams sin. When Christians try to reinterpret Gods infallible Word based on the ideas of fallible men, it undermines the gospel of Jesus Christ.
The Genetic Challenge To Classic Darwinian Evolution
Darwin had no knowledge of genetics, even though Mendels groundbreaking work on genetics was published during his lifetime. When genetics made its way into mainstream science, evolutionists adapted Darwins ideas to fit the emerging study of genetics, forming what is called the Modern Synthesis of Darwinian evolution, or neo-Darwinism. Most evolutionists today are adherents of neo-Darwinism to one extent or another. Neo-Darwinism emphasizes four major forces: gene flow, genetic drift, natural selection, and mutations. From these four forces, neo-Darwinists believe that they can explain the diversity of life on earth.
Natural selection is the primary mover in the evolutionary dogma. Natural selection allows organisms that are best suited to their environment to survive and pass on their genetics with greater frequency. These organisms, because they are best suited for their environment, produce the most offspring. Over time, the traits of these organisms become dominant in a population. This is where mutations come in.
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Which Traits Are The Most Fit
Directional natural selection can be understood as a process by which fitter traits increase in proportion within populations over the course of many generations. It must be understood that the relative fitness of different traits depends on the current environment. Thus, traits that are fit now may become unfit later if the environment changes. Conversely, traits that have now become fit may have been present long before the current environment arose, without having conferred any advantage under previous conditions. Finally, it must be noted that fitness refers to reproductive success relative to alternatives here and nownatural selection cannot increase the proportion of traits solely because they may someday become advantageous. Careful reflection on how natural selection actually works should make it clear why this is so.