Message 1274 of 1323 (843377)
11-17-2018 8:11 AM
Reply to: Message 1268 by creation
11-15-2018 7:54 PM
Re: Conclusion vs Assumption, Belief, teach the difference
|What science covers/deals with the far past early history of man and what nature existed? None. Pretending science is needed/available to deal with this is not honest.|
This thread is about what we should teach in school and whether both evolution and religion should be taught in public schools in the US.
One way to teach learning is to ask questions, so let's ask the question: what can we learn about early humans and the world they live in?
Your answer: nothing. Because you can't know the past nature (whatever that may be).
MY answer: a lot.
First we define the process of Evolution:
(1) The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities for growth, development, survival and reproductive success in changing or different habitats.
Then we note that this is sometimes called microevolution, however this is the process through which all species evolve and all evolution occurs at the breeding population level.
Mutations to existing hereditary traits (ie for eyes and ears) can cause changes in the composition of hereditary traits for individuals in a breeding population, but not all mutations are expressed (and many are in non-hereditary areas). In addition there are many different kinds of mutations and they have different effects (from small to large), especially if they affect the developmental process of an organism.
Natural Selection and Neutral Drift can cause changes in the frequency distribution of hereditary traits within a breeding population, but they are not the only mechanisms known that does so. Selection processes act on the expressed genes of individual organisms, so bundles of genetic mutations are selected rather than individual genes, and this means that non-lethal mutations can be preserved. The more an individual organism reproduces the more it is likely to pass on bundles of genes and mutations to the next generation, increasing the selection of those genes.
The ecological challenges and opportunities change when the environment changes, when the breeding population evolves, when other organisms within the ecology evolve, when migrations change the mixture of organisms within the ecology, and when a breeding population immigrates into a new ecology. These changes can result in different survival and reproductive challenges and opportunities, affecting selection pressure, perhaps causing speciation, perhaps causing extinction.
This is a two-step feedback response system that is repeated in each generation:
Like walking on first one foot and then the next.
Mutations of hereditary traits have been observed to occur, and thus this aspect of evolution is an observed, known objective fact, rather than an untested hypothesis.
Different mixing of existing hereditary traits (ie Mendelian inheritance patterns) have been observed to occur, and thus this aspect of evolution is an observed, known objective fact, rather than an untested hypothesis.
Natural selection has been observed to occur, along with the observed alteration in the distribution of hereditary traits within breeding populations, and thus this aspect of evolution is an observed, known objective fact, and not an untested hypothesis
Neutral drift has been observed to occur, along with the observed alteration in the distribution of hereditary traits within breeding populations, and thus this aspect of evolution is an observed, known objective fact, and not an untested hypothesis.
Thus many processes of evolution are observed, known objective facts, and not untested hypothesies.
Next, if we look at the continued effects of evolution over many generations, the accumulation of changes from generation to generation may become sufficient for individuals to develop combinations of traits that are observably different from and unknown in the earlier parent population.
(2) The process of lineal change within species is sometimes called phyletic speciation, or anagenesis.
This is also sometimes called arbitrary speciation in that the place to draw the line between linearly evolved genealogical populations is subjective, and because the definition of species in general is tentative and sometimes arbitrary.
If anagenesis was all that occurred, then all life would be one species, readily sharing DNA via horizontal transfer (asexual) and interbreeding (sexual) and various combinations. This is not the case, however, because there is a second process that results in multiple species and increases the diversity of life.
(3) The process of divergent speciation, or cladogenesis, involves the division of a parent population into two or more reproductively isolated daughter populations, which then are free to (micro) evolve independently of each other.
The reduction or loss of interbreeding (gene flow, sharing of mutations) between the sub-populations results in different evolutionary responses within the separated sub-populations, each then responds independently to their different ecological challenges and opportunities, and this leads to divergence of hereditary traits between the subpopulations and the frequency of their distributions within the sub-populations.
Over generations phyletic change occurs in these populations, the responses to different ecologies accumulate into differences between the hereditary traits available within each of the daughter populations, and when these differences have reached a critical level, such that interbreeding no longer occurs, then the formation of new species is deemed to have occurred. After this has occurred each daughter population microevolves independently of the other/s. These are often called speciation events because the development of species is not arbitrary in this process.
If we looked at each branch linearly, while ignoring the sister population, they would show anagenesis (accumulation of evolutionary changes over many generations), and this shows that the same basic processes of evolution within breeding populations are involved in each branch.
An additional observable result of speciation events, however, is a branching of the genealogical history for the species involved, where two or more offspring daughter species are each independently descended from the same common pool of the ancestor parent species. At this point a clade has been formed, consisting of the common ancestor species and all of their descendants.
With multiple speciation events, a pattern is formed that looks like a branching bush or tree: the tree of descent from common ancestor populations. Each branching point is a node for a clade of the parent species at the node point and all their descendants, and with multiple speciation events we see a pattern form of clades branching from parent ancestor species and nesting within larger clades branching from older parent ancestor species.
Where A, B, C and G represent speciation events and the common ancestor populations of a clade that includes the common ancestor species and all their descendants: C and below form a clade that is part of the B clade, B and below form a clade that is also part of the A clade; G and below also form a clade that is also part of the A clade, but the G clade is not part of the B clade.
The process of forming a nested hierarchy by descent of new species from common ancestor populations, via the combination of anagenesis and cladogenesis, and resulting in an increase in the diversity of life, is sometimes called macroevolution. This is often confusing, because there is no additional mechanism of evolution involved, rather this is just the result of looking at evolution over many generations and different ecologies.
The process of anagenesis, with the accumulation of changes over many generations, is an observed, known objective fact, and not an untested hypothesis.
The process of cladogenesis, with the subsequent formation of a branching nested genealogy of descent from common ancestor populations is an observed, known objective fact, and not an untested hypothesis.
This means that the basic processes of "macroevolution" are observed, known objective facts, and not untested hypothesies, even if major groups of species are not observed forming (which would take many many generations).
At this point we can pause and note that creationism claims that animals and plants etc are divided into created "kinds" and that each "kind" reproduces after their "kind" ... cows beget cows, dogs beget dogs, etc but cows do not beget dogs. Thus there is a "bovine kind" and a "canine kind" ... and they can microevolve from the original created "kind" to a family of related species -- the "bovine kind" evolving into all the species of cows, buffalos, etc. and the "canine kind" evolving into all the species of dogs, wolves, foxes, etc.
If we compare this to the diagram above we see that all descendants of (A) have each been begat by their parents according to their breeding population at the time. That the breeding pattern of creationist "kinds" matches the pattern of clades, and that there is a "bovine clade" and a "canine clade" ... and the question then becomes what is the original population? Is there a definite original original population that did not evolve from an older parent population? How can we find this out?
Your answer: you can't. Because you can't know the past nature (whatever that may be).
MY answer: by looking at the evidence of the past and seeing what it tells us.
First we define the Theory of Evolution:
(4) The Theory of Evolution (ToE), stated in simple terms, is that the process of anagenesis, and the process of cladogenesis, are sufficient to explain the diversity of life as we know it, from the fossil record, from the genetic record, from the historic record, and from everyday record of the life we observe in the world all around us.
And we note that this theory can be tested by:
- experiments and field observations carried out as part of the sciences of biology, ecology and evolution.
- the fossil record, by comparing fossils to see the relationships in location and time and see how species have evolved from species, we can look for the "original created kind" for each living species by tracing their ancestry into the past. And
- the genetic record, by comparing genomes of living species to each other and to genomes of past species (neanderthals for instance), we can see how the DNA has changed from parent populations to daughter populations, and we can look to see if there is a point at which there was an "original created kind" or whether the pattern of descent keeps extending into the past.
If a species is observed to change over generations (anagenesis), we can predict that it will be due to (a) changes in the expressed hereditary traits (genes, morphology, development), (b) that the changes were either neutral or improved the survival and reproductive success of individuals in response to their ecological challenges and opportunities and (c) that if they improved the fitness of the carriers that it will spread within the breeding population in following generations. We can look for this happening in the past.
If a clade is observed to form (cladogenesis), we can predict that it will be due to (a) reproductive isolation between daughter populations and (b) independent evolution (anagenesis) within each daughter population. We can also predict the formation of the clade will fall within a nested hierarchy pattern, and we can look for this happening in the past.
For instance, we can look at the fossil record for Pelycodus:
A Smooth Fossil Transition: Pelycodus, a primate
Pelycodus was a tree-dwelling primate that looked A complete fossil much like a modern lemur. The skull shown is probably 7.5 centimeters long.
The numbers down the left hand side indicate the depth (in feet) at which each group of fossils was found. As is usual in geology, the diagram gives the data for the deepest (oldest) fossils at the bottom, and the upper (youngest) fossils at the top. The diagram covers about five million years.
The numbers across the bottom are a measure of body size. Each horizontal line shows the range of sizes that were found at that depth. The dark part of each line shows the average value, and the standard deviation around the average.
The dashed lines show the overall trend. The species at the bottom is Pelycodus ralstoni, but at the top we find two species, Notharctus nunienus and Notharctus venticolus. The two species later became even more distinct, and the descendants of nunienus are now labeled as genus Smilodectes instead of genus Notharctus.
As you look from bottom to top, you will see that each group has some overlap with what came before. There are no major breaks or sudden jumps. And the form of the creatures was changing steadily.
Pelycodus is from a group of creatures which collectively are thought to be the ancestors of modern monkeys and apes. The diagram represents the whole of the early Eocene, spanning very approximately 55 million years ago to 50 million years ago. The fossils are from sediment in the Bighorn Basin of Wyoming.
Each horizontal line shows the range, the mean, and the standard error of the mean. As you can see from the ranges, a larger sample would have been nice.
This is not a new result. Matthew noted in 1915 that these populations were evolving steadily, not only in size, but also in other characters not clearly correlated with size. The diagram is based on
Gingerich, P.D. 1976. Paleontology and phylogeny: Patterns of evolution at the species level in early Tertiary mammals, American Journal of Science 276:1-28.
Gingerich has since extended this work, but the conclusion has not changed.
Here we can observe both anagenesis in the changes from population to population, level by level, and cladogenesis in the division of the populations at the top.
Similar study can be done with DNA comparisons:
Complete Neanderthal Genome Sequenced
DNA Signatures Found in Present-Day Europeans and Asians, But Not In Africans
Bethesda, Md., Thurs., May 6, 2010 - Researchers have produced the first whole genome sequence of the 3 billion letters in the Neanderthal genome, and the initial analysis suggests that up to 2 percent of the DNA in the genome of present-day humans outside of Africa originated in Neanderthals or in Neanderthals' ancestors.
he current fossil record suggests that Neanderthals, or Homo neanderthalensis, diverged from the primate line that led to present-day humans, or Homo sapiens, some 400,000 years ago in Africa. Neanderthals migrated north into Eurasia, where they became a geographically isolated group that evolved independently from the line that became modern humans in Africa. They lived in Europe and western Asia, as far east as southern Siberia and as far south as the Middle East.
Approximately 30,000 years ago, Neanderthals disappeared. That makes them the most recent, extinct relative of modern humans, as both Neanderthals and humans share a common ancestor from about 800,000 years ago. Chimpanzees diverged from the same primate line some 5 million to 7 million years ago.
The researchers compared DNA samples from the bones of three female Neanderthals who lived some 40,000 years ago in Europe to samples from five present-day humans from China, France, Papua New Guinea, southern Africa and western Africa. This provided the first genome-wide look at the similarities and differences of the closest evolutionary relative to humans, and maybe even identifying, for the first time, genetic variations that gave rise to modern humans.
To understand the genomic differences between present-day humans and Neanderthals, the researchers compared subtle differences in the Neanderthal genome to the genomes found in DNA from the five people, as well as to chimpanzee DNA. An analysis of the genetic variation showed that Neanderthal DNA is 99.7 percent identical to present-day human DNA, and 98.8 percent identical to chimpanzee DNA. Present-day human DNA is also 98.8 percent identical to chimpanzee.
"The genomic calculations showed good correlation with the fossil record," said coauthor Jim Mullikin, Ph.D., an NHGRI computational geneticist and acting director of the NIH Intramural Sequencing Center. "According to our results, the ancestors of Neanderthals and modern humans went their separate ways about 400,000 years ago."
So once again we can see that anagenesis has occurred in the evolution of humans and neanderthals from a common ancestor by the 99.7 percent similarity inherited from a common ancestor, and we can see cladogenesis by the 0.3% differences that have built up since divergence from a common ancestor.
Likewise we can see that anagenesis has occurred in the evolution of humans and neanderthals and chimpanzees from a common ancestor by the 98.8 percent similarity inherited from a common ancestor, and we can see cladogenesis by the 1.2% differences that have built up since divergence from a common ancestor.
So the ToE predictions can be tested against the fossil record, the genetic record, the historical record, and the everyday record of life we observe in the world all around us. Biologists have been testing this theory for 150 plus years, and thus far they have confirmed that the process of evolution, and the process of speciation, are sufficient to explain the diversity of life as we know it.
Furthermore, there has been no evidence of this process halting at some common point in time that would indicate diversification from an original common ancestor "kind" -- either after Noah (circa 4,500 years ago), nor from original creation (circa 6,000 years ago). The evidence shows that the creationist interpretation of the bible is in error. The earliest common ancestor found is single cell organisms back at the dawn of life.
We can know parts of the past by studying the evidence that has been left for us to find and study, with the brains we have been given, to understand what has happened ... to the best of our abilities to understand.
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| ||Message 1268 by creation, posted 11-15-2018 7:54 PM|| ||creation has responded|