Discussion of everything related to the Theory of Evolution.
Gamila, this explanation of species was recommended to me by a science teacher who uses it a resource. Since it's not all that bad I'm considering using this one to help form my explanation. It shows why speciation is sometimes so hard to define:
http://evolution.berkeley.edu/evosite/e ... cept.shtml
What do you think?
OK.. we're done. I am just wasting my time with you. Go ahead and continue repeating yourself if you like. You won't learn anything new, but clearly you don't want to.
the resource says
with this definition you get the contradiction colin leslie dean pointed put
the bactrian and dromardry camles interbreed so they must be the same species
thery are different specis
thus a contradiction
From what I can see it is the farmers who first considered them another kind of camel, not scientists who are documenting them. In either case: Would you consider them the exact same species or a crossbreed "hybrid species" as scientists did?
I'm done! This should be a much better definition that any you have seen elsewhere. Or I hope so anyway.
Theory Of Intelligent Design
Speciation is a process that causes enough change in genotype or phenotype that they branch off from the lineage they once were to become a new "subspecies" that with further change becomes a new "species". In farming there are "breeds" of plants, camels and cows that are still able to interbreed with each other but farmers consider them a new breed. In science different breeds of cows would be considered a new subspecies so they can be given a unique scientific name. Therefore we can say that all cows are the same species and all camels are the same species, but there are subspecies of different kinds of cows and subspecies of different kinds of camels.
In the wild there is what are called "ring species" that slowly extended their territory in a direction that in time brings them back to where they started, forming a ring. By the time the ring forms a complete circle back again they are no longer able or no longer choose to breed with each other. In this case it is obvious that speciation occurred but there is no one place along the way where they suddenly changed, which then makes it impossible to find one single point along the way that they became a new subspecies (or possibly new species).
To further complicate the defining of a species some are different colors or are born with unique markings, yet they are all the same species and subspecies. Ants and bees are a good example where members of the same colony look entirely different depending on what they do.
Although it is sometimes very difficult or impossible to determine exactly where and when a "speciation event" occurred, the mechanisms that cause speciation can be listed as the following. In some cases speciation happens very slowly. In other cases it is immediate in which case there are no transitional forms, and there can be no transitional fossils.
Behavioral Speciation (very slow)
Speciation is in part guided by what the organism itself finds desirable in the variety available to select as a mate. This includes extreme examples such as peacocks where females selecting the largest most attractive tail design has led to males with giant brilliant displays, even though this makes it more difficult to fly from predators.
Although not a product of behavioral speciation, humans display this same mate selection preference behavior. In magazine advertising the looks of "sex symbols" are sometimes computer enhanced to represent the conscious ideals not yet common in our morphology. What is added or removed from the picture helps show what human intelligence finds most desireable.
In behavioral speciation there is no one day and time that a pivotal event occurred, no single genome change resulted in a "speciation event" that created a new species. And the genome must first be already drifting in that direction or else such morphological change is impossible. In the peacock example we can say that the peacocks are aroused by the direction their genome is already set to go, anyway. Therefore what they in their mind find desirable is the same as what the genome finds desirable at the molecular level being expressed at the level of the emergent peacock brain. What they find desirable is not here hard-wired into neurons as an image or picture of what it should find desireable in a mate, it is an expression of the molecular genome itself that even responds chemically with hormones that cause physiological change where in humans just a picture of a desireable mate causes this molecular "arousal" to be produced.
We can to some degree predict where a species is drifting towards, by how it idealizes itself. For our species there is all of art and culture where we find exaggerations of real life where the size of Betty Boops pupil alone is the size of her whole mouth yet we still recognize this image as being human and sexy. What produces this may be that it is epigenetically possible to drift in that direction, or already are.
How long it would take an isolated genome to speciate depends on its genetic learning rate (how fast it gains or changes new information/genes). Sexual reproduction has a good amount of crossover exchange which greatly accelerates the ability to adapt and change. Asexual reproducers such as E. coli produce clones of itself which are identical to the parent. Fast responses to environment is then from exchanging plasmids but these are separate transient genomes, not the primary genome that accomplishes cell growth and reproduction.
There are "living fossils" that have changed so little it seems to us that they should have become a new species by now or at least new morphology. But this change is relative to how fast our genome changes in comparison to theirs. So it is not time alone that matters, we must also consider the genome learning rate in our consideration of how long it takes for a given genome to speciate.
Hybridization Speciation (immediate)
Common in plants and used in agriculture a hybrid species is produced when two species combine to form a new non-sterile species. In single cell organisms one species may retain all or part of its original form inside of the other (endosymbiosis). In complex animals hybridization can be more difficult. Horses and donkeys normally give birth to a sterile mule but on rare occasions a fertile mule is born.
Polyploid Speciation (immediate)
Polyploid speciation is the result of all chromosomes doubling, tripling or more in number. With twice or more of everything the cells are proportionately larger, resulting in a larger plant or animal. This is relatively common in self-reproducing plants. In animals reproducing the new genome structure requires a genome compatible mate, therefore surviving polyploidy species are less frequent but are still found in some insects, fishes, amphibians, reptiles and rat.
Paleopolyploidy is the scientific study of prehistoric polyploid speciation events.
Chromosome Speciation (fast - Human, Fruit Fly, Mosquito)
Chromosome fusion speciation is the result of two chromosomes joining to become a single one which in turn causes enough of a change in behavior and morphology a new species is produced. First the telomeres at each end of the 2 supercoiled chromosomes that fused became sticky by removal of the repeating code that forms a protective layer that makes the ends not-sticky. Then when not-sticky ends are in close enough proximity molecular forces of attraction take over then fusion occurs.
What causes telomeres to become not sticky to fuse like this, is not fully known. Phylogenetic evidence from the human genome indicates this has happened a number of times to increase chromosome complexity, along with extra copies of chromosomes being added to increase the number of chromosomes to increase total genome complexity. It is possible that through time an epigenetic mechanism has learned how to take good guesses this way, using an additional mechanism that when necessary prevents fusion by adding telomere repeat coding on ends to make not-sticky.
Fusion changes the locations of at least some of the chromosome territories that are formed upon uncoiling of the supercoiled chromosomes where each territory works as a single system, with neighboring specialized chromosome territory systems. The fusion event also scrambles some of the genes at each end as would be expected where there is a collision, and is evidenced at the fusion site of human chromosome number two where fragments from each side still embedded in the other. Even though there was not a significant amount of gene scrambling the rearranging of the chromosome territories may have already produced a noticeable morphological change. The mother of a child with this large a fusion might have been able to tell there was something unique about them but would be expected to still love them just the same, or more.
There is a small amount of random replication error that is always present that produces slow change. But in this case there must be a fast response to adapt a relatively large sudden genome arrangement through its metabolic epigenetic control systems that maintain cell chemistry through its life, and expresses itself in offspring (but here not DNA code changes).
The fused chromosome is in either allele (either mother or father) of the haploid (has one of two sets of chromosomes) germ cell (egg or sperm) that divides down to develop into a 47 chromosome heterozygote (alleles are different not homozygous where alleles the same) humanoid that has the human chromosome #2 being expressed along with copy of the two chromosomes with no fusion that provides all that the cell had before, with something new in the fused copy for epigenetic systems to control to meet the needs of the growing cell. The fusion now replicates in the population as follows:
48 and 48 parents produce a 48 offspring only.
48 and 47 parents produce a 48 or 47 offspring.
47 and 47 parents produce a 48 or 47 or 46 human offspring.
47 and 46 parents produce a 47 or 46 human offspring.
46 and 46 parents produce a 46 human offspring only.
The first 46 chromosome humans who were born to the existing 47 chromosome lineage may have right away been fertile, or at first had sterility problems in which case human chromosome #2 had to first learn to survive to replicate without the unfused chromosomes of the other allele there to help maintain proper cell functions. It would then become increasingly difficult for a 46 to reproduce with 48 and possibly 47 in part because along with the new genome design came a new self-image that made the 48's look "apish" and 47's relatively "unattractive" to 46's.
Where "human" is defined as having the unique 46 chromosome genome design that separates us from 47 and 48 ancestors there was a first human couple in our ancestry that was already fully human. There is here a human man and a woman Chromosomal Adam and Eve who together could only produce 46 chromosome descendants whose children would prefer to be with their own kind as would their children's children through time, all the way from them to us.
they are different species as their scientific names shows
Dromedary (C. dromedarius) · Bactrian Camel (C. bactrianus)
http://au.encarta.msn.com/media_1461504 ... ution.html
they interbreed so they should be the same species but they are different species
thus a contradiction
if you cant see that biology ends in meaningless nonsesnce as colin leslie dean has pointed out it classificatory systen is meaningless nonsense
That's why I'm including a proper definition in the theory. The camel example I got from your thread would be like in different "breeds" of cows and only qualify as a new "subspecies" not an entirely new "species".
There might still be exceptions where species can interbreed, but at least this sets the record straight by including "subspecies".
at present scientist define the two species of camel as
so what do these names become under your new classification
bear in mind that this present classification makes biology a lot of meaningless nonsense
darwin finches interbreed
https://www.researchgate.net/publicatio ... 7s_finches
http://en.wikipedia.org/wiki/Canid_hybr ... dog_hybrid
for a whole list of interbreeding species
I have been studying camels and you are right about it being a classification disaster! I will have to update my section on speciation because of it.
First there is the wild species they came from, that were classified as two seperate "species", that have been bred together to form hybrid species. At first I thought it would be possible to group them into one but this is most unusual.
Thankfully I'm OK with cows where there is only one species but many breeds which are all subspecies.
I'm not sure what to do. So for now anyway, I will take out the camel and just go with the cow example. Perhaps I could then describe the camel problem in the paragraph after that.
What would you do? I could argue they can be considered the same species but I'm not sure whether that creates a second problem with the hybrids.
Gamila, here is an interesting wiki answers on the topic of cow species that I found, you might like. Three species of cows are now being grouped as one:
I changed the first paragrph to read:
I will put camels back in when I find more information. If there is a scientist level discussion of reclassifying them as a single species then I can mention it in the theory. But at this point it's hard to say which way that will go.
Yes, natural selection was always complemented by artificial selection in become. Besides, were see and other factors to breedings:
http://translate.google.ru/translate?hl ... ge_id%3D49
I must indefinietly agree: NS is a completely disprooven theory.
I must say that you could disproove evolution just off of your second reason. NS does not allow the increase of genetic information so as to creatre a new generation of species.
If so, where would the genetic information come from to advance a species so as to make it better? I mean, genetic information cannot just pop out of the blue by chance!!!
If you have further questions, please search for profile/send a message to Sophyclese.
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