Dinosaurs after the flood

[AlaskanDan]

i see where you are coming from, and i thank you for your time and effort on explaining this to me. Yet i always have questions, thats why i am a teenager Are there superior races? I mean, like the aboriginies (sp?) in australia have a huge jaw bone compared to the rest of humanity, while it seems like caucasions have a thinner skull with a longer nose, i mean, it seems to me like evolution teaches that there is some species more advanced than the others, i hope this is not the case, being i believe rascism is completely ethically, and morally wrong, let alone dumb. Once again i always appreciate all the effort you have put forth, thank you.

 

[notto]

i see where you are coming from, and i thank you for your time and effort on explaining this to me. Yet i always have questions, thats why i am a teenager Are there superior races? I mean, like the aboriginies (sp?) in australia have a huge jaw bone compared to the rest of humanity, while it seems like caucasions have a thinner skull with a longer nose, i mean, it seems to me like evolution teaches that there is some species more advanced than the others, i hope this is not the case, being i believe rascism is completely ethically, and morally wrong, let alone dumb. Once again i always appreciate all the effort you have put forth, thank you.

There are no 'superior' races in evolution. The only thing that matters is survivability. Individuals that have advantages that allow them to get to breeding age and breed are 'superior'. All other individuals are 'inferior'. (don't take this as a social comment, it only relates to the issues that drive evolution of a population).

Evolution depends on the success of an individual. The traits of these individuals and what is passed on lead to evolution of the population.

Evolution does NOT teach that there are some species more 'advanced' than others.

If we were to judge the level of advancement or superiority on the evolutionary history or such, then bacteria and cockroaches would be superior. They have been around a long time, they adapt quickly and well to new environmental pressures, and they survive, even when we try to specifically devise ways to kill them. In that way, they would be superior to us.

Glad you enjoyed the conversation. You will find that you will get many informed responses if you ask questioins instead of openly saying that science is wrong without first looking at it and researching it. If you have detailed questions, be sure to ask lucaspa. Lucaspa is a scientist, professor, and has spent many years studying the details of what we have been discussing. Lucaspa also seems to always be willing to put time in to explain things to those who truly wish too understand.

 

[AlaskanDan]

Awesome, where does he teach? Sorry about the rascism thing, it was almost a trap you did a good job explaining that to me. How did humans get to be sooo spread out anyways?
You just said that evolution depends on the individual, yet back in your earlier posts you say that evolution depends on the species.

Lucaspa:
"Just a little bit of thought should show you this is wrong. An individual is born, lives, and dies. It remains a member of that species all its life.

What evolution says is that the population (of individuals) changes over the course of generations until that population is different from the original."

Notto:"Evolution is about populations"

those are just the 2 off the top of my head...i'm getting confused here...i thought it was about the population, yet now you say it is about the survival of the individual? Am i missing something?

 

[notto]

Evolution depends on the success of individuals to breed. If none of the indivduals in a population bred, there would be no population.

The traits of the individuals that breed successfully accumulate over time and the population evolves based on the traits of its individulas.

We discuss populations as evolving. Individuals do not evolve. Once an individual is born, that is it, it has the traits it has. It does not 'evolve' while it is alive.

The variation (mutations) of these traits among the individuls is the raw material for evolution. The selective pressure put on those individuals in a population will dictate what the next generation of individuals within the population will look like.

Evolution only needs two things to happen. Variation in a population, and environmental pressure that favors certain traits in that variation.

 

[AlaskanDan]

well...thank you for your time, you have been of great help for me to understand, i really do appreciate your time and effort in talking to me, i hope i am not getting on your nerves with some of my questions, but i have plenty of them. Anyways, i just looked at the clock, and well...it is about 5:30, and i havent gone to bed yet (thank God i dont have class tomarrow), so i must leave now, but i assure you that i will be on once again tomarrow night, i love these forums. Once again, thank you for your time.

P.S. How did humans get to be everywhere, except antarctica?? Like the indians in the "new world" when columbus came over

Anyways, Good night, or good day, whatever suits you, thanks for writing

 

[lucaspa]

Awesome, where does he teach?

New York Medical College.

Sorry about the rascism thing, it was almost a trap you did a good job explaining that to me.

It's OK. Racism is a very powerful idea and it grabs any other idea to justify itself. Originally, racism was based on the idea that the races were separate creations by God! No kidding. Evolution destroyed this reason for racism, but soon racism invented the "superior race" thing and then said that was part of evolution.

How did humans get to be sooo spread out anyways?

The grass is always greener on the other side of the hill. Seriously. People live in small tribes or clans. The clans move in search of better food or to get away from nasty neighbors. If the clan moves just 10 miles every 10 years, it only takes 10,000 years to go from Africa to Australia!

You just said that evolution depends on the individual, yet back in your earlier posts you say that evolution depends on the species.

Lucaspa:
"Just a little bit of thought should show you this is wrong. An individual is born, lives, and dies. It remains a member of that species all its life.

What evolution says is that the population (of individuals) changes over the course of generations until that population is different from the original."

Notto:"Evolution is about populations"

those are just the 2 off the top of my head...i'm getting confused here...i thought it was about the population, yet now you say it is about the survival of the individual? Am i missing something?

Evolution is about the change in the population.

But natural selection selects individuals.

That is the source of the confusion. Each generation there are thousands of individuals in a population. Each is a little different from the others. However, the environment can't support all of them. Let's just try a simple example. Suppose there are 1,000 rabbits in a population. But wolves, cold, hunger, etc. are going to kill all but 400 of those rabbits. They will make 200 breeding pairs and each pair has 5 babies, so that next year you have 1,000 rabbits again.

Now, suppose the environment is getting colder. Of the 600 who die each year, all do so from cold. (I told you this was simple.) The 400 who survive do so because they are the ones with slightly longer fur that keeps them warmer. So, next year the 1,000 rabbits are all descended from those with longer fur. Most of them have longer fur. But the winter is still cold and 600 die. The 400 that survived are those with the longer fur. So the next generation (population) has even longer fur. This keeps up for 1,000 years -- 1,000 generations. At the end of that time you have a population that has very long fur and doesn't look at all like the original population of rabbits.

The population has evolved, but that is because individuals within the population were selected at each generation.

There, does that clear up the confusion?

 

[lucaspa]

Evolution only needs two things to happen. Variation in a population, and environmental pressure that favors certain traits in that variation.

It needs one more thing: more to be born than the environment can support. This is hidden in your "environmental pressure" but I think you need to make it out in front.

 

[notto]

It needs one more thing: more to be born than the environment can support. This is hidden in your "environmental pressure" but I think you need to make it out in front.

Thanks for the clarification (and your explaination to Alaska on the population/individual thing - you stated clearly what I was attempting to say)

 

[AlaskanDan]

Thanks for clarifying that up, but even though the rabbits dont look the same, they are still rabbits by genetic definition (not sure if that is a good term), i mean, they still have the same genetic makeup as the original rabbits, is there eventually going to be a shift in the genetic information causing it to be a non-rabbit, with a different number of chromosomes? I mean i can see the population changing to adapt to its environment, but i still cant see that the genetic material will differ so extravegently that there is going to be a bunch of different chromosomes, so forth.

Oh, and with the whole, if a tribe travels 10 miles a day, i dont think that is fair to say because i love to hike...and hiking for consecutive days at 10 miles, let alone with more than 1 other person gets very tiring. Maybe they traveled 3 miles a day

 

[notto]

Thanks for clarifying that up, but even though the rabbits dont look the same, they are still rabbits by genetic definition (not sure if that is a good term), i mean, they still have the same genetic makeup as the original rabbits, is there eventually going to be a shift in the genetic information causing it to be a non-rabbit, with a different number of chromosomes? I mean i can see the population changing to adapt to its environment, but i still cant see that the genetic material will differ so extravegently that there is going to be a bunch of different chromosomes, so forth.

Oh, and with the whole, if a tribe travels 10 miles a day, i dont think that is fair to say because i love to hike...and hiking for consecutive days at 10 miles, let alone with more than 1 other person gets very tiring. Maybe they traveled 3 miles a day

Here again, you need to define 'rabbit'.

Just as we have zebras, horses (and different species of horses) and donkeys with different number of chromosomes, we have domestic rabbits, hares, and cottontails that have different numbers of chromosomes.

Chromosome count can change due to duplication (this is only one of several ways that new DNA is added or changed in a population). No big surprise. This has been observed in the lab and is common in flower breeding.

The alternative is to assume that horses (and the different species with different chromosome counts), zebras, and donkeys are distinct 'kinds', but the fossil record and further study doesn't support that and there is evidence that they are related. The same goes for the rabbits, hares, and cottontails, they are closely related, just as man and the (other) apes are.

Same with wolves, foxes, and coyotes.

We can trace their evolutionary history through the fossil record and through the study of their dna similarities and differences.

 

[AlaskanDan]

Can domesticated rabbits eventually produce a hare? Or a hare a cottontail?

 

[notto]

Can domesticated rabbits eventually produce a hare? Or a hare a cottontail?

The chance that an evolutionary event will repeat itself is extremely rare. What could happen is that a new type of 'rabbit' could come about if a population is divided and different selective pressure is put on it. It would not produce a 'hare' as we know it, but could produce a new species of a small, long eared furry animal with sharp teeth. The chromosome count of this new population could change again if the event mutation happens and that is passed down through the population. Whether we commonly would call this animal a 'hare' or a 'rabbit' or a 'cottontail' really doesn't matter. It would still be different then the population it evolved from.

Again, all of the names we use for animals don't really mean much and do not define the animal or population beyond a laymans defininition. After all, 'dogs' are many breeds, and even many different species, but we consider them all 'dogs'. Why don't we consider a wolf a 'dog' or a coyote a 'dog'?

 

[gluadys]

1

Oh, and with the whole, if a tribe travels 10 miles a day, i dont think that is fair to say because i love to hike...and hiking for consecutive days at 10 miles, let alone with more than 1 other person gets very tiring. Maybe they traveled 3 miles a day

Notto and lucaspa are doing such a great job of answering your questions I won't add much. But I noticed that you misread what lucaspa said about migration.

He said "if a tribe travels 10 miles every 10 years" I don't think they would find that too tiring, do you?

 

[AlaskanDan]

oh....hahahaha, oh well. And i have always considered a wolf and coyote a kind of non-domesticated dog, heck, i own a dog that is part wolf

 

[lucaspa]

Thanks for clarifying that up, but even though the rabbits dont look the same, they are still rabbits by genetic definition (not sure if that is a good term), i mean, they still have the same genetic makeup as the original rabbits, is there eventually going to be a shift in the genetic information causing it to be a non-rabbit, with a different number of chromosomes?

No, they won't be rabbits by genetics. We need to talk about genes and alleles. These terms are often mixed up.

You have a gene for eye color. However, you have several different forms of that gene. Those forms are called "alleles". I have blue eyes, which is one type of allele. People with brown eyes are another allele. It's a bit more complicated than that becaue there are "recessive" and "dominant" alleles, but we are trying to keep it simple.

As natural selection works, some alleles are lost from a population while some other alleles are "fixed", which means that every member of the population has them. So, over the generations the genetic makeup of the population changes. At point 0 in time, the population would have alleles 1, 2, 3, 4, and 5 at different genes. But at point 1,000 generations later, the population would have alleles 1, A, B, 4, C at those genes. The genetic makeup of the population has changed.

Now, this has been done in bacteria, where measuring genetic makeup is easier. In invertebrates and vertebrates, what has been looked at are traits. The traits are based on the genes, but we don't have the genes or alleles exactly. However, we can see that some traits totally disappear while other traits become fixed. This means, of course, that some alleles have disappeared and new alleles have replaced them.

Now, sometimes chromosomes do change because chromosomes merge or chromosomes are duplicated. Within the genus rats is a species called the visatch rat. Most rat species have 26 chromosomes. The visatch rat has 50. All the chromosomes except the sex chromosomes have been duplicated.

Oh, and with the whole, if a tribe travels 10 miles a day, i dont think that is fair to say because i love to hike...and hiking for consecutive days at 10 miles, let alone with more than 1 other person gets very tiring. Maybe they traveled 3 miles a day

I said 10 miles every 10 years! That means living in one place for 10 years, and then getting up and walking 10 miles before settling down again for another 10 years. THat's not very tiring, is it? One 10 mile hike every 10 years? Even the worst couch potato can manage that!

 

[lucaspa]

Can domesticated rabbits eventually produce a hare? Or a hare a cottontail?

Probably not. Because alleles have been gained and lost in each species (hare and cottontail) as they diverged from the common ancestor. So, for a hare to produce a cottontail, the alleles in the cottontail would have to be introduced by mutation of the alleles in the hare. That's not likely.

Can you, by selection, get a hare to look more like a cottontail? YES. But the alleles would be different even tho the trait to the naked eye would look similar.

Now, generalizations are tough. There is at least one case where a species can be reproduced genetically. This, however, comes by means of hybridization. This is when two closely related species interbreed. In animals this usually doesn't happen because of either the animals don't look on the other species as a mate or the genitals don't fit. But plants hybridize easier.

Here's one example:

Speciation in action Science 72:700-701, 1996

What happened was that the researchers produced in the greenhouse the genetic changes leading to the formation of a naturally occurring species of sunflower. The species is Helianthus anomalus and molecular evidence suggested it was formed by recombinational speciation of H.annuus and H. petiolarus. This is a process in which two species hybridize, and the mixed genome of the hybrid becomes a third species that is reproductively isolated from its ancestors.

So what the researchers did was hybridize H. annuus and H. petiolarus and produced 3 independent hybrid lines undergoing different regimes of mating to siblings and backcrossing to H. annuus. After 5 generations the DNA was analyzed for comparison to the wild type and to see which ancestral genes persisted in the hybrids. It matched with the wild type. Remarkably, despite the different crossing regimes, all 3 lines converged to nearly the identical gene combinations. The gene recombinations were complex, but repeatable in all 3 hybrid lines.

The fact that the genes in the lab hybrid matched wild H. anomalus indicates that artificial selection and natural selection both selected many genes for fertility rather than adaptations to the environment.

The fact that all 3 hybrid lines converged to nearly identical genetic content and these matched the wild type (a 4th hybrid line) shows that several paths of evolution in this case reach the same point. As Jerry Coyne says in discussing the research "In Helioanthus, however, the sequence of evolutionary change is largely repeatable over both the long and short term: When this tape is rewound, it plays pretty much the same program."

 

[AlaskanDan]

yeah, i was familiar with all the alelles and all that stuff, phyenotype and genotype, all that, took an intro to cellular and molecular bilogy, yeah, miss read that 10 miles thing

 

[lucaspa]

yeah, i was familiar with all the alelles and all that stuff, phyenotype and genotype, all that, took an intro to cellular and molecular bilogy, yeah, miss read that 10 miles thing

You're giving me the razz when you misread the miles thing?

Good about the course. When people say "genes change" what they usually mean is that the alleles change. The gene is still there and it codes for a protein that even does the same job, but the base seqeunce of the gene has changed. It's a new allele.

So, as the generations pass and there is a steady environmental selection, some alleles are removed from the population and some alleles that weren't there before are added by mutation (to get the new allele) and then selection to fix the new allele in the population. As I said, after many generations, the genetic composition of the population changes. The individuals in the population have different alleles than the individuals several generations back.