Re: Evolution: Survival of the Miss-est

On Jun 11, 11:44 am, "[M]adman" <ad...@xxxxxxxxxxx> wrote:
John Harshman wrote:
[M]adman wrote:
Gerard wrote:

<cut to one point>

According to evolution, miscopies during cell replication (random
mutations) are the cause for all of life's end product species
today. Each miscopy or new code (random mutation) that became
predominant by pure chance through genetic drift and then more
accessible to key regulators for trial and error utilization, each
of these is responsible for all of the diverse and complex
lifeforms observed on earth today. This is not survival of the
fittest, but survival of the miss-est. The fittest, those who made
no mistakes, couldn't keep up with the advantages that the others
who made mistakes obtained, so they went extinct. Is this rational
science? No. Is this real science? No.

The citizens around the world are expected to believe that the exact
same random mutation is just suppose to target a segment of a
particular population, like fish. If the random mutation is actually
random, then why does the same mutation target the same segment of
fish and continue to target just that same segment for millions of
years in order to change that segment of fish into land animals?

Fascinating confluence of different misunderstandings here. Madman and
Gerard both have no clue, but in quite different ways. Gerard seems to
think that natural selection doesn't exist, and all evolution is
drift. Madman seems to think that natural selection doesn't exist,
and all evolution is multiple, directed mutations.

It's really quite simple. If an advantageous mutation occurs in a
single individual, that individual will on average have more
offspring than other individuals, and so the mutation will increase in
frequency in
the population. And thus adaptive evolution happens.

Here you say the mutation is advantageous and occurs in a single individual





Many creationists, in fact, accept that natural selection works. It's
microevolution, you know.

If you ask me that is selective mutation,
not random mutation.

Yes, that would be, if it happened, or if anyone claimed that it
happened, which it doesn't, and they don't.

The same process is suppose to happen with natural
selection. Natural selection is suppose to target the same segment
of fish for millions of years to slowly change that segment into
land animals despite the fact that what may be causing the natural
selection is a random force, such as weather for instance. The
natural selection itself may not be random, but the forces that can
cause natural selection seem to be or can be.

I'm not sure what this objection is supposed to mean. Natural
selection doesn't "target" anything. It's something that happens. A
change in habits can cause a change in environment, which makes particular
features advantageous that were not advantageous previously, and so
the population evolves in that direction through selection. Which
results in a further change to the experience environment, and so on.

Here you say the population evolves.

Which is it. The population, or the individual.

Your willful ignorance notwithstanding, this is a question that does
bother some people. The answer is that changes in alleles- from
mutation- happen to individuals. But the individual has the same
genetic makeup over its entire lifetime- it does not change. You're
born with it, and that is that. So it's meaningless to talk of a
change in allele frequencies in an individual. But that makes perfect
sense when you speak of a population. If an individual is born/hatched/
spawned with a mutation that does not appear in its parents, the
overall frequencies of the alleles in the population has changed.
Likewise, selection will favor some particular alleles and they will
increase, while others will decrease in frequency.

Most middle-school kids get this easily.

Then there is genetic drift. We are expected to believe that (all) of
just a segment of fish had the exact same genetic drift. Has anyone
observed anything that "drifts" unguided have the same outcome each
time? A bottle drifting in water will end up in a different place
each time.

Yes, and so will drift. But you don't seem to know what genetic drift
is. It makes no sense to talk of it happening in an individual. It's
something that happens in populations. The frequency of a particular
allele in the population wanders up and down at random. Eventually,
and necessarily, it arrives at a frequency of either 0 or 1. Most new
mutations settle on 0. A few (a proportion of 1 divided by twice the
population size) get to 1. Most evolution is neutral, but most
evolution we find interesting -- the part that changes fish to land
animals, for
example -- is not.

How about making evolution so clear that /everyone/ will know what it is?

It's been done- repeatedly. But here it is again:

"Now that's rather amusing. In fact, every semester I explain the
basics of evolution to General Biology classes, and the vast majority
of students agree it makes perfect sense. Many of them had it in high
school (were you asleep? Were you home-schooled?) and they understood
it then. My kid understood it before high school.

It really is very simple. You want a precis?

Evolution is a change in the genetic makeup up of a population. This
change can stay within that population (microevolution) or lead to
speciation (many biologists but not all call this macroevolution).

Five phenomena are generally credited as the causes of evolution:
1. Selection, either natural or artificial
2. Drift, the effect of small population sizes on genetic makeup
3. Nonrandom mating
4. Gene flow, either into or out of the population, and
5. Mutation, either point mutations or larger chromosomal mutations
like deletions and translocations.

Speciation comes in two flavors: anagenesis and cladogenesis.
Anagenesis occurs when the ancestral population disappears in the
process of speciation. Cladogenesis is the process of a new species
evolving from the parent species, and the two species, parent and
daughter, are contemporaneous for at least a short time. Most
biological diversity on the planet arose from cladogenesis.

Either of these processes can occur as allopatric speciation or
sympatric speciation (we'll leave off paripatric speciation for now-
Wilkins can tutor you on that).

Allopatric speciation is presumably the process by which most animal
species arose. It occurs when a population fragments. The two (or
more; we will assume two) populations are now subject to different
selection pressures, different mutations, different environments.
Natural selection and drift play roles here. Drift becomes especially
important if one of the populations is small- in that case you will
almost certainly not have the full range of genetic diversity in the
small population as you do in the large population. If that's the case
the two populations can diverge genetically much more rapidly. If
efficient reproductive isolating mechanisms evolve that prevent the
populations from interbreeding (we use the biological species concept
here) you have two new species. This process requires rather long
periods of isolation.

Sympatric speciation occurs much more rapidly. It is quite common in
plants. In plants it typically takes the form of allopolyploidy. Some
authors have estimated that up to 30-40% of extant plant species have
an allopolyploid event in their evolutionary history. A typical, well-
known and well-studied example is in cordgrass, _Spartina_ spp. In
pre-
Columbian times there were distinct endemic species of _Spartina_ in
North America and Europe. _Spartina maritima was in western Europe and
_Spartina alterniflora_ was in North America (there are other species
of _Spartina_ but the pertinent events involve these species and their
ancestors). _S. alterniflora_ was introduced to Europe in the 1800's.
It interbred with _S. maritima_ and produced a sterile hybrid, labeled
_S. townsendii_. Although sterile, _S. townsendii_ like all plants is
capable of asexual reproduction, and it rapidly spread through
England, France and the Low Countries. But at some later time, yet
another species of _Spartina_ appeared. This was named _Spartina
anglica_ and it is an extremely aggressive species, displacing other
cordgrasses with a vengeance. It was soon realized that _S. anglica_
is a direct descendant of _S. townsendii_, but fertile. Chromosomal
analysis revealed that _S. anglica_ is a tetraploid of _S.
townsendii_. In other words, some _townsendii_ individual
spontaneously doubled it's chromosome number. As I said, this is
common in plants, but not in animals.

So there we have two documented speciation events in the space of a
single human's lifespan. Further genetic analysis has confirmed these
hypotheses, and the various _Spartina_ species (and others) have been
generated in laboratories in Europe. There is considerable interest in
these species since as I said some are very aggressive, and are
displacing native vegetation. On the plus side, the recent species are
desirable as they seem to do a better job stabilizing dunes and soil
in polders- not an inconsequential consideration in many parts of
Europe.

Now. If you have failed to understand this material, it is NOT the
fault of biologists or teachers. "

The above is taken from an earlier post:

http://groups.google.com/group/talk.origins/msg/52c088ae9c40b3f0?hl=en

You argued strawmen the first time it was posted and I fully expect
you'll ignore this, because you are a dishonest coward.

Chris







Then add to this that evolution does indeed seem to go against
"survival of the fittest". Why would a segment of a population of
fish even need to diverge if they are surviving in the water and
there is enough food? There would be no motive for the fish to move
onto land.

How can you know that? You seem to be saying that things are always
perfect just as they are. Think back a bit. There was lots of
competition for food in the sea, less on land. It would be highly
advantageous for an individual who could begin to exploit this new
resource.
The fish that already take
food from the land do so successfully already. Take dolphins for
instance. A dolphin is a highly intelligent creature. A dolphin will
swim onto shore after it's food and then use it's fins to work back
into the water. But in all this time dolphins have not evolved
larger fins to act as feet. If fish such as dolphins had the
propensity or even desire to come to land then the dolphin should be
showing clear observable signs of evolving into a land animal today.
We see no such evidence.

But there already are land animals. A dolphin can't be as good a land
animal as the land animals that are already there, so there is no
selective advantage in moving in that direction. Incumbency is a big
advantage, and has much influence. Then again, being able to breath
air seems to have certain advantages in the water, and land animals
have frequently taken to the water. Your dolphin clearly had
ancestors with legs, living on land. We have the anatomy, DNA, and
fossils to show that. Poor choice for you.

Reverse evolution?

[throws hands in the air]

What next? double reverse evolution?

.

Relevant Pages

  • Re: Blog: The Scars of Evolution.
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  • Re: Professor of genetics says No! to evolution
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