From: js@ee.tut.fi (Salmela Jarmo)
Subject: Re: Tarjous, josta ei voi kielt{yty{
Organization: Tampere University of Technology
Distribution: sfnet.keskustelu.evoluutio
Date: Fri, 6 Nov 92 13:10:14 GMT


Markus.Lampola@ntc.nokia.com voi sitten l{hett{{ rahat
tililleni Sp-TAP 452110-40214926

>Yleens{ esitetyt todisteet eiv{t tyydyt{ kysymyksen esitt{j{{.
>Jos luomisuskossa ja evoluutiouskossa olisi kyse tieteest{,
>esitetyt todisteet lopettaisivat keskustelun, koska tosiasioita
>vastaan olisi turha v{itell{.

Evoluutio voidaan osoitta helposti v{{r{ksi, kuten muutkin
tieteelliset toriat. Mill{ tavalla kreationismi osoitetaan
v{{r{ksi?

>Todistus: Tarjoan 1000 mk ensimm{iselle, joka tuo vastaansanomattoman
>	todisteen t{lle palstalle siit{, ett{ mit{{n oletuksesessa
>	mainittua evoluutiota on KOSKAAN tapahtunut. 

Olisit tietysti voinut m{{ritell{ sanan 'vastaansanomattoman' itsesi
kannalta selke{mmin, mutta omapa oli mokasi. Luonnollisesti osoittanet
vastauksessasi mill{ tavalla viitatut alkuper{iset artikkelit
ovat v{{r{ss{ - aloittanet tuosta Scientific Americanin jutusta.

ja sitten tienaamaan:

Newsgroups: talk.origins
Subject: FAQ: Species and creation
Date: 10 Sep 91 22:41:54 GMT

Topics:
}No new species (alternately, "kinds") are evolving today. 
}Slight variation can't turn one kind into another. 
}Just because two animals LOOK similiar does not mean there is "common ancestor
}Mendelian inheritance says that recessive characters reappear
}Hybrids are infertile, so a newly evolved individual couldn't breed. 
}The animals couldn't have distributed themselves all over the globe. 
}"impossible gulfs" 
}The failure of some organisms to evolve at all.
}No new phyla, classes, or orders have appeared. 
}The occurrence of parallel evolution, in which similiar structures evolve
}Many species have remained absolutely fixed throughout geologic time.
}A great many modern species are very evident degenerate
}All the great phyla appear quite suddenly in the fossil record.
}Selection cannot change the frequency of variants

----------------------------------------------------------------------

}- No new species (alternately, "kinds") are evolving today. 
"Three species of wildflowers called goatsbeards were introduced to the
United States from Europe shortly after the turn of the century.  Within
a few decades their populaltions expanded and began to encounter one another
in the American West.  Whenever mixed populations occurred, the specied
interbred (hybridizing) producing sterile hybrid offspring.  Suddenly, in
the late Fourties two new species of goatsbeard appeared near Pullman,
Washington.  Although the new species were similliar in appearance to the
hybrids, they pproduced fertile offspring.  The evollutionary proces
had created a separate species that could reproduce but not mate with
the goatsbeard plants from which it had evolved."

The article is on page 22 of the February, 1989 issue of
_Scientific_American_.  It's called "A Breed Apart."
It tells about studies conducted on a fruit fly,
Rhagoletis pomonella, that is a parasite of the hawthorn
tree and its fruit, which is commonly called the thorn
apple.  About 150 years ago, some of these flies began
infesting apple trees, as well.  The flies feed an breed
on either apples or thorn apples, but not both.
There's enough evidence to convince the scientific
investigators that they're witnessing speciation in action.
Note that some of the investigators set out to prove that
speciation was not happening; the evidence convinced them
otherwise.

In 1916, a single pair of wallabies escaped from a zoo in Oahu.  They survived
and bred in the wild, and now there is a whole population.  They are smaller
and more lightly colored than the Aussie wallabies.  They eat Hawaiian plants
that are poisonous to the Aussie wallabies, because they evolved a new liver
enzyme to detoxify them.  They can no longer breed with the Australian
wallabies, so they qualify as a new species.

Sources:  "Instant Evolution", Science Digest, July 1982
   Saladin / Gish debate at Auburn University at Montgomery, 24 March 1984

How can you say that no new species have arisen when dozens of previously
undiscovered species are found each year in Costa Rica alone?
Also, isn't the latest evidence that maize evolved about 4000 years ago?

}- Slight variation can't turn one kind into another.  "One lion may be fitter
}  than another lion, but ... all his offspring will still be lions." 

What is a "kind"?

}Just because two animals LOOK similiar does not mean there is "common
} ancestory"

The interesting point is that, when checked, there IS.

Genetic comparisons reveal (objectively) a kinship where it was before
predicted on evolutionary grounds.

I believe the error rate is less than 1%.  What is facinating 
about the comparisons of the numbers of genes shared between
species is that when you draw a genetic tree of what species 
are related to what, it looks almost identical to the tree 
drawn by anthropologists who make their tree based on comparisons 
of morphology (humans look more like chimps than turtles therefore 
chimps are more closely related).  This is the beauty of science that
a hypothesis (relatedness of species) is shown by two completely 
differing mechanisms just as the age of artifacts can be 
determined by rock layers (those on top are newer) and carbon 
and other radioactive dating techniques. 

How is this done?
In brief:  DNA similarity is measured by mixing fragments of DNA from 
the two species and measuring the thermal stability of the resulting 
hybrid molecules, which is proportional to the degree of matching.
It can be calibrated by using DNAs of known composition, for example 
the genomes of completely sequenced viruses.  Accuracy is limited by 
the ability to measure the melting temperature and by the slight 
difference in stability between A-T base pairs and C-G ones.  There
has been heavy theoretical debate (ending in an amazing shouting 
match at a meeting last summer, alas--I was there, and it was embarrasing) 
about whether the method is accurate enough to resolve the chimp/ 
human/gorilla trichotomy.
 
DNA similarity does measure overall composition, and two organisms
could be very different morphologically while still having high DNA 
similarity (indeed, chimps and humans are much more dissimilar than 
most pairs with the same DNA distance).  However, overall composition
is probably a better guide to relatedness than specific genes, which 
are likely to be under different selection in humans and chimps. 
 
What is the noise, and what is the signal?  "Junk" DNA is the most 
useful for determining phylogeny, because it is more likely to 
evolve in a gradual time-dependent fashion.  Coding and controlling 
regions are interesting in that they tell us about the differences. 
 
}- Mendelian inheritance says that recessive characters reappear, and thus we
}  should expect humans with characteristics of apes. 
They do.  Tails, for instance.
And other "ape" traits that happen to also be "human traits".
Like toes, body hair, simian crease (XRHAH@scfvm.gsfc.nasa.gov for 
instance),...

This disregards the basic mechenisms of natural selection and
genetics. It makes the wrong assumption that ape-like
characters are recessive and that all of the traits in the
ancestor population are present but usually unexpressed in the
supposed descendant population. Neither idea is true.

}- Hybrids are infertile, so a newly evolved individual couldn't breed. 
       Hybrids are often not fertile or robust. They may be desirable to
        man if man amde, but they may not succeed in an evolutionary
       sense.

The premise is incorrect.  First, what is meant by "hybrid" is unclear
in this context - is it a hybrid only if it is infertile?  And even in
those cases in which the offspring is usually infertile, that is not
always the case.  As witnessed the horse and the donkey.

}- There exist "impossible gulfs" between animal/vegetable,
}  invertebrate/vertibrate, marine animals/amphibians, amphibians/reptiles,
}  reptiles/birds, reptiles/mammals, mammals/humans. 
}   Eight impossible gulfs:

Impossible to find gulfs.

}   1) Between the living and non-living or dead matter;

        This is the abiogenesis debate.

        The rest is a taxinomy of man with the similarity argument turned
        into the gaps argument. Is the glass half empty or half full?

What is this gulf? I have yet (despite looking and asking many) found it at all,
let alone found it to be an impossible gulf.

The spectrum between clearly living and singular elementary particles
is wide, and not linear (few things really are) but it appears to be
continuous.

}}   2) Between the vegetable and the animal kingdoms;

        Animal cells have some similarity with plant cells, and indeed there
        are forms, euglena, with cloroplasts and flagellae, that look like
        intermediates. Cells from both kingdoms are eukeryots that are distinct        from other cell types belonging to at least three other kingdoms.

There are quite a few plant/animals in the same creature.  Most microscopic
because a plant doesn't collect enough energy to be mobile in large scale.
But there are plenty of small ones.
What is a euglena?  And where do protista & viri fit in here?

}   3) Between the invertebrates and the vertebrates;

        The vetebrates are biochemically closest to the echinodermata, and
        urochordates. The free swimming soft chord animals are similar to
        the sessile forms.

See also sharks and squids.

}   4) Between marine animals and amphibians;

        A steady change from fish to lobefined air breathing fish to amphibians        with fish like larval stages can be observed in extant species
        and in the fossil record.

See also mudpuppies and frogs.  An amphibian that never leaves the water is a
marine animal.  This gulf is not only impossible, it is non-existant.

}   5) Between amphibians and reptiles;
        Amphibians predate reptiles in the fossil record. The development
        of the amneonic egg, with shell and the difference in the skin of
        extant reptiles and amphibians suggests that the reptilian characters
        were adaptaions developed on amphibian ancestors. The time in
        the fossil record when the reptiles became important was one when
        amphibian habitats were being reduced and when reptiles could have
        succeeded on drier continents.

What is this gulf, and what was a dinosaur? (warning: trick question!
Specifically what is the impossible gulf between, for instance, a salmander
and a chamelion?

}   6) Between reptiles and birds;

        The ornithischia, with bird-like pelvises appeared before the modern
        birds, whch began to appear in Cretaceous time. Intermediates are
        known.

}   7) Between reptiles and mammals;

        The therapsida in permean time, Mammal-like reptiles appear before
        the first mammals, but intermediate forms are known, and a fairly
        complete record of the changes in the facial bones between these
        reptiles and true mammals is known from Permean time. Does anyone
        know if mammalian dentition is documented into this time. Did the
        Therapsida have differentialted dentition?

}   8) Between mammals and the human body;


The distinguishing characteristic of living MAMMALS is lactation. 
Despite the invention of baby bottles, human females still lactate.


}12) The failure of some organisms to evolve at all.

If it passes the selection filter, no change required.  These
organisms are excellently adapted to their particular niche in their
environment.  (like sharks: the "perfect eating machine", right?)

Like the brachiopod Lingula, and the cockroach, identifiable through
most of the phanerazoic and still with us. If an organism is well adapted
to a niche it can readily occupy, then why should it evolve?

}- No new phyla, classes, or orders have appeared. 
Subsequently to what?

Trees of descent for organisms are drawn by grouping organisms together
based on common features.  Twigs which are close together are organisms
which differ only in few and minor respects.  Main branches, down at
the bottom of the tree, are groups of organisms that differ in many and
major respects.  One of the main premises of evolution is that this
tree is (more or less) proportional to time.
Asking for a phylum to appear today is asking for
a major branch to be up at the tip of the tree--it makes no sense,
considering the way such trees are drawn!

It is perfectly possible that in several million years there will
be recognizable phyla which were just differentiating today, but
there is no way to recognize a "new phylum" in the bud.  For example,
modern plants use two different photosynthesis reactions.  It is
quite possible that those two groups will eventually be so different
that we will call them seperate phyla, because the two reactions
probably favor different evolutionary pathways.  But how can we
know in advance whether or not this will happen?  That's what you're
asking for when you want to see a new phylum arise today.

This is just not true. while most of the phyla present today
were present at the beginning of the Cambrian, and their origin is shrouded,
there is enough of a fossil record from the so-called eo-cambrain to suggest
that some of the animals found in Australia are different phyla that became
extinct by the time fossils became abundant. The affinities of several
Cambrian groups is by no means clear, and they might be separate phyla,
such as the archeocyathids. Our phylum, Vetebrata (Chordata), appears
no earlier than Ordovician, and then only the cartilagenous and jawless
fish are known. All the other classes appear later than that.

Vascular plants, and all more advanced plant phyla appear no
earlier than Silurian time.

There are now five kingdoms known, based on their biochemistry and
there are enough precambrain microfossils to document their appearence.
The geochemistry of sediments in Precambrain rocks is understood well enough
to establish when the oxygen level of the biosphere was high enough to
support modern plants and animals, that comprize two of the five kingdoms.
Before this date it can be infered that the Plant and Animal kingdoms did
not exist. I am not faliliar with Precambrain events to fix this date,
1.8 billion years B.P. ?, or to document the micro fossils that might
bear this out.


}- The occurrence of parallel evolution, in which similiar structures evolve
}  in quite different circumstances. 

If you start with the same ancestor, they can only vary so much.  Also, what
he thinks are "different circumstances" are not necessarily so.  Physics
has an interesting set of constraints...

}Many species have remained absolutely fixed throughout geologic time.

     There are no known examples of organisms that have not evolved
     over a period of time and this includes cockroaches, lungfish,
     lampreys, sharks, bacteria, and all other organisms that some 
     people claim are "frozen in time". Some of these species appear
     to be morphologically similar to ancestors that lived in the
     past but evolution is much more than external appearance. When
     the structure of their genes and proteins are examined it becomes
     obvious that they have evolved at the molecular level. In fact
     the rate of evolution of these species is similar to that of
     species whose external appearance has changed more drastically.
     It is incorrect to claim that some organisms have not evolved
     simply because their external morphology has not changed.

     The problem here is that the fossil record only 
     preserves some parts of an organism. The fact that these parts
     have not changed very much doesn't mean that the species has not
     evolved.

}A great many modern species are very evident degenerate, rather than
}higher, forms of those found as fossils.

     There is no hierarchy to evolution. There is no reason to suppose
     that modern organisms should be "higher" than extinct ones. Loss
     of a structure is just as much evolution as gain of one. If
     Creationists admit that some organisms have become "degenerate"
     then they are admitting to evolution.


}All the great phyla appear quite suddenly in the fossil record.

Marvelous.  As long as he gets to pick which ones he wants, they do.
Collect the data to support you conclusion.  Keep throwing out the
outliers (97% discarded?) till it fits.


}Selection cannot change the frequency of variants
     Since evolution is, by definition, a change in the frequency of
     genes in a population, then this statement is equivalent to 
     saying that selection cannot cause evolution. There are many
     experiments in the literature that directly demonstrate how 
     false and ridiculous this statement really is. Perhaps the 
     easiest examples for the non-biologist are those that involve
     human selection, as in breeds of dogs or cattle. In those cases
     selection for distinct characteristics has led to populations
     with differing frequencies of alleles (variants). Thus selection
     has been PROVEN capable of changing the frequency of variants or
     alleles in a population and we have every reason to believe that
     it did so in the past as well.

 
Directional selection (selection "for" or "against" something) in a static
environment will lose variation.  To get a more interesting result, you
can look at either of two things:
 
1.  Selection which is not directional.  Here are some examples:
 
Frequency dependent selection.  Forms which are rare are at an advantage.
There are several decent real-world examples of this; female fruit flies
prefer males who look "different", and animals which have immune system
genes different from their neighbors' seem less likely to get
diseases from them.
 
Heterozygote advantage.  The organism with two different forms of the gene
has an advantage over others.  The classical example is sickle-cell
anemia in humans, where the person with one sickle and one normal allele
is protected from malaria.
 
Two kinds of selection pulling in different directions.  For example,
females may prefer brightly colored males, but so may predators.  Some
values for the parameters here will give a balance of different
forms in the population.
 
2.  Non-static environments.  This is much harder to model, but interesting.
You can easily get frequency-dependent selection out of an environment
with two food sources, both subject to overexploitation.  Environments
which change over time either randomly or in a cycle can also maintain
variability.
 
***
                                   
The simplest model I know in which something like speciation can be seen
to happen is one that contains two factors:
 
There is a gene with two variants, and the heterozygote is worse than
either homozygote.
 
There is the possibility for evolving reproductive isolation based on the
first gene.
 
Reproductive isolation could be modeled in several ways.  You could
explicitly add a gene that controls mate recognition.  You could arrange
your simulated organisms on a grid and restrict most mating to near
neighbors, and see if two populations seperated from an initial mixture.
 
Don't forget that if you use random rather than strictly proportional
selection (that is, if you use a random number to see who lives
and who dies), population size makes a huge difference.  It is almost
impossible to maintain high variability in a tiny population, even
with strong selection.

ja sitten lis{ksi m{{ritel{:

Newsgroups: talk.origins
Subject: Definition of Evolution
Date: 6 Apr 92 04:28:50 GMT


                            WHAT IS EVOLUTION?

Most non-scientists seem to be quite confused about precise definitions of
biological evolution. Such confusion is due in large part to the inability of 
scientists to communicate effectively to the general public and also to
confusion among scientists themselves about how to define such an 
important term. When discussing evolution it is important to distinguish 
between the existence of evolution and various theories about the mechanism
of evolution. And when referring to the existence of evolution it is important
to have a clear definition in mind. What, exactly, do biologist mean when they
say that they have observed evolution or that humans and chimps have evolved
from a common ancestor.

One of the most respected evolutionary biologists has defined biological
evolution as follows,

     "In the broadest sense, evolution is merely change, and so is 
      all-pervasive; galaxies, languages, and political systems all
      evolve. Biological evolution ... is change in the properties
      of populations of organisms that transend the lifetime of a 
      single individual. The ontogeny of an individual is not considered
      evolution; individual organisms do not evolve. The changes in 
      populations that are considered evolutionary are those that are
      inheritable via the genetic material from one generation to the 
      next. Biological evolution may be slight or substantial; it embraces
      everything from slight changes in the proportion of different
      alleles within a population (such as those determining blood 
      types) to the successive alterations that led from the earliest
      protoorganism to snails, bees, giraffes, and dandelions."

      Douglas J. Futuyma in Evolutionary Biology, Sinauer Associates 1986

It is important to note that biological evolution refers to populations and
not to individuals and that the changes must be passed on to the next 
generation. In practice this means that,

      Evolution is a process that results in heritable changes in a 
      population spread over many generations

This is a good working scientific definition of evolution; one that can be 
used to distinguish between evolution and similar changes that are not 
evolution. Another common short definition of evolution can be found in 
many textbooks,

     "In fact, evolution can be precisely defined as any change in the
      frequency of alleles within a gene pool from one generation to 
      the next."

      Helena Curtis and N. Sue Barnes BIOLOGY 5th ed. 1989
      Worth Publishers, p.974

One can quibble about the accuracy of such a definition (and we have often
quibbled on these newsgroups) but it also conveys the essence of what 
evolution really is. When biologists say that they have observed evolution 
they mean that they have detected a change in the frequency of genes in a 
population. (Often the genetic change is inferred from phenotypic changes that
are heritable.) When biologists say that humans and chimps have evolved from
a common ancestor they mean that there have been successive heritable changes
in the two separated populations since they became isolated.

Unfortunately the common definitions of evolution outside of the scientific
community are different. For example, in the Oxford Concise Science Dictionary 
we find the following definition;

     "evolution: The gradual process by which the present diversity
      of plant and animal life arose from the earliest and most primitive
      organisms, which is believed to have been continuing for the
      past 3000 million years."

This is inexcusable for a dictionary of science. Not only does this definition
exclude prokaryotes, protozoa, and fungi, but it specifically includes a term
"gradual process" which should not be part of the definition. More importantly
the definition seems to refer more to the history of evolution than to 
evolution itself. Using this definition it is possible to debate whether
evolution is still occurring but the definition provides no easy way of
distinguishing evolution from other processes. For example, is the increase
in height among Caucasians over the past several hundred years an example of
evolution? Are the color changes in the peppered moth population examples
of evolution? This is not a scientific definition.

Standard dictionaries are even worse. 

     "evolution: ...the doctrine according to which higher forms of
         life have gradually arisen out of lower.."   Chambers

     "evolution: ...the development of a species, organsim, or organ
         from its original or primitive state to its present or
         specialized state; phylogeny or ontogeny:  Webster's

These definitions are simply wrong. Unfortunately it is common for non-
scientists to enter into a discussion about evolution with such a definition
in mind. This often leads to fruitless debate since the experts are thinking
about evolution from a different perspective. When someone claims that they 
don't believe in evolution they cannot be referring to an acceptable 
scientific definition of evolution because that would be denying something 
which is easy to demonstrate. It would be like saying that they don't believe 
in gravity!

Recently I read a statement from a creationist who claimed that scientists
are being dishonest when they talk about evolution. This person believed that
evolution was being misrepresented to the public. The real problem is that
the public, and creationists, do not understand what evolution is all about.
This person's definition of evolution was very different from the common
scientific definition and as a consequence he was unable to understand
what evolutionary biology really meant. This is the same person who claimed
that one could not "believe" in evolution and still be religious! But once
we realize that evolution is simply "a process that results in heritable 
changes in a population spread over many generations" it seems a little silly 
to pretend that this excludes religion!

Scientists such as myself, must share the blame for the lack of public 
understanding of science. We need to work harder to convey the correct
information. Sometimes we don't succeed very well but that does not mean that
we are dishonest. On the other hand, the general public, and creationists
in particular, need to also work a little harder in order to understand
science. Reading a textbook would help.

April 5, 1992

Laurence A. Moran (Larry)
Dept. of Biochemistry               lamoran@gpu.utcs.utoronto.ca
Medical Sciences Blgd.                    (416) 978-2704
University of Toronto               FAX   (416) 978-8548
Toronto M5S 1A8, CANADA

Ett{ helpollapa taas tuli tienattua.

terv, - jarmo salmela


-- 
- jarmo salmela - the Man with the Muckrake - diurnarius scientificus -
Newsgroups: sfnet.keskustelu.evoluutio