Preponderance of Evidence for
Naturalistic Origins and Evolution of Life
(1 of 3)
(Top Posts - Science - 073102)

[expanded to 4 posts on 031909 - click
the following to access the 4th post]
  http://prohuman.net/science/evidence_for_evolution_4_of_4.htm

- - -

Intelligent Design advocates (i.e., the latest phase in
the evolution of creationists/goddidditists) seem to
be steadfastly committed to dismissing out-of-hand
the preponderance of evidence for the naturalistic
origins and evolution of life against the extreme lack
of evidence for "goddiddit" or "aliensdiddit" ...

- - - Preface : Speciation - - -

Speciation occurs in previously interbreeding populations
which have separated and evolved mutually exclusively
as separate groups based on differing environments ...

... also, severe environmental stress has been demonstrated
to cause genetic mutations manifested as dramatic changes
and contributory to sexual mating/non-mating capabilities ...

... also, ongoing random mutations play a role ...

... symbiotic relationships also must be factored in - for
example, each human carries around something on the
order of 100 *trillion* microbes, many of which are
essential for our survival ...

- - - yikes! - - -

that's substantially more than the number of cells each
human consists of - - - also, microbes account for *most*
of the biomass on earth, have been around far longer (over
3.5 billion years) than any present-day macro species, are
essential for all life on/in/around earth, and only *1 percent*
of them have been identified ...

- - -

FAQ - Observed Instances of Speciation
http://www.talkorigins.org/faqs/faq-speciation.html

- - -

FAQ - Some More Observed Speciation Events
http://www.talkorigins.org/faqs/speciation.html

- - -

Recent details of speciation and other naturalistic origins and
evolutionary iterations follow ...

- - -

Insect Yields Clues To Evolution Of Species
Date: Posted 5/23/2002
http://www.sciencedaily.com/releases/2002/05/020523075718.htm

Excerpt: Studies of a California insect, the walking stick, are
helping to illuminate the process of evolution of new species,
according to research published in this week's issue of Nature.

The insect ... is found in the Santa Ynez Mountains on two
types of plants. Essentially the walking sticks have evolved to
look like a leaf of the plant they inhabit. Birds and lizards are
its main predators.

"You've got to have very good camouflage to trick a bird,"
said Sandoval, noting that birds have very good vision and
are visual predators.

The insect exhibits two genetically determined color patterns.

The unstriped insect is more commonly found on the plant
Ceanothus spinosus (commonly called blue lilac) and a striped
design is more common on those insects inhabiting the plant
Adenostoma fasciculatum (commonly called chemise).

According to the study, the research provides the first clear
demonstration that host-plant adaptation can promote the
parallel evolution of reproductive isolation.

The researchers tested hundreds of insects in the lab and
found that those inhabiting the same type of plant were more
likely to mate with each other than they were to mate with
those residing on different plants -- even though they are the
same species. The research indicates that habitat may play
a crucial role in the early stages of separation into different
species (speciation).

"We don't know why, but something about adapting to a
host plant - smell, size, or a combination of things - drives
this reproductive isolation," said Sandoval. "This is an
example of speciation in process."

Additionally, information from DNA sequences revealed
that such divergence in mating preferences and morphology
has evolved numerous times in this species, according to
the article. Thus, the research indicates that adaptation to
different habitats may play both a crucial and repeatable
role in the early stages of speciation. ...

- - -

Mating Molds Provide New Insights Into
Speciation And Human Reproduction
Date: Posted 2/11/2002
http://www.sciencedaily.com/releases/2002/02/020211075951.htm

Excerpt: A new study on the sex life of molds is raising
startling new questions about gene silencing, speciation and
perhaps some facets of human reproduction.

The study ... focuses on the mating habits of Neurospora
crassa, commonly called pink bread mold - a fungus that has
been a useful genetic model organism for more than half a
century.

... When it comes to sex, molds and humans share at least
one fundamental principle: In both species, the parents must
donate a copy of their DNA to the offspring in order to suc-
cessfully reproduce.

... This complex cellular process - in which parental chromo-
somes pair up and split apart to form offspring or sex cells
(sperm and eggs) - is called meiosis and occurs in all organ-
isms that reproduce sexually, from people to plants to fungi.

... Shiu and his colleagues took a closer look at meiosis in
mold and made a surprising discovery:

Each cell with 14 chromosomes has some kind of internal
mechanism that scans the paired chromosomes before they
split apart. The researchers determined that, if one chromo-
some in a pair carries an extra copy of a gene not found in
its partner chromosome, the fungus will turn off all copies
of that gene in the cell.

Because the genes are turned off in the early stages of meiosis
before the two parental chromosomes separate and still have
the chance to check for mismatched (unpaired) genes, Shiu
and his co-workers have dubbed the process MSUD - "meiotic
silencing by unpaired DNA."

The results of MSUD are devastating. Instead of turning out
healthy black spores capable of reproduction, silencing of
essential genes by MSUD produces white spores that are
dead - or no spores at all.

... "If there's a gene missing or appears in one chromosome
but not in its mating partner, the cell says, 'Something is wrong.
There's something from one of the parents that doesn't belong
there," he added.

The extra gene may be from a virus that jumped into the chro-
mosome or from an insertion sequence - a mobile segment of
DNA that can interfere with normal genetic function.

... With MSUD, organisms can prevent unwanted viral genes
and insertion sequences from spreading.

... Humans and speciation

In addition to eliminating deleterious genes in mold, ... MSUD
could be involved in screening out genetic parasites in other
organisms that reproduce sexually - plants, insects and even
people. One example is oogenesis in women - a biological pro-
cess in the ovary that results in the formation of eggs.

"Human oogenesis is, at first glance, a bizarre process," ... at
birth, a girl already will have developed some seven million egg
cells that are "frozen" in an early stage of meiosis during which
all 23 chromosomes sets are paired.

Remarkably, the chromosomes remain in this frozen state until
menstruation begins some 12 years later. Of the original seven
million cells, only 400 or 500 will be made available for repro-
duction during a woman's lifetime.

"We speculate that this is not a random process ... It's a per-
fect situation for weeding out extra genes or seeing if there's
a bad match or too many bad matches in the chromosomes.
We suspect that there is a system in humans that causes gene
silencing, but we don't know the mechanism yet."

The researchers made another surprising discovery with evolu-
tionary implications.

Animals, plants and fungi are divided into species based, in
part, on their ability or inability to interbreed. Redwoods and
Douglas firs have some physical similarities, but it's unlikely
that they will be able to mate to give hybrids, especially fertile
ones. Clearly, they are different species of trees.

Likewise several species of Neurospora - N. crassa, N. sitophila
and N. tetrasperma - are normally infertile when crossed in the
laboratory. Yet, by including a dominant mutant gene called Sad-1
in the DNA of the three mold species, Shiu and his colleagues
were able to produce viable spores through cross-breeding of
species that normally are sterile with one another.

The ability of Sad-1 to breach interspecies sexual barriers appar-
ently works by preventing meiotic silencing from occurring,
according to Metzenberg.

"To our knowledge, this is the first case where the barrier be-
tween interspecies crosses has been observed to break down
as a result of mutation in a single gene," Shiu added, "but since
gene silencing is universal, it could occur in other kingdoms,
including plants and animals." ...

- - -

Genetic Evidence: How Evolution Redesigns Bodies
Date: Posted 2/7/2002
http://www.sciencedaily.com/releases/2002/02/020207075601.htm
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1806000/1806757.stm

Excerpt: Biologists have uncovered important genetic evidence
about how evolution redesigns animals. It explains how large-
scale changes to body plans can arise from very simple genetic
mutations, or errors. The scientists say these mutations occur
in regulatory genes that control embryonic development.

---
Graphic:
http://prohuman.net/pix/gene_evolution_evidence.gif
---

They believe such "mistakes" would have caused crustaceans
with limbs on every segment of their bodies to evolve 400 million
years ago into a radically different shape: six-legged insects, and
then into other types of animals.

... "How can evolution introduce big changes in an animal's body
shape and still generate a living animal? ... "Until now, no one's
been able to demonstrate how you could do that at the genetic
level with specific instructions in the genome." Writing in the
journal Nature, the researchers show that this could be accom-
plished with relatively simple mutations in a class of regulatory
genes, known as Hox. These act as master switches by turning
on and off other genes during embryonic development. ...

- - -

Gondwana Split Sorts Out Mammalian Evolution
Date: Posted 1/21/2002
http://www.sciencedaily.com/releases/2002/01/020121090546.htm

Excerpt: ... "Based on molecular clocks, we found that the
deepest split occurs between

- Afrotheria (elephants, hyraxes, manatees and dugongs, aard-
varks, golden moles, tenrecs, and elephant shrews)

and

- other placentals (armadillos, anteaters, sloths, carnivores [e.g.,
bears, cats, dogs], pangolins, whales and dolphins, even-toed
ungulates [e.g., hippos, cows, pigs], odd-toed ungulates [e.g.,
horses, rhinos], bats, and insectivores [e.g., shrews, moles,
hedgehogs], rodents, rabbits, tree shrews, flying lemurs, and
primates [e.g., humans, monkeys, lemurs])

at ~103 million years, a date that coincides with a major plate
tectonic separation."

The result is controversial. Some researchers cite fossil evi-
dence that suggests that mammals diversified only ~65 million
years ago.

But Springer and colleagues argue that the separation of South
America and Africa around 100 million years ago during the
Cretaceous in Gondwana (the southern hemisphere super-
continent that incorporated Africa, Antarctica, Australia, India,
Madagascar and South America before it broke apart) explains
the split.

"We suggest that the common ancestor of living placental mam-
mals occurred not in the northern hemisphere, as is commonly
believed, but in the southern hemisphere instead, in Gondwana,"
says Springer. "Furthermore, our study provides the first con-
vincing molecular evidence that flying lemurs and tree shrews
are the closest relatives to primates."

... Such deciphering of higher level relationships among mam-
malian orders is important because of its ramifications for
evolutionary biology and genomics. ...

- - -

NASA Scientist Finds Some Meteorites Not Sugar-Free
Date: Posted 12/28/2001
http://www.sciencedaily.com/releases/2001/12/011221082306.htm

Excerpt: A discovery by a NASA scientist of sugar and several
related organic compounds in two carbonaceous meteorites pro-
vides the first evidence that another fundamental building block
of life on Earth may have come from outer space. A carbona-
ceous meteorite contains carbon as one of its important consti-
tuents.

... Scientists have long believed meteorites and comets played
a role in the origin of life. Raining down on Earth during the
heavy bombardment period some 3.8 billion to 4.5 billion years
ago, they brought with them the materials that may have been
critical for life, such as oxygen, sulfur, hydrogen and nitrogen.

Sugars and the closely related compounds discovered by
Cooper, collectively called "polyols," are critical to all known
life forms. They act as components of the nucleic acids RNA
and DNA, constituents of cell membranes and cellular energy
sources.

"This discovery shows that it's highly likely organic synthesis
critical to life has gone on throughout the universe," said Kenneth
A. Souza, acting director of astrobiology and space research at
Ames. "Then, on Earth, since the other critical elements were in
place, life could blossom."

... There still are many unknowns though about the chemistry
that existed before the origin of life on Earth, according to
Cooper. "What we found could just be interesting space chem-
istry, and polyols could be just relatives of the compounds that
actually gave rise to early life." ...

- - -

Fish May Show How Nature Diversifies
Date: Posted 12/27/2001
http://www.sciencedaily.com/releases/2001/12/011220081713.htm

Excerpt: ... The scientists were able to study the molecular
evolution of the threespine stickleback due to its recent evolu-
tion since the end of the last Ice Age, which occurred 15,000
years ago.

When the giant glaciers melted, they created thousands of lakes
and streams in North America, Europe, and Asia. These waters
were colonized by the stickleback's marine ancestors, which
adapted to life in fresh water.

The spiny fish, which are one- to six-inches long, were remark-
ably successful in adapting to various niches in their new habi-
tats.

"The fish have evolved so recently that it is still possible to
carry out crosses between the new species using artificial
fertilization," said Kingsley. "This makes it possible to use
genetics to study the number and location of genetic changes
that are responsible for evolutionary change."

The isolated pockets of sticklebacks have created thousands
of evolutionary experiments, he added. By studying the gen-
etic variation among various species, Kingsley said it should
be possible to discover how evolution generates new species
adapted to life in different environments.

... "There is a lot of interest right now in comparative geno-
mics," said Kingsley. "But for most of the species proposed
to be studied, the timescale of evolutionary divergence is
enormous, making it difficult to sort out which genetic changes
are truly responsible for species differences.

In contrast with the sticklebacks, this genetic approach lets the
organism tell us where the relevant genes are. Rather than bet-
ting on a favorite gene being important, we let the fish tell us
which chromosome regions we should pay attention to. Those
regions can then be studied in detail to identify the molecular
basis of evolutionary changes in vertebrates.

- - -

Primitive Microbe Offers Model For Evolution Of Animals
Date: Posted 12/18/2001
http://www.sciencedaily.com/releases/2001/12/011218072534.htm

Excerpt: A microorganism whose evolutionary roots can be
traced to the era of the first multicellular animals may provide
a glimpse of how single-celled organisms made a critical evolu-
tionary leap.

In analyzing the single-celled choanoflagellates, scientists dis-
covered that the organisms have a type of molecular sensor
usually found in multicellular animals.

... Choanoflagellates are a group of about 150 species of single-
celled protists, which use a whip-like flagellum to swim and
draw in food. Surrounding this flagellum is a circle of closely
packed, finger-like microvilli that filter food from the water.

Scientists have long suspected that choanoflagellates might
represent modern examples of what the ancestors of multi-
cellular animals, or metazoans, looked like. ...

- - -

Geophysicist Studies Life In The Early Solar System
Date: Posted 12/17/2001
http://www.sciencedaily.com/releases/2001/12/011217082959.htm

Excerpt: Between the cataclysmic impact that created the
Moon around 4.5 billion years ago and the first evidence of
life 3.8 billion years ago, there may have been long periods
during which life repeatedly spread across the globe, only
to be nearly annihilated by the impact of large asteroids.

The early Earth, in other words, may have been an interrupted
Eden - a planet where life repeatedly evolved and diversified,
only to be sent back to square one by asteroids 10 or 20 times
wider than the one that hastened the dinosaurs' demise.

When the surface of the Earth finally became inhabitable again,
thousands of years after each asteroid impact, the survivors
would have emerged from their hiding places and spread across
the planet - until another asteroid struck and the whole cycle
was repeated.

... "An asteroid a few hundred kilometers in diameter will boil
off much of the ocean and leave the rest of the ocean very hot,
so all that will survive will be high-temperature organisms living
deep in the subsurface," he says. Rock vapor and water would
fill the atmosphere, killing off any life on the surface with temp-
eratures upwards of 1,000 C (1,800 F).

The only organisms that could survive such an impact are
thermophiles - heat-loving microbes - buried half a mile or
more below the Earth's surface, where the effects of the burning
atmosphere would have been muted to a survivable 100 C
(212 F). Those organisms may have given rise to much of the
life on today's Earth.

Sleep calls the region where those organisms would have lived
the "Goldilocks Zone" - deep enough for microbes to avoid
the heat of the burning atmosphere, but not so deep that they
ran afoul of the Earth's internal heat. ...

- - -

Link To Our Ancient Past Is Confirmed
In Potassium Channel Research
Date: Posted 11/9/2001
http://www.sciencedaily.com/releases/2001/11/011109075413.htm

Excerpt: Research on components of the brain's electrical sig-
naling system has answered a basic question about our human
evolution, confirming scientific belief that we two-legged, com-
puter-using creatures are descended from prokaryotes -- cellular
organisms so primitive and simple that they exist without nuclei
or cell walls.

... Lu and his collaborators devised a project in which the pore
of a prokaryote's potassium channel (the interior core of the
channel) was substituted for the pore of a potassium channel
in a euokaryote. The scientists found that the eukarotic channel
continued to function essentially as it had previous to the sub-
stitution.

"This has very profound implications for evolution," Lu said.
"It appears the potassium channels in advanced brains and
hearts of mammals have evolved from something like this
bacterial channel. So what we learn from the more easily stud-
ied bacterial channels can be directly applied to our under-
standing of potassium channels such as those in our brains."

- - -

New Fossils Suggest Whales And Hippos Are Close Kin
Date: Posted 9/20/2001
http://www.sciencedaily.com/releases/2001/09/010920072245.htm

Excerpt: Partial skeletons of ancient whales found in Pakistan
last year resolve a longstanding controversy over the origin of
whales, confirming that the giant sea creatures evolved from
early ancestors of sheep, deer and hippopotami and suggesting
that hippos may be the closest living relatives of whales.

The new finds ... are the first and only specimens known that
combine sheep-like ankle bones and archaic whale skull bones
in the very same skeletons.

The 47-million-year-old fossils ... also show how early whales
swam.

"Whales are warmblooded animals like we are---that has been
known for a long time," Gingerich explains. "Yet they're so
different from other warmblooded, furry things that it's been
a mystery, both how they came to live in the sea and what
ancestors they might have come from on land."

Some clues have come from studies using immunological,
molecular, and genetic techniques to explore relationships
among groups of animals.

... "In the last few years, 15 or 20 DNA studies have come
out supporting this artiodactyl connection," says Gingerich. ...

- - -

University Of Maryland Researchers Locate Genes
That Speed Up Formation Of New Species
Date: Posted 9/6/2001
http://www.sciencedaily.com/releases/2001/09/010905073214.htm

Excerpt: Like a family that splits in a feud, many species share
common ancestors, but they never have much to do with their
cousins. In fact, many life forms actually develop into entirely
new species as they change to adapt to new environments.

Scientists have theorized that how fast one species branches
out to become two, a process called speciation, is in the genes.
If a couple of key genes are located close to each other on the
species' genome, the theory goes, formation of a new species
will move along more quickly.

By studying the genes of a common insect that appears to
evolving into two separate species adapting to different envir-
onments, two University of Maryland researchers have con-
firmed that theory for the first time.

In a study published in the August 30 edition of the journal
"Nature," Sara Via, an evolutionary biologist, and insect gen-
eticist David Hawthorne discovered that genes involved in
speciation are indeed located very close to each other. ...

- - -

First Land Plants And Fungi Changed Earth's Climate,
Paving The Way For Explosive Evolution Of Land
Animals, New Gene Study Suggests
Date: Posted 8/10/2001
http://www.sciencedaily.com/releases/2001/08/010810070021.htm

Excerpt: ... plants paved the way for the evolution of land
animals by simultaneously increasing the percentage of
oxygen in the Earth's atmosphere and decreasing the per-
centage of carbon dioxide, a powerful greenhouse gas.

"Our research shows that land plants and fungi evolved
much earlier than previously thought--before the Snowball
Earth and Cambrian Explosion events--suggesting their
presence could have had a profound effect on the climate
and the evolution of life on Earth," says Blair Hedges.

... The researchers found that land plants had evolved on
Earth by about 700 million years ago and land fungi by
about 1,300 million years ago--much earlier than previous
estimates of around 480 million years ago, which were
based on the earliest fossils of those organisms.

Prior to this study, it was believed that Earth's landscape
at that time was covered with barren rocks harboring
nothing more than some bacteria and possibly some algae.

No undisputed fossils of the earliest land plants and fungi
have been found in rocks formed during the Precambrian
period, says Hedges, possibly because their primitive
bodies were too soft to turn into fossils. ...

- - -

DNA Analysis Of Salamanders Turns Up New Species
Under Almost Every Log, UC Berkeley Zoologists Find
Date: Posted 7/5/2001
http://www.sciencedaily.com/releases/2001/07/010704092634.htm

Excerpt: A new species of salamander discovered in an iso-
lated range of hills in southeastern Mexico highlights the agile
inventiveness of evolution as well as the many species still
waiting to be discovered in out of the way spots and even
under our noses.

The soil dwelling salamander looks identical to a salamander
living in mountain foothills several hundred miles away, but
DNA analysis by zoologists at the University of California,
Berkeley, showed them to be distinct species. Experts can't
tell them apart, but they apparently evolved from different
ancestors and are not one another's closest relatives.

The finding, reported this week in the online edition of the
Proceedings of the National Academy of Sciences, demon-
strates an evolutionary concept called parallelism, a situation
where two organisms independently come up with the same
adaptation to a particular environment.

The discovery is one of many surprises that have emerged
in the past few years as biologists use DNA comparisons
to distinguish species and chart family trees.

More and more researchers are finding that what once were
thought to be separate populations of the same species are,
in fact, different species or lineages, each as genetically dis-
tinct as a horse from a cow.

"Biodiversity has been grossly underreported," said David
Wake.

This unsuspected diversity, often termed "cryptic biodiver-
sity," is turning up in everything from whales to birds, fungi
to flowering plants. It has implications for those who keep
track of species, such as those who enforce the Endangered
Species Act, as well as for biologists attempting to assess
diversity in a particular region. Plus, it raises questions about
the preservation of biodiversity. ...

- - -

Where There's Soup, There's Life
Date: Posted 7/2/2001
http://www.sciencedaily.com/releases/2001/07/010702085730.htm

Excerpt: Where there's soup, there's life. But we're talking
gourmet soup. That is, gourmet geochemical "primordial soups"
in hot springs and hydrothermal springs in the oceans that sup-
port novel chemolithotrophic thermophiles. If we can understand
these heat-loving little critters, then we may confirm what micro-
bial ecologist Anna-Louise Reysenbach suspects;they were the
earliest ancestors of all life.

Early Earth was a hot environment, and it's possible that some
of the life that we see today in hot springs in places like Yellow-
stone National Park and at deep-sea hydrothermal springs along
mid-ocean ridges may share some common metabolic features
with their early Earth ancestors. So determining what life exists
in hot springs today is one of the first steps to define what early
life on a hot planet may have been like. ...

- - -

Evolution At A Snail's Pace: It's Faster Than You Think
Date: Posted 6/5/2001
http://www.sciencedaily.com/releases/2001/06/010605074047.htm

Excerpt: By studying genetic data and fossil records of a
common California snail, biologists from Louisiana State
University and the University of California, San Diego have
found that a change in a species' territory can bring on rapid
morphological, or structural, evolutionary changes.

... By studying different populations of Acanthinucela spir-
ata, a marine gastropod found throughout the rocky coastal
regions of California, the researchers discovered that past
climatic changes altered the range of the species, which in
turn, caused the species' shell shape to evolve.

The scientists believe their findings can be applied to other
animals, and that any change in an animal's environment or
range, whether caused by climate changes, deforestation
or any other means of relocation, could bring about the
same results.

Fossil records show that the Earth's most recent series
of ice ages pushed the Acanthinucela spirata species from
northern California into the southern part of the state, where
a number of genetic variations took place within the species.

When conditions in the northern part of the state eventually
warmed - some 10,000 to 14,000 years ago - some mem-
bers of the snail species worked their way back in that dir-
ection, where they repopulated their old territory.

The scientists discovered that the snails in the repopulated
area to the north began to evolve differently from their south-
ern counterparts, most noticeably in the shape of their shells.
Snails with a thicker, shorter and broader shell emerged.
This new shell shape had not previously existed. ...


- - -

(continued in post 2 of 3)

Posts in this series:

Preponderance of Evidence for Naturalistic
Origins and Evolution of Life (1 of 3)
http://prohuman.net/science/evidence_for_evolution_1_of_3.htm

Preponderance of Evidence for Naturalistic
Origins and Evolution of Life (2 of 3)
http://prohuman.net/science/evidence_for_evolution_2_of_3.htm

Preponderance of Evidence for Naturalistic
Origins and Evolution of Life (3 of 3)
http://prohuman.net/science/evidence_for_evolution_3_of_3.htm

Preponderance of Evidence for Naturalistic
Origins and Evolution of Life (expanded - 4 of 4)
  http://prohuman.net/science/evidence_for_evolution_4_of_4.htm


- - - Additional Information of Relevance - - -

Origins of Energy, Matter, Space, Time, and Life (1 of 2)
http://prohuman.net/science/origins_1_of_2.htm

Origins of Energy, Matter, Space, Time, and Life (2 of 2)
http://prohuman.net/science/origins_2_of_2.htm

- - -