Tuesday, August 27, 2013

Evolution


"Nothing in biology makes sense except in the light of evolution."
Theodosius Dobzhansky


"Darwin continually emphasized the difference between his two
great and separate accomplishments: establishing the fact of evolution, and
proposing a theory- natural selection- to explain the mechanisms of evolution."
Stephen Jay Gould








People that do not accept evolution (despite the overwhelming
amount of evidence to support it) sometimes ask: If humans
evolved from monkeys or apes, why do apes still exist? (It might
as well be asked, Why are there still fish or reptiles?) Or even
better: Why don't chimpanzees change into humans now?
Homo sapiens and chimpanzees (and all primates in you go back
far enough) share a common ancestor. Humans did not directly
evolve from monkeys or apes. About 6 million years ago there existed
the common ancestor of humans and chimpanzees. Groups got separated
from each other and evolved differently. Sometimes animals with common
ancestors evolve (change) to become much different from their ancestor.
So a group (branch) of these ancestors became chimpanzees over many
years and another group evolved into the many hominins/hominids
(early humans) groups and eventually one of those groups produced modern 
humans. Most of all, the process take much time, millions of years. I understand
that if you believe the world to be only thousands of years old, you don't
stand a chance of understanding, or believing the process or mechanisms
 of evolution (and you probably refuse to try to understand).
 SH

Love it. I really like shawn the baptist's tiny stool.


http://youtu.be/68g0MBO_uTM  Richard Dawkins on YouTube



"And at the very heart of life on Earth-the proteins that control cell chemistry, and the
acids that carry the hereditary instructions-we find these molecules to be essentially
 identical in all the plants and animals. An oak tree and I are made of the same stuff.
If you go far enough back, we have a common ancestor."  
Carl Sagan



Evolution isn’t just a story about where we came from. It’s an epic at the center of
life itself. Far from robbing our lives of meaning, it instills an appreciation for the
beautiful, enduring, and ultimately triumphant fabric of life that covers our planet.
Understanding that doesn’t demean human life — it enhances it. We may be animals,
but we are not just animals. We are the only ones who can truly appreciate, as
Darwin put it, that there is “grandeur in this view of life,” and indeed there is.
Ken Miller, “America’s Darwin Problem”


Fact of evolution?

Richard Dawkins on evolution

Stephen Jay Gould on evolution

The key components in evolution are:
replication (reproduction)
variation (recombination and mutations)
selection (natural selection)

Variation is random, but selection
absolutely is not random.




"True, the raw materials for evolution-the variations between individuals-are indeed
produced by random mutations. These mutations occur willy-nilly, regardless of
whether they are good or bad for the individual. But it is the filtering of that variation
by natural selection that produces adaptions, and natural selection is manifestly not
random. It is a powerful molding force, accumulating genes that have a greater chance
of being passed on than others, and in so doing making individuals ever better able to
cope with the environment. It is, then, the unique combination of mutation and selection-
chance and lawfulness-that tells us how organisms become adapted. Richard Dawkins
provided the most concise definition of natural selection: it is "the non-random survival
of random variants.'"
Jerry Coyne



The best definition of life that I have encountered is
from a DK book entitled, Prehistoric Life:

"Life can be defined as a condition in which organic, animate matter is
distinguished from inorganic, inanimate matter by its ability to renew its
complex, highly ordered structure. This includes a capacity for change,
growth and reproduction, with functionality maintained until death, when
its constituents disperse back into the environment. In order to maintain itself,
life must be able to get energy and raw materials from the environment as well
as manufacture everything necessary for growth, repair, and replication. The
only element that is known to form living structures is carbon, which can
combine with itself, and other elements, notably nitrogen, oxygen, and
hydrogen, to form molecules of great diversity and complexity. Four main
groups of organic carbon compounds are found in living organisms:
carbohydrates and fats, which supply energy; proteins, built from amino
acids, which from structural tissue; and nucleic acids, the basic
components of genes."  

Or slightly shorter definition:
"Life is a self-sustaining chemical system capable of
undergoing Darwinian evolution."
G.F. Joyce



 RNA is as old as life. RNA, and the more complex, DNA, evolve.







 Essential amino acids must be obtained from food
whereas non-essential ones are produced in the body.


There are twenty kinds of amino acids that support the body, each having their
own functions. There are as many as one hundred thousand kinds of proteins
that constitute the body, and these comprise only twenty kinds of amino acids
in various combinations. These twenty amino acids are essential to the body. In
addition to being the materials for proteins, they are used as an energy source for
the body when needed.     www.hornetjuice.com


amino acids





Animal cell





There are more atoms in a human body
than there are stars in the universe.




http://youtu.be/6bCz2eFTBig   Carl Sagan: Evolution is Fact










Prokaryotes reproduce asexually.
 Eukaryotes all reproduce sexually, with very few exceptions,
 like sponges and certain types of plants (dandelions) and some lizards.
A few species of lizard are only females (or primarily)
and are able to reproduce due to an extra chromosome.
















































"Opponents of evolution always raise the same argument when vestigial
traits are cited as evidence for evolution. "The features are not useless,"
they say. "They are either useful for something, or we haven't yet discovered
what they're for." They claim, in other words, that a trait can't be vestigial if
it still has a function, or a function yet to be found.
But this rejoinder missed the point. Evolutionary theory doesn't say that
vestigial characteristics have no function. A trait can be vestigial and functional
at the same time. It is vestigial not because it's functionless, but because it's
no longer performs the function for which it evolved."
Jerry Coyne



vestigial structure



atavistic structure








vestigial wings and feathers





atavistic tail: proof of evolution






"One of my favorite cases of embryological evidence for evolution is the furry human fetus.
We are famously known as "naked apes" because, unlike other primates, we don't have a
thick coat of hair. But in fact for one brief period we do- as embryos. Around six months
after conception, we become completely covered with a fine, downy coat of hair called
lanugo. Lanugo is usually shed about a month before birth, when it's replaced by the
more sparsely distributed hair with which we're born. (Premature infants, however, are
sometimes born with lanugo, which soon falls off.) Now, there's no need for a human
embryo to have a transitory coat of hair. After all, it's a cozy 98.6 degrees Fahrenheit
in the womb. Lanugo can be explained only as a remnant of our primate ancestry."
Jerry Coyne 


























Every living organism evolved from bacteria.
In fact, we still live in a world dominated by bacteria.
37% of all organisms on the Earth are bacteria.









Tube worms near hydrothermal vents



http://youtu.be/21zgkg5pCaE  Origin of Life with David Attenborough
          First Life, BBC




trilobite fossil








In the world today there exists
the following known species:

~5,200 species of mammals
(~435 species of primates)

~7,500 species of reptiles
(~2,800 species of snakes)

 ~6,000 species of amphibians
(~4,800 frogs and toads)

~27,500 species of fish
(~400 species of sharks)

~10,400 species of birds
(~60 species of eagles)

 ~900,000 species of insects (could be up to 5 million)
(~350,000 species of beetles)

~275,000 species of plants
(~23,000 species of trees)
(~20,000 species of orchids)


The average life-span of a species is 4 million years.
99.9% of all species that have existed are now extinct.














If life on Earth was represented by a 24 hour day,
it would look like this. Very cool!

























 http://youtu.be/k-5oQlnXSTM  tetrapod evolution








































From bacteria to vertebrates




Phylogenetic Tree of Life







































































"Lucy" Australopithecus afarensis (3.2 mya)


Kingdom:
Phylum:
Class:
Order:
Family:
Subfamily:
Genus:
Species:
A. afarensis
Australopithecus afarensis


I have heard many creationists claim that Lucy was simply an ape,
a chimpanzee. This is incorrect, Lucy is classified as Australopithecus
afarensis. She certainly would have looked more like an ape than a
human, but she was bipedal.




"Tautavel Man" Homo erectus



















http://youtu.be/Cwc03uAQnxs  Homo Sapiens: The Birth of Humanity HD | NOVA Documentary

http://youtu.be/qc3QIk__aJw  NOVA | Becoming Human

http://youtu.be/vwa6o-s1Yvs  BBC - The Incredible Human Journey  -Out of Africa

http://youtu.be/2HgVl27j4Mk  The Human Spark : Becoming Us (PBS)

http://youtu.be/gfRHLjS_mBo  Ape To Man (History Channel)









Denisova and Neanderthal (named for where they were found)
are hominin relatives of modern humans; they also lived at the
same time as homo sapiens.
















There no longer are "missing links" in regard to humans and
 hominins and apes. There are plenty of transitional (intermediate) 
fossils that have been discovered, in Africa, and Asia and Europe.

According to Richard Dawkins, "Homo ergaster/erectus, of which
we have many fossils specimens, is a very persuasive halfway link,
no longer missing, between Homo sapiens today and Homo habilis
two million years ago, which is in turn a beautiful link back to
Australopithecus three million years ago, which, as we saw, could
pretty well be described as an upright-walking chimpanzee. How
many links do you need before you concede that they are no longer
'missing'? And can we also bridge the gap between Homo ergaster
and modern Homo sapiens? Yes: we have a rich lode of fossils,
covering the last few hundred thousand years, which are intermediate
between them. Some have been given species names, like Homo
heidelbergensis, Homo rhodesiensis and Homo neanderthalensis.
Others (and sometimes the same ones) are called 'archaic' Homo
sapiens. But, as I keep repeating, names don't matter. What matters
is that the links are no longer missing. Intermediates abound."
The Greatest Show on Earth 



Australopithecus--Homo habilis--Homo erectus--Homo neanderthalensis--Homo sapiens    

(This shows intermediates between Australopithecus and Homo sapiens:
Not direct descendants)



"In terms of anatomy and behavior, some australopithecines really do appear
to do be "half human." And, it's widely believed that early Homo descended
from some variety of late Australopithecus.
But since there were many varieties of Australopithecus, as well as many
varieties of early Homo, there's no obvious place to draw a discrete line
separating a shade of late Australopithecus from an early shade of Homo."
Cameron Smith and Charles Sullivan




There have been ~5,000 hominid fossils discovered.
Of the 141 most famous, this is the distribution.

Late Miocene 7-5.3 million years old (2 fossils)
Pliocene 5.3-2.58 million years old (12 fossils)
Pleistocene, Lower Paleolithic 2.58-300,000 (57 fossils)
Middle Paleolithic 300,000-50,000 (29 fossils)
Upper Paleolithic 50,000-10,000 (31 fossils)
Holocene, Mesolithic/Neolithic 10,000-5,000 (10 fossils)

Remember that approximately only 1 out of every 
100,000 species leaves a fossil.

Just as 99.9% of species that have existed have gone extinct,
99.9% of species do not leave fossil evidence.
























Genus versus Species
"Genus is the more inclusive division. A species belongs within a genus,
and often it shares the genus with other species. Homo sapiens and
Homo erectus are two species within the genus Homo. Australopithecus
africanus and Australopithecus afarensis are two species within the
genus Australopithecus."   Richard Dawkins











 


Migration of Homo sapiens



Sites where Neanderthal fossils found


Range of the Homo-Neanderthalensis
The Neanderthals were our close relatives and neighbors.




Range of Homo erectus / ergaster
(includes Java Man & Peking Man)
(Homo ergaster in Africa: Turkana Boy)





Predominat range of late Australopithecus and early Homo



Sites of the discovery of Australopithecus fossils.









  
























http://youtu.be/W10juYAax-8  Finding your inner fish




















"To doubt that life evolved...is to doubt the convergence of evidence,
from molecules to men, from bacteria to planetary systems. It is to doubt
the evidence of biology, and its concordance with physics and chemistry,
geology and astronomy. It is to doubt the veracity of experiment and
observation, to doubt the testing in reality. It is, in the end, to doubt reality."
Nick Lane


concise, interesting, and easy to read





















 Archaeopteryx
Dinosaur or bird?

Transitional (intermediate) fossils are rare, well so are
fossils in general, especially complete and well preserved ones.
(It is estimated that one bone in one billion gets fossilized.)
I hate the term "missing link," because evolution is a gradual
process and there were/are many "steps" from amphibians to
reptiles to mammals (for example). These fossils are certainly not "missing."
Any other of Australopithecus or early Homo hominids fossils are transitional.
Do not expect to find what might be called a perfect 50-50 amphibian-reptile
fossil (see Tikataalik below) or a reptile-mammal. Sticking to just mammals,
the now infamous question, "Why are there no fossils of a crocoduck?"
All animals share a common ancestor and are not directly evolved from
each other, especially not from another contemporary species.

brain child kirk cameron and crocoduck
Kirk is proof that not everyone has evolved equally.
Crocoduck also shows how creationists do not understand evolution at all.



Creationists say that there are "missing links" in the fossil record, not true.
Creationists say that evolution is just a theory, not true.
Creationists say that Intelligent Design is science based, not true.
Creationists say that microevolution is possible, but not macro evolution, not true.






Richard Dawkins










A Coelacanth fish is more closely related to reptiles
and mammals (humans) than to most other fish. They are
called living fossils since they were thought to have gone
extinct with the dinosaurs. Fossils of this fish have also
been found. It was first found (alive) in the 1930s.

"Although all species evolve, they don't do so at the same rate. Some, like
horseshoe crabs and gingko trees, have barely changed over millions of
years. The theory of evolution does not predict that species will constantly be
evolving or how fast they'll change when they do. That depends on the
evolutionary pressures they experience. Groups like whales and humans
have evolved rapidly, while others, like the coelacanth "living fossil," look
almost identical to ancestors that lived hundreds of millions of years ago."
Jerry Coyne



This is a transitional fossil, a mammalian cousin of humans.
It is the first ever link to humans. It is names Darinius masillae.

This fossil, nicknamed Ida, is 47 million years old. It connects (links, haha)
the human skeletal structure to early mammals. The fossil was found
in Messel Pit, Germany. The fossil is 20 times older than any fossil ever
found connected to human evolution.  It is classified as an early prosimian,
between lemur-like and monkey-like. It has human characteristics like
forward facing eyes and an opposable thumb. The most complete primate
fossil has not only bones, but skin, hair, and some internal organs.







Tiktaalik is one of the most amazing fossils ever found.
It lived around 375 million years ago.






Tiktaalik is nearly a perfect transitional fossil;
it is "half amphibian-half reptile" if you will.


A reconstruction of Tiktaalik

http://youtu.be/yvDQCa7rleI  Finding Tiktaalik









Puijila Darwini  http://youtu.be/ChbYLm25ors
Pujila lived about 24 million years ago.

Puijila is a transitional fossil that provides information about how the seal
family returned to the seas, similar to the way that Archaeopteryx illuminates
the origin of modern birds.
Wikipedia





Love it



water to land (and some back again)
Read about the fascinating evolutionary history of whales.
http://youtu.be/Lp6KKg1MVtA  Whale evolution






Fossil of "first turtle." It had half of a shell.




Queen ant


Honey bees killing an Asian wasp by heating it.




 http://youtu.be/L6zXpCM1w1Y  Evolution of flat fish







A kakapo can't fly.



























snapping shrimp


mudskipper fish  http://youtu.be/FLh4ODMBGJE


lungfish in water

lungfish on land


Brachiopsilus dianthus


Mexican axolotl walking fish








The llama comes from North America, although now it
exists only in South America. North and South America
plates separated from Pangea and reconnected about
3 million years ago.








Despite its name, the maned wolf is not a wolf at all, nor is it a fox, coyote, or dog.
It is the only member of the Chrysocyon genus, making it a truly unique animal,
not closely related to any other living canid. One hypothesis for this is that the
maned wolf is the last surviving species of the Pleistocene Extinction, which
wiped out all other large canids from the continent

Canid Phylogeny



The Amazing Platypus    National Geographic







Eomaia fossil
Eomaia was an early mammal that lived approximately 125 million years ago.

As Richard Dawkins states in his book, The Greatest Show on Earth:
" ...you can see that a lot of evolutionary change has taken place along both
pathways from an Eomaia-like ancestor to an elephant descendant, and
from the same Eomaia-like ancestor to a chimpanzee descendant. But it
is not in any sense an elephanzee."




  


Two photos I tool at the Beijing Zoo. 


人 (rén) means human, people



















































Many people state that everybody has a right to an opinion about God and religion,
and every one should respect those opinion (because nobody knows the truth).
We might not know why we are here, but we know how we got here.
This is complete bullshit. If I believe that Papa Smurf is God, you absolutely
have the right (obligation) to call me insane. Truth is truth (backed by evidence)
and crazy is crazy. In addition, an opinion without evidence is exactly that,
just an opinion. If someone believes (and sadly many do) that all organisms,
and the Earth itself, were created at the same time (during one week about 6,000 years
ago), they are simply wrong (and a bit delusional). The provable fact is that the Earth
is more than 4 billion years old. DNA alone disproves all of the creationists' claims,
add the fossil record and it cannot be disputed











"The often-quoted figure of about 98% for the shared genetic material
of human and chimps actually refers neither to numbers of chromosomes
nor to numbers of whole genes, but to number of DNA 'letters' (technically,
base pairs) that match each other within the respective human and chimp genes."
Richard Dawkins






Homo sapiens are obviously more closely
related to Neanderthals than to chimpanzees.

 Homo sapiens and chimpanzees share 96% of genetic material.
 Homo sapiens and Neanderthals share 99.7% of genetic material.

After the chimp genome project was completed, the figure 
was changed to 96% for humans and chimps instead of 98.8%.
(Creationists are saying, "See how science changes!"
As if this is a victory for them).



Of the 23 human chromosomes, 18 are nearly
identical to chimpanzees (chimps have 24).

It is truly amazing that the extinct Neanderthal genome has been mapped.
DNA was obtained from a femur bone.

A complete genome has been done for bacteria and fungi, as
well as for many insects and animals (ranging from a fruit
fly to an elephant). From the Hominidae family, the genome
has been completed for humans, orangutans (Borneo & Sumatra),
gorillas, chimpanzees and bonobos, as well as the extinct
Homo neanderthalensis. Other primates that have been
mapped are the galago and the macaque.



Humans share 90% of DNA with cats
80% with cows,
75% with mice,
60% with fruit flies and
50% with bananas.

Animals and plants share a lot of ancient DNA coding since they
diverged from each other about 1.5 billion years ago.



 Of course 4% of 3,000,000,000 is a large number, but...






infant and adult chimpanzees
  





Male Birds of Paradise in New Guinea







Male Bower-birds in Australia


Expending energy and having structures that may
impede movement are worth it, if in the end, a bird
mates and spreads its genes.




Great webpage: 101 Reasons why evolution is true



walking shark




http://youtu.be/21zgkg5pCaE   David Attenborough, The Origin of Life, BBC Doc










The human eye is a favorite topic of both creationists and evolutionists.
Creationists claim that only a designer (God) could have created
such a perfect structure as the eye. Would a designer create an
eye with a blind spot (a flawed creation)?
The human eye, just like humans themselves, were
obviously not created at a single point in time, they evolved.
It started about 600 million years ago with a simple retina
(which was formed from proteins, crystals and minerals)
and one small step after the other occurred over as little
as 500,000 years to form a more complex eye.

The human eye is anything but perfect.
As Jonathan Silvertown states, the human eye is
only sensitive to a narrow range of radiation (visible
light spectrum), it works well only in bright light,
there is a blind spot in the retina, and the lens
and retina often fail with age. Eyes of squid and
octopuses are more efficiently constructed and
the eyes of insects have features that humans lack.


 http://youtu.be/qV_TKi266bE   How Eyes Evolved

http://www.wimp.com/eyeevolution/  The Evolution of the Eye: David Attenborough

"...the eye evolved very quickly: the entire process from rudimentary light-patch to
camera eye took fewer than 400,000 years. Since the earliest animals with eyes
date back 550 million years ago, there was, according to this model, enough
time for complex eyes to have evolved more than fifteen hundred times over.
In reality, eyes have evolved independently in at least forty groups of animals.
As Nilsson and Pelger noted dryly in their paper, "It is obvious that the eye
was never a real threat to Darwin's theory of evolution."'
Jerry Coyne



















"If the history-deniers who doubt the fact of evolution are ignorant of biology, those who
think the world began less than ten thousand years ago are worse than ignorant, they
are deluded to the point of perversity." They are denying not only the facts of biology
but those of physics, geology, cosmology, archaeology, history and chemistry as well."
Richard Dawkins


"...the morphing of Wegener's hypothesis of continental drift into the modern theory
of plate tectonics is a textbook example of the solidification of a tentative hypothesis
into a universally accepted theorem or fact."
Richard Dawkins




Fossil distribution is evidence of plate tectonics
(and evolution) just as location of present-day species.






















      
Homologies: cellular/molecular evidence
All living things are fundamentally alike. At the cellular and molecular level living things are remarkably similar to each other. These fundamental similarities are most easily explained by evolutionary theory: life shares a common ancestor.  The cellular level
All organisms are made of cells, which consist of membranes filled with water containing genetic material, proteins, lipids, carbohydrates, salts and other substances. The cells of most living things use sugar for fuel while producing proteins as building blocks and messengers. Notice the similarity between the typical animal and plant cells pictured below — only three structures are unique to one or the other.
Animal and plant cell comparison
The molecular level
Different species share genetic homologies as well as anatomical ones. Roundworms, for example, share 25% of their genes with humans. These genes are slightly different in each species, but their striking similarities nevertheless reveal their common ancestry. In fact, the DNA code itself is a homology that links all life on Earth to a common ancestor. DNA and RNA possess a simple four-base code that provides the recipe for all living things. In some cases, if we were to transfer genetic material from the cell of one living thing to the cell of another, the recipient would follow the new instructions as if they were its own.        http://evolution.berkeley.edu






Adaptive radiation can lead to a new species, speciation.








 There are around 140 species of finches in the world today.




Speciation (macro-evolution) is when a new species arises, thus
interbreeding with original species is not possible. For most species
this process takes ten of thousands to millions of years.

Geographic (isolation) speciation, also called allopatric speciation
This is the most common type of speciation.












Sympatric speciation.
This type of speciation is rare, occurring primarily in plants.








 Speciation can take place in two general ways. A single species may change over time into a new form that is different enough to be considered a new species. This process is known as anagenesis. More commonly, a species may become split into two groups that no longer share the same gene pool. This process is known as cladogenesis. There are several ways in which anagenesis and cladogenesis may take place. In all cases, reproductive isolation occurs.

Sympatric Speciation

Sympatric speciation occurs when populations of a species that share the same habitat become reproductively isolated from each other. This speciation phenomenon most commonly occurs through polyploidy, in which an offspring or group of offspring will be produced with twice the normal number of chromosomes. Where a normal individual has two copies of each chromosome (diploidy), these offspring may have four copies (tetraploidy). A tetraploid individual cannot mate with a diploid individual, creating reproductive isolation.
Sympatric speciation is rare. It occurs more often among plants than animals, since it is so much easier for plants to self-fertilize than it is for animals. A tetraploidy plant can fertilize itself and create offspring. For a tetraploidy animal to reproduce, it must find another animal of the same species but of opposite sex that has also randomly undergone polyploidy.

Allopatric Speciation

Allopatric speciation, the most common form of speciation, occurs when populations of a species become geographically isolated. When populations become separated, gene flow between them ceases. Over time, the populations may become genetically different in response to the natural selection imposed by their different environments. If the populations are relatively small, they may experience a founder effect: the populations may have contained different allelic frequencies when they were separated. Selection and genetic drift will act differently on these two different genetic backgrounds, creating genetic differences between the two new species.

Parapatric Speciation

Parapatric speciation is extremely rare. It occurs when populations are separated not by a geographical barrier, such as a body of water, but by an extreme change in habitat. While populations in these areas may interbreed, they often develop distinct characteristics and lifestyles. Reproductive isolation in these cases is not geographic but rather temporal or behavioral. For example, plants that live on boundaries between very distinct climates may flower at different times in response to their different environments, making them unable to interbreed.


















recurrent laryngeal nerve

"The indirect path of this nerve does not reflect intelligent design but can
be understood only as the product of our evolution from ancestors having
very different bodies."
Jerry Coyne






so true... so goes the male




http://youtu.be/dK3O6KYPmEw  How to Shut up Creationists

(proof humans share common ancestor with chimpanzees)


http://youtu.be/txzOIGulUIQ   Shortest Debate Ever with a Creationist (a must see)

http://youtu.be/CvrmZLGWfFs  Evolution in 5 minutes (good vid)




A very intelligent scientist who worked on the
Human Genome Project. He is a Christian
and an evolutionist.

O.K., he's a bit delusional.





The isolation of Australia has produced some interesting animals.
Nearly all marsupials in the world live in Australia 70%, with the
remaining in South America and New Guinea.



 Marsupials are ~60 million years older than placentals.












"There's really only one difference between artificial and natural selection.
In artificial selection it is the breeder rather than nature who sorts out which variants
are "good" and "bad." In other words, the criterion of reproductive success is human
desire rather than adaptation to a natural environment."
Jerry Coyne











 New species of insect and frog recently discovered
in the rainforests of South America. Millions of
species in the world have yet to be discovered.
Possibly billions of species have gone extinct
since the beginning of life on this planet.




Psychrolutes marcidus
aka the blob fish



How did life originate?

Living things (even ancient organisms like bacteria) are enormously complex. However, all this complexity did not leap fully-formed from the primordial soup. Instead life almost certainly originated in a series of small steps, each building upon the complexity that evolved previously:
  1. Simple organic molecules were formed.
    Simple organic molecules, similar to the nucleotide shown below, are the building blocks of life and must have been involved in its origin. Experiments suggest that organic molecules could have been synthesized in the atmosphere of early Earth and rained down into the oceans. RNA and DNA molecules — the genetic material for all life — are just long chains of simple nucleotides.
    a nucleotide, composed of carbon, hydrogen, nitrogen, oxygen and phosphorus atoms
  2. Replicating molecules evolved and began to undergo natural selection.
    All living things reproduce, copying their genetic material and passing it on to their offspring. Thus, the ability to copy the molecules that encode genetic information is a key step in the origin of life — without it, life could not exist. This ability probably first evolved in the form of an RNA self-replicator — an RNA molecule that could copy itself.
    a chain of nucleotides forms an RNA molecule
    Many biologists hypothesize that this step led to an "RNA world" in which RNA did many jobs, storing genetic information, copying itself, and performing basic metabolic functions. Today, these jobs are performed by many different sorts of molecules (DNA, RNA, and proteins, mostly), but in the RNA world, RNA did it all. Self-replication opened the door for natural selection. Once a self-replicating molecule formed, some variants of these early replicators would have done a better job of copying themselves than others, producing more "offspring." These super-replicators would have become more common — that is, until one of them was accidentally built in a way that allowed it to be a super-super-replicator — and then, that variant would take over. Through this process of continuous natural selection, small changes in replicating molecules eventually accumulated until a stable, efficient replicating system evolved.
  3. Replicating molecules became enclosed within a cell membrane.
    The evolution of a membrane surrounding the genetic material provided two huge advantages: the products of the genetic material could be kept close by and the internal environment of this proto-cell could be different than the external environment. Cell membranes must have been so advantageous that these encased replicators quickly out-competed "naked" replicators. This breakthrough would have given rise to an organism much like a modern bacterium.
    genetic material enclosed in membranes
    Cell membranes enclose the genetic material.
  4. Some cells began to evolve modern metabolic processes and out-competed those with older forms of metabolism.
    Up until this point, life had probably relied on RNA for most jobs (as described in Step 2 above). But everything changed when some cell or group of cells evolved to use different types of molecules for different functions: DNA (which is more stable than RNA) became the genetic material, proteins (which are often more efficient promoters of chemical reactions than RNA) became responsible for basic metabolic reactions in the cell, and RNA was demoted to the role of messenger, carrying information from the DNA to protein-building centers in the cell. Cells incorporating these innovations would have easily out-competed "old-fashioned" cells with RNA-based metabolisms, hailing the end of the RNA world.
    DNA contains instructions.  RNA copies DNA.  Proteins are made from copies instructions.
  5. Multicellularity evolved.
    As early as two billion years ago, some cells stopped going their separate ways after replicating and evolved specialized functions. They gave rise to Earth's first lineage of multicellular organisms, such as the 1.2 billion year old fossilized red algae in the photo below.
    Bangiomorpha pubescensBangiomorpha pubescensThese fossils of Bangiomorpha pubescens are 1.2 billion years old. Toward the lower end of the fossil on the left there are cells differentiated for attaching to a substrate. If you look closely at the upper part of the fossil on the right, you can see longitudinal division that has divided disc-shaped cells into a number of radially arranged wedge-shaped cells, as we would see in a modern bangiophyte red alga.

www.evolution.berkeley.edu



http://youtu.be/5JzUgi6YNlY    Evolution:  Deep Sea Vents and Life's Origins

http://youtu.be/8SgnnV8nV9g   Origin And Evolution Of Life


The evidence only confirms evolution.





Birds under water, God must have whispered into their ears.






Don't listen to warped creationists.
95-99.9% of scientists accept evolution.
  




Sometimes I'm embarrassed to be a U.S. citizen.

So we can deduce from this chart that
47% of U.S. citizens are morons.




required reading for agnostics, lol




Scopes Trial, 1925


Tammy Kitzmiller, et al. v. Dover Area School District, et al., 2005
Holding
Teaching intelligent design in public school biology classes violates the Establishment Clause of the First Amendment to the Constitution of the United States (and Article I, Section 3 of the Pennsylvania State Constitution) because intelligent design is not science and "cannot uncouple itself from its creationist, and thus religious, antecedents."

Evolution ALWAYS wins in court!
(Even with fundamentalist judges)


John Edward Jones III (born June 13, 1955) is an American lawyer and jurist from the U.S. state of Pennsylvania. A Republican, Jones was appointed by President George W. Bush as federal judge on the United States District Court for the Middle District of Pennsylvania in February 2002 and was unanimously confirmed by the United States Senate on July 30, 2002. He is best known for his presiding role in the landmark Kitzmiller v. Dover Area School District case, in which the teaching of intelligent design in public school science classes was ruled to be unconstitutional.



There is no debate!







1 comment:

  1. just excellent and marvelous work I am sharing it with my friends .

    ReplyDelete