Re: Further Evidence that there is no "genetic barrier"
im going to research this.anymore proof apart from a chart that what you say here:
quote:Cartilaginous fish diverged from the branch that mammals are on over 450 million years ago, and pre-date "true fish" ... that's a lot for one "kind" eh.
is actually true or you just defending a belief system?i see similarities in this example and to me its the strongest one you have provided.dont take it personally razd im in no way attacking you. and its unlike talking to fanatical atheists to whom talking about this type of topic is akin to entering a mosque wearing a shirt of mohammed eating a pork chop.i can see why a deist is a deist.and in some ways i believe god has left us to run the world the way we want.start another thread coyote.thanks.
Edited by seekingfirstthekingdom, : No reason given.
Edited by seekingfirstthekingdom, : No reason given.
Edited by seekingfirstthekingdom, : No reason given.
this tends to render most of your examples that you have provided rather moot.
Denial of evidence is like that. What the evidence shows is that there is no genetic barrier to what organisms can evolve. A placental mammal can become a flying squirrel, while a marsupial can become a sugar glider; a mammal can become an orca, while a cartilaginous fish can become a white shark. You can dodge the issue or you can address it and show that there is some mechanism that actually stops evolution.
i have a problem with.
.1.simple lifeforms like bacteria being able to become superior lifeforms .2.reptiles being able to become mammals,especially reptiles becoming birds. .3.habilis being a link in mans ancestry.
Curiously, the fact that you have a problem has absolutely no effect on the validity and reality of the fossil record, nor does it stop evolution as one organism evolves into another, generation by generation.
This article also discusses the transitional features that exist in Tiktaalik and later tetrapods and ones that don't exist in previous fish forms.
quote:First described in 2006 and quickly dubbed the “fishapod,” it had the fish-like features of a primitive jaw, fins and scales, as well as a skull, neck, ribs and parts of the limbs that are similar to tetrapods (four-legged animals).
“The braincase, palate and gill arch skeleton of Tiktaalik have been revealed in great detail by recent fossil preparation of several specimens,” said Jason Downs, a postdoctoral research fellow at the Academy of Natural Sciences and lead author on the new study. “By revealing new details on the pattern of change in this part of the skeleton, we see that cranial features once associated with land-living animals were first adaptations for life in shallow water.”
Fish in deep water move and feed in three-dimensional space and can easily orient their bodies in the direction of their prey. A neck, seen for the first time in the fossil record in Tiktaalik, is advantageous in settings where the body is relatively fixed, as is the case in shallow water and on land, appendages support a body planted against a substrate.
Note that a transitional fossil is defined as one that shares characteristics with older life forms and with later life forms, and that the characteristics shared with later life forms did not exist during the time of the older life forms, while they develop further in later life forms.
you seem to know a lot more about this "transitional" creature than scientists who have studied it and have decided to put it on a seperate branch rather than a direct ancestor between reptile and bird.
See definition of transitional fossil above, and demonstrate how archaeopteryx does not meet these criteria.
Next cite your sources for these scientists and what they actually say, so we know you are not citing some creationist hoax site or people that don't know what they are talking about. I suspect your sources are of a questionable nature.
quote:Archaeopteryx is a bird because it had feathers. However, it retained many dinosaurian characters which are not found in modern birds, whilst having certain characters found in birds but not in dinosaurs. By virtue of this fact Archaeopteryx represents an example of a group in transition - a representative which, although on the sidelines in the dinosaur to bird transition, an echo of the actual event, still allows a brief glimpse into the possible mechanism which brought about the evolution of the birds and by its very existence shows that such a transition is possible.
It meets the definition of transitional.
cold blooded probably reptilian.warm blooded probably mammal.i have issues with evolutionary artistry and creative license.lets see some actual fossils please.and without step by step fossil links to prove this is a link,it becomes just another variety.
Again, the fact that you have issues does not mean that therapsids are not transitionals showing generation by generation the adaptation of features that don't exist in reptiles and that become more and more developed in later generations.
Your opinion does not change, alter nor affect the fossil record in any way, nor does it invalidate the transitional development of fossils in time.
Features that did not exist in previous forms are seen developing in transitional fossils, becoming more developed in later fossils, and eventually reaching the stage of development seen in life today.
quote:Denial of evidence is like that. What the evidence shows is that there is no genetic barrier to what organisms can evolve. A placental mammal can become a flying squirrel, while a marsupial can become a sugar glider; a mammal can become an orca, while a cartilaginous fish can become a white shark. You can dodge the issue or you can address it and show that there is some mechanism that actually stops evolution.
whats this got to do with what i specifically asked for regarding reptile to mammal?quite clearly the 1st example has nothing to do with what im debating.please stay on point.secondly give me time to research your claims regarding how closely related the shark and orca actually are.its so glaringly obvious to me there are barriers inbetween reptiles and mammals.surely you must know this.
quote:Curiously, the fact that you have a problem has absolutely no effect on the validity and reality of the fossil record, nor does it stop evolution as one organism evolves into another, generation by generation.
not to the extent you are claiming.the reality is you are taking tenuous examples,ignoring the obvious and attempting to put pieces where they dont fit.theres nothing in the natural world that backs you up.nothing.
quote:This is what makes Tiktaalik a transitional fossil
once again you need more than 1 fossil and a few drawings to convince anyone who doesnt share your faith.closer inspection to me that could be anything.im always amused at evolutionists unseemly haste to claim what is transitional on the merest hint of evidence.give it time.
quote:Again, the fact that you have issues does not mean that therapsids are not transitionals showing generation by generation the adaptation of features that don't exist in reptiles and that become more and more developed in later generations.
unseemly haste to claim it as a transitional.i suspect that you arent open to the possibility that you are wrong.that makes this debate invalid.you cant even tell me what temperature its blood was or distinguishing features that could help identify it properly.in your eyes its transitional already.youve made a conclusion without giving it time or considering new evidence.how is that true science?
Edited by seekingfirstthekingdom, : No reason given.
after reading ancestors tale and taking into account the replies here im still no further along in my pursuit of the holy grail of bacteria that can evolve into higher lifeforms.reptile to mammal is 99% obvious that it doesnt happen but we have a transitional that may or may not turn up trumps.it obviously seems to have a lot of hopes and dreams resting on its furry shoulders.and habilis is looking for bananas and picking lice out of its partners.and trying not to get eaten.im done debating you i dont bother repeating myself.its a waste of time.i will research the orca shark thing tho but i suspect its just another atheist red herring.
Edited by seekingfirstthekingdom, : No reason given.
i find the 95% figure misleading .to me theres a huge difference between chimps and man.
Curiously the natural world in completely unaffected by what you "find," and what your opinion is, of the degree of difference between man and chimp.
you ignored my example of evidence of young male pharoahs 3000 odd years old that show no sign of being more primitive.
Because it is irrelevant, as you can go back 30,000 years to cro-magnon and find little difference to modern humans while there is detectable difference between them and neanderthals:
quote:A 2003 study on Cro-Magnon and Neanderthal mitochondrial DNA, published by an Italo-Spanish research team led by David Caramelli, concluded that Neanderthals were far outside the modern human range, while Cro-Magnons were well in the average of modern Europeans. mtDNA retrieved from two Cro-Magnon specimens was identified as Haplogroup N. [5] Haplogroup N is found among modern populations of the Middle East, North Africa and Central Asia, and its descendant haplogroups are found among modern Eurasian and Native American populations. [6].
Are neanderthals human or ape? (or both?) ... the DNA difference between Cro-Magnon\sapiens and neanderthal is almost the same as the difference between Cro-Magnon\sapiens and chimp ... and the difference between neanderthal and chimp (ie there are different differences to neanderthal than to chimp).
dna similarities are due to being designed to cohabit.
Another wild assertion not supported by the evidence. Again we look at convergent evolution:
These guys are similar, but have quite difference DNA sequences, so their similarity is NOT due to common design elements.
Curiously it is not just that DNA is ~95% similar, but the places similarities occur that are completely unnecessary:
quote:Identical pseudogenes in apes and humans that corroborate the powerful fossil evidence.
Primates, unlike all other mammals (with the exception of guinea pigs), cannot synthesize Vitamin C. In days long past, this led to tragic outbreaks of scurvy on seafaring voyages. Using the predictions of evolution, scientists hypothesized that the gene for vitamin C production would be found in humans as well, despite our not being able to produce it.
Lo and behold, a GLO (ascorbic acid pseudogene) was identified in humans at exactly the same spots other mammals have functional vitamin C genes. What's more, the other great apes (chimps, gorillas and orangutans) had an identical broken pseudogene!
The common ancestor of apes and humans lived in a fruit-rich environment and had no need to synthesize their own vitamin C, making the loss of that gene entirely neutral. Guinea pigs also have a damaged GLO pseudogene, but the mutation that crippled it is different, as expected if it was an independent occurence.
Other occurences of shared pseudogenes include the one coding for Urate Oxydase, which make our species vulnerable to gout, and dozens of them that code for powerful smell in other animals but are crippled in humans, but one should suffice for now.
Observations in the area of pseudogenes that would falsify evolution include finding the same pseudogene in humans and dogs but not apes; since apes and humans share a closer ancestry than dogs and humans, any pseudogenes found in dogs and humans MUST be found in humans and apes because they belonged to the common ancestor of the latter. Hence, the theory of evolution passes this series of empirical experiments as well.
Care to discuss the design that copies the failure to produce vitamin C is due to exactly the same damage in exactly the same DNA sequence in chimps and humans? Care to discuss the design that includes a damaged copy of a gene that is functional in other mammals, related by more distant common ancestors?
Why does your designer copy something that doesn't work?
interesting strategy.you are using chimp behaviour to justify that habilis isnt a chimp.chimps use stone tools as well according to jane goodall.
Some scientists think chimps should be included as a hominid.
except you would need a lot of 3.5 foot high small brained chimps to take anything down.how many fossils of handyman have been found in the area again?
Again this is just your opinion, and irrelevant. Number of fossils does not equal the number of organisms related to the fossil.
convergent evolution means no "genetic boundary" to evolution
hey S1tk
whats this got to do with what i specifically asked for regarding reptile to mammal?
Let's not start playing games now. You can very easily track the posts back to Message 21 and your claim that
still stand by my comments that the overwhelming evidence in the fossil record points to kinds staying within genetic boundaries instituted by our creator in genesis.
Convergent evolution invalidates that concept, as you see completely different lineages converging on the same form.
With the flying squirrels and sugar gliders, one is a placental mammal and the other is a marsupial.
With the orcas and the white sharks, one is a mammal and one is a cartilaginous fish.
For these forms to be limited to one "kind" by some mystical "genetic boundaries instituted by our creator in genesis" means that these organisms must be of the same "kind" ... or such convergence would be blocked.
secondly give me time to research your claims regarding how closely related the shark and orca actually are.its so glaringly obvious to me there are barriers inbetween reptiles and mammals.surely you must know this.
What I know is that the difference between shark and orca should be even MORE "glaringly obvious" to you than the difference between reptile and mammal.
not to the extent you are claiming.the reality is you are taking tenuous examples,ignoring the obvious and attempting to put pieces where they dont fit.theres nothing in the natural world that backs you up.nothing.
Yes, denial is like that. Curiously denial does not mean that you have shown that the examples are tenuous, or that they are put in the "wrong" place, so we just have your opinion.
On the other hand you could attempt to show how a genetic barrier would work, and then we can look to see if that in fact is supported by the evidence.
definition of transitional: applied to archaeopteryx evidence
thanks S1tk, but this is not your source is it?
quote:Archaeopteryx is a bird because it had feathers. However, it retained many dinosaurian characters which are not found in modern birds, whilst having certain characters found in birds but not in dinosaurs. By virtue of this fact Archaeopteryx represents an example of a group in transition - a representative which, although on the sidelines in the dinosaur to bird transition, an echo of the actual event, still allows a brief glimpse into the possible mechanism which brought about the evolution of the birds and by its very existence shows that such a transition is possible.
Note first off, that it is a bird. That means it is part of the lineage from dinosaur to bird.
Second, that modern birds are not direct descendants of Archaeopteryx also does not mean that it is not transitional, as it is also clearly labeled.
Third, given that most bird species went extinct at the same time as the dinosaurs, 65 million years ago, it is not surprising that modern birds are not direct descendants of one pre-extinction type of bird, but of a close relative.
you cant even tell me what temperature its blood was or distinguishing features that could help identify it properly.
Curiously, the article linked provided many such distinguishing features. Here are some more:
quote:As promised, here are the derived characters with which Gauthier (in his 1986 paper) unites Archaeopteryx with modern birds, outside of all other theropods (with Gauthier's original clarifiers in parens) [and with my editorial comments in brackets]: (list of features) Thus, there are derived features linking Archaeopteryx to modern birds.
Note that these are features not found in dinosaur ancestors, while this list:
quote:Here are 20 to get you started (characters shared with/retained from dromaeosaurids and other related theropods and dinosaurs): (list) There are dozens more--I've scarcely touched the skull in this list. But you get the idea, yes?
These are features found in dinosaurs but not in modern birds.
.in your eyes its transitional already.youve made a conclusion without giving it time or considering new evidence.how is that true science?
No, it is transitional in my mind because it has features intermediate between ancestral forms and descendant form, features that don't exist in previous organisms, and that are more derived in later forms.
It is transitional because the evidence shows this is so:
Review definition of transitional Review of Evidence Result: the evidence matches the definition Conclusion: it is transitional
Should new evidence show that a different conclusion is warranted, I'll be happy to look at it.
Curiously that is precisely how science works. By practical necessity science only considers all the evidence that is known in deriving the best explanation for that evidence.
And it doesn't wait for something new to show up - it looks for it.
once again you need more than 1 fossil and a few drawings to convince anyone who doesnt share your faith.closer inspection to me that could be anything.im always amused at evolutionists unseemly haste to claim what is transitional on the merest hint of evidence.give it time.
Again, this is not "unseemly haste" it is looking at the evidence that exists.
Again, we look at the definition of transitional fossil:
A transitional fossil is defined as one that shares characteristics with older life forms and with later life forms, and that the characteristics shared with later life forms did not exist during the time of the older life forms, while they develop further in later life forms.
There are several such traits listed in the article on Tiktaalik that show that it too meets the definition of a transitional fossil.
quote:Tiktaalik is a transitional fossil; it is to tetrapods what Archaeopteryx is to birds. While neither may be ancestor to any living animal, they serve as proof that intermediates between very different types of vertebrates did once exist. The mixture of both fish and tetrapod characteristics found in Tiktaalik include these traits:
* Fish o fish gills o fish scales * "Fishapod" o half-fish, half-tetrapod limb bones and joints, including a functional wrist joint and radiating fish-like fins instead of toes o half-fish, half-tetrapod ear region * Tetrapod o tetrapod rib bones o tetrapod mobile neck o tetrapod lungs
Tiktaalik generally had the characteristics of a lobe-finned fish, but with front fins featuring arm-like skeletal structures more akin to a crocodile, including a shoulder, elbow, and wrist. The rear fins and tail have not yet been found. It had rows[8] of sharp teeth of a predator fish, and its neck was able to move independently of its body, which is not possible in other fish. The animal also had a flat skull resembling a crocodile's; eyes on top of its head, suggesting it spent a lot of time looking up; a neck and ribs similar to those of tetrapods, with the latter being used to support its body and aid in breathing via lungs; well developed jaws suitable for catching prey; and a small gill slit called a spiracle that, in more derived animals, became an ear.[9]
It is also intermediate between Panderichthys and later forms.
quote:Panderichthys is a 90-130 cm long fish from the Devonian period 380 million years ago, (Frasnian epoch) of Latvia. It has a large tetrapod-like head. Panderichthys exhibits transitional features between lobe-finned fishes and early tetrapods such as Acanthostega. The evolution from fish to land dwelling tetrapods required many changes in physiology, most importantly the legs and their supporting structure, the girdles. Well preserved fossils of Panderichthys clearly show these transitional forms[1], making Panderichthys a rare and important find in the history of life.
Notice that these features are less developed than they are in Tiktaalik, while still being more developed than in lobe-finned fish.
quote:Ichthyostega (Greek: "fish roof") is an early tetrapod genus that lived in the Upper Devonian (Famennian) period, 367-362.5 million years ago. It was a labyrinthodont that represents an intermediate form between fish and amphibians. Ichthyostega possessed lungs and limbs that helped it navigate through shallow water in swamps. Though undoubtedly of amphibian build and habit, it is not considered a true member of the group in the narrow sense (the Lissamphibia, as they first appeared in the Carboniferous period.
Again, features that appeared in earlier transitional fossils are more developed, and they become even more developed in later tetrapods.
What we see is that Tiktaalik fits between these two fossils, in time, in features, in habitat.
All three are transitional fossils by a review of the definition presented above, and by a review of the evidence of intermediate forms and traits.
It is not a "rush to judgment," nor is it based on a "preconceived conclusion," to note that these are in fact transitional fossils: that is what the evidence shows.
Re: lets recap now shall we (before you run away?)
okay, S1tk, I'll recap:
Evidence presented by you = 0
No definition of your "Amazing Magical Yeast" concept or revision of it to be a logically derived organism based on actual definitions of evolution.
No evidence of any "genetic barrier" to evolution, nor any refutation of the evidence that shows the ability of quite different lineages to evolve similar forms.
Flying Squirrels and Sugar Gliders show there is no barrier between their lineages to evolve into similar organisms.
White Sharks and Orcas also show there is no barrier between their lineages to evolve into similar organisms.
No refutation of the transitional nature of
Tiktaalik,
Therapsids,
Archaeopteryx,
based on (a) the definition of transitional fossil and (b) the evidence of intermediate traits in all these fossils.
Dropped, like a hot rock, is any discussion of evolution or speciation, the theory of evolution, the cladograms of life showing development from bacterial form to all currently known existing life forms.
Failure to engage the evidence of evolution, speciation and the diversity of life produced by these simple mechanisms as shown by the greenish warbler, pelycodus and foraminifera.
Blank refusal to deal with the genetic similarity between human and chimp.
after reading ancestors tale and taking into account the replies here im still no further along in my pursuit of the holy grail of bacteria that can evolve into higher lifeforms.
Your "pursuit" seems to be comprised of a fair bit of blank denial of evidence. A person who is convinced they cannot walk across the country will never try.
reptile to mammal is 99% obvious that it doesnt happen but we have a transitional that may or may not turn up trumps
And we have not one, but hundreds. The evidence of therapsids shows 100% development of mammalian ear from reptile ear, an ear that no reptile has, but all mammals have. Just hitting the high points:
Each of these groups represent several sub-groups, each representing several species, each one including multiple fossils.
I provided a link before and suggested that you browse it as it is interactive. You can even work your way to Primates and Hominoidea
Depending on how far you are willing to walk.
im done debating you i dont bother repeating myself.its a waste of time
Ah, the old "declare victory and RUN from the debate and the overwhelming evidence that you are wrong. Delusion is like that:
Now there are many levels of delusion, from plain ignorance coupled with poor or wrong teaching, or people telling you falsehoods, up to clinical delusion. Simple forms can be cured with education and checking facts for validity.
i will research the orca shark thing tho but i suspect its just another atheist red herring.
Atheist? Curiously that includes a lot of christians, including Linnaeus. How about realist people that cover the full spectrum of beliefs.
quote:Chondrichthyes or cartilaginous fishes are jawed fish with paired fins, paired nostrils, scales, two-chambered hearts, and skeletons made of cartilage rather than bone. They are divided into two subclasses: Elasmobranchii (sharks, rays and skates) and Holocephali (chimaera, sometimes called ghost sharks, which are sometimes separated into their own class).
quote:Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. They are united by having, at some time in their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail.
That's a pretty big group. Classification is by existing observable traits.
Hey S1tk, perhaps what we need is a different tack.
im still no further along in my pursuit of the holy grail of bacteria that can evolve into higher lifeforms.
Part of your problem is that you know so little about how biology works and the process of evolution, that you can't formulate your question with any meaning.
Do you mean the first life form?
The earliest life known is 3.5 million years old, and it is a cyanobacteria:
quote:The cyanobacteria have an extensive fossil record. The oldest known fossils, in fact, are cyanobacteria from Archaean rocks of western Australia, dated 3.5 billion years old. This may be somewhat surprising, since the oldest rocks are only a little older: 3.8 billion years old!
No currently known older rocks have fossils (not fossil carrying types of rocks).
quote:Cyanobacteria are among the easiest microfossils to recognize. Morphologies in the group have remained much the same for billions of years, and they may leave chemical fossils behind as well, in the form of breakdown products from pigments. Small fossilized cyanobacteria have been extracted from Precambrian rock, and studied through the use of SEM and TEM (scanning and transmission electron microscopy).
Cyanobacteria used photosynthesis for energy, and over time changed the atmosphere of the planet by adding more oxygen in gas form. Note that these cyanobacteria are also multi-cellular in a simple way: they form threads (complex multi-cellular forms also have specialization, where different cells take on different tasks).
quote:The ability of cyanobacteria to perform oxygenic photosynthesis is thought to have converted the early reducing atmosphere into an oxidizing one, which dramatically changed the composition of life forms on Earth by provoking an explosion of biodiversity and leading to the near-extinction of oxygen-intolerant organisms. Chloroplasts in plants and eukaryotic algae may have evolved from cyanobacteria via endosymbiosis.
The forms of life before that are unknown, nor is the number of different forms that existed before this known.
quote:In particular, it emphasizes the separation of prokaryotes into two groups, originally called Eubacteria and Archaebacteria. Woese argued that, on the basis of differences in 16S rRNA genes, these two groups and the eukaryotes each arose separately from an ancestor with poorly developed genetic machinery, often called a progenote. To reflect these primary lines of descent, he treated each as a domain, divided into several different kingdoms.
A phylogenetic tree based on rRNA data, showing the separation of bacteria, archaea, and eukaryotes.
quote:The term progenote refers to a "living organism" that was the precursor to all living things. The progenote refers specifically to the ancestor to prokaryotes and the decendant of protobionts. (The term protobiont refers to a vessel (like a liposome) that has the ability to maintain an inner environment differnt from the outer environment and that also has the ability to "reproduce".)
quote:A protobiont is an aggregate of abiotically produced organic molecules surrounded by a membrane or a membrane-like structure. Protobionts exhibit some of the properties associated with life, including simple reproduction, metabolism and excitability, as well as the maintenance of an internal chemical environment different from that of their surroundings. It has been suggested that they are a key step in the origin of life on earth. Experiments by Sidney W. Fox and Aleksandr Oparin have demonstrated that they may be formed spontaneously, in conditions similar to the environment thought to exist on an early Earth. These experiments formed liposomes and microspheres, which have membrane structure similar to the phospholipid bilayer found in cells.
Note that all "higher" life forms are eukaryotes. Note that these eukaryotes did not evolve from the first (theoretical Progenote or known Cyanobacteria) life, but from some archea organisms that evolved later.
Do you mean the first life eukaryote/s?
The first known eukaryotes occur in the fossil record long after the first fossils of life.
quote:The origin of the eukaryotic cell was a milestone in the evolution of life, since they include all complex cells and almost all multi-cellular organisms. The timing of this series of events is hard to determine; Knoll (2006) suggests they developed approximately 1.6 - 2.1 billion years ago. ... Fossils that are clearly related to modern groups start appearing around 1.2 billion years ago, in the form of a red alga.
That means 1.4 to 2.3 billion years after the first known cyanobacteria.
It is possibly there were several different varieties of basal eukaryotes, once a nucleus formed (if a current theory concerning the incorporation of some single cell-life forms inside other single-cell life forms is correct), because there are fundamentally different groups of eukaryotes:
quote:Animals, plants, fungi, and protists are eukaryotes ... organisms whose cells are organized into complex structures enclosed within membranes. The defining membrane-bound structure that differentiates eukaryotic cells from prokaryotic cells is the nucleus. The presence of a nucleus gives these organisms their name, which comes from the Greek (eu), meaning "good/true," and (karyon), "nut." Many eukaryotic cells contain other membrane-bound organelles such as mitochondria, chloroplasts and Golgi bodies.
There are many different types of eukaryotic cells, though animals and plants are the most familiar eukaryotes, and thus provide an excellent starting point for understanding eukaryotic structure. Fungi and many protists have some substantial differences, however.
Eukaryotes are a very diverse group, and their cell structures are equally diverse. Many have cell walls; many do not. Many have chloroplasts, derived from primary, secondary, or even tertiary endosymbiosis; and many do not. Some groups have unique structures, such as the cyanelles of the glaucophytes, the haptonema of the haptophytes, or the ejectisomes of the cryptomonads. Other structures, such as pseudopods, are found in various eukaryote groups in different forms, such as the lobose amoebozoans or the reticulose foraminiferans.
Rather than all eukaryotes coming from one single archaea we see multiple branches into very distinct groups.
quote:Here is a picture that summarises the evolution of eukaryotes as we know it today:
Note on this picture that fungi and animals (and thus human) are not as evolutionary distant as is commonly thought. Especially, you can see that plants have diverged before.
If the cyanobacteria is connected directly to eukaryotes it is as chloroplasts in plants.
quote:Chloroplasts found in eukaryotes (algae and plants) likely evolved from an endosymbiotic relation with cyanobacteria. This endosymbiotic theory is supported by various structural and genetic similarities. Primary chloroplasts are found among the green plants, where they contain chlorophyll b, and among the red algae and glaucophytes, where they contain phycobilins. It now appears that these chloroplasts probably had a single origin, in an ancestor of the clade called Primoplantae. Other algae likely took their chloroplasts from these forms by secondary endosymbiosis or ingestion.
Eukaryotes are fundamentally different from bacteria and archaea, probably more different than any life form since. All "higher" multi-cellular life forms are eukaryotes, and the branch that leads to animal life is only one of many of the branches within Eukaryotes, while plants are on an entirely different branch.
Do you mean the first multi-cellular eukaryotic life ?
Multicellular structures are not unique to eukaryotes. There are many kinds of multicellular bacteria.
(PZ Myers)The obvious feature is that cells must stick together; specific adhesion molecules must be present that link cells together, that aren't generically sticky and bind the organism to everything. So we need molecules that link cell to cell. Another feature of multicellular animals is that they secrete extracellular matrix, a feltwork of molecules outside the cells to which they can also adhere.
A feature that distinguishes true multicellular animals from colonial organisms is division of labor ” cells within the organism specialize and follow different functional roles. This requires cell signaling, in which information beyond simple stickiness is communicated to cells, and signal transduction mechanisms which translate the signals into different patterns of gene activity.
We can agree with his statement that two requirements of multicellularity are the ability of cells to stick together and the division of labor where cells differentiate to carry out specialized functions. Lest anyone imagines that these properties were invented by animals”or even by eukaryotes”let's look at some simple multicellular bacteria.
Under certain conditions the single cells of myxobacteria come together to form fruiting bodies that consist of hundreds of cells. In the most extreme examples, some cells form the stalk, some cells form sprangia and others form spores. These are multicellular bacteria with specialized differentiated cells.
It is likely that multicellular forms developed many times, in bacteria and in eukaryotes. Within eukaryotes multicellular life developed several times as well, as multicellular forms occur in branches after they have diverged. Multicellular plants and multicellular animals do not have a multicellular common ancestor.
Summary
Thus we can see that no single form of life sequentially budded off increasingly complex life forms, rather all life evolved generation by generation, and those that took a step towards more complexity were different organisms from their ancestors.
In other words, there is no "Amazing Magical Yeast" ... and searching for it is like looking for a straw man in a stack of needles.
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