Evolution, Morphology and Exobiology

I'm looking for good "case studies" documenting an obvious branching in a phylogenic tree, or a large phenotypical change within the species itself. Preferably the case study would include potential selection factors and evidence for each, fossil evidence of the change, and any other evidence that would help bring the whole story together. I have a friend who is having a hard time understanding how selection pressures can lead to large changes in a species over time. I know there are some good papers out there, but I'm not sure how to go about finding them.

Has any one been to the dentist office lately and read the October 04 National Geographic article about the Phoenicians? They claim in that article that all modern males trace their ancestory back to a common ansector who lived 60,000 years ago. This seems surprising to me because modern people were supposed to be migrating out of Africa (by the replacement theory) by 110K years ago. So our intrepid ancestor would have had to rack up a lot of milage on his frequent flier card. Also, there seems to be too much genetic variation in the human genome to have a common ancestor as recently as 60K years ago. National Geographic is not exactly a super market tabloid so I …

early Cretaceous, ancestor of T. Rex, with fossil feathers http://pharyngula.org/index/weblog/comments/why_it_looks_like_a_big_chicken/ theory is that in the process of getting larger Tyrannosaurids lost their feathers because they didnt need so much insulation(being bigger) anyway at one point the really had them

I recently had a convorsation with one of my teachers about belifes on evolution... And I was wandering if maybe some hallucenogenic drugs helped guide us down the path of evolution that we currently travel. My teacher and I were both curious about the subject, and I have been searching all nite and this is the first thing that I have found that may give me some answers... When you look at some of the basic facts and opinions of history it does kind of make some sence... For example... You have the theory of Christianity... is it possible that maybe a neandrathol found some mushrooms thereby tripping up the the whole religion of christianity? The bible also speaks of Mo…

I was talking to a friend the other day, and found out that she didn't believe that man and chimps share the same ancestor, or that man evolved from the animal kingdom at all (in other words, she, being christian, thought God created us). I was stunned, as up until then I couldn't really imagine that anyone who wasn't a bit of a fanatic would doubt our "monkey-like" origin. I was just as stunned when I realized I couldn't counter any of her arguments ("it's never really been proven" etc), as I've always thought of Darwin's theory as the absolute truth and I've never bothered to read or think twice about the subject. So, in hopes of not being so embarrassingly uneducat…

Some point in the evolution of life on earth, it is said that almost all of the twenty-six phyla simply appeared, where once everything was essentially goop (a gross oversimplification, I know, but I just wanted to type the word 'goop'). This point is called the 'Cambrian explosion', and I'm just curious to know more about it. Has anyone come up with a plausible explanation for it, or is it still a big mystery to everyone?

I was just curious about what people thought about the origins of life on earth. I could not start a poll so Ill just do it like this. Do you believe that: A) Life originated on earth through natural processes and has formed independently on many planets and it’s a common occurrence with the right circumstances. B) Life originated on Earth by natural processes but it’s a very rare occurrence. C) Life originated on another planet and migrated to Earth (Panspermia). D) God must have created life all at once (creationism) or He helped out with evolution. E) Aliens created life on Earth because they were lonely or because they wanted to see if they could do it. F)…

http://math.ucr.edu/home/baez/timeline.html this is a pretty extensive timeline, with a lot of important dates in the evolution of life it also has big bang stuff and it projects several billion years into future (we have to get off this planet!)

Occasionaly (for example http://www.the-scientist.com/yr2003/oct/research2_031006.html, "Microbial Co-op in Evolution"), I come accross articles that "discover" in "scientifically sophisticated” verbiage, plainly ubiquitous phenomena of cooperation in evolution between cells or organisms or between their communities. In my opinion co-op in evolution started, most probably, much earlier than in microbial communities; it started between individual pre-celled genes, who eventually formed and elaborated the cooperative associations we call genomes. Prior to this, even the genesis of Life itself is a product of cooperation, of molecules that were precursors to Life. …

Sorry, but I don't have a link to a picture of a Wooly Mammoth. Instead, I'm asking if one of you might know one. I remember seeing, once, in a book or something, a black and white picture of a frozen real Wooly Mammoth. I was wondering if anyone knows of a link to one. Thank you.

How and why did there become two sexes? I understand that it greatly sped up the evolutionary process, but its not advantageous to sustaining life. Also, many mechanisms would have had to developed for sexual reproduction to be effective. These would have been unlikely to occur all in one generation. This would have left many organisms unable to reproduce, because all the mechanisms are not there; hence the genes for sexual reproduction would not be passed on and it would terminate.

I've heard this saying so many times, I don't know if it is true. It is that the bumblebee aerodynamically shouldn't be able to fly, but it does anyway.

I had a thought a while ago about the state of natural selection as it pertains to modern humans. I'll define modern humans as those living in industrialized nations. My idea is that natural selection no longer applies to modern people. Why? With health care as advanced as is, most people surivive for a very long time, a long enough time so that they have children. This may be based on a flawed perception, as i have not looked at census numbers, but i would guess that a very high percentage of people have children and thus pass their genes onto the next generation. Moreoever, our incredible mobility alows us to find mates where ever we'd like. If no one in our home towns …

Humanity will eventually come to and end because of... overpopulation, disease, starvation, war, nuclear destruction, politics, greed, other, or all the above.

Hey, I was wondering today, What is the exact difference(s) between Frogs and Toads. Thanks!

does anyone have any good links for info on primordial soup????

we have vestigial vermiform appendix and canines as well.today we are omnivorous but what was our feeding habit in the beginning?carnivore or herbivore ? vermiform appendix shows we were once herbivore. i think human started to eat plants ie crops after learning to farm (they maybe eating fruits before) and before learning the farming, they were carnivore. ++ if human ancestors were either carnivorous or herbivorous and now we've evolved to become omnivorous then " can the present herbivorous/ carnivorous turn into omnivorous in future?" need help from specialists..

There are some interesting debates about the early members of our species, that I'd like to share and have a debate here. Is visual thinking mean the same thing as symbolic thinking? Can a picture drawn of some object be though of as symbolic - therefore requiring a more complicated though pattern or is it merely an icon? Some of the earliest, most detailed artwork found was the one by the Cro-Magnons. That is highly suggestive that the Cro-Manon(humans) who lived from about 40,000-10,000, was the first early members of the genus Homo that was able to process all 3 of the components that clearly separate us from all other animals on this planet. Those being an…

It is universally excepted that genetic mutations drive evolution forward with natural selection cropping off the weakest links but what actually causes the mutations in the first place? If its random 'copying' errors then how did we manage to achieve the extent of biodiversity we currrently have. And how come we fill ecological niches in such a fitting way? The majority of evolution is due to a changing enviroment but an organism cannot choose the genetic mutations that occur so how did we come to be so perfect? If its design then what process accounts for the random factors from mate selection to the success of gametes and zygotes? Not being a biologist I fi…

If all the animals on arth evolved from the same original species, where did trees come from? (I missed the tree Discovery Channel for a few months.)

Is anyone familiar with Richard Jeffries calcichordate theory of chordate origins (linking chordates and echinoderms through the unusual mitrate and cornute echinoderms)? I'm curious what the current thought is on this theory - whether cornutes and mitrates are believed to be part of a common chordate/ echinoderm lineage or whether they are thought to have independantly evolved some of their more chordate-like features.

Yes, yes..its time to think about our own species. Are we destined for the big check out soon? Will an asteroid do us in, like one did for the dinos. (Whispers:) They say the big one is coming in 2014. Or will some super Virus, like Captain Trips in King's The Stand, do us all in or a super Alien Invasion for our precious metals or maybe just water be our demise? Will one day we be nothing more than a gigantic archelogical dig for some aliens?

does anybody know where i can find a complete copy of the ladder of evolution? or does anybody know the complete ladder?

Re Scientific American July 2004 Detecting Mad Cow Disease, Stanley B. Prusiner Genesis and replication modes of pathogenic prions curiously connote initial genesis and evolution of life, maybe from an RNA-related conformation. In both cases the process-enabling-moving circumstances are presence of the precursors of the Bingo Conformation plus a favorable energy balance. Is it probable/possible, therefore, that the switch from normal to pathogenic prions is enabled and moved by a replacement of a component amino-acid such as tryptophane/niacin ? Dov Henis

I'm still debating with the same guy and tearing apart his arguments, but I have a second question. He posted this Sure, scientists created a few proteins from amino acids in a lab under extremely impossible conditions for what the first cell would have undergone. However, take into account that life must have water to survive, yet amino acids are destroyed instantly in water. So the cell would have to overcome extreme odds of left hand amino acids matching up perfectly with right hand amino acids (also virtually impossible) in completely waterless conditions and then IMEDIATELY be taken to water to survive, despite the fact that the cell would have to create, from nothin…