MattofVA

Ok, I am more scientifically literate than the average dumb-ass American, but not as much as most of those who post on the E/C forum, I guess(I work in broadcasting). I know that the overall evidence for evolution is pretty good, but here are what I perceive to be possible holes, or areas requiring lots of investigation, from my lay perspective at least:

1. Ecology. how is it that organisms that require each other to survive just happen to evolve at the same moment or at least in a parallel way? Exs. Bees and Flowering plants. There is also one species of hummingbird and one species of plant that cannot survive without each other.

2. How does necessity so often precipitate useful bodily forms. DNA does not have its own brain, so how does it so often mutate in just the right way so that the organism's descendants can survive for the long-haul or even do cool new stuff like crawl up on land(fins---limbs, gills---lungs, etc.). I am an agnostic, but does this not point to at least the possiblity of some sort of intelligent, teleological process going on?

3. Some far fetched phylogenetic relationships. Man descending form other primates does not seem far-fetched to me, but here is one relationship that DOES seem far-fetched: Whales descending from a hoofed land mammal during a span of time more recent than the dinosaurs. What caused this unusually dramatic piece of evolution in almost the blink of an eye on the geologic timeline?

Sorry if these somehow sound lame actually coming from an infidel, if I had the attention span I'd just look for some books or articles, but again my beef is not with the whole deal, just these peculiarities.

Also, thought I could throw this one extra bit out. A while back, there was a thread about Oliver the Chimpanzee, who preferred the company of humans and walked upright. Could he be a living missing link of sorts(is he still living)? Could he demonstrate some of the mutations that occurred in our ancestors in the first step down our road?

lpetrich

MattofVA:
1. Ecology. how is it that organisms that require each other to survive just happen to evolve at the same moment or at least in a parallel way? Exs. Bees and Flowering plants. There is also one species of hummingbird and one species of plant that cannot survive without each other.

There are numerous examples of "coevolution", as it's called. Such relationships can emerge from the interactions of generalized ancestors -- they can evolve from facultative interdependence (can do it, but don't have to) to obligate interdependence (must always do it).

Thus, when flowering plants emerged in the Jurassic or thereabouts, they would not have been very selective in pollinators -- whatever bug that stopped by will do. And many present-day plants do not show much evidence of pollinator selectivity. But some have evolved ways of selecting very specific pollinators, like moths with very long mouthparts, bumblebees with some specific size, flies, etc.

Also, flowers being abundant allows some insects to specialize in living off of nectar and pollen -- bees.

2. How does necessity so often precipitate useful bodily forms. DNA does not have its own brain, so how does it so often mutate in just the right way so that the organism's descendants can survive for the long-haul or even do cool new stuff like crawl up on land(fins---limbs, gills---lungs, etc.). I am an agnostic, but does this not point to at least the possiblity of some sort of intelligent, teleological process going on?

Trial and error in a BIG population is all that is necessary in the natural-selection mechanism. Being able to see only the successes can create a false impression.

Furthermore, many of the changes of evolution are rather simple and straightforward ones.

Vertebrate lungs have not developed from gills, but instead from outpouchings in the throat.

Land vertebrates' limbs are simply modified fins. Their bones continue to have a finlike pattern, though this is often obscured by some of the bones growing relatively long and some of the digits disappearing.

Furthermore, land vertebrates that become aquatic often turn their limbs back into fins.

And although teleology is not an absolute impossibility, it could be the result of time travelers or extraterrestrial visitors or other such nontheological entities.

However, if such entities are responsible for major events in evolution, then they are often remarkably uncreative and fond of using kludges. And apparently willing to make some curious mistakes.

3. Some far fetched phylogenetic relationships. Man descending form other primates does not seem far-fetched to me, but here is one relationship that DOES seem far-fetched: Whales descending from a hoofed land mammal during a span of time more recent than the dinosaurs. What caused this unusually dramatic piece of evolution in almost the blink of an eye on the geologic timeline?

Except that 55 million years is not exactly short. And that the closest relative of cetaceans is likely the hippopotamus -- which is partially adapted to living in water.

RBH

Matt wroteCount generations. For whales it's around 15 years. That's on the order of 3.67 million generations in 55my. I don't know the generation length of hippopotami, but I'd guess it's in the same ball park. So 3 to 4 million generations are available. That's a whole lot of evolutionary time. "Blink of an eye" is not the appropriate phrase here.

RBH

Late_Cretaceous

1. Organisms evolve in response to their environment. Other species that exist around them are part of that environment. Relationships exist between different species within the environment, over generations those relationships can become symbiotic, parasitic, or predatory.

2. Let me respond to that question with another question. Look at a forest, how do all the trees know where to grow? Jackpines will grow in sandy soil, fir will grow in shady areas, whitespruce in sunny areas. Why do you see valleys with one type of vegetation on one side and another type of vegetation on the other? How do trees, which don't move, get there? Well the fact is that hundreds of thousands of seeds are dispersed around the forest from all species, and only those that find suitable locations thrive. Well evolution works just like that. Many offspring are produced, and only some are lucky enough to have the right combination of traits to thrive.

3. Far fetched? How far fetched is it that a husky, a toy poodle, a great dane, a bichon freise and a doberman are all the same species - and after only 15 thousand years of artificial selection? Morphology is very maleable;. Remember that all organisms start off as single celled organisms - the possibilities of growth patterns are endless.

MattofVA

Okay, Those answers mostly made perfect sense, but as far as the whales go-were there hoofed mammals for the cetaceans to evolve from already 55 mil yrs ago? I thought we were mostly still little shrews at that time. Is there an actually family tree somewhere online perhaps showing the branches and movements in time of the major mammal groups.

Coragyps

Matt - the April 2003 National Geographic has a pretty nice article on mammal evolution, with a little timeline sort of info. For whales, Google up "whale" with each of the names "Gingerich" and "Thewissen" to get some pretty current research summaries from two of the leading "ancientwhaleologists" in the world.

MattofVA

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Ok, great, I think I remember seeing that cover actually(before the question came up for me), I'll have to actually pick it up-what a stroke of "luck"

scigirl

DNA doesn't know what it is doing. It simply follows the natural laws that govern its replication. The trouble with this argument is - natural selection only publishes the success stories, so it appears that DNA is planning to create complexity, or new body plans.

However if you look closely at nature, you will see the 'failures' of DNA mutation. For instance, 1/2 to 1/3 of all human fertilizations end in a miscarriage. This is usually due to genetic mutations that were fatal. Occasionally however, one of those genetic mutations does something to benefit the organism, and voila you have evolution.

scigirl

Eric H

quote Late_Cretaceous
Remember that all organisms start off as single celled organisms - the possibilities of growth patterns are endless.
-----------------------------


Going from single cell to mating age reuires a lot of luck and support; and that is the part that troubles me the most, when you take into account death before mating.

How did the first male and female four legged creature come together? If the male and female arrive a hundred years apart, they could die without mating. If the male arrives in China, and the female arrives in France, they don’t meet up. If they do meet up and have all male offspring’s; that’s the end of that species.

Now supposing that the very first male and female of a species arrive over a period of evolution and die before mating, does that still leave thousands of others of that species in the waiting to have another go?

Or does creation revert back to something that is tens or hundreds or thousands of times more simple.

When you are talking about single cell life, or simple multy cell life I can understand how there might be billions of these about.

But I do have problems believing that there would be large quantities of four legged creatures around that might be the size of a rat or bigger.

Peace

Eric

Dr.GH

Eric,

The evolution of sexual reproduction happend millions of years before the appearance of terrestrial quadrupeds.

The core issue you seem to have is how do mutations enter into the genome of a species. If you read Late_Cretaceous' responce, particularly their point #2, I think you will get the idea.