extinction

[border_ruffian]

If you exclude global environmental catastrophes, is there a realistic way to calculate the lifetime of a species? For the purposes of The Drake Equation, what factors would weigh most heavily on the outcome?<br /><br />

 

[qso1]

I'm not a scientist by profession but IMO, there are no realistic ways to calculate the lifetimes of species that I'm aware. The whole reason species go extinct is some influence beyond their control generally cause it. Mass extinction could be brought on by a number of things. The early theories behind dinosaur extinctions were eventual lack of enough food to support such large beasts. Later the asteroid impact theory took root in part because there was pretty good supportive data. But if we cannot be there to witness the cause of a mass extinction. We can never really know for certain how to calculate the lifetime of a species.<br /><br />For the Drake equation, I would say that if it could be shown that species simply die off over many many generations...weak DNA carried over generation after generation for lack of a better explanation. But to simply die off is the only way I can think of that the Drake equation could be affected by the outcome short of a global catastrophe. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[border_ruffian]

Not counting mass extinction due to global catastrophes, I'm interested in why some species live much longer than others. Microbes, for example, which make up most of the species on Earth, may last for as much as a billion years, while in the world of plants and animals (the metazoans), the average lifetime of a species is only a few million years.

 

[qso1]

Afraid I won't be able to help much there. I don't think anyone knows the answer to that for sure. I would say that it may have something to do with non catastrophic environmental changes. Among them food source quantities. Relatively large animals may over a long period of time simply deplete their food supplies to the point of eventual, gradual, mass extinction. Microbes have the advantage of being small and relatively hardy which probably enables them to endure sub catastrophic but significant environmental changes.<br /><br />We may be currently witnessing one involving polar animals, particularly polar bears. This situation however, is probably human generated. And that is, global warming which has affected polar ice cap temperatures enough over three decades to cause polar bears to scavenge human waste dumps for food. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[border_ruffian]

I agree that microbes have the advantage due to their size and hardy nature. So I wonder why the universal common microbial ancestors ever bothered to evolve into more complex organisms at all? Clearly microbes are better adapt to disasters.

 

[CalliArcale]

Cooperation does have its benefits -- enough to allow organisms to exploit niches which bacteria cannot exploit. In particular, it can allow one group of cooperative cells to outcompete a similarily-sized collection of non-cooperative cells. This is what has allowed multicellular organisms to evolve. But obviously there are still advantages to the bacterial lifestyle, as evidenced by their sheer quantity today. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[doubletruncation]

<font color="yellow">I'm interested in why some species live much longer than others. Microbes, for example, which make up most of the species on Earth, may last for as much as a billion years, while in the world of plants and animals (the metazoans), the average lifetime of a species is only a few million years.</font><br /><br />I think this is a really interesting question. I'd really like to know if there is actually an empirical correlation between the time that a species exists (when it first appears in the fossil record and when it is last seen I suppose) and its mass or some other measure of size, and how strong that correlation is. Is it true that most unicellular organisms last for as long as a billion years, or is that just the tail of a distribution that is perhaps more pronounced by the sheer number of unicellular organisms? Everyone's posts so far have made a lot of sense - I'm just wondering if anyone knows what the actual data looks like? <div class="Discussion_UserSignature"> </div>

 

[qso1]

border_ruffian:<br />So I wonder why the universal common microbial ancestors ever bothered to evolve into more complex organisms at all?<br /><br />Me:<br />Although I think all creatures have some level of intelligence, it seems doubtful that microbes would be intelligent enough to determine it would be to their advantage to remain microbial. Perhaps some have remained in the same state they were in pre-history. We are self aware and collectivelly believe that we should or are evolving to some higher state. But we don't know what the next level is for us.<br /><br />As for adaptibility to disasters, so far we have survived any and all thrown our way except for planetwide disasters as far as we can know. But suppose an asteroid hits the earth but does not render it totally lifeless and small bands of humanity survive. For generations these bands slowly crawl back so to speak, to the level of tech we have today. In that sense, humanity survives like bacteria. In a planetwide catastrophe of a magnitude where Earth is rendered lifeless. Even bacteria might not survive but will probably really never know. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

doubletruncation:<br />I'm just wondering if anyone knows what the actual data looks like?<br /><br />Me:<br />Indeed very interesting questions. I don't know if there is a significant data base on this particular subject. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[agnau]

I personally do not believe in evolution, however I do think that without the microbe, multicelled species would not be able to function/survive.<br /><br />As far as extinction goes - climate, food supplies, solar-radiation, magnetic field changes, predator levels....

 

[border_ruffian]

<font color="red">Is it true that most unicellular organisms last for as long as a billion years, or is that just the tail of a distribution that is perhaps more pronounced by the sheer number of unicellular organisms?</font><br /><br />I think that billion-year-figure refers to the life span of the microbial species as a whole (not individual microbes). <br /><br />You and I, for example, won't be here in a million years, but other humans (probably) will be. So in that sense our species lasted a million years.<br /><br />Sorry if I misunderstood your question. <br /><br />I also want to see the data.

 

[border_ruffian]

<font color="orange">Although I think all creatures have some level of intelligence, it seems doubtful that microbes would be intelligent enough to determine it would be to their advantage to remain microbial. Perhaps some have remained in the same state they were in pre-history. </font><br /><br />Yet the microbial ancestors were intelligent enough to determine it would be of benefit to them to evolve and not remain microbial? I'm trying to understand because it just seems so contradictory to me.

 

[border_ruffian]

<font color="blue">As far as extinction goes - climate, food supplies, solar-radiation, magnetic field changes, predator levels.... </font><br /><br />That's right. But microbes and metazoans are both exposed to these factors. So the question is still the same for me... How come one group lasts a lot longer than the other?

 

[tom_hobbes]

Aren't we in the middle of a mass extinction right now? <div class="Discussion_UserSignature"> <p><font size="2" color="#339966"> I wish I could remember<br /> But my selective memory<br /> Won't let me</font><font size="2" color="#99cc00"> </font><font size="3" color="#339966"><font size="2">- </font></font><font size="1" color="#339966">Mark Oliver Everett</font></p><p> </p> </div>

 

[qso1]

Unfortunately, this is a question IMO, nobody can honestly, accurately answer. I'm not sure intelligence alone was the reason they evolved beyond the microbiological stage. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[border_ruffian]

I'm not sure I understand what you mean.... <br /><br />Whereabouts you live? Are people dropping dead like cattle on the streets? <br /><br />

 

[doubletruncation]

not people.<br />see for example:<br />http://www.sciencedaily.com/releases/2002/01/020109074801.htm <div class="Discussion_UserSignature"> </div>

 

[border_ruffian]

Thanks for the link... I didn't think the situation is this bad: "...a distinct species of plant or animal becomes extinct every 20 minutes."<br /><br />But there's hope...<br /><br />"Biological diversity ultimately recovered after each of the five past mass extinctions, probably requiring several million years in each instance."

 

[qso1]

Tom_Hobbes:<br />Aren't we in the middle of a mass extinction right now?<br /><br />Me:<br />Assuming we are, this is most probably the result of habitat encroachment by human expansion into areas once favorable for the species in question. This type of extinction is of course, relatively new in Earths history and one that is not covered by what are normally considered natural extinction events described per topic here but one that can be included since its kind of a catastrophic human induced event for said species. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[border_ruffian]

As for human activities' role in the extinction of some species, the article has this to say: "...disturbances caused by human beings do not eliminate habitats, but merely change them." I don't think that's completely true; if you paved over a habitat to build a mall or parking garage, I think it's fair to say you eliminated the habitat. But some ecologists believe that changing the size of habitats, for example, will "promote the evolution of new species."

 

[qso1]

border_ruffian:<br />But some ecologists believe that changing the size of habitats, for example, will "promote the evolution of new species." <br /><br />Me:<br />That may be but the ones who think habitats just change and are not eliminated probably work for land developers. Bottom line however is that human caused mass extinction is an emerging reality and on the geological timescale, one that has appeared overnight. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[newtonian]

agnau - Hi! I also do not believe in evolution and I agree that various symbiotic relationships involving microbes help mankind both function and survive.<br /><br />To clarify, though, I believe in micro-evolution involving speciation but not in macroevolution from one Biblical kind to another.<br /><br />Pinning down stable, permanent definitons for both species and kind are difficult since we are still learning which species are or are not part of any specific kind.<br /><br />Suffice it to say for thread theme that the various kinds have built in (in both genetic coding and epigenetic coding) ability for variations (compare speciation) for survival.<br /><br />Thus, the elephant kind survived the last catastrophe - however the mammoth species, part of the elephant kind, became extinct.<br /><br />Ditto Neanderthal man became extinct while mankind survived.<br /><br />Sadly, even Biblical kinds are becoming extinct of late due to man's ruining of the earth.<br /><br />Another point relevant to thread theme is the reasons why God would have allowed various species to become extinct in the past.<br /><br />Take Dinosaurs, for example. In those ancient times (avoiding the glaring disagreement on dating) the earth had a much higher CO2 content and also a stronger greenhouse effect such that the earth's climate was conducive to intense vegetative growth - far mor intense than the jungles of the Amazon.<br /><br />Under such conditions many mammals would have difficulty surviving - and therefore were not yet created.<br /><br />Dinosaurs were well equipped to survive in both the prevalent bogs (which helped support their vast weight) and in the otherwise impenetrable jungles. For three obvious examples: stegasaurus (sp?) could have used its upper armor to allow it to penetrate the lower canope of dense growth and feed on lower vegetation. Triceratops (sp?) would have been able to use its powerful head like a pitchfork to fork out of its way - and then eat, the extremely thick vegetati

 

[newtonian]

crazyeddie - Hi! I see we still disagree on this detail.<br /><br />However, why not comment on the scientific input in my post - e.g. the purpose various species have served in the past to pave the way for our human friendly environment and complex ecological systems?<br /><br />You don't have to agree with me about this being evidence of God's love for us - you could simply add input on how changes in earth's environment - notably the lower CO2 content and lowered greenhouse effect I posted on above - and how this is linked to extinction of species.<br /><br />In other words - if you are really interested in science and not in God, then why not post on science on this thread?<br /><br />To repeat for emphasis - my beliefs are similar to Isaac Newtons - hence my handle - and Newton saw how science and the Bible are linked in harmony. As you probably know by now, Newton wrote more on Biblical research than on scientific research - and he used the same scientific method in both avenues of research.<br /><br />Your disagreement is duly noted. <br /><br />I hope you can add some scientific input on this thread!

 

[derekmcd]

I'm glad you typed what I was thinking Eddie. <br /><br />No offense Newt, but go back and look at the number of posts that you have made where you have injected your religious beliefs. It is fairly rare that it is fitting in the moment. You are intelligent enought to NOT turn to scriptures for everything. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[agnau]

There are intermediate ways of handling the situation as well. Religion and Science can be in balance, but it does require that you not promote unprovable interpretations of either. Macro-evolution and Creationism are both a matter of belief at this time.