Jump to content

Mass Extinctions 6 lifeforms 0


studiot
 Share

Recommended Posts

 

studiot, I've read about this one but this is not a discovery per se, but just an attempt to re-classify the known extinction to be on a separate list. Look, for example, at the chart below. The peak of extinction just before the Permian-Triassic "Great Dying" is the one that they want to re-classify. It's already been known and the scale of it is known as well. So this is similar to re-classifying Pluto or Ceres to a dwarf planet. Not really a science, just some administrative work :)

 

I would also like to correct your scoreboard:

 

Mass extinctions: 6

Lifeforms: Gazillion

 

I10-33-extinction.jpg

Edited by pavelcherepan
Link to comment
Share on other sites

I wonder what sort of evidence makes 'mass extinction' true? How does the reasoning go?

 

Do they find fossils of a wide variety of life forms at one period of time and the a complete lack of fossil evidence in the time that follows?

 

Surely the evidence must come from fossil records. How come we don't hear of alternative explanations a la dinosaur extinction. There are competing explanations for the Cretaceous mass extinction.

 

Also, if these are truly mass extinctions, what caused them? Isn't that relevant to our own survival as a species?

Link to comment
Share on other sites

 

studiot, I've read about this one but this is not a discovery per se, but just an attempt to re-classify the known extinction to be on a separate list. Look, for example, at the chart below. The peak of extinction just before the Permian-Triassic "Great Dying" is the one that they want to re-classify. It's already been known and the scale of it is known as well. So this is similar to re-classifying Pluto or Ceres to a dwarf planet. Not really a science, just some administrative work :)

 

I would also like to correct your scoreboard:

 

Mass extinctions: 6

Lifeforms: Gazillion

 

I10-33-extinction.jpg

 

 

Call me wathever you want but I don't like this graph. It is cut at 60% and gives a wrong impression.

It should be like the one below updated roughly by me. The 100% is shown.

 

post-19758-0-04432500-1429701095_thumb.jpg

 

Life is in colour, death in black as usual.

Edited by michel123456
Link to comment
Share on other sites

I guess that was simply to save space because on your updated graph the top part has no information at all. Although cutting at 60% is uncool too, gives a wrong impression, you're right.

The information is that not everything got extincted. The coloured part is evidently more important than the black fringes, and there is no interruption.

 

It looks like an ancient fabric, a papyrus, or a flag after many years.

and because the time scale on the horizontal is really huge, it should look like this below

post-19758-0-57400700-1429712848_thumb.jpg

 

Now it ressembles a North-South section through India and the Himalayans.

It is much like extinctions happen all the time.

----------------------------

IOW on the diagram, there is never 100% of genera.

Edited by michel123456
Link to comment
Share on other sites

Forgive me for commenting on your discussion about playing with the presentation of the figures, and I do understand the issues about improper scaling of charts, but what about the provenance of those figures themselves.

 

What does the 'fraction of the general' mean?

 

figures I have seen are between 90% and 99% extinction for the end permian event, and the references I gave go with this figure.

 

Please also note that the original BBC report I linked to presented a balanced view that the BBC are famous for in that they presented both sides of the discussion ie they presented the counter argument as well.

Edited by studiot
Link to comment
Share on other sites

Forgive me for commenting on your discussion about playing with the presentation of the figures, and I do understand the issues about improper scaling of charts, but what about the provenance of those figures themselves.

 

What does the 'fraction of the general' mean?

 

figures I have seen are between 90% and 99% extinction for the end permian event, and the references I gave go with this figure.

 

Please also note that the original BBC report I linked to presented a balanced view that the BBC are famous for in that they presented both sides of the discussion ie they presented the counter argument as well.

 

Not commenting on reliability or conflict of figures. fraction of "genera" not "general"

 

genara is plural of genus . Genus is the taxonomical rank between family and species. Using the wider grouping genus rather than species has both benefits and problems; but it is just as relevant.

90 - 95 percent of species could well only entail 50-60% of genera. Many species were wiped out - but fewer genera (consisting of multiple species) were erased. It is quite easy and plausible to construct a toy scenario in which this is the case - for instance if genera contained 2 - 5 species and in the event on average the 3 least well adapted/most under pressure species from each genera were removed...

Link to comment
Share on other sites

interpretation of graphs are difficult. They give you an image that may not coincide with what really happened.

I don't know for example if it would be reasonable to make a graph of the casualties of a mass extinction. I guess we don't have the data for that, but in everybody's mind a mass extinction means a lot of dead animals, I think. And i don't know if an extinction is something like that: a catastrophic event that kills, or a smooth change (over thousands of years)where a specie has fewer and fewer descendants, or some other mechanism.

Link to comment
Share on other sites

studiot, I've read about this one but this is not a discovery per se, but just an attempt to re-classify the known extinction to be on a separate list. Look, for example, at the chart below. The peak of extinction just before the Permian-Triassic "Great Dying" is the one that they want to re-classify. It's already been known and the scale of it is known as well. So this is similar to re-classifying Pluto or Ceres to a dwarf planet. Not really a science, just some administrative work :)...

That's true more-or-less, although it may be new to tie the eruption of the Emeishan Traps to this particular extinction event.

 

As to your graph -which I note is not part of Studiot's article- it is well labeled so really not deceptive at all. I would also note that while Studiot's article focuses on animals, plants also go extinct.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.