THE CONCEPT OF EXTINCTION

Forums: Science, Evolution, Extinction
Email this Topic • Print this Page

Although he got the idea from Buffon,GEORGE CUVIER, actually developed the concept of a "species extinction" from studying fossil reptiles and brachiopods. He made a discovery that , today wed just say duuhhh, whats so difficult , but in Cuviers time we must remember that the foundations in evidence were just not there until someone like he, began peering into rock layers to examine the critters therein.

Cuvier convinced his colleagues that, the earth wasnt populated by everything in its"kind", and all at once but was somehow sequentially populated by beings that show up in successive layers of the fossil record, and these beings are different, and often more complex, with ascending layers of the strata.

This seems like such a simple minded concept to us but back then it was huge. In fact, it was the idea of extinction that gave Darwin his own ideass for the mechanisms of natural selection, namely competition for resources through time.
As Dobzhansky said that"Nothing in biology makes sense except in the light of evolutionary theory", nothing in evolutionary theory can be clerly demonstrated except in the light of extinction .

Topic Stats
Top Replies
Link to this Topic

Type: Discussion • Score: 12 • Views: 3,856 • Replies: 25

No top replies

@farmerman,

And I forgot toadd Cuvier also discovered that once species left the planet, they didnt return. OH of course there are a few of what we call "Lazarus species" like Onicophorans or the Coelecanth, but these species show that they are able to stay in equilibrium with their environment for long periods of time, whereas most species are finely tuned to their environment and therefore would be subject to extinction should the environmental conditions change ever so slightly.

However, for the most part, we know fairly little about why the species went extinct . We have hypotheses of "bad design over the laung haul" or cosmic smackdowns causing changes in predator prey conditions. ALL the available hypotheses are reasonable but untestable so far.

1 Reply

@farmerman,

Extinction does seem like a obvious concept now. Hard to imagine the world without it.

Maybe the next perception in biology which needs to change is the habit of seeing species as "snapshots" of populations at a particular period of time, rather than seeing all of biology as a constant flow of genetic combinations.

In a sense, each unique individual is a population of one, and each time it dies that population goes "extinct". It all depends on the granularity at which you focus, both in physical structure (genetics) and in chunks of time (large or small).

1 Reply

I am happy to live at a time when so much of this knowledge has been and still is coming to light.

2 Replies

@rosborne979,

correct. As humans we dont do well at viewing dynamics, we tend to do the snapshot thing. I wish the teachers in HS bioilogy would make the connections, itd be so much easier to grasp the concepts of species through time, AND it even may help those new converts to evolution (like Pat Robertson) see how theor own worldviews may fit into a more scientific base

0 Replies

@edgarblythe,

aint it so? almost every day I get news on something that totally knocks out yesterdays knowledge. Its hard to be a practicing guy when all these changes occur in your field. Im startin to get too old for all this ****

1 Reply

@edgarblythe,

PS saw you in that pic with P Diddie. Did he need a permit for that shirt?

1 Reply

@farmerman,

I was careful to skirt around the issue.

0 Replies

@farmerman,

As humans, are we already multiple species? Meaning, for example, if one is a math teacher and cannot get certain children to understand concepts like fractions, and other children learn it readily, can it be "nature" and not "nurture"? And, if it is "nature," is it "deeper" than family that do not understand fractions, but a limitation of the brain itself? Not necessarily a "throwback," but a continuation of an earlier brain potential of a line of humans that never died out? Do we really know if earlier hominids could not understand the concept of fractions, and if not, why?

All would go well, if all humans continued to interbreed, and the "fraction competent" would eventually replace the "fraction challenged"; however, if certain groups are not interbred with, and only breed with their own types, will the reality of two hominid species be more evident eventually?

1 Reply

@Foofie,

a lot of "challenged" are results of post conception oxygen starvation in the womb or early natal or childhood infections so youll always be thinking catch up .
Our own fossil record is kinda slim and is based entirely upon morphological chnges in skeletal; material. The only different genetic species we can see is the result of genomic studies of H ss and H neanderthalensis.
They tried H s idaltu and no luck, too degraded DNA

1 Reply

I'm comfortable with the thought that my death means my extinction. No afterlife for me, thanks, one is enough.

1 Reply

@farmerman,

farmerman wrote:

a lot of "challenged" are results of post conception oxygen starvation in the womb or early natal or childhood infections so youll always be thinking catch up .
Our own fossil record is kinda slim and is based entirely upon morphological chnges in skeletal; material. The only different genetic species we can see is the result of genomic studies of H ss and H neanderthalensis.
They tried H s idaltu and no luck, too degraded DNA

Or not?

http://www.sciencedaily.com/releases/2012/12/121207101606.htm

1 Reply

@Foofie,

guess Ive missed your point, whatwas it??

0 Replies

@farmerman,

A relatively young field has popped up that compliments well with evolutionary theory. Evolutionary developmental biology (evo devo) has enabled evolutionary theory to take a big step in a direction to create a better understanding of evolution through modeling organisms. Very interesting mix of two scientific disciplines in hopes to better understand the processes of developments in specimens influenced by evolutionary forces, as well as how developmental processes have influenced the evolutionary process. The latter is more difficult to study, however a better understanding of it is required to have a detailed and fuller understanding of evolution. Somewhat circular by nature, I suppose, seeing that developmental mechanisms, and evolutionary processes and forces are interdependent of each other.

1 Reply

@farmerman,

Whaddya mean, 'starting'?

1 Reply

@Mame,

Ouch!
Be gently on the guy, will ya?

0 Replies

@Val Killmore,

weve looked at ththe development of feathers in an evo/devo discussion herein. One of our Creationist types had been poo pooing the "lack of evidence in development of flight feathers) and It was rosborne(I think) who dropped in some evidence from embryonic feather buds .

We will still need to discuss the rise of the higher taxa based solely on fossil and genetic evidence from present day species, but form-festures and such thinbgs as "Why is a dinosaur different from a lizard" can be looke at developmentally

0 Replies

@farmerman,

The use of the term "Lazarus species" is clever but indicative of the often expressed egoism of the mavens of science. Obviously Coelecanth was never rendered extinct, it was just shy and escaped the attention of the people who know everything.

Somehow though "We Were Wrong species" doesn't trip off the tongue.

1 Reply

@Setanta,

Setanta wrote:

I'm comfortable with the thought that my death means my extinction. No afterlife for me, thanks, one is enough.

yup

1 Reply

@Finn dAbuzz,

Quote:

"Lazarus species" is clever but indicative of the often expressed egoism of the mavens of science. Obviously Coelecanth was never rendered extinct, it was just shy and escaped the attention of the people who know everything.

Thats whgat it actually means. In the past, weve missed some species and these (they are extremely long occuring species) were given the term "lazarus". The coelocanth, as a gerea, has existed fairly the same since the early devonian. The Horshoe crab, another Lazarus species, has existed unchanged (pretty much except for a few segments and carapace doo dads) , since the Late Ordovician.
Methuselan species had aleready been used as a term so the originator of the term was probably trying to apply a clever name that recognizs
11long term species morphology and
2The fact that we may have missed it the first time (although we didnt miss the horshoe crab)

1 Reply

THE CONCEPT OF EXTINCTION

Related Topics

Quick Links

My Account

able2know