is it possible for large lifeforms to dominate earth in the future?

[boo]

it seems that over the course of history, earths lifeforms tend to get very large before a mass extinction event happens, which reduces life back to small life forms again

so,  would it be reasonable to believe that earth may be headed, over the course of millions of years, back to a dinosaurlike environment again at some point in the future with large animals of some description roaming the earth, weather they be reptiles, or mammals?

 and the human era is possibly just one of the early phases in that process.

or is there some physical reason why earth can no longer support such a thing, such as weaker atmosphere, or colder planet temperature or something to do with how the eco system has been altered by us humans which makes it impossible?

Edited October 29, 2020 by boo

[Bufofrog]

On 10/29/2020 at 6:50 PM, boo said:

it seems that over the course of history, earths lifeforms tend to get very large before a mass extinction event happens, which reduces life back to small life forms again

Do you have any evidence to support this?  Large dinosaurs existed for more than 150 million years with no mass extinctions.  Large mammals have existed for tens of millions of years with no mass extinctions.  I do not think the evidence supports your proposition.

It is certainly possible that large animals are more susceptible to dying off during an extinction event than small animals.  I don't think that large animals cause extinction events (with the possible exception of humans).

Edited October 31, 2020 by Bufofrog
Added thought.

[boo]

20 minutes ago, Bufofrog said:

Do you have any evidence to support this?  Large dinosaurs existed for more than 150 million years with no mass extinctions.  Large mammals have existed for tens of millions of years with no mass extinctions.  I do not think the evidence supports your proposition.

It is certainly possible that large animals are more susceptible to dying off during an extinction event than small animals.  I don't think that large animals cause extinction events (with the possible exception of humans).

i probably phrased my question badly.

I was not suggesting that the large animals were the cause of the extinction.

but rather, i was suggesting that it is a natural for animals to continue to grow larger and larger unless inhibited by mass extinction events , whatever the cause

[Bufofrog]

1 minute ago, boo said:

i probably phrased my question badly.

I was not suggesting that the large animals were the cause of the extinction.

but rather, i was suggesting that it is a natural for animals to continue to grow larger and larger unless inhibited by mass extinction events , whatever the cause

Again I have to point out that large dinosaurs were around for more than 150 million years, and large mammals have been around for tens of millions of years.

 

[dimreepr]

7 minutes ago, Bufofrog said:

Again I have to point out that large dinosaurs were around for more than 150 million years, and large mammals have been around for tens of millions of years.

Why the fixation? 

Large is just a number...

[Bufofrog]

2 minutes ago, dimreepr said:

Why the fixation? 

Large is just a number...

Because that is what is discussed in the OP.  Large not really a number...

[zapatos]

19 minutes ago, boo said:

but rather, i was suggesting that it is a natural for animals to continue to grow larger and larger unless inhibited by mass extinction events , whatever the cause

Perhaps you can show that animals have been growing larger since the last mass extinction?

[dimreepr]

3 minutes ago, Bufofrog said:

Because that is what is discussed in the OP.  Large not really a number...

Imagine that...

The OP didn't...

[Bufofrog]

13 minutes ago, dimreepr said:

The OP didn't...

Uh, OK, it certainty seems that large animals and extinction events was the crux of the discussion to me.

Edited October 31, 2020 by Bufofrog
Damn autocorrect

[Moontanman]

I think your larger just before a mass extinction effect is a bit of an illusion but there are some real world reasons this appears to be true even though currently I would say that mammals had their heyday around 2 million or more years ago and currently land animals are bit smaller on average than during Pliocene but Dinosaurs are or were "pre evolved" to be larger, this can be seen from modern living dinosaurs who have hollow bones and more advanced circulatory and lung systems compared to mammals. The largest mammal that ever lived was related to rhinoceros's and was as large as many dinosaurs. Mammals are burdened by heavier but less strong skeletons, less advanced breathing/circulatory systems, and a reproductive system that puts larger adults in a precarious place the larger they get.      

[boo]

2 hours ago, Moontanman said:

I think your larger just before a mass extinction effect is a bit of an illusion but there are some real world reasons this appears to be true even though currently I would say that mammals had their heyday around 2 million or more years ago and currently land animals are bit smaller on average than during Pliocene but Dinosaurs are or were "pre evolved" to be larger, this can be seen from modern living dinosaurs who have hollow bones and more advanced circulatory and lung systems compared to mammals. The largest mammal that ever lived was related to rhinoceros's and was as large as many dinosaurs. Mammals are burdened by heavier but less strong skeletons, less advanced breathing/circulatory systems, and a reproductive system that puts larger adults in a precarious place the larger they get.      

this is fascinating information, i wasnt aware of it,  thankyou

 

so, have the conditions also changed on earth since the dinosaur era ,  like is earth colder or something else that would make life impossible for such reptiles to live today?

 

[Bufofrog]

29 minutes ago, boo said:

so, have the conditions also changed on earth since the dinosaur era ,  like is earth colder or something else that would make life impossible for such reptiles to live today?

Dinosaurs could certainly live in many areas of the earth today.  Birds are direct descendants of feathered dinosaurs, so birds are actually the only remaining dinosaurs.

[Danijel Gorupec]

2 hours ago, Bufofrog said:

Dinosaurs could certainly live in many areas of the earth today.

Supposing that those areas remain stable as it is now. But I am not sure this is the case... Some people think that we are going through a mass-extinction phase right now, caused by rapidly changing environment due to human activity.

In any case, it might be that at the moment the environment is changing too fast on the global scope that very large animals could thrive. My understanding is that large animals have difficulties in rapidly changing environments because they are generally slow to reproduce (and thus adapt by evolutionary change). Humans might be an exception because we have a technology that we can adapt instead of our own bodies.