Question For Intelligent People about Biology and Genetics?

Question

Here is a very possible scenario:

Human population continues to grow exponentially. Eventually, resources are depleted, pollution is rampant, and the population will suffer a steep crash as is the case in laboratory population tests using bacteria in petri dishes etc. Perhaps even nuclear wars over resources etc.

End result: Oceans are virtually lifeless, hardly any trees, pollution covers entire earth, no wildlife, no humans..

The only animals that seem to posses the resiliance to survive in such environments are primarily rats and bugs/roaches.

Here is the question:

Considering what we know about genetics, in terms of evolution, and biology, would planet earth (assuming there are no more humans) recover and again produce the variety of wildlife and plant species it once had?

Also considering that there would be a massive population of rats and roaches, would newly evolved species even stand a chance against these resiliant animals? Or would they be immediately killed off?

Answer 1

What you are describing has happened numerous times in the geological past. The most extreme example is the Permian-Triassic boundary mass extinction. Oceans became anoxic for millions of years and 96% of marine species went extinct. There was, it seems, massive global warming, and probably sulphide poisoning of the atmosphere. Terrestrial vegetation was temporarily wiped out, only fungi growing for a long time. And most terrestrial vertebrate species disappeared.

It took tens of millions of years but diversity of life eventually recovered and biogeochemical cycles came back in to balance. But life as a whole was very different to before (hence we separate the Paleozoic before and Mesozoic afterwards). In fact thoughout the Phanerozoic (time since readily fossilisable life arose), although there have been many extinction events and a lot of up and down in diversity, the overall trend is towards increasing diversity of life. In a sense, life has become adapted to recovering from mass extinctions as it is always the survivors who give rise to the next explosion of diversity.

In a modern-day mass-extinction, rats and roaches and other 'disaster taxa' would do well in the short term, sure. But there would be refuges where some other species could hang on. And following a mass extinction, many many ecological niches are opened up that were closed before. So whatever survives will eventually split and radiate in to different species.... eventually there may be whale-rats and tiger-rats etc.

But I'm for keeping our present diversity, rather than hanging around 10's of millions of years waiting for a new one!

Answer 2

It is possible. However, some of the very basic forms of life began when the environment of the world was much different from what it is now or what would probably be in future and I don't think it is possible to some how recreate that environment. For example. life begun when the earth was still young and its temperature was much higher than what it is today; and even though global warming is happening I don't think it will ever be possible to increase the temperature to the levels of the early days of Earth.
The other thing that was much different thousands of years ago is the composition of the atmosphere.
Although Evolution tells us that all the species have a common ancestor, it doesn't mean that one day man can evolve from mouse. In fact different species differentiated from that common ancestor many many years ago. And I don't think that it is possible to recreate all these species without having that common ancestor.

And about the rat population, it will eventually go down after they eat all the edible material on the Earth.

Answer 3

Sure, its a possible scenario, but the sun exploding and consuming us all is also possible. Anything is possible. However, is it likely? I don't think so.

We're not bacteria; we're not going to reproduce until the 'petri dish' is full and then all die. Most post industrial countries like the US and countries throughout Europe aren't actually increasing in population very much at all anymore. The population growth in 3rd world areas is still high, but eventually the globalization process will bring everyone up to a post-industrial mode (though it's going to take awhile!). Furthermore, we are on the edge of major breakthroughs in technology that'll hopefully reduce our dependence on natural resources. Finally, there is enough arable land on Earth to feed a population several times greater than what we have now, if we used it efficiently. I just don't see these 'end of the world' scenarios everyone keeps talking about as very likely.

Answer 4

The simple answer is , no.

Entropy is irreversible. The Earth would loose almost all evolutionary windows once the core cools and solidifies. We freeze into a rock like Mars. (Time is costly , not only in business ,, but in evolution we may have only one chance.)

,, If we suppose , niche evolution , then yes. Life would evolve to fill the gap that we leave. But , if we loose 20% of soil fertility every 2 000 years , and volcanos (being not violent enough) are not kicking the material elementry diversity onto the crust , into the bio-sphere ,, we loose the overall enthalpic potential.

,, thereby ,, we loose the opportunity for similar width in bio -diversity ,, and the very expensive organ as a large brain.

The planet is queer in that it is a Life dynamo. Which itself also has a shelf-life. A "Use By" date !!

** The energy level our foods allow us , is the enthalpic value we need to fuel Life. This is treatened in an expanding universe.

** If we can guarantee a healthy state of chemical enthalpy for the span of evolution , then we will return ,, with a rodent for an ancesstor.

Answer 5

No matter what survived the ecoclysm, there is likely to be ecological niches opening due to the loss of species that occupied those spots. This would almost certainly result in evolutionary pressure to fill those niches.

If animals and plants survived, they would already be competing with rats and roaches for available for resources. So before evolution (which can take years and centuries and eons) can start, these animals would already be on their way to adapting and surviving.

The one thing that I would be really worried about would be if a massive proportion of oxygen-producing organisms died off. If that happened, then we'd probably be looking at a condition similar to Pre-Cambrian period. You'd probably have to wait until the next Genesis event occurred for life to take place.

Answer 6

It's difficult to imagine any man made scenario that would wipe out ALL life on earth, unless we figure out how to cause the entire planet to either enter a black hole, or to turn it into a fusion reactor.

Those aside, some form of life would most likely persist no matter what we do. It will then begin to evolve in its new environment and fill the planet once again with diversity, though it might not look like anything we could imagine.

Answer 7

Evolution as origins is an adult fairy tale and many of its believers are very devout. If dna 'evolved' through slow random directionless changes, then so did computer programs. Darwin said if there was any one thing that could not have come about through slow random directionless changes, his theory was proven false. This of course was before we learned the common molecule is not a blob, but is a communication network as intricate and complex as a major metropolis, and before we knew about the dna code in all living things.. - Many folks think natural selection, which is also called mini evolution is the same as maxi evolution, also called evolution as to origins. But natural selection is merely the separation of traits or abilities "already present", not the evolving of new ones. I.e. there are many species of dogs, but no dog/cat "kind". - It's also very much a mystery how any form of life survived while taking thousands, millions of years to develop its survival mechanism.

Answer 8

Your question has no validity. If you flew over most of the U.S.. You would find vast areas of land that are not developed. We have plenty of room for twice the current world population. We must manage it and distribute it's resources without prejudice to nationality or status. If we treated each other like a true family hunger would be eliminated.

Answer 9

I recently saw a great documentary on this very issue. It is called "The Future is Wild". It looks at what evolution may produce in the next few hundred million years, long after humans have vanished. It is fascinating and somewhat frightening.

Answer 10

To quote Ian Malcolm from "Jurassic Park", "Life will not be contained. Life finds a way."