All you biology people, species interaction discussion w/ friend

[surftheiop]

First off forgive my lack of biology knowledge, ive only taken 9th grade bio and all we talked about was plants.

Ok this is stemming from a discussion i have been having with a friend. Specifically about if we should attempt to reduce/stop the growth of the human world population.
This conversation has nothing to do with standard of living or stuff like that but is more of a biological conversation.

Here is my question, from a biological standpoint is a species ultimate goal to maximixe their own population with no regard to other species?

He claims this isnt true and sights the fact that except for predator/prey animals dont tend to harm other species. He also points out that no other species has dominated the earth in the way humans have.

My responce to this is
I) Just because something hasnt happened before doesnt mean it should never happen (ie a species completly dominating the world).
II) The animals seem to coexist because the energy they would spend harming each other would have no benefiet to their population (as opposed to humans who do benefiet from harming other species ie. killing rats to prevent disease spread).
III) If any other species had the means to dominate the earth like humans have they would have surely done it.

Im just curious what people who actually know stuff about biology have to say about this.

Related Question
He says that humans are turning too much of the earth's biomass into "human mass" through food production and this is biologicaly bad because it limits diversity.

I can see his point but over the course of evolution life has become increasingly more complex. Wouldnt nature "want" as much of its mass as posible to be locked up in the most complex organisms?

[madnak]

Biology isn't about goals. It's about mechanics. Large populations aren't necessarily adaptive - they might even lead to extinction. So your friend is pretty much wrong.

[surftheiop]

Madnak, could you help me out a little more hehe, i dont really care who is right/wrong i just wanna understand. Are you saying its not "biologicaly bad" for humans to be a completly dominate species at the cost of other populations?

My friend read the book "Ishmael" written by some anthropologist, which is where this discussion sprang from. He must be misrepresenting the points made in the book to me, or I must be misrepresenting them here because i have to think they guy who wrote the book would be pretty knowledgable about biology.

[Rduke55]

[ QUOTE ]
except for predator/prey animals dont tend to harm other species.

[/ QUOTE ]

Certainly not true. And what you're arguing isn't neccessarily biology.

And Madnak's right, there isn't a goal and sometimes a bunch of conspecifics is good, sometimes it is bad.

[madnak]

Nothing is inherently "biologically bad." Virtually every trait could be adaptive in some environment, hypothetically. In terms of what's good for humans, I won't even venture a guess. The environment right now in modern society is so radically different from anything that preceded it that we have no strong basis for determining which traits are (or will prove to be) most adaptive.

That doesn't prevent people from venturing opinions, of course. I haven't read the book, so I can't comment on that. But scientists of all stripes - and, arguably, especially anthropologists - engage in heavy speculation. However, the idea that humans are "evolving toward" some "goal" is flawed. There's no issue of what we "should do" in biology, it's a question of what we expect to happen. A trait that's selected for is essentially a trait that we expect to see increase in frequency.

Biological imperatives exist not because nature has some greater order but because organisms that possess such imperatives are more likely to propagate than those that don't. But that likelihood is intrinsically tied to the environmental conditions - a thick black fur coat is a good adaptation in a cold environment, but not in a hot one, for example. If a species is built for the cold, and the environment suddenly becomes hot, the whole species might go extinct - this is the impact of environmental changes.

And our environment is now changing in qualitative ways that we have no way to measure or track. So even if a desire to dominate other populations has been a valuable trait for us, there's no guarantee that it will continue to be so. For example, other life forms are critical components of human technology. As we become more reliant on technology and learn to harness the core mechanics of nature to a greater degree, other species may become more important to our well-being.

Things are changing so much that many biologists believe the mechanism of natural selection will no longer be a relevant part of our development. Under such conditions, I'm suspicious of anyone suggesting any kind of necessary directive for our species.

[Skidoo]

[ QUOTE ]
Here is my question, from a biological standpoint is a species ultimate goal to maximixe their own population with no regard to other species?

[/ QUOTE ]

If a species has goals, can the goals of its individual members be significantly different?

If a species does not have goals, how could its individual members have (the necessary mechanisms for) any?

[Girchuck]

The genes which drive the behaviour of each species are optimized for maximum possible replication. In effect, each species tries to take over the world, but none has the capacity to do so, creating a dynamic equilibrium.
Humans, on the other hand, have the capacity to take over the world, and put a large portion of the biomass to humanity's purposes, potentially wiping out species which are at least in the short term not useful. We do this because we can, because our culture and technology enables us to do it. No other species on the planet has similar capability, if they had, they'd be doing it as well.
If one introduces a weedy species to an unfamiliar environment, that species can displace and wipe out many native species because weedy species can adapt to a large variety of environments. Humans are the ultimate weedy species.