Agree, the last question was the best, and yet, the least answered: Dr. Carroll craftily avoided the issue of how to control (aka reduce) overpopulation, and the fact that we are depleting our natural resources, particularly the non-renewable.
The Serengeti Rules (Rules of regulation / How life works / to intervene in ecosystems) 1). Keystone Species: Some animals are more equal than others. Keystone species regulate community diversity. 2). Trophic Cascades: Some species have strong indirect effects on others through trophic cascades. 3). Density: The regulation of some species depends upon their density (ie. numbers and distribution). 4). Nature is resilient: Given a chance (habitat, protection, time), populations can rebound dramatically. In general... * Identify the key players (/species, factors, molecules) that regulate a process. * Identify the rules that govern the interactions. * Replace what is missing or fix broken links. A very informative and interesting talk on evolutionary biology by Sean B. Carroll :)
Hate how some people asking questions drone on and on trying to show off, rather than simply asking the question in a clear, 1-2 lines!!. Really irritating.
The teen's question starting at 25:28 is key here. It seems we humans are affecting the laws and the rules of organic evolution and things are gonna get worse if we through science and technology don't do something (speeding up space colonization, say) to control our population; look at this problem in real time: www.worldometers.info/world-population/ :D
@Delta Fox looks like we're on the same page; 'inverted drawing pin', which end up did you mean? bullet shape, interesting; my pref for govt is u s, govt by 'a well regulated militia' (see 2d Ammendment to u s constitution); mekong delta fox? i've been 40K S of danang 4mo now, Hoi An old city (escape from Ph)
it would be cool, if we brought animals like elephants and rhinos and such into USA. After all, before humans came to the americas there were all kinds of big animals. I live in Finland and i think its a shame how little wildlife here is. Sure we have lots forests, but almost all of the trees are farmed (Finland is europes biggest producer of wood). Even Estonia has more big (wild) animals than Finland has. And thats despite Estonia having a lot higher population density and the landmass being 7,5 times smaller compared to Finland.
I may be wrong, but I don't believe the US is the right kind of habitat for elephants. And we may not have any mammals as big as elephants, but neither does any continent aside from Africa and Asia, and we do have lots and lots and _lots_ of wildlife. We also have big animals; just not as big as elephants.
Relating to the last question about human population increase, production limitations, etc; One movement that is gaining traction that, in my opinion, shows tremendous hope is the healing (using natural methods) of degraded landscapes that were decimated by agricultural practices of the past 10,000 years. Many areas of desertification used to be farmed intensively by humans, without a natural rest and recovery period for the soil and native plant species, resulting in the complete breakdown of the soil biology and the natural symbiotic relationships. These degraded landscapes are beginning to be healed by bringing in less expensive plant material (such as hay) and feeding it on the degraded landscape to (mainly ruminants, like) cattle, sheep, goats, buffalo, etc. The large herbivores provide a vital missing piece of the puzzle by processing the material through their gut, resulting in urine and manure to restart the natural processes of the soil biology. Then dung beetles and earthworms are brought in or allowed to propagate to incorporate the nutrients in the manure into the soil, where microorganisms make it even more available to plant roots, etc. And the cycle is reborn. BUT, the critical step is to remove the move the large herbivores and allow the plants to recover fully, mimicing the cycle that the Wildebeast use to move around the Serengetti. Only returning to grasses, forbs, etc when they are fully recovered and can withstand grazing again. Once the soil is healed, it can be farmed on a less intensive, more sustainable schedule... without man-made inputs such as inorganic fertilizers and pesticides.
Climate change will only be combated with restoring our arid lands, we are talking 12 billion acres. This will also allow for humans to keep increasing in number.
I wish he'd actually answered the question about why predators are so small, because I was wondering about that too. But then he never answered it, he just affirmed the observation that they're small.
I think what he was getting at is that they don't need to be big if they can work together as a team. I feel that some of the reason is psychological too. Fear clouds the mind, prey live in fear which possibly means that prey never think about using team work and if some do they are often too discouraged to follow through because everyone that could help defend is running away in fear. But it could also be that larger predators require more sustenance which means they need to spend more time and energy hunting which would be unsustainable to the individual predator unless that predator learned how to outwit his prey rather than try to out maneuver his prey.
