In part. They also changed the environment due to their grazing habits, affected many other species, and changed their behavior due to the lack of threats. Really fascinating what happened when wolves were reintroduced
Following what happens after removal and reintroduction of large predators has been really informative. Yellowstone is a good example.
The most drastic examples are from cases where extermination of predators and provision of food (cultivation of fodder and edible crops) have given small rodents an opportunity to multiply.
Simple math gives a grasp of what happens:
- typical gestation period for small rodents is three weeks.
- litter size is commonly 4-8 young, half of that females.
- voles have typically postpartum oestrus, meaning that after giving birth, the female seeks a male and copulates. As a consequence, the interval between litters can be as small as three weeks.
- in optimal conditions, female young get so much hormones through lactation that a female vole may become pregnant before it leaves the nest, at the age of less than three weeks.
- reproduction continues as long as conditions are sufficient for reproduction. Sufficient conditions mean enough of high quality food and not too cold or too dry (drought probably has an indirect effect, through the availability of food). In snowy areas, reproduction may continue even below snow cover, although the litter size is small in winter and the rodent needs to have high quality food available to reproduce during winter.
Using these facts, you can calculate how fast a population of small rodents can multiply.
There is a potential for disasters in nature. It’s wise to respect the facts and act accordingly.
And selfishness of species has almost caused the destruction of certain biota. When we accidently introduce an invasive species into a biota they cause huge damage because the natural selfishness of the invasive species uses mechanisms to horde ressources in a way that no other species can counter or balance out. If their was a moral mechanism this would not happen. And this happens not fundamentally because species are selfish but because selfishness of one is not balanced out by the selfishness of others.
It can rely on such mechanism but their are others. Do symbiosis form because one specie is being generous to an other or do they do it because it in their best interest. Do plants give fruit and nectar to feed the animals or is it to give animal an incentive to spread their seeds and pollen. the latter are all selfish actions, its just that those selfish actions happens to benefit others.
Maybe the issue is we disagree on the definition of selfishness. My definition is doing actions that would bring the most benefit to one self and this doesn’t always lead to actions that are detrimental to other. Maybe greed is a better term.
I remember a study from decades ago that showed that prairie supports a mouse per square meter; the main prey of wolves.
- t:17, topic:46745"]
If herbivores are given a possibility to live without predators, they multiply until they have overconsumed their resources. After that, they starve to death. There are examples from the wild and we have also experimental evidence of this.
Why would herbivores be given “the possibility of living without predators?” That is not evolution. That is not nature. What you are saying is that evolution does not work properly, if there is no symbiotic relationship between herbivores and predators.
This of course is true. The system does not work if it is broken. This is evident in the experience of rabbits in Australia the 1700’s. European rabbits were brought by English into a land that had no mammals. Some escaped into the wild where they multiplied like crazy because there were no predators for these invasive fauna. They almost destroyed the ecosystem, but the introduction of deadly rabbit fever eventually brought the population under control.
The problem was not with the rabbits, but with humans who imported them into an ecosystem where they did not belong, where they did not fit. The evolutionary power of the rabbits, their ability to survive and reproduce, was in fact a negative, until nature could find a solution. I expect that it was humans, who actually introduced the fever, as we did the rabbits, but nature created it.
The reason that predators react to the loss of predators differently from herbivores is because their symbiotic relationship to the ecology is different. It includes territoriality, which limits competition, generalist diets, and the ability to emigrate to a different niche, as you say. Again symbiosis/ecology determines how fauna act, not selfishness and the ability to survive and reproduce is not an evolutionary strength if it destroys the balance of nature.
There is harmony in nature. It is based on the rules of symbiosis and the laws of ecology. Just because we do not fully understand how they work does not mean that they do not exist. Localextinctioncan be used to restore the harmony of nature when a species gets out of hand ,because of the absence of the balance of nature.
Biota eat and reproduce because of biological necessity, not out of selfish desire as humans can and do. Science is asking for confusion and misunderstanding when it uses non-neutral human traits to label biological needs as Dawkins has done.
Symbiosis is not based the selfishness or cooperation of biota. Symbiosis generally rewards those creatures who act cooperatively such as bees, lions, and humans. It is the source of the harmony of biological nature,
Creatures do not create themselves. We do not make symbiosis. Symbiosis creates us. Symbiosis sets the limits under which biota live. Those who cooperate do well, those who don’t, don’t.
Humans have the choice of living within the limits of Love God sets upon humanity, or rejecting these limits and our own way of pride and selfishness.
My definition of selfishness is any action which is based on my benefit and not on the common good. They need not be different, but the common good must come first…
Watch Nature’s Fear Factor
For animals in Mozambique’s Gorongosa National Park, the normal balance of competition and predation was upended when a war wiped out the top predators. The remaining animals didn’t simply grow in numbers—they began behaving in unusual ways, veering outside their typical territories and feeding patterns. Could it be that it’s not just predators’ kills that keep other populations in check, but also the fear they inspire? NOVA joins a team of scientists as they reintroduce wild dogs to Gorongosa to find out if restoring the park’s “landscape of fear” can restore balance to an entire ecosystem. (Premiered October 14, 2020)
I’m curious where is the idea of scarce amounts of food as a drive for evolution? In the case of events leading to global extinctions that may be the case. But overall I normally just head it described as events and environments just happen to favor a specific mutation and since that specific mutation ends up being favored, it results in those specific individuals have better odds at reproduction and the offspring with that favorable mutation ends up having the best chance at offspring and over time these by chance survivors results in speciation. While this speciation is happening because of a favored trait, there can be other ones with other mutations also occurring resulting in multiple lineages carrying the favorable trait and other traits. As time goes on one of these other traits may become favored and the offspring will begin to shift in that direction.
The cause of global extinctions is ecological change. Changes in the climate and the topology of the earth causes changes in the amount and type of food available and this caused extinction the numerous species.
What does it mean that something “just happened.” If I run the fastest, do I “just happen” to win the race or do I win it because I run the fastest? Do polar bears “just happen” to live near the North Pole? Why haven’t sharks changed in a very long time? These things and many more did not “just happen.” Magic does not have a physical cause. Magic just happens. Science is not magic, no matter what some may say.
There are two issues here. One is predation, which is not survival of the fittest, because predator and prey are not in conflict over scarce resources. The lion does not become fit by defeating the zebra. They both survive in the same environment because the lions cull the herd which makes more food for the survivors and the zebras provide food for the lions from their surplus members.
Predation makes the fullest use of all the resources of nature to provide life to the greatest variety of species.
Symbiosis encourages members of the same species to cooperate to make the most of the resources available. Survival of the fittest describes a scenario where everyone in in conflict with everyone else for the basics of life. This makes cooperation impossible, when actually iris essential.
Survival of the fittest is either true or false. If it is false and I see no other reasonable possibility, science needs to admit this and look for a viable alternative scenario.
I feel like you are creating a false dichotomy of it just be this or that. It’s either survival of the fittest or ecology. But that’s just not true. The ecological beauty in the world does not change that ones best fit to survive a situation tends to survive snd have offspring and if that survival hinged on a mutation then thst mutation will be passed among.
Deer that are faster and deer that blends in better with their environment tend to do better and tend to be the ones that have offsprings. Deer who work together better as a herd to keep an eye out tend to also do better. Both circumstances are at work.
“Predation makes the fullest use of all the resources of nature to provide life to the greatest variety of species.”
And the ones that tend to survive tends to be the ones that have offspring.
Yes. It begins with the battle for sunlight, soil, and water. On a quiet night, you can hear the ghostly shrieks of the carboniferous forests which were strangled by the flowering plants. Then throughout the animal kingdom, every species avoid extinction only by siring more offspring than will ever leave offspring themselves, failing to mate or often, to live. Population is only constrained by either the limits of resources which are claimed by force or by, well, animals do not use birth control.
Cooperation is just banding together to maximize the chances. Alliances can work in favor of survival.
Your use of terms is unusual. If the words mean something else than how they are used in science and ‘normal’ conversation, an attempt to discuss leads to confusion.
The term ‘symbiosis’ is a vague term. If I got the history right, originally (100+ years ago) it was used from people living together. At some point, it was used as a synonym for mutualism, or of certain kind of mutualism. As the wide sense of the word just means ‘living together’, professional ecologists prefer to use the term mutualism.
Mutualism is a +/+ relationship, a relationship where both partners benefit.
Predation is a +/- relationship, a relationship where the other benefits and the other suffers.
Competition is a -/- relationship, a relationship where both partners suffer.
Predation is not symbiosis, except in the sense that both the prey and the predator live in the same area. There is no ‘harmony’ between predators and prey, just conflicting interests to avoid or meet in a deadly encounter. A prey has no interest to cooperate with predators, as it would be the paying partner in the relationship. There are some exceptions but these are cases where ‘the enemy of the enemy is a friend’. These exceptions are cases where the prey choses a strategy that minimises harm.
There is constant change in nature. Sometimes the change is fast, sometimes slow but there is no balance of nature. The same for ‘common good’, there is no such thing in nature.
Human societies are a different thing than nature. We can talk of ‘common good’ in the context of human societies but using that term in the context of wild nature is confusing.
How do biota who cannot think make alliances with others who are in conflict for basic needs?
I do not hear the noise because it did not happen. Flowering plants did not strangle the carboniferous. A cooler climate froze them out, as it did the dinosaurs.
Maybe to you. I hope that you know what the word “sym-pathy” means. It means “caring about others,” as opposed to “anti-pathy”- hatred for others, and “a-pathy”- no feelings toward others.
The word sym-biosis refers life forms (biosis) which positively related to each other, as opposed to unrelated or independent of each other or hostile to each other. Dawkins used the term “selfish” to indicate that genes and therefore life forms are apathetic toward each other. Survival of the fittest is a term that indicates that lifeforms are antipathy or conflict with each other.
Symbiosis does mean mutualism. In fact that is how Richard Dawkins used it in the Selfish Gene. “A relationship for mutual benefit between members of a different species is called mutualism or symbiosis.” p. 181 2006. If members of different species work together, it follows that so can members of the same species.
Please explain where you found this information. For the most part it is incorrect. Only the definition for mutualism is right.
Humans are predators. We eat chickens, cows, fish, pigs, sheep, etc. as well as fruits and vegetables. How have they are we suffered biologically? Predation is symbiosis BECAUSE both parties, the chickens and those who love fried chicken benefit. At one time science seemed to understand this. Now science has gone backward.
Most scientists say that evolution is based on 'competition." If so how can competition be mutually harmful to both parties?
Evolution, the balance of nature, symbiosis is not based on feelings and friendships. It is based on what works to produce the proper results. Just because some biota are are prey and predators does not mean that they do not have objective mutual interest, which is their mutual survival, which symbiosis protects and promotes.
That would be figuratively speaking, of course – you introduced the word make. And species that become symbiotic in relationship to one another are not in conflict for basic needs because their basic needs are different, and the benefit between them is reciprocal.
Are you trying to work in the commercialization of chickens for meat as a evolutionary development that’s beneficial for chickens? As in because we mass breed them we are helping them out in the long run?
The use of the word ‘symbiosis’ has been vague. A paper showing this is
Martin & Schwab 2013 Current usage of symbiosis and associated terminology. International Journal of Biology 5: 32-45.
Those are basic ecological definitions, simplified to signs.
Interspecific competition happens in situations where species compete for shared resources that are limited (not enough for everybody). What one competitor has taken is not available for the other species. Resource competition harms because it means losing space, food or other resources that could be used for growth, survival and reproduction. Interference competition is another form of competition. It harms because it steals time and energy from other activities.
Mathematical simulations can show that competition slows population growth. In this sense, competition has a negative effect on both competitors.
I used the word predation (sensu lato) where I could have used ‘consumer-resource interactions’. It includes herbivory and parasitism and could even be used from social interactions. Consumer-resource interactions are cases where one partner takes from the other. After that, the other partner has gained something (+) and the other has lost something, maybe even the life (-).
Mathematical simulations show that predator-prey interactions can stabilize population fluctuations, but only in a limited set of circumstances. In a simulation with single prey - single predator, the endpoint is more often extinction than coexistence.
Even if predation would stabilize population fluctuations, a killed prey individual loses everything. If it has not yet reproduced, its’ genes will not continue to the next generation (dead end). If we assume selfish genes, a predation event might be beneficial for a gene but only in a case where the death of an individual improves considerably the offspring production of its relatives.
I would not say that predators benefit prey, unless the predator kills or drives away more harmfull predators.
From a human perspective I agree, we should follow the common good.
But that nature follow that principle is I think demonstrably false. I means If that were true there would be no such thing as an invasive species.
The idea that their is no true competition in nature is also false. The basis of how the original antibiotics works take advantage of the competition between bacteria. Penicillium doesn’t produce penicillin for the fun of it, to produces it to kill bacteria to have access to more ressources. All bacteria do something similar.
Simple, if you have a large population of a species that interacts with an other species. If cooperating is advantageous in this case, those that have characteristics that are more favorable for this type of cooperation survive better and reproduce more and slowly but surely you form a new symbiosis. No thinking needed.
It’s competition and predation by fungi
I don’t know about predation but it’s definitely competition.