Question 1 Answer:Group selection is the idea that natural selection can sometimesact on a group of individuals at a time, favoring some groups overothers, eventually leading to the evolution of traits beneficial to the groupas a whole. In my opinion, migration and genetic mixing does pose as a problemfor Darwin’s theory of group selection. This is because this theory was formedon the basis that organisms with more complex social organization will help toincrease the survival and reproduction of the group, at the cost of theorganism. However, if migration between discrete groups occurs, the individualswill inevitably breed and produce offspring. This means the resulting offspringwill have genetic components of both discrete groups.Consequently, if these groups that were once separate beginto migrate and partake in genetic mixing, wouldn’t the group’s geneticcomponents change? Why would individual organisms continue to sacrifice theirwellbeing for that of the group if some individuals are not even a part of thegroup or kin? Given the above, we can conclude that the intensity of movement ofindividuals between populations should be suitably low in order for groupselection to be viable. Thus, the two important musts to group selection arespatial proximity and relatedness.
Individuals will be more willing to performacts of group selection when the group is within close proximity and closelyrelated to that individual. In this way, migration and genetic mixing can poseas an issue since this can disturb the level of relatedness between individualsin the vicinity. Question 2 Answer:(a)According to Lorenz, aggressiveness is beneficial and allows for the successand survival of populations of species over the course of evolution. He claimsthat inter-specific aggression – aggression between predator and prey – has anobvious survival benefit. This type of aggression allows species to defendtheir territory fromcompetitors that are hunting for food or seeking their resources. Thisaggression also helps predators catch their prey in an attempt to subsist.
However, Lorenz was more specifically interested in the traitof intra-specific aggression – aggression between members of the same species.This type of aggression also seems to promote the survival of the species as awhole, only if the aggression does not escalate to the level of total combatwithin species. He remarks a shared instinct of individuals to defend theirterritory from intrusion by animals of the same species and defeat a rival fora desired female. He states that such aggression benefits the animal kingdom sinceit results in the balanced distribution of animals of the same species over theavailable environment and insures that resources are shared equally.Additionally, intra-specific aggression gives rise to a healthiergene pool that is continually modified toward strength. Another instinct ofindividuals to protect the young and defenseless of the species allows an increasein the likelihood of the young of a species growing to adulthood.
In these waysLorenz shows how aggression actually helps to preserve the species, regularlyimproving it to make it more adaptive to the environment. Additionally, Lorenzattributes aggression to playing a huge role in developing social structure withinspecies. This is due to aggression’s critical role in clarifying the rankingorder of the members of a group; when met with hostility, the position of thestronger individuals will rank above weaker individuals.In his 1966 book ‘On Aggression’, Lorenz argued that thoughanimal and human aggressive behaviour was motivated by survival, aggressivebehaviour in humans is not appropriately shaped and modified. Lorenz stated thatthe degree of violence that humans direct toward their own kind is unmatched byany other organism in the animal kingdom.
He talks about the fact that humanshave gone through alarming escalations in aggression through technology,allowing us to kill each other from a distance. This is well representedthrough the illustration of war; the invention of nuclear bombs threatens thisspecies-preserving function of aggression because inhibitory factors such asempathy for the victim are not activated. (b) Group-level selection is defined as selection inwhich traits evolve according to the survival and reproductive success of thegroup, even if it results in the decreased chance of individual survival. Onthe other hand, species-level selection is the process responsible for theexplosion of species that have lower extinction rates and higherspeciation rates. I think it is useful to differentiate group-levelselection from species-level selection because they are two different processthat can easily be confused. Over time group-level selection can lead to theextinction of species because, at the end of the day, sacrificing yourself forthe improvement of the whole group does not pose any real benefits. On theother hand, species-level selection is accountable for an increase inspeciation, allowing species to prosper with lower extinction rates.Question 3 Answer:In these series of paragraphs, Dawkins takes the perspectiveof a group selectionist into consideration.
The argument of a groupselectionist is that species or populations with members who are willing tosacrifice themselves for the welfare of the group may be less likely to goextinct than a rival group whose individual members place their own selfishinterests first. Thus, the world becomes occupied mainly by groups consistingof self-sacrificing individuals. He states that we all know that evolutionworks by natural selection, and natural selection means survival of thefittest. Now, what we don’t know is at what level organisms are competing witheach other. It could be the fittest individual, the fittest races, or thefittest species.
If it were to be the fittest species, that means individualswould easily sacrifice themselves for the greater good of the whole.This seems to make sense at first, but Dawkins quicklyknocks down the argument by saying that even in the group of altruists therewill be a small number of selfish individuals that refuse to sacrificethemselves for the betterment of the group. The presence of just one selfishindividual means that individual is more likely to survive and produceoffspring in comparison to the rest of the group.
Consequently, the selfishindividual’s offspring will likely inherit the trait of selfishness. Aftergenerations of natural selection, the new selfish individuals will inevitablyoverrun the group of altruistic individuals. Dawkins then goes on to state thateven if a group of pure altruistic individuals exists, though unlikely, thereis not much that would stop selfish individuals from migrating and contaminatingthe altruistic group.However, groups can die out, and whether or not a group goesextinct may be influenced by the behaviour of the individuals in that group.Dawkins also mentions that although it may be true that the selfish behaviourof the individual jeopardizes the fitness of the group, group extinction is a veryslow process in contrast to individual competition. Granting a group is headedtowards extinction, the selfish individuals will prosper in the short term atthe expense of the altruistic individuals.
This serves as an advantage toorganisms with selfish motives because they will benefit while altruisticindividuals continue to sacrifice their well-being in an attempt to help the overallgroup prosper. So, if beingaltruistic does not do any good for a group in the long term, wouldn’t it bemore advantageous for individuals to act in a selfish manner? One of the reasonsthat the group selection theory has been so appealing to biologists is because itis in line with the moral and political ideals that most humans share. Darwinproposes that we may at times act selfishly at the individual level, but in ourmore principled moments as a group we look up to and admire individuals who putthe welfare of others before their own. As a result, this theory seems logicaland plausible since we believe that being altruistic is the right thing to dofor group benefit.