Unit 6 Lesson 8: Group Behavior Flashcards
Some forms of group behavior can be easily understood as adaptive—that is, a means of ensuring the survival of the species. For example: Prey animals herding:
Many species, from antelopes to wildebeests, travel in large herds. While this behavior doesn’t necessarily extend the life of any one wildebeest, it makes it much more likely that the herd as a group will survive the attack of a predator. It also makes it easier for groups of animals to find and share habitat and resources and to find appropriate mates.
Some forms of group behavior can be easily understood as adaptive—that is, a means of ensuring the survival of the species. For example: Fish schooling:
Some species of fish move in large schools, making it harder for predators to see and single out individual fish for prey. There is no particular advantage to this behavior for any individual fish, but it does promote the survival of the entire school.
Some forms of group behavior can be easily understood as adaptive—that is, a means of ensuring the survival of the species. For example: Group hunting:
Certain species of predators, such as wolves and hyenas, hunt in groups, making it easier to surround and kill prey. This cooperative behavior ensures the survival of the group as a whole, though it doesn’t necessarily benefit from the traits of an individual animal.
altruistic behavior
behavior exhibited by individuals within a group that potentially reduces the fitness of that individual but enhances the fitness of other members of the group
Examples of altruistic behavior. Monkeys warning:
Certain species of monkeys are known to call out to their peers to warn them of approaching danger. By calling out a warning, the individual monkey draws attention to itself, thus increasing its own risk, but it also ensures the safety of the group.
At first, it was believed that altruistic behavior was simply a strategy for protecting a species. What would this mean
According to this theory, if an animal protects others of its species (even to its own cost), the species will survive. This idea, however, seems to contradict Darwin’s theory of survival of the fittest.
Examples of altruistic behavior Birds protecting nests other than their own:
It’s easy to understand why birds will protect their own young. It’s more difficult to understand why some birds will risk their own safety (and the safety of their own young) to protect other birds’ nests from predators.
Examples of altruistic behavior Bats sharing food:
Vampire bats will sometimes regurgitate food they have eaten to share with others in the group who have not had a successful hunt. This behavior helps the hungry bat, but it reduces the altruistic bat’s nutrition.
What would it mean if the fittest animal is the most alturistic
If the fittest animal is the most altruistic, it is also the most likely to be killed by predators or hunger, and therefore, the least likely to pass its genes along to offspring.
Moreover, altruistic behavior is only adaptive as long as everyone in the group is also altruistic. What happens when one selfish animal is born into a community of altruists?
The selfish animal gathers all the resources to itself, leaving the altruists to die.
How does altruism evolve
Altruism, it was revealed, can only evolve if those animals that benefit from altruistic acts return the favor. For altruism to evolve, it must be the case that altruistic animals usually find altruistic partners—either from their own families or from their own larger social group.
Describe Darwin’s theories regarding group behavior and evolution.
Darwin had a few ideas about group behavior and evolution. One of his ideas was that technological sharing within a group would give the group an advantage and thus make it more likely to survive and reproduce. Another idea was that altruism within a group would make the group itself stronger.
Which statement is true?
Altruism leads to a greater success for the altruistic individual.
Altruism can have a positive impact on group survival.
Schooling is an example of altruistic behavior.
Darwin developed the theory of kinship selection.
Altruism can have a positive impact on group survival.
One of the most important forms of altruistic adaptive behavior is called “kin selection.” what is kin selection
Kin selection describes the process by which individual animals choose to protect and care for their closest relatives, even if the decision to do so causes them harm. Researchers have found that the nearer the kinship, the more likely animals are to be protective. Thus, kin are more likely to risk their own safety to protect their offspring than to protect their cousins.
example of kin selection
For example, a chimpanzee might protect its young from a predator even if doing so makes it vulnerable to attack.
Altruism can play an important role for the survival of the species.
. Fitter animals may protect weaker animals from predators and kin may share resources, such as food and habitat, to ensure the survival of the group. By supporting and helping close kin, individual animals can help ensure that their genetic material will be passed along to the next generation, even if they themselves don’t reproduce.
Selfish animals in altruistic groups
. They argued that since evolution by natural selection acts on the individual and the individual’s traits are passed on through the inheritance of DNA, then a selfish individual would eventually out compete any individual that depended on altruistic behavior. Over time, you would expect this selfish trait to spread throughout the population. However, you do not see this in the data. Selfish individuals do not do well in altruistic groups.
Why does altruism remain in a population?
When an individual has offspring, that offspring has about half of the individual’s DNA, since half comes from one parent and the other half of the offspring’s DNA comes from the other parent. You also share approximately half of your DNA with your siblings as well. So, both your children and your offspring share half of your DNA. Because of this, by protecting your close relatives, you are essentially ensuring that your DNA makes it to the next generation. This is the basis for kin selection. Even if you do not have offspring, if your siblings or close relatives have offspring, part of your DNA will make it to the next generation. This explains why altruism remains in a population since that DNA would likely carry traits that code for altruistic behaviors.
altruism remains in a population since that DNA would likely carry traits that code for altruistic behaviors.
What is the wekaness of this arugemnet?
For example, there are certain bird species that will help protect the nest of unrelated individuals. Since the offspring do not share any DNA with the altruistic individual, the theory of kin selection does not explain this type of behavior. The debate on how this type of altruistic behavior develops is still ongoing, but as mentioned in the previous lesson, most evolutionary biologists believe that altruistic behavior in unrelated groups can only exist if individuals reciprocate the altruism. In other words, if one individual displays altruistic behavior, it is expected that other individuals will also display altruistic behavior in return.
