例五：
[Reading]
Altruism is a type of behavior in which an animal sacrifices its own interest for that of another animal or group of animals. Altruism is the opposite of selfishness; individuals performing altruistic acts gain nothing for themselves.

Examples of altruism abound, both among humans and among other mammals. Unselfish acts among humans range from the sharing of food with strangers to the donation of body organs to family members, and even to strangers. Such acts are altruistic in that they benefit another, yet pro- vide little reward to the one performing the act.

In fact, many species of animals appear willing to sacrifice food, or even their life, to assist other members of their group. The meerkat, which is a mammal that dwells in burrows in grassland areas of Africa, is often cited as an example. In groups of meerkats, an individual acts as a sentinel, standing guard and looking out for predators while the others hunt for food or eat food they have obtained. If the sentinel meerkat sees a predator such as a hawk approaching the group, it gives an alarm cry alerting the other meerkats to run and seek shelter. By standing guard, the sentinel meerkat gains nothing--it goes without food while the others eat, and it places itself in grave danger. After it issues an alarm, it has to flee alone, which might make it more at risk to a predator, since animals in groups are often able to work together to fend off a predator. So the altruistic sentinel behavior helps ensure the survival of other members of the meerkat's group.
 
Listening Script
 
The following is the script of the lecture that you heard and were asked to summarize.
 
You know, often in science, new findings force us to re-examine earlier beliefs and assumptions. And a recent study of meerkats is having exactly this effect. The study examined the meerkat's behavior quite closely, much more closely than had ever been done before. And some interesting things were found.., like about eating habits.., it showed that typically meerkats eat before they stand guard -- so the ones standing guard had a full stomach! And the study also found that since the sentinel is the first to see a predator coming, it's the most likely to escape... because it often stands guard near a burrow, so it can run immediately into the burrow after giving the alarm. The other meerkats, the ones scattered about looking for food, are actually in greater danger.

And in fact, other studies have suggested that when an animal creates an alarm, the alarm call might cause the other group members either to gather together or else to move about very quickly, behaviors that might actually draw the predator's attention away from the caller, increasing that animal’s own chances of survival.
And what about people what about some human acts that might be considered altruistic? Let's take an extreme case, uh, suppose a person donates a kidney to a relative, or even to a complete stranger. A selfless act, right? But... doesn't the donor receive appreciation and approval from the stranger and from society? Doesn't the donor gain an increased sense of self-worth? Couldn't such non-material rewards be considered very valuable to some people?
 
Question
Summarize the points made in the lecture you just heard, being sure to specifically explain how they cast doubt on points made in the reading.
 
Topic Notes
You should understand tile meaning of altruism and altruistic acts. The definitions are given in the reading: altruism describes behavior that is the opposite of selfishness; it is behavior that benefits another individual or the group with no reward. The lecturer questions whether the examples meet the definition.
A high-scoring response will include the following points made by the lecturer:

POINT MADE IN READING
Human organ donors gain nothing from their action.
Sentinel meerkats go without food to stand guard.
Sentinel meerkats place themselves in danger from predators.
 
CONTRASTING POINT FROM THE LECTURE
The donors receive appreciation and approval from the rest of society.
Sentinels actually eat before the other meerkats.
Sentinels are actually the first to escape the predators.

Responses scoring 4 and 5 discuss altruistic/non-altruistic aspects of the three points in the table: human organ donation, meerkat sentinel eating behavior, and meerkat sentinel ability to escape.