托福阅读真题+题目+答案：Altruistic Behavior

托福阅读真题+题目+答案：Altruistic Behavior

Behaviors that lower the fitness of the individual but increase the fitness of another individual are termed altruistic. Examples of such behaviors are seen widely across the animal kingdom. Social insects such as worker bees have no ability to reproduce, yet they maintain the queen so she can populate the hive with her offspring. Meerkats keep a member of the group standing guard to warn the rest of the colony about intruders, even though the guarding meerkat is putting itself at risk. Wolves and wild dogs bring meat to pack members not present during a hunt. Although on the surface, these behaviors appear to be altruistic, it may not be so simple.

1. According to paragraph 1, which of the following is true?

A. Altruistic actions in nature decrease one’s ability to survive while improving the fitness of others

B. Worker bees are social insects that guard the colony and produce offspring with their queen

C. Meerkats work in groups to defend and warn their community against intruders

D. Wild dogs bringing meat back from a hunt is a well-understood altruistic behavior

There has been much discussion over why altruistic behaviors exist. Do these behaviors lead to overall evolutionary advantages for their species? Do they help the altruistic individual pass on its own genes? One explanation for altruistic-type behaviors is found in the genetics of natural selection. In the 1976 book, The Selfish Gene, scientist Richard Dawkins attempted to explain many seemingly altruistic behaviors from the viewpoint of the gene itself. Although a gene obviously cannot be selfish in the human sense, it may appear that way if the sacrifice of an individual benefits related individuals that share genes that are identical by descent (present in relatives because of common ancestors). Mammal parents make this sacrifice to take care of their offspring. Emperor penguins migrate miles in harsh conditions to bring food back for their young. Selfish gene theory has been controversial over the years and is still discussed among scientists in related fields.

2. The book “The Selfish Gene” deals with

A. The debate about why organisms behave altruistically

B. The popular theories scientists have on altruistic behaviors

C. The author’s explanation of altruistic behaviors

D. Altruistic behaviors in humans with genes of identical descent

3. Why does the author say, “Emperor penguins migrate miles in harsh conditions to bring food back for their young” ?

A. To explain why emperor penguins travel so far for food

B. To show that emperor penguins are birds that sacrifice the most for their young

C. To provide an example of altruistic behavior

D. To highlight how some altruistic behaviors fit the model of selfish gene theory

Even less-related individuals with less genetic identity than those shared by parent and offspring benefit from seemingly altruistic behavior. The activities of social insects such as bees, wasps, ants, and termites are good examples. Sterile workers in these societies take care of the queen because they are closely related to it, and as the queen has offspring, she is passing on genes from the workers indirectly. Thus, it is of fitness benefit for the worker to maintain the queen without having any direct chance of passing on its genes due to its sterility. This phenomenon can explain many superficially altruistic behaviors seen in animals. However, these behaviors may not be truly defined as altruism in these cases because the actor is actually increasing its own fitness either directly (through its own offspring) or indirectly (through the inclusive fitness it gains through relatives that share genes with it).

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