Question

For group living to evolve, the benefits of living in a group must have been greater than the costs. Which of the following is an example of a benefit of living in a group? a. reduced spread of disease and/or parasites b. increased food availability c. reduced competition for mates d. decreased risk of predation e. all of the above

Short answer

The benefits that universally apply to group living include increased food availability and decreased risk of predation. Therefore, the correct options are b and d.

Step-by-step solution

Analyze the options

Evaluate each option based on the knowledge about benefits of group living: \n - option a (reduced spread of disease and/or parasites) is incorrect as living in a group can actually increase the risk of disease transmission; \n - option b (increased food availability) could be correct, as some species hunt in groups, making the food capture more successful; \n - option c (reduced competition for mates) highly depends on the species and the group structure and generally group living may even increase mate competition; \n - option d (decreased risk of predation) is true for many species as 'safety in numbers' works as a crucial protection mechanism; \n - option e (all of the above) implies all previous options are correct, which we've seen isn't the case.

Select the correct option

After analyzing the options individually, it becomes clear that the only benefits that apply universally are found in options b and d. However, since the question isn't asking for all possible benefits, but only for an example, either of these could be a correct answer. The option that groups them both, e, is incorrect as it includes options that aren't considered universal benefits.

Key concepts

Disease transmission

Living in a group can increase the risk of disease transmission. When individuals are in close proximity, pathogens and parasites can easily spread from one member to another. This is because they share the same space and often come into direct or indirect contact. For example, illnesses can be transmitted through shared food, grooming, or even breathing the same air.

Despite this negative aspect, some group-living species have developed strategies to counteract disease spread. These can include:

• Hygienic behaviors, such as regular grooming, to remove parasites and reduce infection risks.
• Social structures that limit physical contact between group members.
• Rotating communal sleeping areas to minimize contamination.

Nevertheless, the risk of disease transmission remains a significant cost of group living.

Food availability

One of the significant benefits of group living is increased food availability. Many animals, like wolves or lions, engage in group hunting. By working together, they can tackle larger prey that would be challenging for a single individual to subdue.

This cooperative hunting strategy increases the chances of a successful hunt and ensures more food for the entire group. It also allows members to exert less individual energy compared to hunting alone. In some cases, group living can also help locate and protect food resources from competitors.

Animals often display teamwork where each member fulfills a specific role. This specialization can enhance efficiency, ensuring all group members get enough food.

Predation risk

Group living significantly decreases predation risk, which is one of the core benefits seen in many animal species. The principle of "safety in numbers" reduces an individual's chance of being preyed upon. This is because predators are more likely to be deterred by a large group.

Within a group, individuals can engage in "vigilance sharing." While some members keep watch for predators, others can safely rest or forage. This division of labor helps the group identify threats more quickly and react more effectively. Furthermore, larger groups can sometimes successfully confront and drive away predators, enhancing their collective survival.

This protective advantage allows individuals to spend more time on essential activities like foraging or caring for young, instead of constantly being on alert.

Group hunting

Group hunting is a sophisticated behavior that many carnivorous species have developed to maximize their feeding success. By collaborating, members of a group can capture larger prey and divide the spoils among themselves. This increases the food intake compared to solitary hunting.

For example, wolves coordinate hunts to outmaneuver and take down large mammals like elk or moose. Similarly, lions can surround a herd and individually steer prey into ambushes. Such techniques require planning, communication, and synchronized efforts.

Benefits of group hunting include:

• Reduced individual energy expenditure.
• Higher success rates in capturing prey.
• Improved defense against competing predators.

Although it requires cooperation, the advantages gained from successful hunts often outweigh the costs.

Mate competition

While living in groups can have numerous benefits, increased competition for mates is often a drawback. In many species, close proximity results in rivalry among group members, as individuals vie for the same mating partners.

Higher mate competition can lead to complex social hierarchies, where dominant individuals typically have more access to mates. Non-dominant members may need to employ alternative strategies, such as forming alliances or being more cooperative, to have mating opportunities.

However, living in groups can also increase the likelihood of finding a mate due to larger pool sizes. Some species have evolved mating rituals and displays specifically designed to stand out in these crowded environments.

• Dominance hierarchies often dictate mating rights.
• Increased opportunities for selection of mates.
• Potential for innovation in mating strategies.

Ultimately, the intense competition requires group members to adapt and innovate constantly.