Question 1

Why did Darwin struggle to explain altruistic behavior in bees?

Accepted Answer

Darwin observed that worker bees sacrificed their own reproduction to care for the queen's offspring, contradicting his theory that natural selection favored individual reproduction. He lacked knowledge of genetics and inheritance, so he couldn't explain how self-sacrificing traits could evolve. Later scientists discovered that genetic relatedness between individuals was key to understanding altruism.

Question 2

What does Hamilton's equation reveal about altruistic behavior?

Accepted Answer

Hamilton's equation (r × B > C) mathematically determines when altruism benefits an individual genetically. The equation compares genetic relatedness (r), fitness benefit to the recipient (B), and cost to the altruist (C). When the product of relatedness and benefit exceeds the cost, altruistic behavior becomes evolutionarily favorable, especially among close relatives.

Question 3

What are the three defining characteristics of eusocial societies?

Accepted Answer

Eusocial societies exhibit communal brood rearing, where multiple individuals care for offspring together. They have overlapping generations, allowing siblings to care for younger relatives. Finally, they display division of labor based on reproductive castes, with some individuals forgoing reproduction to support colony members, as seen in bees, ants, and termites.

Question 4

How does haplo-diploidy increase genetic relatedness among sisters?

Accepted Answer

In haplo-diploid species like bees and ants, males carry one chromosome set while females carry two. Males inherit 100% of genes from their mother, while females inherit 50% from each parent. This means sisters share 75% of genes with each other, compared to 50% in diploid species, making cooperation more genetically beneficial.

Question 5

What does the ecological hypothesis suggest about eusocial evolution?

Accepted Answer

The ecological hypothesis proposes that environmental factors favor eusocial living. For example, termites benefit from cooperating to gather food from dead wood and defending against neighboring colonies. Group living provides protection from predators and reduces competition, making eusocial organization advantageous regardless of genetic relatedness alone.

Question 6

How does inclusive fitness theory redefine evolutionary success?

Accepted Answer

Inclusive fitness theory extends the measure of evolutionary success beyond individual reproduction to include the reproductive success of genetic relatives. Since relatives share genes, helping them reproduce can increase an individual's overall genetic contribution to future generations, explaining why altruistic behavior toward kin can evolve through natural selection.

Question 7

Which animal groups besides insects exhibit eusocial behavior?

Accepted Answer

While most eusocial species are insects like bees, ants, and termites, naked mole rats represent eusocial mammals. Marine snapping shrimp also display eusocial characteristics. Understanding population growth exponential logistic growth patterns helps explain how eusocial colonies expand and sustain themselves over time.

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