Problem 2 - Biology: The Unity and Diversity of Life

Question

Dodos were driven to extinction _____. a. when humans arrived in North America b. by overharvesting and introduced species c. as a result of global warming d. by volcanic eruptions

Step-by-Step Solution

Answer

The dodo was driven to extinction by overharvesting and introduced species (option b).

Step 1: Understand the Context

The Dodo was a flightless bird that lived on the island of Mauritius in the Indian Ocean. It became extinct in the late 17th century.

Step 2: Identify the Causes of Extinction

The extinction of the dodo was primarily due to overhunting by humans and the introduction of animals such as pigs, monkeys, and rats, which ate dodo eggs and competed for food sources.

Step 3: Evaluate the Options

Look at the provided options: a. Dodos did not live in North America, so human arrival there is unrelated. c. Global warming was not a factor in the 17th century extinction of the dodo. d. There is no record of volcanic eruptions affecting dodo extinction. b. Overharvesting and introduced species match historical accounts.

Step 4: Select the Correct Answer

Based on the known historical causes of dodo extinction, the most accurate choice is b. by overharvesting and introduced species.

Key Concepts

Overharvesting

Overharvesting refers to the excessive hunting or gathering of a species beyond what their population can sustain. In the case of the dodo, these flightless birds became easy targets for humans when they discovered the island of Mauritius in the 16th century. The dodos had no fear of humans, making them even more vulnerable. As people began to settle on the island, they relied on the dodo birds for food, harvesting them in large numbers.
This unsustainable hunting practice significantly reduced the dodo population in a short period of time. The dodo's lack of natural predators before human arrival contributed to their downfall. Their nesting behavior and inability to fly made them especially susceptible to human predation. Here's a quick summary of the impact of overharvesting in the dodo's extinction:

• Humans harvested dodos for food, taking advantage of their tame nature.
• Overhunting led to a rapid decline in their population.
• The dodo had no previous experience with predators, worsening the impact of human hunting.

In essence, overharvesting by humans was one of the leading causes that drove the dodos to extinction.

Introduced Species

Introduced species are animals that have been brought to a new habitat where they are not naturally found. These species can cause significant disruption to the ecosystem. In the case of the dodos, settlers brought animals such as pigs, monkeys, and rats to the island of Mauritius.
These animals either preyed upon dodo eggs or competed with them for resources. The impact of introduced species on the dodo population cannot be overstated:

• Pigs, monkeys, and rats are some of the notable animals introduced.
• They ate dodo eggs, reducing their chances of reproduction.
• Competition for food with these new species placed further stress on the dodo population.

The dodo was not evolutionarily prepared for these new challenges and unable to adapt quickly to the presence of these new competitors and predators. Therefore, the introduction of non-native animals to Mauritius played a crucial role in the extinction of the dodo.

Extinction Causes

The extinction of a species is usually the result of a combination of factors, rather than a single cause. This was true in the case of the dodo. While overharvesting and introduced species were critical factors, they were among several variables that contributed to this unfortunate event. Here's a closer look at the main causes behind the extinction of the dodos:

• Overharvesting: Excessive hunting by humans drastically decreased their population.
• Introduced Species: New species consumed dodo eggs and competed for resources.
• Ecosystem Changes: The arrival of human settlers transformed the natural habitat of dodos, disrupting their way of living.

The dodos' extinction serves as a poignant reminder of the fragility of ecosystems and the impact human actions can have on biodiversity. Understanding these causes highlights the importance of sustainable practices and careful ecological management to prevent further loss of species.