Question

Most recorded extinctions have been caused by a. invasive species. b. habitat destruction. c. overexploitation. d. a and b equally. e. a, b, and c equally.

Short answer

The correct answer is b. Habitat destruction.

Step-by-step solution

Identify the Biggest Threat to Species Extinction

There are numerous threats leading to species extinction, some being human-induced and others associated with natural processes. Invasive species, habitat destruction, and overexploitation have all been significant contributors to extinctions.

Evaluate Each Option

Let's evaluate each option. (a) Invasive species: invasive species often compete with native species for resources and could lead to the extinction of native species. (b) Habitat destruction: habitat destruction due to urban development, agriculture, logging and other activities contributes significantly to extinctions. (c) Overexploitation: overexploitation often leads to a severe decrease in the population of a species, and could potentially result in extinction. However, based on various scientific studies, the most prevalent cause is considered to be habitat destruction.

Select the Correct Answer

Based on the analysis in Step 2, it can be determined that the most recorded extinctions have been predominantly due to habitat destruction.

Key concepts

Invasive Species

Invasive species are one of the main drivers of biodiversity loss and species extinction across the globe. These are organisms that are not native to an ecosystem and, when introduced, can cause harm to the environment, the economy, or human health. Since they are in a new habitat, invasive species often lack natural predators or controls to keep their populations in check.

The Ecological Impact of Invasive Species

When an invasive species enters a new ecosystem, it can quickly become a top competitor for resources such as food and habitat, edging out native species. This can lead to a reduction in biodiversity as native plants and animals struggle to survive or adapt. Some invasive species are also known for altering the physical environment, which can have cascading effects on the entire ecosystem.

Invasive Species Management

Managing invasive species can be challenging and requires a multi-faceted approach. To combat these species, authorities often employ strategies such as physical removal, chemical treatments, and biological controls. However, the most effective way to mitigate the impact of invasive species is through prevention and early detection.

Habitat Destruction

Habitat destruction is the process where a natural habitat is made incapable of supporting its native species. In terms of causing species extinction, it is recognized as the primary threat to the survival of wildlife globally. This destruction is mainly due to human activities that alter landscapes, such as agriculture, urbanization, logging, and mining.

Effects on Species and Ecosystems

Habitat loss leads to smaller populations, reduced genetic diversity, and increased vulnerability to environmental changes such as climate events. It also disrupts the connections between species, leading to the collapse of food webs and other ecological relationships essential for a functional ecosystem.

Conservation and Restoration Efforts

In response to habitat destruction, conservation efforts include establishing protected areas, enforcing environmental regulations, and restoring degraded habitats. Educational campaigns are also vital to raise awareness about the importance of conservation and responsible land-use practices.

Overexploitation

Overexploitation refers to harvesting a renewable natural resource to the point of diminishing returns. This has historically been a significant cause of extinction, particularly for species that have been hunted, fished, or harvested faster than their populations can recover.

Impact on Species Sustainability

Species overexploitation can have immediate and devastating effects. For example, the overfishing of particular fish species has led to a collapse in their populations, affecting both the species itself and the larger marine ecosystem. Likewise, the poaching of elephants for ivory and rhinos for their horns are well-known cases where illegal hunting significantly threatens wildlife.

Strategies to Prevent Overexploitation

To combat overexploitation, enforcement of laws against illegal hunting and trading is critical. Sustainable management practices, quotas, and breeding programs are also employed to balance the use of species with their ability to naturally replenish. Conservation organizations work to ensure that international agreements like CITES (Convention on International Trade in Endangered Species) are effective in protecting vulnerable species from overexploitation.