Explain why organisms become endangered or extinct, including: climate change, habitat destruction, hunting, overharvesting, pollution and introduced species

Organisms become endangered or extinct due to a combination of environmental pressures and human activities. Key factors contributing to this decline include climate change, habitat destruction, hunting, overharvesting, pollution, and the introduction of invasive species. Here’s a detailed explanation of each factor:

1. Climate Change

Climate change significantly alters the habitats and conditions necessary for many species’ survival. Rising global temperatures, changing precipitation patterns, and increased frequency of extreme weather events (such as droughts and floods) can lead to:

• Habitat Loss: Many species are unable to adapt quickly enough to the changing climate, resulting in loss of suitable habitats.
• Disrupted Ecosystems: Altered temperature and weather patterns can affect food availability and breeding cycles, leading to population declines.
• Increased Competition: As some species migrate to cooler areas, they may outcompete native species for resources, further threatening their survival.

2. Habitat Destruction

Habitat destruction is one of the primary drivers of species extinction. It occurs through:

• Urbanization: Expansion of cities leads to the clearing of forests and wetlands, displacing countless species.
• Agricultural Expansion: Converting natural landscapes into agricultural land reduces biodiversity by destroying habitats and fragmenting ecosystems.
• Deforestation: The logging of forests not only removes trees but also disrupts the entire ecosystem that depends on those trees for shelter and food.

The loss of habitat directly impacts species by reducing their living space and resources, leading to population declines.

3. Hunting

Hunting, whether legal or illegal, poses a significant threat to many species. Overhunting can lead to:

• Population Declines: Targeted hunting can drastically reduce numbers of specific species, pushing them toward extinction.
• Disruption of Ecosystems: Removing key species from an ecosystem can disrupt food chains and lead to unforeseen consequences for other organisms.

4. Overharvesting

Overharvesting refers to the unsustainable extraction of resources from the environment. This can include:

• Fishing: Unsustainable fishing practices deplete fish stocks faster than they can replenish, leading to population crashes.
• Wildlife Trade: The illegal trade in animals and plants for pets, medicine, or decoration can drive species to extinction as demand outpaces their ability to reproduce.

5. Pollution

Pollution from various sources significantly impacts both terrestrial and aquatic ecosystems. Key effects include:

• Chemical Contaminants: Pesticides, heavy metals, and plastics can poison wildlife, disrupt reproductive systems, and lead to population declines.
• Water Quality Degradation: Nutrient pollution (eutrophication) leads to algal blooms that deplete oxygen in water bodies, harming aquatic life .

Pollution can create inhospitable environments for many species, making survival difficult.

6. Introduced Species

The introduction of non-native species into ecosystems can have devastating effects on local biodiversity through:

• Competition for Resources: Invasive species often compete with native species for food and habitat, sometimes leading to the latter’s decline or extinction.
• Predation: Non-native predators can decimate populations of native species that have no natural defenses against them .
• Disease Transmission: Introduced species may bring new diseases that native populations are not equipped to handle.

This combination of factors creates a complex web of threats that can lead to the endangerment or extinction of organisms worldwide.