Reduction of Biological Diversity and Causes of Extinction

The way human beings act can determine biological diversity. This influence is the primary reason for the establishment of protected areas such as nature reserves and national parks.
The Role of Zoos: Zoos play an important role in preserving biodiversity through the use of breeding programs (programmes de s lection).
Human-Induced Environmental Change: Without knowing it, human modification of the environment has rendered many species incapable of adapting, which has consequently led to their disappearance.
Impact of Industrialization: Certain species and various ecosystems are put under severe strain due to the processes of urbanization and industrialization.

Extinction: This is defined as the disappearance of every single individual of a species from the entire planet.
Temporal Patterns of Extinction: While the majority of extinctions occur over long periods, the current rate of extinctions is increasing. This acceleration reduces the overall biological diversity of the planet.
Local Disappearance (Extirpation): Known in the text as "Disappearance of the country" (disparition du pays), this refers to a local extinction or the disappearance of a species from a specific, particular geographical area.

Threatened (Menac e): A species is classified as threatened if it is likely to become endangered if the current declines in its population are not addressed or taken into account.
Special Concern (Pr occupante): This refers to species that are particularly vulnerable to natural events and the impacts of human activity.

Natural Selection: This is generally a slow process. Although there are many variations within a single species, changes in the environment can sometimes be so drastic that no individual within a species can survive.
Historical Causes of Extinction: In the past, the majority of extinctions were attributed to the following factors:
- Catastrophic Events: These include volcanic eruptions, earthquakes, floods, and fires.
- Lack of Food: Often resulting from overpopulation within a given area.
- Disease: Pathogens that can wipe out entire populations.

Definition: Overspecialization occurs when organisms possess adaptations that only suit them for a very highly restricted set of environmental conditions.
Environmental Context: This typically happens in relatively stable zones where the environment does not change for a very long period of time.
Consequences: Sursp cialisation is considered a significant cause of extinction because these organisms cannot adapt if their specific conditions change.

Primary Driver: Today, the majority of extinctions and local disappearances (disparitions du pays) are caused by human activity.
Habitat Destruction: This occurs as a consequence of several human activities:
- Urbanization.
- Construction.
- Agricultural development.
- Logging (Enregistrement).
- Damming of rivers.
Pollution: The introduction of harmful substances into the environment, specifically:
- Pesticides.
- Herbicides.
- Fertilizers.
Introduction of Non-Native Species: The introduction of foreign species affects biodiversity in two major ways:
- Resource Competition: When introduced species utilize the same resources as native species, competition results in a decline in the population of native species because there are fewer available resources.
- Lack of Natural Predators: Introduced species often do not have natural predators in their new environment to limit their population growth. Over time, they will take over the habitats of native species.