Summary Notes on Biodiversity: Speciation, Extinction, and Human Activities
Speciation
- Definition: The process by which new species arise.
- Mechanisms:
- Allopatric Speciation: Occurs when populations are geographically isolated.
- Sympatric Speciation: Occurs without geographic isolation, often through polyploidy or behavioral differences.
- Impact on Biodiversity:
- Increases biodiversity by adding new species to ecosystems.
- Enhances ecosystem resilience and stability.
Extinction
- Definition: The end of an organism or a species.
- Causes:
- Natural factors (climate change, volcanic eruptions).
- Anthropogenic causes (habitat destruction, pollution, overexploitation).
- Impact on Biodiversity:
- Reduces biodiversity, leading to less resilient ecosystems.
- Can lead to a cascade effect, disrupting food webs and ecosystem functions.
Human Activities
- Major Activities:
- Habitat Destruction: Urbanization, deforestation, and agriculture lead to loss of natural habitats.
- Pollution: Chemicals, plastics, and emissions harm organisms and ecosystems.
- Overexploitation: Overfishing and poaching reduce population sizes and extinction rates.
- Climate Change: Alters habitats, shifts species distributions, and affects migration patterns.
- Impact on Biodiversity:
- Rapidly diminishes biodiversity, contributing to increases in extinction rates.
- Alters ecosystem services that humans rely on, such as clean water, food production, and carbon storage.
Diagram
+------------+
| Speciation |
+------------+
|
| Increases
| biodiversity
v
+----------------+
| |
| |
| Species Pool |
| |
+----------------+
|
| Affected by
v
+------------------------------+
| |
| Extinction and Human Impact |
| |
+------------------------------+
|
| Decreases
| biodiversity
v
+----------------+
| |
| Reduced Species|
| Pool |
+----------------+
Conclusion
The interplay between speciation, extinction, and human activities is critical to biodiversity. While speciation can enhance biodiversity, extinction and negative human impacts can severely diminish it. Conservation efforts are essential to protect existing species and habitats to maintain the balance of ecosystems.