Biodiversity Study Notes

Definition: Biodiversity refers to the variability among living organisms on Earth, including variability within and between species and ecosystems.
Importance:
- Increases adaptability and survivability of species.
- Maintains healthy ecosystems:
- Each species plays a unique role.
- Higher chance of organisms adapting to changing conditions (e.g., droughts, natural disasters).
- Diverse ecosystems are more resilient and more likely to recover from environmental changes.

Species Richness:
- Total number of species within a specified region.
Genetic Diversity:
- Total variety of genes within a single species.
Endemic Species:
- Species that occur in a specific area and nowhere else in the world.
Ecosystem Diversity:
- Total number of ecosystems in the region.
  - Unique ecosystems are those found only in certain regions, contributing to ecosystem diversity.

Increasing Biodiversity:
- Commonly found closer to the equator due to:
- More direct sunlight, precipitation, and chemical weathering.
- Mountainous regions host diverse ecosystems due to:
- Varied water sources, altitudes, and climates.
  - Mountains, covering 25% of Earth's land area, are home to 85% of amphibian, bird, and mammal species.

Definition of Adaptations: Changes that help organisms survive in their environment.
Types of Adaptations:
- Physical Adaptations: Traits that enhance survival, such as:
- Insulating fat in cold animals.
- Camouflage through fur or feathers.
- Plants' short root systems in cold climates.
- Behavioral Adaptations: Actions that enhance survival, including:
- Hibernation, migration, food storage, climbing for sunlight, avoiding predators, etc.

Definition: Species that are not native to a particular region and can disrupt local ecosystems.
Characteristics of Invasive Species:
- Lack natural predators in their new environment.
- Can reproduce rapidly and adapt easily.
Consequences:
- Harm to native species and ecosystems.
Examples:
- Zebra Mussels: Introduced to the Great Lakes; they outcompete native species and clog water systems.
- Cats on Marion Island: Introduced for pest control; led to decline of local seabird populations.
Not all non-native species are harmful; some, like food crops, are beneficial.

Removal of species can have drastic interconnected effects on ecosystems.
Observed a ~70% decrease in global wildlife populations over the last 50 years due to climate change and habitat loss.
Consequences of lower biodiversity include:
- Increased vulnerability to pests and diseases.
- Negative impact on food security (e.g., reduction of pollinators).
- Economic implications tied to biodiversity loss (e.g., reduction in raw materials).

Endangered Species: A species is classified as endangered if its population declines by 70% due to known causes or 50% if the cause is unknown.
Main drivers of endangerment include habitat loss and decreased genetic variation.
Extinction: The permanent disappearance of a species, linked to human activities.
Present loss rate: ~1 species per million species annually, typically accelerated by human actions.

Habitat Loss: Destruction of ecosystems affecting resources.
Invasive Species: Disruption of colonized ecosystems.
Overexploitation: Unsustainable harvesting leading to species depletion.
Pollution: Environment alteration exceeding its natural capacity.
Climate Change: Modification of climate due to greenhouse gas emissions.
- Influenced by population growth, consumption rates, and resource efficiency.

Ethical responsibility towards preserving biodiversity:
- Belief that species and ecosystems have inherent rights to exist.
- Loss of biodiversity diminishes fascination and study of the environment.

Legislation: 1973 US Endangered Species Act aims to protect threatened and endangered species and their habitats—99% on the list have survived.
Establishment of natural preserves and national parks (e.g., Yellowstone National Park).