Unit 2 APES

1. Biodiversity Overview

Definition: Biodiversity includes genetic, species, and habitat diversity.
Importance:
- Genetically diverse populations are more resilient to stressors.
- Ecosystems with high biodiversity recover better from disruptions.
Key Terms:
- Species Richness: Number of different species in an ecosystem.
- Species Evenness: Distribution of individuals among species.

2. Genetic Diversity and Population Resilience

Bottleneck Effect: Reduction in population size leads to loss of genetic diversity.
Specialist vs. Generalist Species:
- Specialist: Thrive in narrow conditions; first to be affected by habitat loss.
- Generalist: Can adapt to broader conditions but are affected after specialists.

3. Ecosystem Services

Categories:
- Provisioning: Materials from nature (e.g., timber, medicine).
- Regulating: Processes that moderate natural phenomena (e.g., air quality).
- Cultural: Non-material benefits (e.g., recreation, tourism).
- Supporting: Underlying processes (e.g., photosynthesis, nutrient cycling).
Anthropogenic Impacts: Human activities disrupt ecosystem services, causing economic and ecological consequences.

4. Island Biogeography

Concept: Study of ecological relationships and species distribution on islands.
Key Factors:
- Larger, closer islands have higher biodiversity.
- Island species are often specialists; invasive generalists can outcompete them.
Application: Habitat fragmentation mimics island conditions.

5. Ecological Tolerance

Definition: Range of conditions an organism can endure (e.g., temperature, salinity).
Impact:
- Moving outside tolerance range causes physiological stress.
- Applies to individuals and species.

6. Natural Disruptions to Ecosystems

Scales: Periodic, episodic, random.
Climate Changes:
- Caused by variations in Earth’s orbit, solar radiation, volcanic activity, greenhouse gases.
- Sea level changes due to glacial ice melt.
Migration: Wildlife migrates due to natural disruptions.

7. Adaptation and Natural Selection

Process:
- Short- and long-term adaptations occur through genetic changes.
- Species must adapt, migrate, or face extinction due to environmental changes.
Example: Natural selection drives adaptation over generations.

8. Ecological Succession

Types:
- Primary Succession: Starts without soil (e.g., after volcanic eruption).
- Secondary Succession: Starts with soil (e.g., after forest fire).
Key Species:
- Pioneer Species: First to colonize; e.g., lichens, mosses.
- Keystone Species: Critical to community structure.
- Indicator Species: Reflect ecosystem health.
Impact: Succession affects biomass, species richness, and productivity.

9. Eutrophication

Definition: Nutrient enrichment in water leading to algal blooms.
Process:
- Algae grow rapidly, die, and decompose, depleting oxygen.
- Causes hypoxia and aquatic die-offs.
Anthropogenic Causes: Agricultural runoff, wastewater release.
Oligotrophic Waterways: Low nutrients, high dissolved oxygen, stable algae populations.

10. Thermal Pollution

Definition: Release of heated water into ecosystems.
Effects:
- Causes physiological stress, thermal shock.
- Reduces dissolved oxygen levels.

Key Vocabulary

Key Equations