Understanding Biodiversity

• Biodiversity is a key indicator of an ecosystem's health and stability.
• High biodiversity allows ecosystems to recover quickly from disturbances and resist extinction events.
• Low biodiversity results in slow recovery and increased susceptibility to collapse.

Biodiversity Definition

• Biodiversity measures diversity within living systems at multiple levels.
• These levels include the number of species, genetic diversity within species, and the variety of ecosystems.
• Scale is important, ranging from microscopic diversity to the entire biosphere.
• Earth is the most biologically diverse planet known.
• Biodiversity depends on the type of diversity measured and the scale.

Types of Biodiversity

• Three commonly measured types are species, genetic, and ecological biodiversity.
• High biodiversity is found in areas with high solar energy, large ice-free terrain, variable terrain, climate stability, and intermediate disturbances.
• Equatorial rainforests often have the highest levels of diversity.

Species Biodiversity

• Species biodiversity measures the number of species in an area.
• It can focus on specific organisms depending on the context.
• Can be considered at varying levels of the phylogeny
• Estimates range from 3.5 million to over 100 million species on Earth, but the exact number is unknown.
• Aquatic and terrestrial environments should be considered unless excluded.
• Alpha diversity is the number of species within a defined area.
• Beta diversity compares the species overlap between two ecosystems.
• Gamma diversity is the total number of species across all given ecosystems.

Genetic Biodiversity

• It considers the diversity of genomes within an ecosystem.
• On a small scale, it can involve nucleotide diversity within a population.
• Low genetic diversity can lead to inbreeding, increased susceptibility to disease, and population crashes.
• On a large scale, it can involve diversity of genome size between species.

Ecological Biodiversity

• It considers the number of different ecosystems.
• Often measured on a large scale, such as the number of ecosystem types within a continent.
• It can also be measured on small scales like microclimates.

Biodiversity and Ecosystem Stability

• Biodiversity is closely related to ecosystem stability.
• Ecosystems with few species in each niche are more vulnerable.
• High diversity ecosystems have overlapping species within niches, buffering against the failure of a single species.
• A stable ecosystem maintains relatively constant species evenness, density, and population sizes.
• Rainforests are known for their stability due to high species, genetic, and ecological diversity.
• Can still be threatened by: Habitat destruction and overuse of resources undermine stability.