biodiversity lecture

Species Count:

• Mammals: 5,500 species

• Ferns: 10,560 species

• Agaric fungi: 21,000 species

• Ray-finned fishes: 32,500 species

• Insects: 1,000,000+ species

Biodiversity Measurement:

• Species Diversity: Combination of species richness (number of different species) and species evenness (how evenly distributed species are)

Ecological Comparisons:

• Tall grass prairies typically have higher biodiversity than agricultural fields (e.g., Kansas wheat fields) due to more diverse plant and insect life

• Coral reefs vs. seagrass beds show significant differences in species richness

Biodiversity Hotspots:

• Defined as areas with at least 1,500 endemic plant species and 70% habitat loss; focus on conservation efforts

• Example: California Floristic Province has ~2,125 endemic species with around 75% habitat loss

Drivers of Biodiversity:

• Geologic history influences modern biodiversity (e.g., continental drift, Pangaea)

• Changes in sea levels can create or isolate land connections for species distribution

• Abiotic factors, such as precipitation and solar radiation, significantly impact species diversity

Rain Shadow Effect:

• Moisture-laden air rises over mountains, cools, and precipitates on the windward side, creating dry conditions on the leeward side

• Example: Northern India and the Himalayas show vegetation differences based on this effect

Estimation of Biodiversity:

• Actual biodiversity is often estimated through sampling due to practical limitations

• Mapping species richness over geographic areas reveals patterns influenced by ecological and historical factors.