Chapter 47 - Biodiversity

Biodiversity

Measurement of the number/abundance of species present in a given area (Biosphere, biome, ecosystem)

It is not evenly distributed throughout the Earth (different biomes and their ability to support life)

Three types of biodiversity

Species biodiversity

The number of species, along with their abundance, in a given area (species are interconnected, even losing one has an impact)

Genetic Biodiversity

Genetic variation present in the individuals in a population or species (losing genetic variation results in the inability to evolve due to natural selection)

Ecosystem Biodiversity

Number of ecosystems in a given area (Ecosystem extinction means loss of populations, genetic diversity of species, and of production and services of the ecosystem)

Benefits of biomes being near the equator

Greater biodiversity than biomes in the far North/South

Receives more annual sunlight

Have consistent annual temperatures

Have large annual precipitation

Have been around longer

Increased heterogeneity (diverse in character)

High rate of endism (only in specific geographic area) (“hotspots” of biodiversity)

What are the five major extinction events throughout geologic time

In Order:

Ordovician-Silurian (Life exclusively in the ocean)

Devonian (only affected marine species)

Permian (the largest extinction event, which helped reptiles dominate)

Triassic-Jurassic (Occurred right before Pangea broke off)

Cretaceous (dinosaurs)

Anthropogenic (Human-caused) Extinctions: Holocene

Not a mass extinction yet.

Multiple species lost due to humans, such as the hunting to the extinction of dodo birds.

Coincides with the expansion of European colonies

The extinction rate is increasing exponentially