3.1 and 3.2 Notes

There are three types of diversity:

  • species

  • genetic

  • habitat

Species Diversity: In communities, species diversity is a product of two variable: the richness and evenness of species. Richness refers to the number of species and evenness refers to the relative abundance of each one (think of species being in proportions to each other!!)

Genetic Diversity: Genetic Diversity is the range og genetic material present in a gene pool or population of a species. Typically, genetic diversity wants to be maximized as a high genetic diversity helps prevent disease and illnesses from spreading.

Habitat Diversity: Habitat diversity is the range of different habitats per unit area in a particular ecosystem or biome. Basically just look for as many ecological niches as you possibly can.

Overall high biodiversity generally equated with high ecosystem health. High biodiversity allowes for resilience and stability, genetic diversity to make the population resistant to diseases, and more cycling of nutrients.

Hot spot: A region with a high level of biodiversity that is under threat from human activities. Hot spots contain about 60% of the world’s species so they are crucial for biodiversity. Naming hot spots is important for conservation efforts and legislation.

How does biodiversity arise?

First, through mutations. Mutations are random changes in genetic code. They allow the individual to be better adapted to its environment ocmpared to others. Then, natural selection occurs. Natural selection is the process where organisms better adapted to their environment tend to survive and produce more offspring. The reproduction of the mutated individual results in even more with the mutation that are better suited to the environment with the adaptation. Then, speciation can occur, but only is the species are separated somehow. Speciation is the process by which new, genetically distinct species arise. This results in genetic diversity and overall increased biodiversity of the ecosystem.

Species can be separated through geography, behavior, or time.

Geographic Isolation:

  • Elimination of land bridges —> Bering Strait

  • Continetal drift —> The breakup of Gondwana

  • Plate tectonics