Biodiversity ReviewFall 2010

Definition of Biodiversity

• Sum total of genetic variability within a given ecosystem or globally

Why has diversity remained constant

•The amount of land mass has not significantly changed

•Therefore the number of ecosystems and consequently niches to be filled has remained relatively constant

Causes of decreasing Biodiversity

• Habitat Destruction

• Habitat Alteration (loss of niches)

• Habitat Fragmentation (geographic isolation)

• Genetic dilution (or increase in homozygosity) through the mixing of genetically distinct populations

• Over exploitation of species

• Invasive species

Can we harvest energy from the ocean?

• Open oceans are relatively unproductive:• Resources available are not concentrated

and therefore are difficult to harvest• Light penetration (or lack thereof) limits

productivity to only the top layer• Lack of nutrient availability limits

productivity• When organisms die, most nutrients are

to the deep ocean

Endemic Species

• Definition: Endemics are organisms that are highly specialized for a very specific and localized environment. Endemics typically have low vagility and very narrow range

• Why are endemic species at greater risk for extinction?• Due to low vagility, and narrow habitat range,

any change to habitat will either cause species to be lost or reduce to the point of genetic extinction.

• No other populations are available to draw upon and entire species becomes extinct

Value of Biodiversity

• True Value of Biodiversity• True value of biodiversity is intrinsic. It is the

sum total of what it means to each person

• Problems with assigning value• Ecological systems are so complex that true

value of one species and the cumulative affect of its and other removal cannot be known for certain

• Many of these organisms are not even indentified yet or hold no value to us because of what they are

Problems with Conserving Natural Habitats

• Cost of land

• Public lands are forced into varied intensive uses

• Political institutions favor development for tax base

• Laws are typically designed to encourage development

• Lack of public voice / activism

• Much urban & suburban lands are privately owned

• Greed of society