Biodiversity & Extinction
Biodiversity – the diversity of species in a given area
Why Do We Need Organisms?
Ecosystem Services – functions that organisms within ecosystems provide
What services do healthy ecosystems provide?
EstuariesNatural water purification system
Newport Back Bay
Taken in 1981
Bolsa Chica Wetlands
Why Do We Need Organisms? FOOD!
1/3 of human food crops pollinated by bees
Honeybees pollinate $10 billion worth of food crops annually in the U.S.
Why Do We Need Organisms? Bumble bees & other insects provide $57 billion in pollination services as well as other free labor in the U.S. alone
Without insects as a food source, N. American fisheries would collapse because most freshwater species subsist on insects. This means that the nearly $28-billion fishing industry relies on insects at its base.
Why Do We Need Organisms?
Why are predators important?
Organisms keep other populations in check!
Why Do We Need Organisms?Genetic Diversity
What is more likely to happen if populations have low genetic diversity?
Ex. wheat, corn
Why Do We Need Organisms?Medicinal & Industrial Uses
Marine organisms, plants, insects
25 % of all prescription drugs contain substances derived from plants.
Biologists believe 90% of all insects have not yet been identified.
Why Do We Need Organisms?Medicinal & Industrial Uses
Marine organisms, plants, insects
Ex. Madagascar
Has lost 80% of forests & 50% of native species
Who knows which of the species disappearing could provide new sources of food or medicine?
Why Do We Need Organisms?
Why Do We Need Organisms?
Aesthetics & Ethics
Why Do We Need Organisms?
Many believe that ecosystems with greater biodiversity are better able to provide services.
ExtinctionWhen last individual member of a species dies & leads to complete loss of the species
Natural process?
Irreversible?
Extinction
1.Background Extinction – continuous, low level extinction
2.Mass Extinction – numerous species disappeared during a short period of geological time
Extinction
1. Background Extinction – continuous, low level extinction
2. Mass Extinction – numerous species disappeared during a short period of geological time
3. Ecologically Extinct – species exists in such low numbers that it is no longer able to perform its role in the ecosystem
Watch “The Sixth Extinction” to learn more about our current mass extinction.
What Causes Species Loss?
Quick Changes! Ex. climate change, catastrophes, human impacts
For every 2000 species that have ever lived, 1999 of them are extinct today
Current extinction rate = 50 - 100 times the natural rate of extinctions
Causes Of Species Loss (Quick Changes)What activity is affecting the greatest number of species?
Causes Of Species Loss (Quick Changes)
Habitat LossGreatest threat to biodiversity!
What activity causes the greatest habitat loss?Agricultural lands currently occupy 35% of the earth’s land
Habitat LossGreatest threat to biodiversity!
Every year, humans destroy an area of tropical rain forest equal to the size of West Virginia
Habitat Fragmentation –when habitats are broken up into areas that are too small to effectively support certain species
Habitat Loss
Causes Of Species Loss (Quick Changes)
Exotic Species –foreign species in an ecosystem in which it did not evolve in
How Do Exotic Species Become Introduced?
How Do Exotic Species Become Introduced?
How Do Exotic Species Become Introduced?
Northern Snakehead
Zebra Mussel
Nile Perch
Caulerpa taxifolia
U.S. Exotic SpeciesHow many species have been introduced into the U.S.?
At least 50,000!
How much has it cost us?
$130 billion!
How many species are endangered because of these species?
30 % of E.S. listings are due in part to exotics
Why are exotic species so harmful?Are they Specialists or Generalists?
Causes Of Species Loss
Over-exploitation – purposefully taking species out of the system (for food, to eradicate ‘nuisance’ species, over-hunting, poaching)
Read the article “Counting the Last Fish”
Check out this website http://www.seafoodwatch.org/to help you make better seafood choices for a healthy ocean. Get the Seafood Watch App!