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!