Extinction occurs when the last existing member of a given species diesIn other words…there aren’t any more left!

Genetics and DemographicsSmall populations = increased riskMutations

Causes a flux in natural selectionBeneficial genetic traits are overruled

Loss of Genetic DiversityShallow gene pools promote massive inbreeding

Habitat DegradationOne of the most influentialHas many causesSome due to humansSome due to other factors

ToxicityKills off species directly through food/waterIndirectly via sterilizationCan occur in short spans (a single generation)Can occur over several generations

Increasing toxicityIncreasing competition for habitat resources

Destruction of Habitat“Save the Rainforests!”Elimination of living spaceChange in habitat

Rainforest to pasture landsLeads to diminishing resources

Increases competitionCan be caused by natural processes

Volcanoes, floods, drought, etc…

PredationCompetitionDisease

CoextinctionMass ExtinctionPlanned Extinction

Introduction of predatorsInvasive alien speciesTransported by humans

Cattle, rats, zebra muscles, etc…Sometimes on purpose, sometimes not

Can eat other speciesEat food sourcesIntroduce diseases

The loss of one species leads to the loss of another

Chain of extinctionCan be caused by small impacts in the

beginningA predator looses its food sourceAffected by interconnectedness in nature

Aka: an extinction eventA sharp decrease in the number of species on

Earth in a short period of timeCoincides with a sharp drop in speciation

The process by which new biological species arise

There have been at least 5Last one was 65M years ago

Nearly 2/3rds (or more) of all animal species that ever existed on the planet are now gone.

With contemporary extinction being attributed to HUMAN activity.

Numerous factors go into the extinction of a specific species.

Though all point the finger to climate change.

Began about three-million years ago (Continental Glaciations).

Hypotheses for initial extinction:Sea level depletion vs. Temperature decrease

Though these hypotheses aren’t mutually exclusive, they may have conspired together.

1. Cretaceous-Tertiary Extinction (65). 2. End Triassic Extinction (200). 3. Permian Triassic Extinction (250).4. Late Devonian Extinction (364). 5. Ordovician-Silurian Extinction (440).

(#= millions of years ago)

Human controlledThought of to help humansDeadly viruses

SmallpoxExtinct in the wild

PolioNear extinct (only in small parts of the world)

www.johnstonsarchive.net/spaceart/cylmaps.html

Causes complete devastationFlattening and crater at

or around impact site-hundreds of miles wide

Reverberations felt around the world

www.iit.edu/~ipro313s/home.html

Kills acid intolerant species

Can wipe out entire species

Frog with fungus disease

Killing frogs and other amphibians

Natural factors usually occur at a slower rate and therefore cause a low extinction rate. Human activities occur at a faster rate and cause higher extinction rates. Human activities are mostly responsible for the present extinction rates.

http://www.gov.mb.ca/conservation/sustain/extinct.pdf

Human Causes of Extinction

Top Human Causes of Extinction:

Increased human population

Destruction/Fragmentation of habitat

Pollution

Climate change/Global warming

Based on these, and other studies done by The international Union for Conservation of Nature and Natural Resources (IUCN), human induced extinctions are not necessarily a new phenomena. However, extinction by humans today is becoming much more rapid.

The rapid loss of species today is estimated by some experts to be between 100 and 1,000 times higher than the natural extinction rate, while others estimate rates as high as 1,000-11,000 times higher.

Habitat Degradation

Habitat loss and degradation affect 86% of all threatened birds, 86% of mammals and 88% of threatened amphibians

Biodiversity is the variation of taxonomic life forms for a given biome or ecosystem

Boosts Ecosystem productivityMeasure of the health of a biological

system

Food and drinkMedicinesIndustrial materialsEcological servicesLeisurely, cultural, and aesthetic values

PollutionLoss of tropical forestSpread of urban areasWarfareLarge dam

constructionRoad buildingTourismLoss of traditional

lifestyles

Loss of foodDecrease in biomassCollapse of food webLoss of keystone speciesReduction of ecosystem

efficiency and community productivity

Loss of medicinal supplies

Increased vulnerability of species to disease and predation

Monoculture of crops lets the yield become susceptible to pests or viruses 75% of crop varieties are extinct Due to the spread of modern agriculture

Cover 13% of EarthHome to 50% of all known plant and

animal speciesFAO reports 15.4 million hectares are

destroyed annually