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

Genetics and Demographics Small populations = increased risk Mutations Causes a flux in natural selection Beneficial genetic traits are overruled Loss of Genetic Diversity Shallow gene pools promote massive inbreeding

Habitat Degradation One of the most influential Has many causes Some due to humans Some due to other factors

Toxicity Kills off species directly through food/water Indirectly via sterilization Can occur in short spans (a single generation) Can occur over several generations Increasing toxicity Increasing competition for habitat resources

Destruction of Habitat “Save the Rainforests!” Elimination of living space Change in habitat Rainforest to pasture lands Leads to diminishing resources Increases competition Can be caused by natural processes Volcanoes, floods, drought, etc…

Predation Competition Disease Coextinction Mass Extinction Planned Extinction

Introduction of predators Invasive alien species Transported by humans Cattle, rats, zebra muscles, etc… Sometimes on purpose, sometimes not Can eat other species Eat food sources Introduce diseases

The loss of one species leads to the loss of another Chain of extinction Can be caused by small impacts in the beginning A predator looses its food source Affected by interconnectedness in nature

Aka: an extinction event A sharp decrease in the number of species on Earth in a short period of time Coincides with a sharp drop in speciation The process by which new biological species arise There have been at least 5 Last 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 controlled Thought of to help humans Deadly viruses Smallpox Extinct in the wild Polio Near extinct (only in small parts of the world)

Causes complete devastation Flattening and crater at or around impact site-hundreds of miles wide Reverberations felt around the world

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.

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 productivity Measure of the health of a biological system

Food and drink Medicines Industrial materials Ecological services Leisurely, cultural, and aesthetic values

Pollution Loss of tropical forest Spread of urban areas Warfare Large dam construction Road building Tourism Loss of traditional lifestyles

Loss of food Decrease in biomass Collapse of food web Loss of keystone species Reduction 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 Earth Home to 50% of all known plant and animal species FAO reports 15.4 million hectares are destroyed annually