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BiodiversityBiodiversity
What is Biodiversity?What is Biodiversity?Biological Diversity or BiodiversityBiological Diversity or Biodiversity
““The variety of life in all The variety of life in all its forms, levels and its forms, levels and combinations. Includes combinations. Includes ecosystem diversity, ecosystem diversity, species diversity, and species diversity, and genetic diversity” genetic diversity” (IUCN, UNEP and (IUCN, UNEP and WWF, 1991).WWF, 1991).
BiodiversityBiodiversity• Biodiversity
is currently declining
• Species are going extinct
ExtinctionExtinctionExtinction is a Extinction is a natural processnatural process
~ 99% of all ~ 99% of all species have species have
become extinctbecome extinct
ExtinctionExtinctionNatural ExtinctionNatural Extinction
• Typically occurs at slow paceTypically occurs at slow pace
A few species disappearing A few species disappearing over long time periodsover long time periods
ExtinctionExtinctionNatural ExtinctionNatural Extinction
• though there though there have been have been
rapid, mass rapid, mass extinctionsextinctions
Accelerated ExtinctionAccelerated Extinction
ExtinctionExtinction
• Occurring at a rapid paceOccurring at a rapid pace
Many species are Many species are disappearing every yeardisappearing every year
ExtinctionExtinctionNatural ExtinctionNatural Extinction
• Often old species evolve into Often old species evolve into new species over timenew species over time
ExtinctionExtinctionNatural Natural
ExtinctionExtinction
• Offspring species Offspring species survive and survive and
continue to evolvecontinue to evolve
Accelerated ExtinctionAccelerated ExtinctionExtinctionExtinction
Species are disappearing too Species are disappearing too rapidly to evolve into new speciesrapidly to evolve into new species
No evolutionary or No evolutionary or genetic legacy remainsgenetic legacy remains
We are currently experiencing the We are currently experiencing the greatest extinction event of the greatest extinction event of the last 65 million years – since the last 65 million years – since the disappearance of the dinosaursdisappearance of the dinosaurs
Peter RavenPeter Raven
ExtinctionExtinction
BiodiversityBiodiversityHow many species have How many species have
been identified ?been identified ?
Approximately 1.4 million species Approximately 1.4 million species have been named and describedhave been named and described
VertebratesVertebrates• Mammals 4,000Mammals 4,000
• Birds 9,000Birds 9,000
• Reptiles 6,300Reptiles 6,300
• Amphibians 4,200Amphibians 4,200
• Fish 19,000Fish 19,000
BiodiversityBiodiversityInsects 750,000Insects 750,000
Plants 250,000Plants 250,000Non-insect Non-insect arthropodsarthropods 125,000 125,000
Other species Other species 200,000200,000
How many species have How many species have been thoroughly studied ?been thoroughly studied ?
BiodiversityBiodiversity
Only 1 - 2 %Only 1 - 2 %
We have done little more than name We have done little more than name most of the species that we know aboutmost of the species that we know about
How many species are How many species are currently alive on Earth ?currently alive on Earth ?
BiodiversityBiodiversity
We do not know !We do not know !
How many species are How many species are currently alive on Earth ?currently alive on Earth ?
BiodiversityBiodiversity
In the past, estimates In the past, estimates were 3 –5 million specieswere 3 –5 million species
How many species are How many species are currently alive on Earth ?currently alive on Earth ?
BiodiversityBiodiversity
Recent estimates are more Recent estimates are more than 10 million speciesthan 10 million species
How many species are How many species are currently alive on Earth ?currently alive on Earth ?
BiodiversityBiodiversity
The higher numbers of more recent estimates are due to recognition of vast,
unknown biodiversity in tropical rainforests
How many species are How many species are currently alive on Earth ?currently alive on Earth ?
BiodiversityBiodiversity
Many species will disappear Many species will disappear before we can even identify and before we can even identify and
name themname them
What is the primary cause of What is the primary cause of the current high rates of the current high rates of extinction of species ?extinction of species ?
BiodiversityBiodiversity
Habitat AlterationHabitat Alteration
Habitat AlterationHabitat Alteration• The most significant single factor in The most significant single factor in
extinctionsextinctions
• Habitats are destroyed as human Habitats are destroyed as human societies alter ecosystemssocieties alter ecosystems
Habitat AlterationHabitat Alteration• Rainforest destruction threatens Rainforest destruction threatens
countless speciescountless species
• Human activities have Human activities have significantly altered an significantly altered an
estimated 50-75% of the estimated 50-75% of the ice-free land surface of the ice-free land surface of the
EarthEarth
Habitat AlterationHabitat Alteration
• Will Global Climate Change be the Will Global Climate Change be the greatest habitat alteration of all?greatest habitat alteration of all?
Habitat AlterationHabitat Alteration
According to the IPCC, a According to the IPCC, a warming of 1.5 – 2.5 warming of 1.5 – 2.5 00C would C would
place 20 - 30% of species at place 20 - 30% of species at increased risk of extinctionincreased risk of extinction
Habitat AlterationHabitat Alteration• Will Global Climate Change be the Will Global Climate Change be the
greatest habitat alteration of all?greatest habitat alteration of all?
According to the IPCC, a According to the IPCC, a warming above 3.5 warming above 3.5 00C would place C would place
40 - 70% of species at increased 40 - 70% of species at increased risk of extinctionrisk of extinction
Human Pressures on SpeciesHuman Pressures on Species•Habitat AlterationHabitat Alteration
- most important by far -- most important by far -
• Commercial Hunting and PoachingCommercial Hunting and Poaching• Introduction of Alien SpeciesIntroduction of Alien Species
• Pest and Predator ControlPest and Predator Control
Other pressures include:Other pressures include:
• Commercial hunting and fishing Commercial hunting and fishing have resulted in decline of whales, have resulted in decline of whales,
sea turtles, and other speciessea turtles, and other species
Human Pressures on SpeciesHuman Pressures on Species
• Poaching threatens elephants, Poaching threatens elephants, rhinos and other speciesrhinos and other species
Human Pressures on SpeciesHuman Pressures on Species
• Introduction of alien species and Introduction of alien species and diseases often threatens native speciesdiseases often threatens native species
Human Pressures on SpeciesHuman Pressures on Species
• Efforts to control pests and predators Efforts to control pests and predators can harm species and ecosystemscan harm species and ecosystems
Human Pressures on SpeciesHuman Pressures on Species
Vulnerability of SpeciesVulnerability of SpeciesEcological factors make some species Ecological factors make some species
more vulnerable to extinctionmore vulnerable to extinction• Critical population sizeCritical population size
• Dietary specialistsDietary specialists
• Limited geographic rangeLimited geographic range
• Larger size speciesLarger size species
• Tolerance to human presenceTolerance to human presence
Vulnerability of SpeciesVulnerability of Species
Critical population sizeCritical population size
• Once a population falls to a Once a population falls to a small number, particularly a small number, particularly a
social species, the population may social species, the population may not be able to recovernot be able to recover
Limited geographic rangeLimited geographic range
Vulnerability of SpeciesVulnerability of Species
• Species with a small geographic Species with a small geographic range are more vulnerable to range are more vulnerable to
extinction than are geographically extinction than are geographically widespread specieswidespread species
Dietary specialistsDietary specialists
Vulnerability of SpeciesVulnerability of Species
• Species with highly specialized Species with highly specialized diets are more vulnerable to diets are more vulnerable to extinction than are dietary extinction than are dietary
generalistsgeneralists
Larger size speciesLarger size species
Vulnerability of SpeciesVulnerability of Species
• Larger species more directly Larger species more directly compete with humanscompete with humans
• Larger species tend to have lower Larger species tend to have lower reproductive ratesreproductive rates
Tolerance to human presenceTolerance to human presence
Vulnerability of SpeciesVulnerability of Species
• Some species do not tolerate Some species do not tolerate human presence and will not human presence and will not
inhabit areas where humans are inhabit areas where humans are foundfound
Reasons for ConcernReasons for ConcernBiodiversity is Rapidly Biodiversity is Rapidly
DecliningDeclining
Why should we care and be concerned ?
Reasons for ConcernReasons for Concern
EthicsEthics• We have the power to We have the power to
destroy or save speciesdestroy or save species• It is wrong for us to destroy other species
• It is right for us to save other species
Reasons for ConcernReasons for Concern
AestheticsAesthetics• The diversity of species gives
beauty to our world and the experiences of life
Reasons for ConcernReasons for Concern
EconomicsEconomics• A tremendous portion of our A tremendous portion of our
economy depends on biological specieseconomy depends on biological species
• Species extinctions deny us Species extinctions deny us potential economic opportunitiespotential economic opportunities
Reasons for ConcernReasons for Concern
New MedicinesNew Medicines• Many of our medicines are based Many of our medicines are based
upon biological speciesupon biological species
• Species extinctions deny us Species extinctions deny us potential new medicinespotential new medicines
Reasons for ConcernReasons for Concern
New FoodsNew Foods• All of our foods are based on All of our foods are based on
biological speciesbiological species
• Species extinctions deny us Species extinctions deny us potential new foodspotential new foods
Reasons for ConcernReasons for ConcernEcosystem StabilityEcosystem Stability
• Complex ecosystems with greater Complex ecosystems with greater species diversity are more stable over timespecies diversity are more stable over time
• Species extinctions makes ecosystems Species extinctions makes ecosystems less complex and less stableless complex and less stable
Reasons for ConcernReasons for Concern
Future GenerationsFuture Generations• We must preserve the biological We must preserve the biological wealth of the Earth for the sake of wealth of the Earth for the sake of our children, grandchildren, and our children, grandchildren, and
countless future generationscountless future generations