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Transcript
Biodiversity
Biodiversity
• It is an expression of the energy and richness
of an ecosystem.
• Note on the previous map, the ecosystem
with the most biodiversity lie around the
equator, where you find the greatest
concentration of sunlight.
Biodiversity
• Biodiversity is the result of millions of years of
evolution – new species are born as species
adapt to their environment and are modified
over time by natural selection.
– Adaptation leads to, over time, speciation, which
means one species splits into two (becoming
reproductively isolated) or more new species.
• Biodiversity – bio means life and diversity
means variety. Literally it means the
diversity of life.
Speciation
• Allopatric (Geographic) Speciation
– Division of a single population by geographic
barrier, such as a mountain range, layers in a
rainforest, a glacier, or some other physical barrier.
– Habitat destruction and fragmentation are also
barriers.
• Creates islands of habitat that may or may not be large
enough to support a certain species.
Allopatric Speciation
Habitat Fragmentation
Wild Canine Adaptations and
Diversity
And these are just a few
Other Examples
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Oak trees (an unbelievably impress radiation)
Ants
Beetles
Sharks
And innumerable others
Speciation
• Sympatric Speciation
– Is a speciation that occurs without geographic
separation of the individuals that become
members of the new species.
Speciation
• Sympatric Speciation continued
– Con occur via several mechanisms including:
• Polyploidy – It is when the number of chromosomes of
a species suddenly increases due to some
environmental factor (usually 2 or 4). When polyploidy
takes place, the polyploid individuals cannot interbreed
with their nonpolyploid relatives.
• It has occurred in such animals as gold fish, salmon, and
many species of salamanders.
• It is quite common in wheat, ferns, and many flowering
plants (we have made wheat polyploid).
Each Species is Unique
• Every species represents a unique way of
surviving.
– Therefore, each species genes code for
characteristics that are very unique
– We have barely begun to catalog that uniqueness
and the treasures that it holds.
• The negative part is the minimum rate of
extinction is 3 species per hour.
Biodiversity Hotspots
• Areas needing immediate conservation due to
their singular biodiversity – and there rapid
pace of destruction.
• Example: Centinela
Centinela – a Case in Point
• In the Andean foothills of Ecuador, there is a
ridge called Centinela.
– It is a symbol of the silent destruction of
biodiversity.
– When the forest on Centinela was cut, many rare
species, only recently discovered by botanists,
were reduced from healthy populations to
extinction.
– Unfortunately, this is too common and dangerous
for us – our world loses its living buffer.
Centinela
• Centinela burning
Good News
• The number of protected areas around the
world has exploded.
– Protected areas nominally cover an area of land
equivalent to China and India.
– That is the good news; however, we always need
to remember the reality (see next slide).
Reality
Some Identified Hotspots
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Usambara Mountain Forest – Tanazania
San Bruno Mountain, California
Oasis of the Dead Sea Depression
Madagascar
Uplands of Western Amazonia
Atlantic coast of Brazil
Tallgrass Prairie of North America
Western Ecuador
Southwestern Australia
Lower Slopes of the Himalayas
Northwestern Borneo
Among others
Assignment
• In groups
• Pick a hotspot
• Tell us:
– where it is.
– What makes it special (biological and ecological
characteristics).
• What are the species, animal and plant, that you find there.
– What is happening to it (why is it threatened).
– Find at least 3 sources (split up the work finding them)