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

• 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

• 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)