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Biodiversity
Chapter 10-1, 10-2
Biodiversity Objectives
1.
2.
3.
4.
Ch. 10-1
11
Describe the diversity of species types on
Earth, relating the differences between
known numbers and estimated numbers
List and describe three levels of biodiversity
Explain four ways in which biodiversity is
important to ecosystems and humans.
Analyze the potential value of a single
species
A World Rich in Biodiversity
Biodiversity – def.
“Biological diversity”
referring to the
number of different
species in a given
area
 Why do we want to
preserve
biodiversity?

◦ Our own survival may
depend on maintaining
biodiversity
Unknown Diversity

Currently, we are aware of about 1.7 million different
species living on Earth
◦ This includes, plants, animals, fungi, bacteria, etc.
◦ Most of these species are insects

Scientists believe that more that 10 million species exists on
Earth
◦ We have not adequately studies all the species on Earth
◦ Unknown species may exist deep in forests, in oceans and even cities
Levels of Diversity
Species diversity – the number of different
species in an area
1.
◦
this is what we think of the most when we think of
biodiversity
Ecosystem diversity – the variety of habitats,
communities and ecological processes within
and between ecosystems
3. Genetic diversity – all the different genes
contain within member of a population
2.
◦
A gene is a small piece of DNA that codes for a
trait
Importance of Biodiversity #1: Species are
Connected to Ecosystems

Keystone species – is a species that is so
critical to the healthy functioning of an
ecosystem, that removing it would cause the
whole ecosystem to collapse
◦ Ex: sea otters control the kelp beds by eating urchins

We may not always know how important a
species is until they are all gone
Keystone Species – The Concept
Importance of Biodiversity #2: Species
and Population Survival
Genetic diversity refers to having wide
variety of traits in a population
 This increases the chance that some
members will survive if an environmental
crisis occurs
 The population may re-grow after an
environmental crisis, but with limited
genetic diversity, more member are likely
to inherit genetic diseases

Importance of Biodiversity #3: Medical,
Industrial, Agricultural Uses
Almost all of our antibiotics
come from chemicals produced
by fungi
 About ¼ of pharmaceutical
drugs are derived from plants
 New chemicals and materials
may be created by all kinds of
species!

◦ We can now make plastic from
plants!

What are some other uses you
can think of?
Importance of Biodiversity #4: Ethics,
Aesthetics, Recreation




So why else should we fight to keep
biodiversity high?
Many believe that all species have a right to
exists regardless of their “importance” to us
Other believe that all species should exists
for religious reasons
Other still, believe we should preserve
biodiversity simply to enjoy it in nature
◦ Ecotourism is a form of tourism that supports
the conservation and development of ecologically
unique areas
Biodiversity At Risk - Objectives
1.
2.
3.
4.
5.
Ch. 10-2
Define and give examples of endangered
and threatened species
Describe several ways that species are
being threatened with extinction globally
Explain which types of threats are having
the largest impact on biodiversity
List areas of the world that have high levels
of biodiversity and many threats to species
Compare the amount of biodiversity in the
US to that of the rest of the world
Current Extinctions


We are in the middle of a mass extinction
This one is different that past mass extinctions
◦ Humans are the Cause!!


Endangered species – is a species that is likely to go
extinct if protective measures are not taken immediately
Threatened species – will become endangered soon if
protective measures are taken. Declining numbers.
How do humans
cause extinctions?
Habitat destruction and fragmentation
1.
◦
Invasive Exotic Species
2.
◦
We are carrying species from one place to another that
do not belong. The new species then outcompete the
native species
Harvesting, Hunting and Poaching
3.
◦
4.
By building homes, using land for agriculture and urban
development, we are stealing habitat from animals
Ex: the dodo bird
Pollution
Areas of Critical Biodiversity


Endemic species – a species native to and
limited to one area but may be beneficial for
a much greater area
Areas of high biodiversity:
1. Tropical Rain Forest – cover less than 7% of
the globe BUT contain more than 50% of the
worlds species
2. Coral Reefs and coastal Ecosystems – the
marine version of tropical rain forests
3. Islands – once formed, islands are colonized
by a small group of species from the main land
that evolve into new distinct species
Biodiversity Hotspots
Biodiversity hotspot – a high-diversity area that is
directly threatened
 Many species have already been lost in these areas
due to human activity
 Most of these are Tropical rain forests, coastal
areas and islands
 A few Hotspots are right here in the US!

◦ We have so many different types of ecosystems with
unusual characteristics, we must take care to preserve
every one
◦ Threats to our hotspots come from :
 Agriculture, housing, dam construction, overuse of water,
destructive recreation and mining…all because of population
growth!
US Biodiversity Hotspots