Biodiversity
Objectives:
Define biodiversity
 Explain the impact of various environmental
changes based on the amount of biodiversity in
an ecosystem
 Determine the relationship between the amount
of biodiversity in an ecosystem and the
likelihood of extinction of a species in that
ecosystem

Low or High Biodiversity?
Low or High Biodiversity?
Low or High Biodiversity?
Low or High Biodiversity?
Low or High Biodiversity?
Biodiversity is…

Biodiversity is a measure of how
many different species live in an
ecosystem.
Origins of the term "Biodiversity"
Originally the term was derived from
"biological diversity". The word
BIODIVERSITY originates from the
Greek word BIOS = LIFE and Latin
word DIVERSITAS = VARIETY or
DIFFERENCE. The whole word
BIODIVERSITY generally therefore
means: VARIETY OF LIFE.
Biodiversity
- Biodiversity is a term that
describes how varied living things
are in a specific area.
- Organism are part of
biodiversity may economically and
ecologically valuable.
Value of species.
1. Direct economic Value
2. Indirect economic Value
3. Aesthetic Value
Direct economic Value
-The species is considered to
have direct economic value if their
products are source of food,
medicine, clothing, shelter and
energy.
Indirect economic Value
- A species has an indirect
economic value if there are benefits
produced by the organism without
using them.
Aesthetic Value
- Visual or artistic that provides
enjoyment, like a forested landscape
and calming beauty of a natural
park; or they may be used for
spiritual meditation like the prayer
mountains.
Biodiversity is all the different kinds of
life you'll find in one area—the
variety of animals, plants, fungi,
and even microorganisms like
bacteria that make up our natural
world. Each of these species and
organisms work together in
ecosystems, like an intricate web, to
High vs. Low Biodiversity
Ecosystems with high biodiversity
have many different species of
organisms.
 Ecosystems with low biodiversity
do not have many different
species of organisms.

High Biodiversity
Low Biodiversity
Ecosystem Stability

The higher the biodiversity, the more
stable the ecosystem (stable= stays the
same)
An ecosystem with high biodiversity does
not change easily; it is stable
An ecosystem with low biodiversity is
unstable
One small change could cause many
species to die
Low Biodiversity
Rabbits eat grass. Foxes eat
rabbits
Foxes
Rabbit
Grass
Low Biodiversity
A disturbance hits…
A drought happens and kills all the
grass.
Foxes

Rabbit
Grass
Low Biodiversity
What happens to the
foxes?

How many species do we have left?
0!
BIG change?
Grass
Rabbit
Foxes
Higher Biodiversity
Let’s add a few more
species to our original
ecosystem
Foxes
Lettuce
Rabbit
Chickens
Grass
Higher Biodiversity
A disturbance hits…
A drought happens and kills all the grass.

Foxes
Lettuce
Rabbit
Chickens
Grass
Higher Biodiversity
The food web started with high biodiversity
 High biodiversity = stable ecosystem
 One change didn't`t have a major impact!

Foxes
Lettuce
Rabbit
Chickens
Grass
Example: Low vs. High
Ecosystem 1
Ecosystem 2
Which ecosystem has higher
biodiversity?
Ecosystem 1
Ecosystem 2
Which ecosystem is more stable?
Why?
Ecosystem 1
Ecosystem 2
Which ecosystem would be more
affected by a disease that killed all
the rats?
Ecosystem 1
Ecosystem 2
What might happen to the snakes in Ecosystem
if there are no any of that species of snakes
anywhere else in the world and most of the rats
in the ecosystem die from disease?
Biodiversity and Extinction
Environmental change in an ecosystem with low
biodiversity can even cause extinction of a species
Can occur if there are no organisms of that
species in other ecosystems throughout the world
 Species with specialized diets (low surrounding
biodiversity) and specific habitats are more likely
to become extinct than species with diverse diets
and a wide range of habitats.

Invasive Species



Invasive species are non-native species of organisms
in an ecosystem that reproduce quickly and have few
natural predators
 Native= originally from that ecosystem
 Non-native= originally from somewhere else
Invasive species decrease biodiversity in an ecosystem
by taking over food and space from native species
 Decrease the number of native species
Invasive species are very harmful to ecosystems that
already have low biodiversity
Invasive Species

Examples:
Zebra
mussels
Kudzu plant
Brown tree
snake
Wild hogs

Brown tree snakes are a species of
snakes that were imported to the island
of Guam from South America. Brown
tree snakes eat many different types of
birds and lizards. They reproduce
rapidly and have few natural predators.
What will most likely happen to the
number of native bird and lizard species
on Guam over time?

Does an invasive species
normally increase or
decrease biodiversity in an
ecosystem?
Factors that affects the size
of population
Birth Rate (Natality) – The
number of Births in a
population.
 Death Rate (Mortality) – The
number of organisms that are
dying in a population.

Factors that affects the size
of population
Population Density – The
number of organisms per unit
area.

- Factors that regulates a
population`s growth and is
influenced by population density, is
called density-dependent limiting
factor. If the population density not
directly influence changes in
population, then it is called densityindependent liming factor.
Density-dependent
limiting factor.
- Stop a population from growing
can be such things as natural
disasters. Sunlight, and the activities
of human activities
Density-dependent
limiting factor.
- Natural disaster such as tropical
cyclones, floods, earthquakes and
fire stop a population from
growing no matter how many
organism living in a certain area.
Density-Independent
limiting factor.
- When a population
reaches a certain number of
organisms.
Example:
- When a population
reaches a certain size, there
won`t be enough
resources(Food, shelter,
water) for all of the
organisms.
Logistic Population Growth –
Resources are unlimited.
Exponential Population Growth
– Resources are limited.
Example:
- When a population
reaches a certain size, there
won`t be enough
resources(Food, shelter,
water) for all of the
organisms.
Factors of limiting
Population depends on
Population Density.
Disease and parasites
- Infectious disease and
parasites spread faster in
a densely population
area.
Competition for
Resources – Organism with
better adaptations to obtain
(food) resources will be able
to reproduce more often,
and its population will grow.
Predation – Plenty of prey
are available, predators will
be able to eat sufficiently,
thus have energy to
reproduce much and
increase their numbers.
Emigration – Occurs when, as
a population approaches it
carrying capacity and individual
organism leave and go to a new
area.

Environmental
Problem and
Issues