Grade 9 Science K-12

1. Causes of Species
Extinction
Biodiversity and Evolution
Prepared by:
Sir Archie S. Pagaura

2. Definition of terms:
 Biodiversity or Biological Diversity
 sum of all the different species of animals, plants,
fungi, and microbial organisms living on Earth,
and the variety of habitats in which they live.
 Extinction
 the end of existence of a group of organism, caused
by their inability to adapt to changing environmental
conditions.
 Species
 basic concepts in the classification of organism.
 In simple term, a single species is a distinct kind
of organism with a characteristic, shape, size,
behavior, and habitat that remains constant from
year to year.

3.  An ecosystem
 is a community of living organisms in conjunction
with the nonliving components of their
environment, interacting as a system. These
biotic and abiotic components are regarded as
linked together through nutrient cycles and
energy flows.

4. Classification of Organism

5. Causes of Species Extinction
 Taking Animals for Profit
 Hunting and Trapping
 Overharvesting
 Destruction of Habitat
 Pollution

6. Population
 is a group of living things within a certain area that
are all of the same species
 Several Different Populations may be found in the
community:
example: A Jungle Community - has a greater
amount of biological diversity than a cornfield.
Some Populations may be found in jungle
community
can be very large
in number Have fewer
members
1. Population of
Ants
2. Population of
Fungi
3. Population of
Ferns
1. Population of
Tigers
2. Population of
Snakes

7. Communities
 Communities with many different species (a high
index of diversity) will be able to withstand
environmental changes better than communities
with only few species (a low index of diversity)
Vacant lots
would have low
I.D, since there
are fewer species distribution. Grass lawn also
would have low I.D, the Tree would also have low
I.D. Communities with many different species
have a high I.D
Index of Diversity = Number of species x number of
runs
Number of Trees

8. Measuring Population Density
 Population Density - is a measurement of
population per unit area or unit volume; It is
frequently applied to living organisms, and
particularly to humans.
 Population can be of the same size, but they may
have different densities.
Differences in population density may be
attributed to many factors:
1. When new members move in or out in an
ecosystem
Population Density = number of
individuals
Size of Area

9. Example:
 Suppose 60 ants live in a 4 sq m plot of grass.
What would be the population density of ants?
What would the population density be if 100 ants
live in 4 sq m plot of grass?
Solution 1 :
Solution 2 :
Population Density = number of
individuals
Size of Area
Population Density
=
= 15 ants/sq m
100
ants
4 sq m
60ants
4 sq
m
Population Density
=
= 25 ants/sq m

10. LIMITING FACTORS:
 Anything that limits the size of a population like
certain environmental conditions are called LIMITING
FACTORS
Limiting Factors keep population from:
 Increasing in size and
 Help balance an ecosystem
Examples of Limiting Factors:
1. Availability of food 4. Light Temperature
2. Water and 5. Soil Nutrients
3. Living conditions

11. Carrying Capacity
 The maximum population size an environment can
support is called CARRYING CAPACITY
 If the population size rises above the carrying
capacity, organism die because they cannot meet
all their needs.

12. Endangered but not Extinct
 When species, population becomes so low that
only few remain, the species is considered
ENDANGERED will possibly extinct.
 In the Philippines, some Terrestrial species like:
1. Tamaraw in Mondoro

13. 2. Mouse Deer in Palawan

14. 3. Philippine Deer

15. 4. Monkey-eating eagle, and some

17. Aquatic species like;
1. Dugong(manatee) found in Negros,
Batangas, and Leyte are in danger of
EXTINCTION

18. Dugong(Mantee)

19. Threatened
 There`s a particular species that declines so fast that it
becomes endangered and it is said to be threatened.
 Ex. A study conducted by field biologists on population
size and distribution of Philippine fauna, they reported that
as of 1991,
89 species of birds
44 species of mammals &
8 species of reptiles
These include also the Philippine Eagle or Monkey-
Are internationally
threatened

21. EXTINCTION
 Is the disappearance of a species when the last of its
members die.
Cause:
 Changes to habitats, due to increasing
population
# Natural vegetation in the area has been
cleared.
# Concrete structures and other
organisms gradually take
over the area.
# Some areas were destroyed by natural

22. Local and Global Issues that
contributed to Species Extinction
 Deforestation
- one of the country`s environmental problems is
the rapid rate at which trees are cut down.
- in the Philippines, the major causes of
deforestation are:
@ Kainging Farming
@ Illegal Logging
@ Conversion of agricultural lands to
housing
projects
@ Forest Fires

23.  Kaingin Farming

24. As a consequence of cutting down
trees, the following effects are:
 Soil erosion
 Floods
 Decrease in wildlife resources that will eventually
lead to extinction
 Wildlife Depletion, deforestation is one of the major
causes of the disappearance of wildlife species.

25. Dugong (manatee)
Philippine Eagle
Tarsier

26. Local and Global Issues that
contributed to Species Extinction
 Water Pollution
a major problem in lakes, rivers and
ponds is EUTROPHICATION – is the process
by which a body of water becomes enriched in
dissolved nutrients (such as phosphates) that
stimulate the growth of aquatic plant, life
usually resulting in the depletion of dissolved
oxygen.
- it happens when the concentration
of organic nutrients that comes from domestic
garbage and thrown in bodies of water,
increases rapidly.

27. Local and Global Issues that
contributed to Species Extinction
 Effect on Water Pollution:
@ mass death of fish (fish kill)
- usually happens when there`s an increase in
concentration of organic nutrients in bodies of water –
this condition causes algal bloom and growth of
aquatic plants. When the algae die, they sink to the
bottom and the process of decomposition proceeds. This
process uses up oxygen and as a result, aquatic
animals die due to lack of oxygen.
PCB (polychlorinated biphenyl)
- one class of dangerous chemicals present in
water,
- toxic waste produced in the making of paints,
inks and electrical insulators

28. EUTROPHICATION

29. Local and Global Issues that
contributed to Species Extinction
 PCB(polychlorinated biphenyl)
-through the process of biological magnification,
the PCB becomes concentrated in the body
tissues of water organism.
Biological Magnification is the build up of
pollutants in organism at higher trophic levels in
the food chain
• Other Pollutants found in water are heavy
metals:
lead, mercury, and cadmium – these
metals are come from factories that dump

30. Local and Global Issues that
contributed to Species Extinction
 Air Pollution
cars are the one of the major contributors to air
pollution.
Pollutants can enter the air as gases, liquids or
solids. Cars burn fuel and produce harmful gases:
@ carbon dioxide
@ nitrogen oxides &
@ hydrocarbons

31. Harmful Pollutants found in Air
In Metro Manila where a
great volume of cars
travel each day, smog
blankets the area,
nitrogen oxides and
hydrocarbons from car
exhaust react with water
vapour or dust particles
and produce new
irritating chemicals

32. Greenhouse Effect & Global Warming
 Greenhouse Effect – is the natural process of
warming the Earth.
- is a process of trapping of heat by gases in
the Earth`s atmosphere. Carbon dioxide acts like a
blanket over the Earth, holding in the heat that would
otherwise radiate back into space.
- but as carbon dioxide in the atmosphere
increases, greenhouse effect also intensifies this will
lead to global warming.
Global Warming - is an increase in the earth`s
temperature from the rapid buildup of CO2 and other

33. Local and Global Issues that
contributed to Species Extinction
 Destruction of Coastal Resources
Coral reefs and Coastal mangrove forest in the
Philippines serve as breeding grounds and nurseries
of marine fishes.
But due to man`s activities, coastal areas are getting
destroyed these activities include:
@ deforestation, agricultural activities, and mining
activities
@ dynamite fishing and muro-ami
@ coastal areas` conversion to beach resorts, and
residential

34. Destruction of Coral
Reefs
Dynamite Fishing
Damaged mangrove
areas

35. Local and Global Issues that
contributed to Species Extinction
 Acid Precipitation - commonly known as acid rain.
Rainwater is normally acidic, because carbon
dioxide is normally present. Other pollutants, mostly
sulfur and nitrogen oxides, make rainwater even
more acidic, with pH of 5.6 or lower
Acid Rain, can be harmful to living things.
@ It causes yellowing of leaves of trees and cause
leaves to fall.
@ Nutrients can be lost from the soil.

36. Acid Rain

37. Human Activities and
Overpopulation
have cost the most of the environmental problems
nowadays.
People are beginning to realize that the way they
interact with the environment must change to
ensure the survival of all living things. This is one
of the big challenge to maintain resources
needed for survival while ensuring that they will
still be available in the future. This is a practice
called SUSTAINABLE DEVELOPMENT – Means
that the rate at which society uses renewable
resources does not exceed the rate at which the
resources are generated.

38. THANK YOU!!!!