This document discusses the natural causes of extinction and characteristics of species vulnerable to extinction. It identifies seven natural causes: 1) genetics and demographics, 2) uncontrolled predation, 3) coextinction, 4) mass extinction, 5) climatic heating and cooling, 6) change in sea levels, and 7) acid rain. It also lists six characteristics of species vulnerable to extinction, including large species with low reproduction, species with high economic value, species at the end of long food chains, species restricted to local habitats, highly specialized species, and migratory species.

1. BY
SIR OSCAR MARTINEZ GUZMAN, JR.
SCIENCE TEACHER
CALACAACADEMY INC.
Admana St. Pob 2. Calaca, Batangas Philippines
Earth and Life Sciences/Earth Science
oscarjrg@yahoo.com
www.facebook.com/JrMartinez
+63935-8482-891
+63908-544-0806

2. Diverse forms of organisms become
extinct due to the following natural
causes.
1. Genetics and demographics
If a population becomes small for
any reason, the members of the
population become more inbred,
further reducing population size.

3. A smaller population also loses genetic
diversity because of inbreeding and suffers
reduction in the ability to adapt to the
changing environment.
2. Uncontrolled predation.
Animals becomes extinct when exotic
or non-native species are introduce to a
new habitat. If they have no natural
enemies in their new habitat, then their
prey eventually becomes extinct.

6. 3. Coextinction
The loss of one species leads to
the loss of another. It becomes a
chain of extinction. For example,
when a prey loses its food source, its
population decreases. Therefore, its
predators have lesser food to eat;
hence, the population of predators
also decreases.

8. 4. Mass extinction
This refers to the sharp
decreases in the number of
species on Earth in a short period
of time. These are caused by
asteroids impacts, climate
change, and other catastrophic
events on Earth.

10. 5. Climatic heating and cooling
This natural event has a very
significant effect of extinction.
Many species are not used to
severe weather conditions and
long seasons or a changing
chemical makeup of their
surroundings.

12. 6. Change in sea levels.
The spreading of the ocean floor
causes the rising of the sea levels.
Therefore, a significant amount of water
can displace onto the land that is already
occupied. Gases from volcanic activities
can also be absorbed by the water, thus
changing its chemical composition.
Eventually, water may become unsuitable
for some forms of life.

14. 7. Acid rain
This increases the acidity of the
soil which affects plants and lakes to
possibly lethal levels. Aside from the
natural causes of acid rain, human
activities have led to the presence of
certain chemicals in the atmosphere
that contributes to the formation of
the acid rain.

16. Characteristics of species vulnerable to
extinction
1. Large species with low reproductive
potential such as whales, rhinos,
great apes, condors, and whooping
cranes.
2. Species with high economic vales
such as whales, sea turtles,
elephants, spotted cats, and
rhinoceroses.`

17. 3. Species at the end of long food chains
such as birds of prey, cats, and reptiles.
4. Species restricted to local, insular
habitats such as snail darters and key deer.
5. Highly specialized species such as giant
pandas and black-footed ferrets.
6. Migratory species such as monarch
butterflies, marine mammals, and many
birds.