Transcript Silence of the Frogs

Silence of the Frogs
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An Introduction to Ecology
What is an Ecosystem?
Ecosystem
 A term
used to describe the relationships
between the many species living in a
particular environment and between the
living (biotic) and non-living (abiotic)
components of this environment.
Frogs (as tadpoles and adults)
occupy two different ECOSYSTEMS
Eggs and Tadpoles
 Live in ponds
(aquatic
ecosystems)
Adult Frogs
 Live in forests and
grasslands
(terrestrial
ecosystems)
Model of an Ecosystem
ECOSYSTEM
BIOTIC FACTORS
ABIOTIC FACTORS
A factor in an ecosystem
created by the presence
and roles of other living
things
Non-living agents in an
ecosystem
e.g. number of frogs,
amount of algae, etc.
e.g. water temperature,
amount of light reaching
pond floor, etc.
Each part of
the ecosystem
is affected by
other parts!
What is a Food Chain?
Consumer
Consumer
Consumer
Consumer
Producer
Food Chain:
 A step by step linear sequence
linking organisms that feed on
each other.

Starts with a food source such
as plants (producers) and
continues with animals and
other living things that feed on
plants and on each other
(consumers).

Producers can make
their own food by
taking energy from
the Sun.

Consumers are
unable to create their
own food, therefore
they get energy by
eating producers
(plants) and/or other
consumers (animals).
Frogs (as tadpoles and adults)
occupy two different FOOD CHAINS
Adult frogs are carnivores
(feed on other animals)
e.g. they eat insects
Predatory birds (herons) prey
on them
(1) ADULT FROG – FOOD CHAIN
Grass
Insects
Adult Frog
Heron
Tadpoles are herbivores (feed on
plants). They eat living algae
and dead algae (an example of
detritus – waste from dead plants
and animals)
Larger insects eat tadpoles
(2) TADPOLE – FOOD CHAIN
Algae (living)
or Dead Algae
Tadpole
Insects
Fish
Why should we care that frogs
are dying?
Because frogs and tadpoles are part of two different
ecosystems and two different food chains, their decline
affects many species, including us!
 A decline in the frogs results in an increase in the
number of insects (e.g. mosquitoes). The more
mosquitoes, the more malaria and hence, human death.
This has already occurred in Bangladesh.
 A decline in the reproductive ability of frogs (e.g. from
pesticides) leads to a decrease in number of tadpoles in
the next generation. This increases the amount of algae
(dead and living), thus increasing detritus above normal
levels.
 A decline in the frogs results in a decrease in the number
of species that eat frogs (e.g. snakes and herons)
Why are Frogs Dying?




Loss of habitat (home)
Poor Air and water quality
Increasing ultraviolet radiation
Climate change
Chytrid Fungus
Decreased
resistance
to disease
Increased
stress on
frogs’
immune
systems
1. Loss of Habitat



We are destroying the
water with pollution (e.g.
pesticides, prescription
drugs etc.)
We are cutting down
forests
We are building highways
and cities between the
two ecosystems,
increasing exposure to
predators
2. Poor Air and Water Quality




Frogs have thin, sensitive skin.
Frogs breathe through their skin and by their lungs.
Acid rain and pesticides can therefore go through
their skin easily.
This affects their ability to reproduce
3. Ultraviolet Radiation



Their thin skin is also
susceptible to UV
radiation.
The damage to the
ozone layer (protective
layer of atmosphere
surrounding the Earth)
caused by pollution
increases the amount
of UV waves that reach
the surface of the
Earth.
This causes cell
damage in both frogs
and humans.
4. Climate Change
 Human
activities are causing changes in
the climate.
 Increase use of fossil fuels (coal, oil, gas)
 Increased global temperatures means less
water available.
To Do
 Fill
in missing definitions and examples
from Sections 1.1 and 1.5 from your text.
 Complete “You and Food Chains” Activity.
Pictures from:
 http://picture-book.com/node/7029
 http://www.seppo.net/e/amphibian-ark-an-
international-frog-rescue-effort
 www.edupic.net/sci_gr.htm
 http://allaboutfrogs.org/info/doctor/sicky.gif