Transcript food chains - IES Galileo Galilei

Index
Definition of food chain.
 Endangered species.
 Protection measures.

Every organism needs to obtain energy in order to live. For example, plants
get energy from the sun, some animals eat plants, and some animals eat
other animals.
A food chain is the sequence of who eats whom in a biological community
(an ecosystem) to obtain nutrition. A food chain starts with the primary
energy source, usually the sun or boiling-hot deep sea vents. The next link in
the chain is an organism that makes its own food from the primary energy
source -- an example is photosynthetic plants that make their own food from
sunlight (using a process called photosynthesis) and chemosynthetic bacteria
that make their food energy from chemicals in hydrothermal vents. These
are called autotrophs or primary producers.
Next come organisms that eat the autotrophs; these organisms are
calledherbivores or primary consumers -- an example is a rabbit that eats
grass.
The next link in the chain is animals that eat herbivores - these are called
secondary consumers -- an example is a snake that eat rabbits.
In turn, these animals are eaten by larger predators -- an example is an
owl that eats snakes.
The tertiary consumers are are eaten by quaternary consumers -- an
example is a hawk that eats owls. Each food chain end with a top predator,
and animal with no natural enemies (like an alligator, hawk, or polar bear).
The arrows in a food chain show the flow of energy, from the sun or
hydrothermal vent to a top predator. As the energy flows from organism to
organism, energy is lost at each step. A network of many food chains is
called a food web.
Trophic
Levels:
The trophic level of an organism is the position it holds in a food chain.
Primary producers (organisms that make their own food from
sunlight and/or chemical energy from deep sea vents) are the
base of every food chain - these organisms are called autotrophs.
Primary consumers are animals that eat primary producers; they
are also called herbivores (plant-eaters).
Secondary consumers eat primary consumers. They
are carnivores (meat-eaters) and omnivores (animals that eat
both animals and plants).
Tertiary consumers eat secondary consumers.
Quaternary consumers eat tertiary consumers.
Food chains "end" with top predators, animals that have little or
no natural enemies.
When any organism dies, it is eventually eaten by detrivores (like
vultures, worms and crabs) and broken down
by decomposers(mostly bacteria and fungi), and the exchange of
energy continues.
What happens if a link is
broken?
When
a link in a chain breaks, the entire chain is
broken. A food chain works the same way. When
one animal changes, all the other animals are
affected as well.
Why are bees disappearing?

Kids everywhere may revel
in the fact that bees are no
longer stinging them as
frequently on playgrounds
and in backyards, but the
decline in honeybee
populations in Spain and
elsewhere signals a major
environmental imbalance
that could have farreaching implications for
our agricultural food
supply.
Possible causes:
Chemicals.
Genetically modified crops.

Radiation.

Endangered animals
A species, either a plant or an animal, is
considered endangered when all its living
members are in danger of disappearing. This
could be because of direct predation or as
a consequence or the disappearance of a
resource which their lives depend on, either
by human action, changes in the
environment, acts of nature, like natural
disasters, or because of gradual changes in
the climate.
Endangered species in Spain
Iberian lynx
The Iberian lynx is a rabbit specialist with a low
ability to adapt its diet. A sharp drop in the
population of its main food source, a result of two
diseases, contributed to the feline's decline. The lynx
was also affected by the loss of scrubland, its main
habitat, to human development, including changes in
land use and the construction of roads and
dams.Highways split up their habitat and they are
threatened by car hits. In the past decade more than
10 animals have died under the wheels of a car. A
very high number if we realize we’re talking almost
5% of the total population.
Although it has been legally protected against
hunting since the early 1970s, they are still the
victims of guns, traps and snares, particularly those
set for other animals.
Cantabrian brown bear
The Spanish brown bear or
Cantabrian brown bear is among
the animals most at risk of
extinction in Spain. In the Asturias
region in Spain, there were only an
estimated 80 brown bears left in
2011. Human pressure has caused a
destruction of brown bear habitat
and hunting has caused a reduction
in their numbers. However, recent
protection measures are starting to
prove fruitful. Now in the North of
Spain there are about 200 bears,
triple than two decades ago.
•
The Drago is one of
many endangered
trees. It is considered
as a symbol of the
Canary Islands.
Spanish fir

Spanish firs have high
scenic and scientific
value. Despite the
protection afforded there
are still many threats on
them. Arson, urbanization,
erosion, lack of
regeneration due to
overgrazing, excessive
uncontrolled visitors, etc.
The greatest threat in the
Iberian Peninsula is fire.
Pests and diseases can
also affect these trees.
What must we do?
In Spain there are many animals that are endangered and
we must do everything possible to sow the seeds of their
future, through legislation, recovery programs and other
measures.
Why must we face all these measures? Simply because it’s
our part, as we have altered their habitat, destroying,
polluting, making it fields, recreational areas and how are
you, a hundred thousand things, we must hold what we are
truly guilty. This responsibility calls for thinking that about 40%
of Spain vertebrates are endangered and 7% are close to
extinction.
WORLD WILDLIFE FUND
World Wildlife Fund has been working
for the conservation of the Iberian lynx
for over 10 years, fighting for proper
protection and conservation of vital
habitat. Specific action includes:
Support for the captive breeding
programme.
Sponsorship of the Large Carnivore
Initiative for Europe (LCIE), leading to
the development of an action plan for the
Iberian lynx.
Lobbying for all lynx habitat to be
covered by the EU's Natura 2000
Programme.
Protecting Spain's Coto Doñana
Wetlands.
National parks
Natural parks
The end

Thanks for your attention.