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CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
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ECOSYSTEMS. HUMAN BEINGS AND ECOSYSTEMS
Compare the photographs.
What living things can you see?
What do you see around them?
In what other places can you find animals?
READ AND STUDY.
1. Ecosystems
An ecosystem consists of all the living things in
a specific environment, and their interaction
with their habitat. Ecosystems can be small,
like a pond, or large, like a rainforest.
The components of an ecosystem are:
Living things: the plants in an ecosystem
are the flora. The animals are the
fauna. There are also fungi, bacteria
and algae.
The environment: it refers to the
surrounding conditions, which affect
living things, such as soil, climate,
water, air and light.
2. Types of ecosystems
There are two types of ecosystems, terrestrial
and aquatic:
Forests, grasslands and deserts are
terrestrial ecosystems.
Many living things live in forests and
grasslands. The abundant vegetation provides
them with food.
Freshwater ecosystems, such as rivers and
lakes, and marine ecosystems, such as the
sea, are aquatic ecosystems.
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
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3. Living things and food
Living things obtain food in different ways:
Producers, such as plants and algae, make
their own food. They do this by using light
from the Sun, carbon dioxide from the air and
water from the soil to produce food, in the
form of glucose/sugar. The process is called
photosynthesis
Consumers, animals are called consumers. This
is because they cannot make their own food,
so they need to eat plants and/or animals.
There are three groups of consumers
¬ Primary consumers, such as zebras, and
fish, eat plants and algae.
¬ Secondary consumers, such as lions and
snakes, eat primary consumers.
¬ Tertiary consumers, such as eagles and
owls are secondary consumers, which
eat other secondary consumers.
Decomposers, such as fungi and bacteria, eat
the remains of other living things.
4. Food chains.
Food chains show how food transfers from
one living thing to another in an
ecosystem.
Every living thing needs energy in order to live. Every time animals do something (run, jump) they use energy to do so. Animals get energy from the food they eat, and all living things get energy from food. Plants use sunlight, water and nutrients to get energy (in a process called photosynthesis). Energy is necessary for living beings to grow.
A food chain shows how each living thing gets food, and how nutrients and energy are passed from creature to creature. Food chains begin with plant-life, and end with animal-life. Some animals eat plants, some animals eat other animals.
Food chains make a full circle, and energy is passed from plant to animal to animal to decomposer and back to plant! There can be many links in food chains but not TOO many. If there are too many links, then the animal at the end would not get enough energy.
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
3
PRODUCERS
CONSUMERS
There are 3 groups of consumers.
Animals that eat only plants.
Animals that eat only animals.
Animals that eat both animals AND plants. Humans are
also omnivores!
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
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HERVIVORES
CARNIVORES
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
5
OMNIVORES
DECOMPOSERS
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
6
FOOD CHAINS.
After a hawk died, fungi (like mushrooms) and other decomposer break down the
dead hawk, and turn the remains of the hawk into nutrients, which are released into
the soil. The nutrients (plus sun and water) then cause the grass to grow. It is a full
circle of life and energy.
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
7
READ
1. The environment
People affect the environment and
the environment affects people.
Some human activities, such as
agriculture, construction or hunting,
can be harmful to the environment.
2. Pollution
Pollution is the contamination of air,
soil or water.
The combustion of oil or coal pollutes
the air.
Insecticides pollute the soil.
Urban and industrial waste pollutes
rivers and oceans.
Pollution can change ecosystems.
3. Global warming.
Carbon dioxide in the atmosphere
maintains heat on the Earth. Life on
Earth is possible thanks to this heat.
The atmosphere lets light in but does
not let heat out. This is called the
greenhouse effect.
There is much more carbon dioxide in
the atmosphere now. Consequently, the
Earth’s temperature is increasing
because more heat is retained in the
atmosphere. This is called global
warming.
4. Extinction
Pollution and global warming can cause
species to become extinct. Today many
species are endangered. All species
depend on other species in food chains.
Consequently, if one species becomes
extinct, other species can become
extinct too.
We are causing the extinction of living things.
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
8
We are polluting the water, the air and the ground.
We are creating social injustice.
We are using up resources such as fresh water.
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
9
THE ELEMENTS OF AN ECOSYSTEM (BASIC CONCEPTS)
An ecosystem is a community formed of a habitat, living things and the
interactions between them.
Types of ecosystem: An ecosystem can be aquatic, terrestrial or mixed.
A maritime ecosystem.
Living things adapt to their ecosystem: Living things in each ecosystem
have certain characteristics, called adaptations, which permit them to
survive in that ecosystem. These adaptations can be of the body or
behaviour:
¬ Adaptations of the body are parts of the body that permit the
realisation of certain function.
¬ Adaptations of behaviour are actions.
PRODUCERS, CONSUMERS AND DECOMPOSERS
Depending on what they eat, living things are producers, consumers or
decomposers.
Producers: They make their own food.
Consumers: They feed on other living things.
Decomposers: They feed by decomposing remains of other living things.
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
10
Producers, consumers and decomposers in a forest ecosystem
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
11
HUMAN ACTIVITY ALTERS ECOSYSTEMS
Our activities alter ecosystems for three reasons:
¬ We overexploit natural resources. Natural resources are
everything we obtain from ecosystems, consume, and use to realise
our activities. Overexploiting means, we extract natural resources
from the environment faster than they regenerate or replace.
¬ We occupy the natural environment. We occupy areas that were
once natural ecosystems. For example, we substitute forests for
cities.
¬ We cause pollution. We produce dangerous residues that we
release into the environment.
WHAT PROBLEMS DO WE CAUSE?
These actions cause many problems. For example:
¬ Loss of biodiversity
¬ Loss of natural spaces.
¬ Climate change.
SOME WAYS OF PROTECTING THE PLANET.
¬ Exploit resources carefully
¬ Protect natural spaces
¬ Protect endangered species
¬ Reduce pollution
CONOCIMIENTO DEL MEDIO 6º PRIMARIA/ 6TH GRADE SCIENCE
LOS ECOSISTEMAS. EL SER HUMANO EN LOS ECOSISTEMAS/ECOSYSTEMS.
HUMAN BEINGS AND ECOSYSTEMS.
12
READING
What is the food chain?
Energy flows through an ecosystem as one animal eats another animal or plant. A food chain shows “who eats who” in an ecosystem.
For example:
A hawk — eats a mouse who — eats a caterpillar who — eats leaves.
Each part of the food chain has a name:
Plants make (produce) their own food using water, sunlight and carbon dioxide (photosynthesis). Plants start the food chain. There are more plants than any other living thing because they are the bottom of the food chain. They provide the energy for everything else. They are the PRODUCERS.
The animals (insects, mice, squirrels, rabbits, or deer) that mostly eat plants are the herbivores. There are fewer herbivores than there are plants because each herbivore needs a lot of plant matter to live. Herbivores feed directly on the producers. They are the PRIMARY CONSUMERS.
Animals (spiders, birds, snakes) who eat the primary consumers (herbivores) are the SECONDARY CONSUMERS. There are fewer secondary consumers than there are primary consumers because each secondary consumers needs to eat many primary consumers to live.
Animals (fox, coyotes, eagles, owls) that eat the first & second consumers are carnivores (they eat meat). They are the TERTIARY CONSUMERS. There are fewer tertiary consumers than there are secondary consumers because each tertiary consumers needs to eat many secondary consumers to live. Because there are fewer animals as you move up the food chain, it is really a food pyramid with the big carnivores needing to eat the most and so being the rarest of the animal kingdom.
Because animals eat so many things, the food chain has many overlapping parts, so is really a FOOD WEB.
Finally yet importantly, the DECOMPOSERS eat and so recycle dead animals and plants (mushrooms, fungi, insects, bacteria). They are then consumed themselves by other parts of the food web so nothing is wasted.