ecosystems. human beings and 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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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.




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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.

http://www.sheppardsoftware.com/content/animals/kidscorner/foodchain/photosynthesis.htm




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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!

http://www.sheppardsoftware.com/content/animals/kidscorner/animaldiet/herbivore.htm

http://www.sheppardsoftware.com/content/animals/kidscorner/animaldiet/carnivore.htm

http://www.sheppardsoftware.com/content/animals/kidscorner/animaldiet/omnivore.htm

http://www.sheppardsoftware.com/content/animals/kidscorner/animaldiet/omnivore.htm




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HERVIVORES

CARNIVORES




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OMNIVORES

DECOMPOSERS




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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.




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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.




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We are polluting the water, the air and the ground.

We are creating social injustice.

We are using up resources such as fresh water.




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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.




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Producers, consumers and decomposers in a forest ecosystem




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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




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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.

ecosystems. human beings and ecosystems

Documents

food living things

food chains

food transfers

terrestrial ecosystems

aquatic ecosystems

types of ecosystems

marine ecosystems

freshwater ecosystems