UNIT 6 LIVING THINGS AND HOW WE USE THEM (4º E.P.)

UNIT 6

LIVING THINGS AND HOW WE USE THEM

■ Human beings and other living things

• Primitive societies and other living things

 In primitive societies, human beings:

*  Collected fruit, roots, leaves, grain, etc.

*  Hunted and fished with simple tools.

*  Cut wood to make fire.

• The development of agriculture and fishing

Later, human beings..

*  They learnt to cultivate plants for food.

*  They domesticated animals for their meat, milk, eggs, wool, skin, etc.

*  They used animals for transport and for ploughing fields.

*  They invented more efficient ways of fishing with nets.

Fishing can take place in rivers, which is fluvial fishing, or in the sea, which is maritime fishing. Today, fish are also cultivated in special water farms; this is called aquaculture.

• Modern society and other living things

Today, the population of the world is very large and we cultivate on a massive scale.

We damage the environment and cause some problems. The problems of modern society are:

-  We cut down forests.

-  We cultivate land so intensively that the soil becomes infertile.

-  We use too many fertilizers and pesticides which pollute the soil and the water.

-  Agriculture and stock farming can change or destroy ecosystems.

-  We fish so much that in many places the fish are running out.

-  Some stocks farms produce waste which is very polluting.

■ Agriculture

• Types of crop farming

*  Cereals like wheat, maize and rice.

*  Fruit and vegetables. We cultivate fruit trees in orchards

*  Vines and olive trees.

*  Crops with industrial uses. We also cultivate sunflowers, sugar beet and cotton. They are used to supply the industries which produce oils, sugar and textiles.

■ Stock farming

• Types of stock farming

*  Sheep and goat farming (ganado ovino). We farm sheep and goats for their meat, milk, wool and skin.

*  Cattle farming (ganado vacuno). We farm cows and bulls for their meat, milk and skin.

*  Pig farming (ganado porcino). We farm pigs for their meat which we eat fresh or cured.

*  Poultry farming (ganado avícola). We farm chickens and ducks for their meat and eggs.

*  Other types of stock farming. We also farm rabbits, pheasants and even exotic animals like ostriches.

NATURAL SCIENCE. UNIT 4:  ANIMALS AND PLANTS

The vital functions in animals

There are three vital functions: nutrition, interaction and reproduction.

● The nutrition function

* Animals eat and digest food.

* Animals breathe by using oxygen from water or air.

* By combining oxygen and the substances from food, animals obtain energy to live and make other substances to grow.

* Animals excrete waste products from their bodies, through sweat, urine, faeces, etc.

● The interaction function

They all have parts of their bodies which help them detect and react to changes.

Most animals have: sense organs, a nervous system and a locomotor system.

● The reproduction function

Reproduction in animals is sexual because it involves two different sexes: the male and the female.

Most animals are unisexual, only one sex:

* Male: they produce sperm.

* Female: they produce ovules.

Some animals, like snails, have two sexes. They are hermaphrodites.

The stages in animal reproduction are:

* Fertilization: it is the union of an ovule and a sperm. The result of the union is called zygote. The embryo grows from the zygote.

* The development of the embryo: in viviparous animals the embryo grows in the mother’s womb. It is called gestation. In oviparous animals the embryo grows inside an egg. It is called incubation.

* Birth: Oviparous animals hatch from eggs. Viviparous animals are born from their mother’s womb.

Plants: nutrition and interaction

● The nutrition function

* Plants absorb water and minerals and these rise to the leaves. Leaves absorb carbon dioxide.

In the leaves, plants make photosynthesis. They use The Sun’s energy, the water and carbon dioxide to make their own food.

* Like animals, plants take oxygen. They combine the food with oxygen to obtain energy and to create substances to grow.

* Plants excrete waste products from their bodies. For example, they excrete oxygen.

● The interaction function

Plants do not have sense organs, a nervous system or a locomotor system.

Despite this, plants react to changes in light, temperature, humidity, etc.

● The parts of a plant and their functions

* The roots grow downwards. They have small hairs that absorb water and minerals. The water and minerals rise up the plant.

* Leaves and photosynthesis. Leaves are generally flat and green. Photosynthesis takes places in the leaves:

- The leaves receive the mixture of water and minerals.

- The leaves absorb carbon dioxide from the air.

- Using The Sun’s energy, water and minerals combined with carbon dioxide and form the substances which are the plant’s food, a liquid called sap.

* The stem and the circulation of sap. The stem grows upwards and supports the branches and leaves. The substances the plant needs circulate through the stem:

- Water and minerals move from the roots to leaves.

- Sap moves from the leaves to other parts of the plant.

Plants: reproduction

● Sexual reproduction

The reproduction of plants is sexual because there are both male and female reproductive organs.

Most plants have reproductive organs in their flowers:

- The stamens are the male organs of the flower. They produce grains of pollen.

- The pistil is the female organ of the flower. It produces and contains ovules.

Most plants have flowers with both stamens and pistil. Some plants have male flowers (with stamens) and female flowers (with pistil).

In most flowers, the stamen and pistil are surrounded by special leaves: the petals of the corolla and the sepals of the calyx.

● The reproduction function in plants

There are different stages:

* Pollination. Wind or insects carry the pollen from the stamen of one plant to the pistils of another.

The union of a grain of pollen and the ovule of the pistil is fertilization.

* The formation of the seed and fruit. The fertilized ovule becomes the seed. The pistil grows and becomes the fruit.

The seeds are usually inside the fruit. Fruit can be hard, like walnut, or soft, like an orange, an apple.

* Dispersal of seeds and germination. Some fruits open to disperse their seeds. Others are eaten by animals, which excrete the seeds with their faeces.

When a seed lands in soil with the right conditions it germinates: a new plant grows (the embryo grows with roots and a stem with leaves). At first it feeds on substances in the seed and then it begins to make its own food.

NATURAL SCIENCE. UNIT 3: ROCKS AND LANDSCAPES

● Rocks and minerals

▪ What are rocks?

The Earth’s crust is formed from materials called rocks.

They form the land in whick we live, the mountains, the bottom of the sea, etc.

Rocks are the solid substances which form The Earth’s crust. They are made of other solid substances called minerals.

The little grains we see in a rock are the different minerals which form it.

Some rocks are made of a lot of similar grains: these rocks are formed from one mineral.

Other rocks are made of many different grains of different colours and sizes: these rocks are formed from different minerals.

▪ Characteristics of rocks

Rocks are characterized by different things:

* Composition: the combination of minerals a rock is made of. It affects its hardness, colour, etc.

* Texture: the form and arrangement of the minerals a rock is made of.

* The form in which they appear in nature. Some rocks are found in layers, others in enormous blocks, and some in volcanoes.

▪ Some types of rocks

♠ Limestone: it is a soft rock which can be white, grey or cream. It is formed from a mineral called calcite. It sometimes contains fossils which are the remains of living things from long ago.

♠ Slate: it is a hard rock which is usually dark grey or black. The minerals it is made of are arranged in thin layers. It breaks easily into thin sheets.

♠ Granite: it is a very hard rock which is usually grey. It is formed from three different minerals (cuarzo, feldespato y mica).

♠ Basalt: it is a very hard rock which is dark grey or black. It is made of different minerals. It is formed in volcanoes.

● Rocks and human beings

▪ How we use rocks

Human beings use the different types of rocks for different purposes. In some cases, we use them in their original form for construction, for decoration, to make things, etc. In other cases, we use only one of their minerals as base to make other materials like iron, glass or cement.

* Rocks for construction and decoration

- Granite, basalt and limestone are all used to build buildings. Slate is sometimes used to make roofs.

- Marble is a beautiful form of limestone and it is used to make floors and statues.

- Clay is use to make roof, bricks and containers. We model it and then heat it.

* Rocks from which we obtain minerals

- Iron, copper and aluminium are obtained by transforming the minerals there are in some rocks.

- Glass is made by melting quartz. Quartz is in granite and in some types of sand.

- Cement is made by mixing calcite, a mineral which comes from limestone, with other minerals.

▪ The extraction of rocks

Rocks are sometimes on the surface of The Earth and sometime very deep inside The Earth’s crust. To extract them we have to excavate them in mines. There are two kinds or types of mines:

♠ An open cast mine is used to excavate rocks near The Earth’s surface. It is a huge hole in the ground.

♠ An underground mine is a series of tunnels underground, inside The Earth’s crust. It is used to reach rocks deep underground.

▪ How do rocks influence our lives?

Rocks influence the lives of human being in a lot of ways.

* In a region with mines there is a lot of work and money for the people who live there. But it also damages the countryside and the environment and can damage people’s health.

* When a volcano erupts, very hot melted rocks come out of its crater. This can be very dangerous for people who live near.

* An earthquake moves the rocks of The Earth’s crust. This can damage towns and cities and cause a lot of problems for people who live there.

SOCIAL SCIENCE. UNIT 1

WHAT IS THE WEATHER LIKE TODAY?

What is weather?

The weather is the state of the atmosphere at a given moment.

The weather depends on:

-              Clouds: The day can be cloudy or sunny.

-              Wind: The day can be windy or calm.

-              Temperature: The temperature of the air can be hot, warm, cool or cold.

-              Humidity: The air can be dry or humid.

-              Precipitation: It can fall as rain, snow or hail.

How do we study the weather?

Meteorologists are the people who predict the weather by measuring and studying the atmosphere.

To study the weather we use:

-              Wind gauge: measures how fast the wind is blowing.

-              Weather vane: shows the direction the wind is blowing.

-              Rain gauge: shows how much rain has fallen.

-              Thermometer: measures the temperature of the air.

CLIMATE

What is climate?

The climate is the combination of the different types of weather in a region during the year.

The climate in Spain can be:

-              Subtropical: It is the climate in the Canary Islands The differences between seasons are small. The temperature is high and changes little during the year. There is not much rain.

-              Atlantic: It is the climate in the coastal regions in the north of Spain, next to the Atlantic Ocean. There is a lot of rain all year, because clouds come from the ocean. The temperature is mild all year, even in winter.

-              Continental: It is the climate in the interior regions of Spain. There is not much rain, because the mountains stop clouds coming from the sea. Most of the rain falls in spring and autumn. The temperature is very hot in summer and very cold in winter.

-              Mediterranean: It is the climate in the regions close to the Mediterranean Sea. It rains mostly in autumn and the rain can be very heavy. In the other seasons it rains very little. The temperature in summer and autumn is very hot. The temperature in winter and spring is mild.

-              Mountain: It is the climate in regions more than 1500 metres above sea level. The temperature is very cold in winter and cool in summer. There is a lot of rain. In winter, the cold means the rain falls as snow.