1 Discovering living beings

What a mess I made! I decided to dissect my dinner and look at it under my new microscope. It’s amazing! All the different foods are made up of tiny bricks. Dad says they’re called cells and that food comes from living beings. Do you know anything about it?

What do you think?

Do you ever wonder where your food comes from?

Read the Context. Why is a planet-based diet good for the planet?

Context

In this unit...

Target in action

Analyse different dishes and make an exhibition about where the ingredients come from.

A plant-based diet is healthy for people... and for the planet. Follow the thread!

Features of living beings

1

What is a living being?

Cells and other levels in the body

2

What are living beings made of?

The main groups of living beings

3

How do we classify living beings?

Plant parts and plant classification

4

What are plants like?

Plant nutrition

5

How do plants feed?

Plant reproduction

6

How do plants reproduce?

The interaction function in plants

7

How do plants interact?

What is a living being?

Most of the food we eat comes from living beings. But what does this mean?

Living beings

Living beings are different from non-living things because they perform the vital functions. All living beings are made up of tiny structures called cells.

The vital functions

Living beings perform the vital functions , but non-living things do not.

All living beings perform three vital functions: nutrition, interaction and reproduction.

The nutrition function

Living beings perform the nutrition function to get substances from the environment. They use these substances for energy, to grow and to repair their body. This function also lets living beings excrete waste substances.

Living beings are heterotrophs or autotrophs , depending on how they feed – in other words, how they get energy and substances.

The two types of nutrition in living beings

Heterotrophs

Autotrophs

Autotrophs, such as plants and algae, use the sun’s energy to make their own food. They get food from other living beings.

Heterotrophs, such as animals, can’t make their own food. Instead, they feed on other living beings.

They make their own food.

The interaction function

Living beings use the interaction function to gather information from the environment and react to it.

The reproduction function

Living beings use the reproduction function to make new living beings (offspring) with similar or identical characteristics.

Reproduction can be asexual or sexual.

The two types of reproduction in living beings

Asexual

In asexual reproduction, one individual (progenitor) produces identical offspring.

One progenitor

Identical offspring

Sexual

In sexual reproduction, one male and one female individual (progenitors) produce offspring that are similar to them.

Two progenitors a) They are green. b) They feed. c) They are made up of cells. d) They have hair.

1 Which of these features do all living beings have?

Similar offspring e) They use batteries. f) They interact. g) They produce offspring. h) They eat meat.

2 Why is a robot not a living being? Explain your answer.

3 Find out what these words mean: nutrient, offspring, react. Say which vital function each one belongs to.

Take note!

If something performs the three vital functions, it is a living being.

What are living beings made of?

What do you and a salad have in common? You are made up of cells!

All living beings – cats, flies, plants, algae, mushrooms and more – are made up of cells.

A cell is a tiny structure that can perform the three vital functions.

What cells are like

Cells are too small to see with the naked eye. We need to use a microscope.

Thanks to microscopes, we know that all cells have the following features : a) Elephant b) Poppy c) Bacteria d) Ant

• Membrane: a layer separating the cell interior from the outside environment.

• Interior: contains thousands of substances and tiny structures. They float in a dense liquid called cytoplasm.

All cells have the same structure, but not all cells are the same. Some cells are simple and tiny. Others are bigger and more complex. Cells can be different shapes.

1 Define the word cell.

2 What is in the cell interior?

3 Are there any living beings not made up of cells? Explain.

4 Copy the picture of the cell. Colour the interior structures however you like.

5 Ideas pool Let’s assume all cells are more or less the same size. Order these living beings from least to most cells. Explain your answer.

What cells are like

Living beings are made up of cells.

Cells

We can use a microscope to study cells

Tissues, organs and systems

How many cells do we have?

Some living beings have more cells than others.

Single-celled organisms

These living beings have just one cell. This cell performs the three vital functions. For example, bacteria and protozoa.

Living beings with more than one cell

Some living beings have more than one cell. Animals and plants have millions of cells and different types of cells.

The cells in complex living beings group together to make structures called tissues. Tissues group together to form organs. Organs combine to form systems.

6 Match the labels to the pictures. Then order the labels from the simplest to the most complex.

Organs combine to form systems

See ‘Let me tell you’ on anayaeducacion.es to learn more about cell organisation.

All the systems together make up the body

Take note!

All living beings have cells, but there are lots of different types. Some cells group together to form tissues.

How do we classify living beings?

There are so many different types of living beings. How can we organise them?

What types of living beings are there?

It is easy to identify different types of living beings that we can see. For example, flies, trees and human beings. If we want to classify living beings scientifically, we need to use other features. There are different ways to classify living beings scientifically. One way is to group them into five kingdoms based on how complex they are and how they feed.

Language Bank

Speaking. Make a survey about what living beings your friends like.

Writing. Write sentences with the result of your survey.

Kingdom Monera

Single-celled organisms. They are simple and very small. They include bacteria.

Kingdom Protista

Includes protozoa. These have just one cell and they are heterotrophs.

Also includes algae. These are autotrophs and have many cells.

Kingdom Fungi

These living beings can have just one cell or many cells. They are heterotrophs.

Kingdom Plantae

These living beings are autotrophs. They have many cells and have tissues, organs and systems.

Kingdom Animalia

These living beings are heterotrophs. They have many cells, and most of them have tissues, organs and systems.

Lost beings

These living beings travelled too far and now they’re lost. Can you help them return to their kingdoms?

First, match the pictures to the descriptions. Then draw the route to the correct kingdom. Use your notebook to write the route from the starting square (marked with an arrow) to the kingdom. But watch out – you can’t step on the names of the other kingdoms!

I’m really small. You need a powerful microscope to see me. I only have one very simple cell.

All my cells are similar. I feed on decomposing waste from other living beings.

I’m huge. I have millions of cells. They form different tissues, and these form organs like leaves and roots. I use sunlight to make my own food!

Take note!

We classify livingintobeings five big kingdoms.

What are plants like?

A lot of our food comes from plants. Plants work differently than we do.

Kingdom Plantae contains living beings with many complex cells. They are all autotrophs because they perform photosynthesis.

Most plants are attached to the ground in terrestrial environments. Some plants live in aquatic environments like rivers, lakes and the sea.

What are plants like?

Plants are incredibly diverse, from massive trees to tiny mosses. All plants contain different types of cells that form tissues. These, in turn, form organs with different functions:

Language Bank

Speaking. Tell a partner about what different plants have or haven’t got.

Writing. Write a description of plants, mentioning their parts and smaller components.

1 Are these statements true (T) or false (F)?

a) Some plants don’t perform photosynthesis.

b) All plants are terrestrial.

c) All plants produce flowers.

Plant parts

Leaves

They perform photosynthesis and the nutrition function. They are green. They can have different shapes, but most are flat.

Stem

It supports the leaves and keeps the plant upright. It often has branches.

Root

This part of the plant is underground. It attaches the plant to the soil and absorbs water and mineral salts.

How many types of plants are there?

There are many different types of plants. We usually classify them into plants that produce flowers and seeds for reproduction, and plants that don’t.

Plants without flowers and seeds

For example, mosses and ferns. They live in dark, damp environments.

2 Choose two plants you like. Draw them in your notebook and label all the organs. Describe the plants and write down the group they belong two.

Plants with flowers and seeds

Some have dull flowers and the seeds are not inside a fruit. For example, a pine tree.

Some have bright flowers and the seeds are inside a fruit. For example, poppies, Spanish lavender, apple trees, etc.

Flowers

Many plants use these structures for reproduction.

Stamen: the male part of a flower. It produces pollen. Corolla: made up of petals. These are tiny, brightly-coloured leaves.

Pistil or ovary: the female part of the flower. It contains the ovules.

Fruit

The ovary transforms into the fruit after fertilisation.

Take note!

Calyx: made up of tiny green leaves called sepals. These surround the flower and protect it. Seeds

Most plants have roots, a stem and leaves. Some have flowers.

How do plants feed?

Plants have a very calm and very special way to get nutrients: photosynthesis!

Plant nutrition

Plants are autotrophs. They perform photosynthesis to make their own nutrients. They also perform respiration to get a special nutrient called oxygen.

Plant nutrition step by step

• The roots absorb water and mineral salts to make xylem sap . This sap gets transported to the leaves. 1

• The leaves use sunlight to mix the xylem sap with carbon dioxide (a gas in air) to make nutrients. This process is called photosynthesis, and it releases oxygen. 2

• The nutrients formed in the leaves get mixed with water to make phloem sap. This sap gets transported all around the plant. 3

• Plants perform respiration day and night. They use this process to get oxygen from air and to produce energy (and nutrients). This process releases carbon dioxide. 4

1 Explain these concepts in your own words: a) xylem sap b) phloem sap c) photosynthesis d) absorption e) respiration a) Respiration b) Photosynthesis c) Absorption

2 In your notebook, match the words with the descriptions.

1. Plants get water and mineral salts through their roots.

2. Plants get oxygen and release carbon dioxide.

3. Plants get carbon dioxide and release oxygen.

My job: plant doctor

Hi! I’m Penelope and I’m a plant physiologist. I love plants. My job is to study how they ‘work’. Most of the plants I study are crops like corn, beans and tomatoes. My research helps protect them from diseases and improves the harvest. I’m like a plant doctor!

A group of farmers visited us today. They are worried about their tomato plants. The plants are sick. Look at the drawings and read my notes.

The leaves have small spots and they look like they are covered in cobwebs. The plants are infested with red spider mites.

The leaves have dark round spots. The soil is too damp. The plants are infected with fungus.

1 The notes are mixed up. Which picture does each note belong to?

2 Which treatment is best for each tomato plant?

a) The tomato plant needs proper nutrition. A good organic fertiliser might help.

b) The tomato plant needs less water so the soil is less damp. An anti-fungal treatment might help too.

c) The tomato plant needs a treatment to remove the red spider mite infestation. A natural solution might help. For example, we can introduce ladybirds – these feed on red spider mites.

The leaves aren’t growing and they are yellow. When plants don’t get enough mineral salts, they grow slowly and become ‘malnourished’.

Take note!

Plants don’t need to hunt. They need light and water for their nutrition function.

How do plants reproduce?

Plants need to make tiny offspring, just like other living beings. How can they reproduce if they can’t move?

The reproduction function in plants

Asexual reproduction

In asexual reproduction, part of the plant (usually the stem) develops a new plant that is identical to the progenitor.

Stolons

Special stems that grow above ground and produce new plants.

Fat stems that grow underground and produce new plants.

1 The picture Look at the pictures on the right. Describe what you see.

2 List five tubers and five bulbs people eat or cook with. Which ones do you know? Which ones do you eat? Choose two and research their nutritional benefits. Write your findings in your notebook.

Cuttings

Stem fragments. We can plant them in the ground so they produce roots and turn into a new plant.

Sexual reproduction

Many plants have flowers and perform sexual reproduction.

• Grains of pollen enter the pistil and join with the ovules to form seeds.

• At the same time, the pistil transforms into the fruit.

• When the fruit opens, the seeds fall to the ground and turn into new plants.

Sexual reproduction step by step

Insects, the wind or water transport grains of pollen to the pistil.

Take note!

Lots of things we eat are seeds or fruit. Can you think of any?

The pollen joins with the ovules inside the pistil to form a fruit with seeds inside.

Fruit

Seeds

The new plant grows into an adult plant. It flowers at a certain time of year.

3 Put these pictures in order. Use the diagram above to help you. Then explain this reproduction process step by step.

The seeds turn into new tomato plants.

How do plants interact?

Do you ever wonder if plants know what is happening in the environment?

The nutrition function in plants

Plants are fixed to the ground. They can’t move around and they don’t have sense organs like animals do. However, they can still perceive changes in the environment and react to these changes. This is how they perform the interaction function. Here are some examples:

Language Bank

Speaking. Ask your partner what things plants can do.

Writing. Write some sentences comparing plants and animals.

Plants notice seasonal changes. In spring, they react to longer days and higher temperatures by flowering and producing leaves. In autumn, many plants drop their leaves when the days become shorter and colder.

Some plants can perceive the sun’s position. They turn their leaves to receive more light or heat.

1 Look at the pictures. Choose one you like and describe it in your notebook in your own words.

2 Find another two examples of how plants perform the interaction function. Explain them.

Many flowers open when there is lots of light. They close at sunset when there is less light.

Example of plant interaction

The leaves of mimosa fold when we touch them.

Some plants like acacias react when a herbivore (a giraffe, for example) attacks them. They produce a substance that doesn’t taste good.

Plant interaction. Colourful reactions!

Plants can recognise certain colours. It’s incredible! The following experiment proves it.

Materials:

• Three identical plants.

• Three lights with different lightbulbs: one blue, one red and one white.

Procedure.

Expose the plants to one type of light for at least 24 hours.

You can see the results in the drawings on the right.

1 What happens to the plant stems when they receive white, blue or red light? Use the table to help you – tick the boxes to show what happens.

Type of light

Red light

White light

Blue light

Turns towards the light

Doesn't turn towards the light red light white light blue light

2 How can you check if plants perceive green light? Design your own experiment.

3 Imagine you are a scientist and you want to answer the following question: do plant seeds need light to germinate? Design your own experiment to answer this scientific question. Write the steps in your notebook.

Take note!

Plants can react to environmental changes in lots of different ways.