Life Process: Grade 5 Science – Science Playground

Life processes

Think about it

Look and talk

Think about these: a crow eating, a tree carrying water up its trunk, a plant making food in sunlight, a person breathing, a cow with her new calf, and a cow dropping dung.

a.What are the living things doing in each one?
b.Do all animals eat the same kind of food?
c.Why do living things breathe?
d.How do plants and animals make young ones?
e.How do living things get rid of waste from their bodies?

Answer

a.The crow is eating food. The tree is carrying water up from its roots. The plant is making food. The person is breathing. The cow has given birth to a calf. The other cow is getting rid of waste.
b.No. A cow eats only plants. A tiger eats only meat. A crow eats both.
c.To take in oxygen. Oxygen helps the body get energy from food.
d.Plants grow from seeds (and some from parts like a potato or a piece of stem). Animals lay eggs or give birth to babies.
e.Animals give out carbon dioxide when they breathe out. They also pass urine and dung (feces), and sweat. Plants give out gases and water vapor from their leaves, and some ooze sticky juices from their stems.

Living things need food to stay alive. They take in oxygen when they breathe. With the help of oxygen, their bodies break down food to get energy.

The body also makes waste, things it doesn’t need. Living things throw these out.

Animals, including humans, get rid of carbon dioxide, sweat, urine and feces.
Plants give out carbon dioxide and water vapor as gases. Some also ooze resin or latex from their bark, stems and leaves.

Living things also make young ones like themselves. This is reproduction.

All these jobs, done again and again all through life, are the life processes. In Grade 5 you will study five of them:

Nutrition: getting food.
Respiration: getting energy from food, with oxygen.
Transportation: carrying things around inside the body.
Excretion: getting rid of waste.
Reproduction: making young ones.

Figure 5.1 The life processes work together, like the parts of a wheel. If one stops, the others soon stop too. Grade 7 adds a sixth, metabolism: all the changes going on inside the body.

Which of these is not a life process?

Pick an answer to see why.

Nutrition in plants and animals

A story from science

On the way to school

Raghav (Grade 4) and Rama (Grade 5) are walking to school. They meet their teacher, Kamala Miss, on the way.
Raghav: Rama, why are all these leaves green?
Rama: Leaves have chlorophyll in them. It makes them green. Plants make their food with its help. That is why a leaf is called the plant’s kitchen.
Rama and Raghav: Namaskar, Miss!
Kamala Miss: Namaskar! What are you talking about?
Rama: How plants make food. Is chlorophyll the only thing a leaf needs?
Kamala Miss: What a good question! Let’s talk on the way.
Rama: Do plants need water and carbon dioxide too?
Raghav: Then can’t plants make food when there is no rain?
Kamala Miss: They can, Raghav. Roots take up water stored in the ground. The stem carries it up to the leaves.
Rama: Miss, how does carbon dioxide get into the leaves?
Kamala Miss: Leaves have tiny holes called stomata. Carbon dioxide goes in through them.
Rama: So green plants make food from carbon dioxide and water, in sunlight!
Kamala Miss: Yes. Making food this way is called photosynthesis. Living things that make their own food are called autotrophs.
Raghav: But a mushroom can’t make its food, can it? How does it live?
Rama: A mushroom has no chlorophyll. So it can’t make food. Am I right, Miss?
Kamala Miss: Right. It gets its food from rotting things.
Raghav: Rabbits, goats, tigers and people can’t make food either!
Kamala Miss: True, Raghav. They all depend on green plants, one way or another.
Rama: Herbivores, like goats, rabbits and deer, eat plants.
Raghav: And carnivores, like leopards, tigers, lions and jackals, eat goats, rabbits and deer.
Rama: And omnivores, like people, crows and bears, eat both.
Kamala Miss: Living things that can’t make their own food are called heterotrophs.
Raghav: Here’s the school! Thank you, Miss, and thank you, Rama didi!

Here is what they found out.

Green plants make their own food. They use water, carbon dioxide and sunlight, with the help of their green chlorophyll.

The roots take in water from the soil. The stem carries it up to the leaves.
Carbon dioxide from the air enters the leaves through tiny holes called stomata.
Chlorophyll catches the sunlight. The leaf uses the light’s energy to make food.

This way of making food is called photosynthesis. Living things that make their own food are autotrophs. Green plants are autotrophs.

Animals, mushrooms and plants without chlorophyll can’t make their own food. They take food from others. They are heterotrophs.

A mushroom gets its food from rotting things.
Herbivores (goats, rabbits, deer) eat plants.
Carnivores (leopards, tigers, lions, jackals) eat other animals.
Omnivores (people, crows, bears) eat both plants and animals.

Living things get energy from food. With that energy, the body carries out all its life processes. Without them, there is no life.

Herbivores get energy by eating green plants.
Carnivores get it by eating herbivores.

So every animal depends on green plants for its food, directly or through other animals.

Read each card. Does this living thing make its own food, or take it from others?

Card 1 of 12 · score 0

Mango tree

Green leaves that face the sun.

Does it make its food, or take it? Tap one.

What is a plant’s way of making food called?

Pick an answer to see why.

Which of these is an autotroph?

Pick an answer to see why.

Respiration in plants and animals

Figure 5.2 A tree and a person. In sunlight, the tree’s leaves give out oxygen, which the person breathes in. The person breathes out carbon dioxide, which the leaves take in to make food. The tree also breathes out some carbon dioxide.

All living things need oxygen. Plants and animals on land take oxygen from the air. Fish and water plants use the oxygen dissolved in water.

Breathing takes oxygen into the body. The oxygen reaches every part of it. There, oxygen breaks down food. This gives energy, and makes carbon dioxide and water.

That energy keeps all the life processes going, every moment: nutrition, transportation, excretion, breathing and reproduction.

Breathing organs of animals

Different animals breathe with different body parts.

Fish and tadpoles breathe with gills.
Humans and most land animals (mammals, birds and reptiles) breathe with lungs.
Insects breathe through tiny holes along their sides, called spiracles.
Frogs breathe through their skin when they are in water. On land, they use their lungs as well.

Figure 5.3 Two other ways to breathe. A grasshopper (left) takes in air through a row of tiny holes, the spiracles, along its body. A fish (right) takes water in at its mouth. Its gills take oxygen out of the water, and the water flows out under the gill covers.

Two words sound alike, but they mean different things.

Breathing is taking in oxygen and giving out carbon dioxide. It happens in the breathing organs, such as the lungs.
Respiration is breaking down food inside the body, to get energy. It makes carbon dioxide and water. It happens in every part of the body.

Figure 5.4 Breathing and respiration. Air is breathed into the lungs. The blood takes its oxygen to every part of the body. There, food and oxygen give energy, carbon dioxide and water. The carbon dioxide goes back to the lungs, and is breathed out.

Animals don’t need carbon dioxide. But green plants do: they use it for photosynthesis. So the carbon dioxide that living things give out is used again by green plants. And plants give oxygen back to the air.

In this way, the oxygen and carbon dioxide in the air stay balanced. Plants and animals can go on living.

What do insects breathe through?

Pick an answer to see why.

Where in the body does respiration happen?

Pick an answer to see why.

Internal transport in plants and animals

To stay alive, a living thing must move things around inside its body.

Food, water, oxygen and other useful things must reach every part of the body.
Wastes made in different parts must be taken to the organs that throw them out.

In plants

The roots take in water and minerals from the soil. They go up through the stem to the leaves.
The food made in the green leaves goes through fine tubes in the stem to every part of the plant: the branches, the leaves, the flowers, the fruits and the roots.

In animals

In most animals, blood does this job. The heart pumps the blood all round the body.

Carrying food, water, oxygen, minerals and wastes around inside the body is called internal transport (or internal transportation).

Activity

5.2: watch water climb a stem

Aim: to see that water, and what is dissolved in it, goes up a plant’s stem.

You need: a glass or a beaker, water, red or blue ink (or food coloring), and a white flower with a long stalk.

Fill the glass half full of water.
Add a few drops of ink and stir. Keep adding ink until the water is dark.
Stand the stalk of the white flower in the colored water.
Leave it where you can see it.
Look at the color of the stalk and the flower every hour. Fill in a table like this one.

Time	Change in the color of the flower
One hour later
Two hours later
Three hours later
Four hours later

What you should see

Time	Change in the color of the flower
One hour later	No change in the petals yet. Thin colored lines may show in the stalk.
Two hours later	The color shows at the base of the petals, along their veins.
Three hours later	Colored lines and patches spread along the petals.
Four hours later	The edges of the petals are clearly colored.

How fast it happens depends on the flower and the weather. A warm, sunny room makes it faster. Cut the stalk freshly, just before you stand it in the water.
Conclusion: water goes up the stem to the flower. Things dissolved in the water, like the ink, go up with it.

Figure 5.5 A white flower stood in colored water. A few hours later, the color has climbed up the stalk and shows in the veins of the petals.

Move the hours on, and watch the colored water climb up the stalk. Then try the flower in the shade.

Place:

Hours in the glass: 3 h

Just stood in the glass: the color is only in the water.

The colored water is climbing up the stalk.

The color has reached the flower, and is spreading along the petals’ veins.

The color is in every vein, right to the petal tips.

In warm sunshine, more water evaporates from the flower, so more is pulled up. (A rough model: real flowers vary.)

In cool shade, less water evaporates from the flower, so the color climbs about half as fast. (A rough model: real flowers vary.)

In a plant, what carries water from the roots to the leaves?

Pick an answer to see why.

Excretion in plants and animals

A heart-shaped green leaf with a drop of water hanging from its pointed tip — **Figure 5.6** A drop of water at the tip of a money plant’s leaf, early in the morning. The plant pushed this water out itself. Photo: Adrian Tync, CC BY-SA 4.0

When a living thing carries out its life processes, its body also makes unwanted, harmful things. Getting rid of these wastes is called excretion.

Animals get rid of:

feces (dung or stool);
urine;
sweat;
carbon dioxide, when they breathe out.

Plants get rid of:

carbon dioxide, given out in respiration;
oxygen, given out while making food;
extra water, given off from the leaves as water vapor;
resin and latex, which ooze from the stem.

The trunk of a chir pine with a cut in its bark, and sticky yellow resin running down into a cup — **Figure 5.7** Resin flowing from a chir pine. Pines in Nepal’s hills are cut like this to collect their sticky resin. It is used to make turpentine and varnish. Photo: Ramwik, CC BY-SA 3.0

A slanting cut in the bark of a rubber tree; white latex runs along the cut into a cup tied to the trunk — **Figure 5.8** Latex from a rubber tree. A thin slanting cut is made in the bark, and white latex drips into a cup. Rubber is made from it. Rubber trees are grown in Jhapa, in eastern Nepal. Photo: Vyacheslav Argenberg, CC BY 4.0

Activity

5.5: leaves give off water

Aim: to see that leaves give off water.

You need: a small potted plant, a clear, thin plastic bag, and sticky tape (sellotape) or string.

Cover the leafy part of the plant with the plastic bag.
Tie or tape the mouth of the bag tightly round the stem, so that no air gets in or out. (Don’t cover the pot and the soil.)
Put the plant in a sunny place for two or three hours.
Then look at the bag. Fill in a table like this one, with the changes and their reasons.

No.	Change	Reason
1.
2.

Conclusion: plants take in water from the soil with their roots. The water goes up through the stem to the ______. The extra water is given off into the air as ______, through tiny holes in the leaves called stomata. This is called transpiration.

What you should see

No.	Change	Reason
1.	The inside of the bag turns misty.	The leaves give off water vapor into the bag.
2.	Drops of water form inside the bag.	The vapor cools on the plastic and turns into water drops.

Conclusion: the water goes up through the stem to the leaves. The extra water is given off into the air as water vapor, through the stomata. This is transpiration.
Why tie the bag round the stem, and not over the whole pot? Water also rises from wet soil. If the soil were inside the bag, you couldn’t tell whether the drops came from the leaves or the soil.

Figure 5.9 A plant with its leafy shoot tied inside a clear plastic bag. After a few hours in the sun, drops of water cover the inside of the bag. The leaves gave off that water.

Plants take in water through their roots. It flows up the stem to the leaves. The extra water leaves the plant as water vapor, through tiny holes in the leaves called stomata. Giving off extra water as vapor through the stomata is called transpiration.

Activity

5.6: organs and their wastes

Copy and fill in the table: the parts of plants and animals that get rid of wastes, and the wastes they get rid of.

Organ of the plant	Waste	Organ of the animal	Waste
leaf	extra water	lungs	carbon dioxide
stem		skin

What you should see

Organ of the plant	Waste	Organ of the animal	Waste
leaf	extra water (as vapor), carbon dioxide, oxygen	lungs	carbon dioxide (and water vapor)
stem	resin, latex	skin	sweat
		kidneys	urine
		large intestine	feces

What is giving off extra water as vapor from the leaves called?

Pick an answer to see why.

Reproduction in plants and animals

Think about it

Look and talk

Think about a mango seed sprouting, a hen with her egg and chicks, and a mother pig feeding her piglets.

a.Which animals have you seen hatching from an egg? Which have you seen being born?
b.Have you seen a mango seed sprouting?
c.Like mango, which other plants grow from seeds?
d.How does a new plant grow from a mustard seed?
e.How do new plants grow from a potato, an onion, ginger and garlic?

Answer

a.From an egg: chickens, ducks, pigeons, snakes, lizards, frogs and fish. Born: calves, kids (goats), puppies, kittens, piglets and human babies.
b.Your own answer. A mango seed, thrown away after the fruit is eaten, often sprouts in damp soil in the rainy season.
c.Wheat, rice, maize, gram, peas, beans, mustard, pumpkin, cucumber, tomato, and many more.
d.When the seed gets water, warmth and air, it swells and splits open. A tiny root comes out and grows down. A tiny shoot grows up, with two small seed leaves. Then real leaves grow, and the plant can make its own food.
e.Not from seeds, but from a piece of the plant. A potato is planted whole or in pieces, each with an “eye” (a bud). An onion bulb or a clove of garlic is planted, and grows a new plant. A piece of ginger with a bud grows into a new plant.

A mango stone in soil, with a young reddish shoot and leaves growing up out of it — **Figure 5.10** A mango seed sprouting. The seed grows a root down and a shoot up. Young mango leaves are reddish at first, then turn green. Photo: Suyash.dwivedi, CC BY-SA 4.0

A mustard plant makes mustard seeds. A new mustard plant grows from each seed. An orange tree grows oranges, with seeds that can grow into new orange trees.

Birds, crocodiles, snakes, frogs, fish and insects lay eggs. The young ones hatch out of them.
Humans, dogs, cats, rats and most other mammals give birth to young ones like themselves.

Making young ones like themselves, so that their kind goes on, is called reproduction.

Which animal gives birth to young ones (doesn’t lay eggs)?

Pick an answer to see why.

Activity

5.7: plants and animals compared

How do these life processes happen in plants and in animals? Copy and fill in the table.

No.	Life process	In plants	In animals
1.	Nutrition	Green plants make their own food.	Animals depend on green plants and other animals for food.
2.	Respiration
3.	Excretion
4.	Transportation
5.	Reproduction

What you should see

No.	Life process	In plants	In animals
1.	Nutrition	Green plants make their own food.	Animals depend on green plants and other animals for food.
2.	Respiration	Plants take in oxygen and give out carbon dioxide, mostly through tiny holes in their leaves. They have no special breathing organs.	Animals breathe with lungs, gills, skin or spiracles.
3.	Excretion	Plants give off extra water as vapor from their leaves, and resin and latex from their stems.	Animals get rid of carbon dioxide, sweat, urine and feces.
4.	Transportation	Water, minerals and food move through fine tubes in the stem.	Blood carries things round the body, pumped by the heart.
5.	Reproduction	Plants grow from seeds, or from parts like a potato or a piece of stem.	Animals lay eggs or give birth to young ones.

In short

Life processes

Life processes are the jobs living things do all their lives, to stay alive: nutrition, respiration, transportation, excretion and reproduction.
Nutrition: green plants make their own food from carbon dioxide and water in sunlight, with chlorophyll (photosynthesis). They are autotrophs. Animals and mushrooms take food from others. They are heterotrophs.
Respiration: oxygen breaks down food in every part of the body, to give energy, carbon dioxide and water. Breathing brings in the oxygen: with gills (fish, tadpoles), lungs (people), spiracles (insects) or skin (frogs in water).
Transportation: water and minerals go up through fine tubes in a plant’s stem; food goes from the leaves to every part. In animals, blood carries things round the body.
Excretion: getting rid of wastes. Animals: carbon dioxide, sweat, urine, feces. Plants: carbon dioxide, oxygen, water vapor (transpiration), resin and latex.
Reproduction: making young ones. Plants grow from seeds or plant parts. Animals lay eggs or give birth.

Exercise

1. Is it correct (✓) or wrong (✗)?

a. Without oxygen, living things can’t get energy from food.

Pick an answer to see why.

b. In respiration, plants take in carbon dioxide and give out oxygen.

Pick an answer to see why.

c. Living things making young ones like themselves is called reproduction.

Pick an answer to see why.

d. Fish take in the oxygen dissolved in water.

Pick an answer to see why.

e. Plants give out resin and latex mostly from their leaves.

Pick an answer to see why.

2. Fill in the blanks

blood, carbon dioxide, transpiration, oxygen, eggs

a.

Living things take in ______ and give out ______ in respiration.

Answer

Living things take in oxygen and give out carbon dioxide in respiration.

b.

Animals like fish and frogs reproduce by laying ______ in water.

Answer

Animals like fish and frogs reproduce by laying eggs in water.

c.

Giving off extra water from a plant’s leaves is called ______.

Answer

Giving off extra water from a plant’s leaves is called transpiration.

d.

In photosynthesis, plants take in ______ and give out ______.

Answer

In photosynthesis, plants take in carbon dioxide and give out oxygen.

e.

In an animal’s body, things are usually carried around by the ______.

Answer

In an animal’s body, things are usually carried around by the blood.

3. Choose the correct answer

a. What do insects breathe through?

Pick an answer to see why.

b. What is getting rid of unwanted things from the body called?

Pick an answer to see why.

c. Which of these gives birth to young ones?

Pick an answer to see why.

d. From which part of a plant does transpiration mostly happen?

Pick an answer to see why.

e. Why do living things need oxygen?

Pick an answer to see why.

4. Answer these questions

a.

What is a life process?

Answer

A life process is a job that a living thing does again and again, all its life, to stay alive. Nutrition, respiration, transportation, excretion and reproduction are life processes.

b.

What are the life processes of living things?

Answer

Nutrition: getting food.
Respiration: getting energy from food, with oxygen.
Transportation: carrying food, water, oxygen and wastes around the body.
Excretion: getting rid of wastes.
Reproduction: making young ones.

c.

What does a plant excrete?

Answer

Carbon dioxide, from respiration.
Oxygen, from making food.
Extra water, as water vapor from the leaves (transpiration).
Resin and latex, from the stem.

d.

Can all plants make their own food? Give a reason.

Answer

No. Only green plants can make their own food, because only they have chlorophyll. Chlorophyll catches the sunlight needed to make food. A plant with almost no chlorophyll, like dodder (akashbeli), the yellow, leafless vine that climbs over bushes, can’t make its own food. It takes its food from the plant it grows on. (Mushrooms can’t make food either, but they are not plants.)

e.

Write any two differences between autotrophs and heterotrophs.

Answer

Autotrophs make their own food. Heterotrophs can’t; they take food from others.
Autotrophs have green chlorophyll. Heterotrophs have none.
Autotrophs: green plants, like mango and grass. Heterotrophs: animals and mushrooms.

f.

Breathing and respiration are different. Do you agree? Explain.

Answer

Yes, they are different.

Breathing is taking oxygen into the body and giving carbon dioxide out. It happens in the breathing organs, like the lungs.
Respiration is breaking down food with oxygen, inside the body, to get energy. It makes carbon dioxide and water. It happens in every part of the body.

Breathing brings in the oxygen that respiration uses, and takes away the carbon dioxide it makes.

g.

When we have a headache or a stomach ache, we swallow a medicine. Which life process carries the medicine from the stomach to the part that hurts? Explain.

Answer

Transportation. The medicine dissolves in the stomach and passes into the blood. The heart pumps the blood all round the body. So the medicine reaches every part, including the part that hurts, such as the head.

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