Living Creatures: Exploring their Characteristics Class 6 Question Answer Science Chapter 10

Living Creatures: Exploring their Characteristics Class 6 Questions and Answers NCERT Solutions

Class 6 Science Chapter 10 Living Creatures: Exploring their Characteristics Question Answer

Living Creatures: Exploring their Characteristics Class 6 Intext Questions

Page – 191

Question 1.
How would you now categorise a seed as living or non-living?
Answer:
A seed is categorised as living. Although it does not show active movement or growth at first, it is a dormant form of a plant that has the potential to grow and develop into a new plant under the right conditions. Seeds contain living cells and can undergo metabolic processes when conditions become favourable, such as germination.

Page – 197

Question 2.
How can the life cycle of a mosquito be disrupted?
Answer:
The life cycle of a mosquito can be disrupted through several methods:

• Eliminating stagnant water: Regularly removing standing water sources where mosquitoes lay eggs prevents the larvae from developing.
• Using larvicides: Applying chemical or biological agents to water sources that kill mosquito larvae before they become adults.
• Introducing , predators: Introducing natural predators, such as fish or insects, that feed on mosquito larvae can reduce their numbers.
• Using insecticides: Spraying insecticides to kill adult mosquitoes can reduce their population and prevent them from breeding.

Living Creatures: Exploring their Characteristics Class 6 Textbook Questions

Question 1.
List the similarities and differences in the life cycles of plants and animals.
Answer:
Similarities:
(i) Reproduction: Both life cycles include a reproductive stage where new individuals are produced to continue the species.
(ii) Growth and development: Both involve growth and development phases where the organism increases in size and complexity.

Differences:
(i) Reproductive Mechanism:
(a) Plants: Reproduce through seeds, spores, or vegetative parts.
(b) Animals: Typically reproduce through mating and then fertilisation, with direct development or metamorphosis.

(ii) Life Stages:
(a) Plants: May include stages like seed, germination, vegetative growth, flowering and fruiting.
(b) Animals: Include stages like embryo, larva (in some), pupa (in some), juvenile and adult.
(iii) Nutrient Acquisition:
(a) Plants: Perform photosynthesis to produce their own food at a fixed location.
(b) Animals: Consume other organisms for food and can move to find their food.

(iv) Movement:
(a) Plants: Exhibit movement mainly in response to environmental stimuli (e.g., opening flowers, growing towards light).
(b) Animals: Often have more active movement for locomotion and behaviour.

Question 2.
The table shows some data. Study the data and try to find examples appropriate for the conditions given in the second and third columns. If you think that an example for any of the conditions given below is not possible, explain why.

Answer:
The table presents a simplified model of the characteristics of living and non-living things.

Question 3.
You have learnt that different conditions are required for seed germination. How can we use this knowledge for the proper storage of grains and pulses?
Answer:
(i) Control moisture levels: Seeds require specific moisture levels for germination. By controlling humidity and ensuring grains and pulses are kept dry, we prevent premature germination or mould growth.

(ii) Temperature regulation: Store grains and pulses at appropriate temperatures to inhibit germination. Extreme temperatures can damage seeds.

(iii) Avoid light exposure: Some seeds may germinate* if exposed to light. Store grains and pulses in dark, cool places to prevent any light-induced germination.

(iv) Proper ventilation: Ensure proper airflow to prevent moisture build-up, which can lead to mould and premature sprouting. Use breathable containers or storage methods to keep the environment dry and wellventilated.

(v) Pest control: Implement measures to keep pests away, as they can cause damage to seeds.

Question 4.
You have learnt that a tail is present in a tadpole but it disappears as it grows into a frog. What is the advantage of having a tail in the tadpole stage?
Answer:
In the tadpole stage, the tail provides several advantages:

1. Swimming Efficiency: The tail helps the tadpole move through the water by providing propulsion.
2. Manoeuvrability: A tail enhances the tadpole’s ability to navigate through aquatic environments, allowing it to steer and control its movements effectively.
3. Balance: The tail aids in maintaining balance while swimming, ensuring the tadpole can move smoothly and efficiently.

Question 5.
Charan says that a wooden log is non-living as it cannot move. Charu counters it by saying that it is living because it is made of wood obtained from trees. Give your arguments in favour or against the two statements given by Charan and Charu.
Answer:
Arguments in favor of Charan’s statement:
(i) Lack of movement: Charan’s argument that the wooden log is non-living because it cannot move is based on one of the key characteristics of living beings. While movement alone does not define life, living organisms do exhibit some form of movement or growth during their lifetime.

(ii) Absence of growth: The wooden log does not grow or develop. It remains the same size and shape once it has been cut from the tree, which is a characteristic of nonliving objects.

(iii) No Response to stimuli: The log does not respond to external stimuli (e.g., light, touch), which is a typical feature of living organisms.

Arguments in favour of Charu’s statement:
(i) Origin from Living Trees: Charu’s argument is based on the fact that the Nood comes from trees, which are living organisms. While the wooden log itself is not living, it is made from a material that was once part of a living tree.

(ii) Cellular structure: Wood has a cellular structure derived from the tree. The cells of the tree were once alive and contributed to the formation of the wood, suggesting that the material originated from living processes.

Conclusion: The wooden log, in its current state, is non-living because it does not exhibit the characteristics of life such as growth, movement, response to stimuli, reproduction or metabolism. However, it was the part of a living organism (the tree).

Question 6.
What pre the similarities and distinguishing features in the life cycles of a mosquito and a frog?
Answer:
Similarities in the life cycles of a Mosquito and a Frog:
(i) Egg stage: Both mosquitoes and frogs begin their life cycle as eggs. In mosquitoes, eggs are laid on or near water, while frogs lay eggs in or near water bodies.

(ii) Metamorphosis: Both undergo a metamorphosis process. Mosquito larvae develop into pupae before becoming adult mosquitoes, while frog tadpoles metamorphose into froglets and then into adult frogs.

(iii) Life Cycle stages involving water: For both organisms, certain stages of their life cycle occur in or around water. Mosquito larvae and frog tadpoles are aquatic, highlighting the importance of water for development.

Distinguishing features in the life cycles of a Mosquito and a Frog:
(i) Number of stages:
(a) Mosquito: Has four stages-egg, larva, pupa and adult.
(b) Frog: Has five stages-egg, embryo, tadpole (with two sub-stages: tadpole with tail and tadpole with legs), froglet and adult.

(ii) Pupal stage:
(a) Mosquito: Includes a distinct pupal stage where the ląrva transforms into an adult mosquito.
(b) Frogi Does not have a pupal stage. The transformation from tadpole to adult frog is gradual and involves metamorphosis from a tadpole to a froglet.

(iii) Duration of each stage:
(a) Mosquito: The duration of each stage is relatively short. The entire cycle from egg to adult can be completed in a few weeks.
(b) Frog: The life cycle is longer, with tadpoles requiring several weeks to months to develop into adult frogs, depending on the species and environmental conditions.

Question 7.
A plant is provided with all the conditions suitable for its growth (Fig. 10.8). Draw what you expect to see in the shoot and the root of the plant after one week. Write down the reasons.

Answer:
Recreate and insert attached image 3

• Shoot: The shoot is expected to have grown significantly, with several leaves visible, growing upward, towards the light
• source. This is known as phototropism.
• Root: The root system should have expanded, penetrating deeper into the soil, growing downward, following the force of
• gravity. This is known as geotropism.

Reasons:

• Photosynthesis: The shoot is to perform photosynthesis, using sunlight to produce its own food.
• Anchoring: The root system is growing downward to anchor the plant firmly in the soil, providing stability and access to water and nutrients.
• Hormones: Plant hormones, such as auxin, play a crucial role in directing the growth of the shoot and root. Auxin is produced in the shoot tip and travels downward, promoting cell elongation and root growth.

Question 8.
Tara and Vijay set up the experiment shown in the picture (Fig. 10.10). What do you think they want to find out? How will they know if they are correct?

Answer:
Tara and Vijay are likely to test the direction of shoot and root growth by placing the seedlings in various orientations.
If they observe that the shoots always grow upward towards the sunlight, and the roots always grow downward into the soil in all experimental setups then they can conclude that regardless of how seed is placed, shoot grows towards sunlight and root towards gravity.

Question 9.
Design an experiment to check if temperature has an effect on seed germination.
Answer:
Experiment: Effect of Temperature on Seed Germination
Hypothesis: Higher temperature will promote faster seed germination.
Materials:

• 5 small pots or containers
• Garden soil
• Bean seeds
• Thermometer
• Heat lamps or heat mats
• Refrigerator

Procedure:

• Set up control group: Fill one pot with soil and plant 5 bean seeds. Place this pot in a room with a constant temperature (around 25° C).
• Set up experimental groups: Fill the remaining 4 pots with soil and plant 5 bean seeds in each.

(iii) Vary temperatures:

• Pot 1: Place in a refrigerator (around 5° C).
• Pot 2: Place in a cool, shaded area (around 15° C).
• Pot 3: Place in a warm, sunny location (around 30° C).
• Pot 4: Place under a heat lamp or heat mat (around 50° C).

(iv) Monitor temperature: Regularly check and record the temperature in each pot using a thermometer.
(v) Water regularly: Ensure all pots receive the same amount of water daily.
(vi) Observe germination: Observe each pot daily for signs of germination. Record the number of seeds that germinate in each pot and the time it takes for germination to occur.

Data Analysis:

(i) Compare germination rates: Compare the number of seeds that germinated in each pot and the time it took for germination to occur.
(ii) Analyse temperature effect: Determine if there is a correlation between temperature and germination rate.

Conclusion: Based on the data collected, analyse whether the hypothesis is supported or refuted. If higher temperatures indeed promote faster seed germination, the data should show a positive correlation between temperature and germination rate.

Living Creatures: Exploring their Characteristics Class 6 NCERT Exemplar Questions

Multiple Choice Questions

Question 1.
Which of the following is not an example of a response to a stimulus?
(a) Watering in the mouth when we see delicious food items.
(b) Closing of leaves of Mimosa plant when touched.
(c) Shutting our eyes when an object is suddenly thrown in our direction.
(d) A.chick hatching out of an egg.
Answer:
(d) A.chick hatching out of an egg.
Explanation: The hatching out of a chick from an egg is not a response to stimulus.

Question 2.
Which of the following is an incorrect statement about excretion?
(a) Excretion takes place in plants.
(b) Excretion takes place both in plants and animals.
(c) Excretion is the process of getting rid of excess water only.
(d) Secretion is one method of excretion.
Answer:
(c) Excretion is the process of getting rid of excess water only.
Explanation: Excretion is a process of getting rid of the waste materials produced by the body including water, salts, etc.

Very Short Answer Type Questions

Question 1.
Why is reproduction important for organisms?
Answer:
Reproduction leads to the production of new individuals of an organism of its own kind. It helps in the . continuity of life on Earth.

Long Answer Type Questions

Question 1.
Like many animals, although a car also moves, it is not considered a living organism. Give 2-3 reasons.
Answer:
(i) Living organisms move on their own while a car moves by burning fuel.
(ii) Like living organisms, car does not exhibit any characteristics of living beings like respiration, digestion, growth, etc.

Introduction

Living beings and non-living things are all around us. We can easily differentiate them based on their characteristics. Living beings show signs of life, such as growth, respiration, reproduction and movement. Non-living things do not show these signs.

Activity 10.1 (Page-184)

Let Us Record

Objective: Listing the objects in our surroundings and identifying each of them as living or non-living on the basis of our understanding.

Table 10.1:

What Sets the Living Apart from the Non-living?

Characteristics of Living beings:

Living beings exhibit movement, growth, nutrition, respiration, excretion, response to stimuli and reproduction.
These characteristics are essential for something living.

Movement:

Unlike animals, plants cannot move from one place to another. They are generally immobile; they exhibit various types of movement. For example:
Opening of flowers: Some flowers open and close at specific times or in response to light.
Insectivorous plants: Plants like Drosera trap insects for nutrition. Drosera has saucer-shaped leaves with sticky hair-like projections. When an insect lands on the leaf, these hairs move inward and trap the insect.
Climbers: Plants like vines or creepers wrap around nearby objects for support, which is another form of movement in plants.
This shows that even though plants cannot relocate, they exhibit specialised movements.

Growth:

Growth is a universal trait of all living beings. A child grows larger over time, similar to how plants and animals grow as they mature. Growth results from cell division and nutrient absorption.
Living beings that need food to grow: Plants grow food through processeds like photosynthesis and the absorption minerals from the soil.

Respiration:

Respiration is a vital process for all living organisms.
In animals, it involves the inhalation of oxygen and exhalation of carbon dioxide. The number of breaths varies based on physical activity, as demonstrated by counting breaths after walking, running or dancing.

In plants, respiration occurs through tiny pores called stomata on the surface of leaves. These stomata allow gases to move in and out, enabling respiration.

Excretion:

All living organisms excrete waste products.
In animals, excretion occurs through sweat, urine and other processes. For example, the white patches formed by sweat on shirts during summer are due to the body’s way of excreting water and salts.

In plants, excretion involves removing excess water and minerals. This can be observed as tiny droplets on leaves, especially in plants like grasses and roses.

Response to stimuli:

Living organisms respond to changes in their environment, known as stimuli. This is a crucial characteristic of life.

In humans, touching a hot object or stepping on a sharp object triggers an immediate response, such as pulling back the hand or foot.

In plants, responses to stimuli can be seen in the touch-me-not plant (Mimosa pudica), which folds its leaves when touched. Other plants, like the amla (Indian gooseberry) tree, fold their leaves after sunset in response to light changes.

Reproduction:

Reproduction ensures the survival of a species. All living beings have the ability to reproduce.

• In animals, this involves giving birth to young ones (e.g., kittens, puppies, calves).
• Non-living objects like pencils or chairs do not reproduce.

Death:

When an organism can no longer exhibit these characteristics, despite having access to necessary resources like food, and air, it is considered dead. For example, plants and animals stop showing growth, movement and other vital functions when they die.

Question 1.
Why do you think a pencil is non-living, but a pigeon is living? What do you think are the differences between living beings and non-living things according to you?
Answer:
A pencil is non-living because it does not exhibit the essential characteristics of life, such as growth, reproduction, respiration, excretion, response to stimuli or movement on its own. A pigeon, however, is living because it grows, reproduces, breathes (respiration), excretes waste, responds to stimuli (such as danger or food) and can move independently. The differences between living beings and non-living things are based on these essential characteristics.

Question 2.
What similarities do living beings share with each other?
Answer:
All living beings share certain characteristics:

• Movement: They can move or show internal movements, even if plants don’t move from place to place.
• Growth: They grow by increasing in size.
• Nutrition: They need food for energy and growth.
• Respiration: They take in oxygen and release carbon dioxide.
• Excretion: They remove waste products from their body.
• Response to stimuli: They respond to changes in their environment (e.g., humans moving away from danger or plants responding to touch).
• Reproduction: They reproduce to produce offspring of their kind.
• Death: Eventually, all living beings die when they stop performing these essential functions.

Question 3.
You may have identified movement as one of the similarities among living beings. You have also seen cars moving on the road. Does it mean that a car is living?
Answer:
No, a car is not living even though it moves. The movement in a car is mechanical and powered by fuel or electricity, not by biological processes like those in living beings. Living organisms move due to internal processes, such as muscle movement in animals or growth in plants.

Question 4.
List the tasks that you can do, but a car cannot.
Answer:
As a living being. I can:

• grow and develop (a car remains the same size).
• reproduce to create new life (a car cannot reproduce).
• breathe (respire) to obtain energy (a car does not need oxygen to function).
• excrete waste (a car does not produce or remove waste biologically).
• respond to stimuli, such as pulling my hand away when I touch something hot (a car does not react to its environment unless controlled by external means).

Question 5.
Which characteristics help you differentiate yourself from a car?
Answer:
The key differences are as follows:

1. Growth: I grow and change over time, but a car remains the same.
2. Reproduction: I can reproduce, whereas a car cannot.
3. Respiration: I breathe and respire, while a car does not.
4. Excretion: I excrete waste products, but a car does not.
5. Response to stimuli: I can react to my surroundings, while a car’s movements are controlled externally.

Question 6.
Does a car not growing mean it is non-living? What characteristics have you used to classify a car as nonliving?
Answer:
Yes, a car not growing is one reason it is non-living. However, the main characteristics that classify a car as non-living are as follows:

1. No reproduction: A car cannot create offspring.
2. No respiration: A car does not need oxygen for energy production.
3. No excretion: A car does not excrete waste like living organisms do.
4. No response to stimuli: A car cannot react to its environment on its own.
5. No internal movement: Its movement is dependent on external forces like fuel or electricity.

Question 7.
Can we consider movement as one of the characteristics that differentiates between living and non-living things?
Answer:
Yes, but with caution. While movement is a characteristic of living beings, it cannot be the sole criterion. Some non-living things, like cars or machines, can move, but that movement is mechanical and externally controlled. True living movement is driven by internal biological processes, such as muscle movement in animals or growth in plants. So, while movement is important, other factors like growth, respiration and reproduction must also be considered.

Question 8.
List five ,things around you that can move on their own. Do you think all five things that you have listed can be considered as living just because they can move on their own?
Answer:
Dog, bird, cat, plant and humans.
Movement alone does not classify something as living. Only organisms that show other characteristics like growth, respiration, reproduction and response to stimuli can be considered living.

Question 9.
Even though plants do not move from one place to another, they do show certain types of movements. Can we consider plants as living?
Answer:
Yes, plants are living beings. Even though they do not move from one place to another like animals, they show movements like:

• opening and closing of flowers,
• movements in insectivorous plants like Drosera to trap insects and
• winding movements in climbers, etc.

These movements indicate internal biological processes.

Question 10.
List five living beings that require food to grow.
Answer:
Humans, dogs, birds, fishes and plants.

Question 11.
Do plants also respire?
Answer:
Yes, plants respire. They take in oxygen and release carbon dioxide through small pores called stomata on their leaves. Respiration in plants is essential for energy production, just like in animals.

Question 12.
Do plants also excrete?
Answer:
Yes, plants exçete. They remove excess water and minerals through tiny droplets, especially seen on the leaves of plants like grass or roses. This process helps in eliminating waste materials.

Question 13.
What is your reaction if you unexpectedly step on a sharp object, such as a thorn, while walking without shoes?
Answer:
If I stepped on a thorn, I would immediately pull my foot back. This is a response to the stimulus of pain. It demonstrates how living beings react to changes in their environment (stimuli).

Question 14.
Do plants also respond to stimuli?
Answer:
Yes, plants respond to stimuli. For example:
(i) Touch-me-not plant (Mimosa) folds its leaves when touched.
(ii) Amla planfs fold their leaves after sunset.
These responses indicate that plants, like animals, react to external stimuli.

Question 15.
Why do the leaves of chhui-mui (Mimosa) and amla plants respond in this way?
Answer:
The response is triggered by stimuli. In the case of Mimosa, physical touch acts as a stimulus, causing the leaves to fold. For amla plants, the absence of sunlight (a stimulus) triggers the folding of leaves. This behaviour helps protect the plant and conserve energy.

Question 16.
Why is reproduction necessary for living beings?
Answer:
Reproduction is necessary for the continuity of life. It allows living beings to produce offspring, ensuring that their species continues to exist. Without reproduction, a species would eventually become extinct.

Question 17.
When a living being is not able to exhibit all the characteristics of life, despite the availability of resources, is it considered dead?
Answer:
Yes, when a living being can no longer perform essential functions like growth, respiration, reproduction or response to stimuli even if resources like food, air and water are available, it is considered dead.

Question 18.
In which category would you place a seed-living or non-living? Why?
Answer:
A seed is considered living. Although it mây appear inactive, under the right conditions (water, warmth and soil), it can germinate and grow into a new plant. This ability to grow, move and reproduce makes it living.
Essential Conditions for germination of a seed
Seed germination is the process by which a seed, upon favourable conditions, begins to grow and develop into a new plant. It involves the breakdown of the seed coat, the emergence of a root and the subsequent growth of shoots and leaves.

Activity 10.2 (Page-188)

Let Us Experience

Take four identical pots filled with garden soil. Sow four bean seeds in earl. pot. Now, keep these pots in the following conditions for 15 days.

Table 10.2

Analysis:
(i) Pot A: No germination occurred due to the lack of water. Seeds require water for hydration and to initiate metabolic processes.

(ii) Pot B: Excess water prevented germination. The seeds were likely drowned, as the soil was too saturated. Excess water also replaces the oxygen present in soil which is another essential factor for germination.

(iii) Pot C: Germination occurred despite the lack of sunlight. This demonstrates that sunlight is not essential for germination, but moisture is crucial.

(iv) Pot D: Germination occurred under optimal conditions with both sunlight and moisture present. Both factors are essential for healthy seed germination.
Let us understand how these conditions help in seed germination.

(i) Water: Seeds require water for germination. Water enables the seeds to carry out the processes necessary for their growth. The outer covering of the seed is called the seed coat. Water softens the seed coat and helps the tiny embryo inside it to develop into a plant.
(ii) Air and Soil: Seeds need air for germination. They use the air available in the spaces between soil particles. Moreover, spaces between the soil particles allow roots to grow easily.

(iii) Light and/or dark conditions; We have learnt that for the bean seeds, the presence of light is not essential for their germination. In general, most seeds do not require light for germination. But after germination, sunlight is required for further growth of the seedling.

Do you know? Some seeds of flowering plants, like Coleus and Petunia, require light to germinate. Covering these seeds with soil inhibits their sprouting. Seeds of flowering plants, like Calendula and Zimia, need darkness to germinate. These seeds should be covered with sufficient soil.

Growth and Movement in Plants

Plants grow through cell division and show movement like flower opening, insect trapping and climbing for support.

Activity 10.3 (Page-191)

Let us Design

This activity investigates the influence of light on the growth of plant roots and shoots. By exposing seedlings to different lighting conditions, we can observe how these factors affect the direction of growth.

Table 10.3

From the results of this experiment, we note that:

1. When the plant is kept upright, the root grows downwards and the shoot grows upwards.
2. When the plant is kept inverted, the root bends and grows downwards. Also, the shoot bends and grows upwards.
3. When the plant gets sunlight only from one direction, the shoot grows in the direction of light while the root continues to grow downwards.

Question 1.
What is the direction of growth of root and shoot in beakers A, B and C based on your observations?
Answer:

1. Beaker A: Shoot grows upward, root grows downward.
2. Beaker B: Shoot grows upward, root grows downward.
3. Beaker C: Shoot grows towards the light source, root grows away from the light source.

Question 2.
Do your predictions match your observations?
Answer:
Yes, the predictions match the observations.

Question 3.
What do you conclude from this activity?
Answer:

• This activity demonstrates that the growth of plant roots and shoots is influenced by light.
• Shoots exhibit phototropism, growing towards the light source.
• Roots exhibit geotropism, growing downward in response to gravity.
• The direction of growth of roots and shoots is not affected by the orientation of the plant itself.

Know a scientist

Jagadish Chandra Bose (1858-1937) was an Indian scientist who did some fascinating experiments with plants. He built a machine called a crescograph to record how plants respond to stimuli like light, heat, electricity and gravity. With this machine, he could measure how fast plants grow. He also showed that plants can sense and respond to stimuli.

Life Cycle of a Plant

A plant’s life cycle typically begins with a seed. The seed germinates under favourable conditions, growing into a seedling. The seedling develops into a mature plant that produces flowers, fruits and seeds. These seeds can then germinate, starting the cycle a new.

Activity 10.4 (Page-194)

Life Cycle of a Plant

Table 10.4:

Question 1.
How long does it take for any change to occur?
Answer:
The first noticeable change (seed germination) occurred around day 5 .

Question 2.
After how many days does the first flower appear?
Answer:
The first flower appeared around day 40 .

Question 3.
After some parts of the flower have dried, can you see any further growth?
Answer:
Yes; after the flower petals wither and fall off, the ovary of the flower can develop into a fruit.

Question 4.
Which structure do the remaining parts of the flower develop into a fruit?
Answer:
The ovary of the flower typically develops into a fruit.

Question 5.
Can you notice a pod or a fruit with seeds develop from a flower?
Answer:
Yes, a fruit containing seeds developed from a flower.

Question 6.
What happens to the plant after the fruits containing seeds are formed?
Answer:
After the fruits containing seeds are formed, the plant may start to decline. In some cases, the plant may die after producing seeds.

Life Cycle of Animals

The life cycle of animals involves stages like birth, growth, reproduction and death. Animals undergo various developmental processes, including metamorphosis in some species, such as frogs and butterflies, transforming from larval to adult forms during maturation.

10.5.1 Life cycle of a Mosquito

(i) Mosquito Breeding and Diseases:
(a) Female mosquitoes are bloodsucking insects that transmit diseases like malaria, dengue and chikungunya.
(b) Mosquito breeding occurs in stagnant water, making it essential to prevent water from collecting in any surroundings.

(ii) Relation
Between Stagnant Water and Mosquitoes:
(a) Stagnant water provides an ideal environment for mosquitoes to lay their eggs, leading to an increase in the mosquito population.
(b) Common places for stagnant water: desert coolers, potted plants and open containers.

(ii) Life Stages of Mosquitoes:
(a) Larva and Pupa: These are two distinct life stages of mosquitoes before they become adults.
I. Larva: Worm-like creatures, typically found Inoving near the surface of the water.
II. Pupa: Also worm-like but slightly more developed than larvae.

(i) Observation of Larvae and Pupae:
(a) If larvae or pupae are observed during the safety audit, they should be reported to the teacher to initiate preventive measures.

(b) Differences in shape:
I. Larva is slender and elongated.
II. Pupa is more curled, with a different body structure compared to larvae.

(c) Both larvae and pupae move to the surface of the water to breathe, as they need air for respiration.

(ii) Preventive Measures to Avoid Mosquito Breeding:
(a) Regularly check and eliminate stagnant water in coolers, pots and containers.
(b) Keep surroundings, clean and dry to prevent mosquitoes from laying eggs.
(c) Promote awareness about mosquito-borne diseases and the importance of preventing water stagnation.

Question 1.
Why should stagnant water be avoided?
Answer:
Stagnant water provides a breeding ground for mosquitoes to lay their eggs, leading to an increase in mosquito populations and the spread of diseases.

Question 2.
What is the relation between stagnant water and mosquitoes laying eggs?
Answer:
Mosquitoes lay their eggs in stagnant water, where their larvae and pupae develop into adult mosquitoes.

Question 3.
What differences do you observe in the shape of larvae and pupae?
Answer:Larvae are more elongated and slender, while pupae have a more curved shape and are closer to the adult form.

Question 4.
Why do mosquito larvae and pupae come to the water surface repeatedly?
Answer:
Both larvae and pupae come to the surface to breathe air, as they require oxygen for respiration despite living in water

Question 5.
I have seen my mother spraying kerosene oil on stagnant water. Why does she do so?
Answer:
Kerosene oil forms a thin layer over the water surface. This layer separates water from air and does not allow larvae and pupae to inhale air. As a result, they die.

Activity 10.5 (Page-198)

Let Us Analyse

To determine which stage (larva or pupa) comes immediately after the egg stage in a container with both larvae and pupae.
Activity Design
(i) Preparation:
(a) Obtain a container filled with water from a puddle that contains both mosquito larvae and pupae.
(b) Label the container with the date of observation.

(ii) Observation:
(a) Observe the container daily.
(b) Take note of any changes in the larvae and pupae, including their movement and development.

(iii) Recording Changes:
(a) Document Larval Changes: Watch for any larvae that undergo transformation. Note when they change in appearance or behaviour.
(b) Document Pupal Changes: Observe the pupae to see if they develop into adult mosquitoes.

(iv) Identification of Stages:
(a) Larval Stage: Look for small, worm-like creatures swimming in the water.
(b) Pupal Stage: Identify pupa by their more rounded and enclosed appearance, often seen floating or resting near the water surface.

(v) Comparative Ąnalysis:
(a) Compare observations of the developmental changes of larvae and pupae.
(b) Record the time it takes for larvae to transform into pupae and for pupae to become adult mosquitoes.

(vi) Conclusion:
(a) If larvae transform into pupae, it confirms that the larval stage precedes the pupal stage and larvae develop from eggs.
(b) If pupae eventually become adult mosquitoes, it validates that the pupal stage comes before the adult stage.

(vii) Final Observation:
(a) Note the emergence of adult mosquitoes from the pupae, which verifies the sequence of stages in the mosquito life cycle.

Understanding the Mosquito Life Cycle

1. Egg Stage (Stage I): Mosquito eggs are laid on or near water. They hatch into larvae.
2. Larva Stage (Stage II): Larvae are worm-like creatures that live in water and feed on microorganisms.
3. Pupa Stage (Stage III): Pupae are more rounded and less mobile than larvae. They undergo metamorphosis into adult mosquitoes.
4. Adult Stage (Stage IV): The adult mosquito emerges from the pupa, rests briefly on the water’s surface and then flies away.

Question 1.
How will you decide which stage (larva or pupa) comes immediately after the egg stage?
Answer:
You can determine the correct sequence of stages by observing the developmental changes in a container with both larvae and pupae. By noting which stage transitions to the next, you can infer the sequence. For example, if larvae change into pupae, then the larval stage precedes the pupal stage.

Question 2.
Suppose you are given a container with water from a puddle containing larvae and pupae. Design an activity to find out the correçt sequence of these stages.
Answer:
Activity design:

1. Separate the Stages: Place larvae and pupae into separate containers with the same water and observe daily.
2. Monitor the Changes: Watch for larvae transforming into pupae and pupae developing into adult mosquitoes.
3. Compare Containers: Determine which container shows a mosquito first to identify the correct sequence of stages.

Question 3.
Suppose you are given a container filled with water from a puddle which contains larvae and pupae. Without separating them from the container, how would you design an activity to decide which stage, out of the two, gives way to the next?
Answer:
Activity design:

1. Daily Observations: Monitor the container daily for changes in both larvae and pupae.
2. Track Development: Document any changes in the appearance and behaviour of the larvae and pupae.
3. Identify Emergence: Record when mosquitoes emerge from pupae to confirm the sequence of stages.

Question 4.
What differences do you observe in the shape of larvae and pupae?
Answer:
(i) Larvae: Worm-like, elongated and active in water.
(ii) Pupae: Rounded, less active and often float near the water surface. They are enclosed in a protective casing.

Question 5.
Mosquito larvae and pupae observed in water bodies repeatedly come to the water surface. What can be the reason for this?
Answer:
Mosquito larvae and pupae come to the water surface to respire. They require air to breathe, and their movement to the surface allows them to take in oxygen.
Do you know?
The silk moth also passes through four life stages-egg, larva, pupa and adult. Eggs hatch into larvae, which then grow in size. Larvae secrete thread-like material which they wrap around themselves, before changing ! to pupae. These are the fibres that are used to make silk fabric. In India, the Khadi and Village Industries Commission (KVIC) has set up several centres for silk production.

10.5.2 Life cycle of a Frog

You might notice a white, jelly-like substance on the surface of the water near the pond’s edge (Fig. 10.6). It may also be attached to plants in or around the water. This jelly-like mass is actually a cluster of frog eggs, known as spawn.

Activity 10.6 (Page-199)
Let us Anclyse

Activity to determine sequence of frog’s stages of life:

Observation:
1. Observe the features of each stage (A, B, C, D, E, F) in Fig. 10.6.
2. Record changes in Table 10.4 and compare with Fig. 10.7 to draw the life cycle of a frog.

Table 10.5: Changes in Different Life Stages of a Frog

Stage	Description	Duration
Stage IA – Spawn	Jelly-like cluster of eggs on the water surface	Day 1
Stage IB – Embryo	Developing features within the eggs	Days 3-4
Stage IIA – Tadpole with tail	Tadpole with a tail, no legs	Days 7-10
Stage IIB – Tadpole with legs	Tadpole with developing legs, small tail	8-10 weeks
Stage III – Froglet	Tadpole with legs, reduced tail, beginning to spend time on land	12 weeks
Stage IV – Adult Frog	Fully developed frog with legs for jumping, no tail	14 weeks

Question 1.
How are these eggs of a frog different from other eggs you may have seen?
Answer:
Frog eggs are jelly-like and are laid in clusters. They are different from bird eggs, which are hard-shelled and laid singly or in small numbers.

Question 2.
Which stage has the shortest duration?
Answer:
The embryo stage (Stage Ip) has the shortest duration, lasting 3-4 days.

Question 3.
Is there a change in the habitat during the various stages in the life cycle of a frog?
Answer:
Yes, frogs start in water (eggs and tadpoles), then move to a transition of water and land (froglets) and finally live both in water and on land as adults.

Question 4.
How do the special features support that stage?
Answer:
Each stage has features suited to its habitat and lifestyle. For instance, tadpoles have tails for swimming, while froglets and adult frogs have legs for jumping and can live both on land and in water.

Question 5.
What do the changes fom tadpole to adult frog signify in terms of survival and continuity of their kind?
Answer:
The changes from tadpole to adult frog are crucial for survival and reproduction. The development of legs and loss of tail help the frog adapt to life on land and water, ensuring they can thrive in both environments and continue their life cycle.

Question 6.
Do yqu think that birds also show significant changes in the various stages of their life cycle?
Answer:
Yes, birds do show significant changes in their life cycle, much like other animals. Here’s a detailed look at the stages:

1. Egg Stage: Birds lay eggs, which vary in size, colour and texture depending on the species. The egg contains the developing embryo.
2. Hatchling Stage: After incubation, the egg hatches and a chick emerges. Hatchlings are typically altricial (born in an undeveloped state and requiring care) or precocial (born more developed and able to move around).
3. Nestling Stage: The chick grows in the nest, gaining feathers and developing muscles. This stage involves significant growth and development as the bird prepares to leave the nest.
4. Fledgling Stage: The fledgling begins to fly and learn to forage. It is partially independent but still depends on parents for food and protection.
5. Adult Stage: The bird reaches full maturity, capable of reproduction. Adult birds have fully developed feathers, beak and reproductive organs.
6. Reproductive Stage: Adult birds engage in mating and nesting behaviours, continuing the life cycle.

Question 7.
How does the life cycle of animals differ from that of plants?
Answer:

Keywords

• Breathing: The process of inhaling oxygen and exhaling carbon dioxide, essential for respiration in organisms.
• Excretion: The removal of waste products from the body to maintain internal balance and health.
• Germination: The process by which a seed develops into a new plant, starting with sprouting.
• Life Cycle: The series of stages an organism undergoes from birth to reproduction and eventually death.
• Living: Having life; exhibiting characteristics such as growth, reproduction and response to stimuli.
• Non-living: Objects or substances that do not possess the characteristics of life, such as growth or response.
• Nutrition: The process by which organisms obtain and use food for energy, growth and maintenance.
• Movement: The change in position or location of an organism or part of it in response to stimuli.
• Reproduction: The biological process through which new individual organisms are produced from their parents.
• Response: The reaction of an organism to a stimulus, indicating its ability to perceive and react to changes.
• Stimulus: An external factor or change that elicits a response from an organism or system.
• Death: The cessation of all biological functions that sustain life, marking the end of an organism’s life.
• Growth: The process of increase in size or complexity of an organism or its parts.
• Respiration: A chemical process used by organisms to extract energy from food, typically involving the intake of oxygen and the release of carbon dioxide.
• Larva: An immature stage in some animals’ life cycles, distinct from the adult form. often aquatic.
• Tadpole: The aquatic larval stage of a frog, characterised by a tail and lack of legs.
• Froglet: The juvenile stage in a frog’s life cycle, between tadpole and adult, with developing legs and less tail.
• Pupa: A developmental stage in some insects, where the larva undergoes transformation into an adult.

Curiosity Class 6 Science Book Solutions