CHAPTER- 10 LIVING CREATURES: EXPLORING THEIR CHARACTERISTIC
NOTES
- Plants do not move from one place to another, but they do show certain types of movements, for example, the blooming of flowers.
- Living organisms need food (nutrition) for their growth and development.
2. Respiration— In the process of respiration, when we inhale, air enters our body from the outside. When we exhale, air moves out of our body.
- All living organisms carry out respiration.
3. Stomata— There are small pores on the surface of plant leaves which are called stomata.
- These pores help the plant in taking in air and releasing air from its body.
4. Excretion— The removal of waste products from the body is called excretion.
- In animals, urine is also produced as one of the excretory products.
- Plants excrete excess water and minerals in the form of tiny droplets on the surface of their leaves.
5. Stimulus— Any object or event that triggers a response in living organisms is called a stimulus.
- All living organisms respond to stimuli.
6. Reproduction— The process of producing young ones of their own kind is called reproduction. All living organisms reproduce.
7. Dead— When a living organism is unable to exhibit all the above characteristics even when all the resources required for survival (food, air, and water) are available, it is called dead.
8. Characteristics of Living Organisms—
- Living organisms show movement.
- They need food.
- They grow.
- They carry out respiration.
- They reproduce.
- They perform excretion.
- They respond to stimuli.
9. Non-living— If even one of the characteristics seen in living organisms (such as movement, respiration, excretion, reproduction, etc.) is absent, it indicates that they are non-living things.
10. Seed Germination Process— Seeds require a suitable amount of water and air for germination.
(a) Water— Seeds need water for germination.
- Water enables seeds to carry out the essential processes required for their growth.
- Seed Coat— The outer covering of a seed is called the seed coat. Water softens the seed coat and helps the tiny embryo inside it to develop into a plant.
(b) Air and Soil— Seeds utilize the air present in the spaces between soil particles.
- The spaces between soil particles allow roots to grow easily.
(c) Light and Darkness Conditions— Generally, most seeds do not require light for germination.
- After germination, the seedling requires sunlight for its growth.
11. Growth and Movement in Plants —
- When a plant is kept upright, the root grows downward and the shoot grows upward.
- If a plant is placed upside down, the root bends and grows downward, while the shoot also bends and grows upward.
- If a plant receives sunlight from only one direction, the shoot grows towards the light, while the root continues to grow downward.
- The shoots of plants grow upwards and show movement towards sunlight, while the roots grow downwards.
12. Life Cycle of a Plant— The complete process from a seed growing into a plant and producing the next generation of seeds is called the life cycle of a plant.
- When a plant stops growing and, despite the availability of all necessary conditions, its life activities gradually come to an end, the plant is considered dead.
13. Life Cycle of a Mosquito— The female mosquito is a blood-sucking insect that can transmit many diseases such as malaria, dengue, and chikungunya.
- Life Cycle— Egg, larva, pupa, and adult are the four stages of the mosquito’s life cycle.
- A mosquito begins its life as an egg. The egg develops into a larva, the larva develops into a pupa, and the pupa transforms into an adult mosquito. The adult female mosquito lays eggs directly on water or near water, and this cycle continues.
14. Life Cycle of a Frog— The life cycle of a frog has four stages:
- Egg Stage, The egg transforms into an embryo.
- Tadpole Stage, Initially, the tadpole has a tail and no legs; later, it develops hind legs.
- Froglet Stage, The transitional stage between tadpole and adult frog.
- Adult Frog Stage, When fully developed, adult frogs can live both in water and on land.
LET US ENHANCE OUR LEARNING
Question- 1. List the similarities and differences in life cycles of plants and animals.
Answer- Similarities in the Life Cycles of Plants and Animals—
- Both life cycles begin with a small unit.
- Both show growth: plants germinate from seeds and grow into trees, while animals develop from eggs into adults.
- Both have several developmental stages during their life cycle.
- Both reproduce and give rise to the next generation.
Differences in the Life Cycles of Plants and Animals—
- Plants remain fixed in one place, whereas animals can move from place to place.
- The duration of their life cycles is different.
- In plants, growth mainly occurs in the vertical direction, whereas in animals, development occurs in different parts of the body.
- Plants have roots, stems, and leaves, while animals have a group of organs.
Question- 2. The Table on the next page shows some data. Study the data and try to find out 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-
Question- 3. You have learnt that different conditions are required for seed germination. How can we use this knowledge for proper storage of grains and pulses?
Answer- Seeds require moisture, air, and a suitable temperature for germination. This knowledge can be used for storing grains and pulses. If seeds are kept away from moisture, air, and light, the chances of their germination decrease. Grains and pulses should be stored in dry, well-ventilated, and cool places so that they do not germinate and remain safe for a long time.
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- The tail of a tadpole helps it to swim. The tail provides mobility, allowing it to escape from predators. It also helps the tadpole search for food. Through its tail, the tadpole can maintain balance and swim at high speed, which is important for its survival.
Question- 5. Charan says that s wooden log is non-living as it cannot move. Charu counters it by saying that it is living because it is mode of wood obtained from trees. Give your arguments in favour or against the two statements given by charan and charu.
Answer- Charaṇ’s Argument— Charaṇ says that a log of wood is non-living because it does not show movement. This argument is correct because one of the main characteristics of living beings is movement, and a log of wood does not exhibit any movement in its present state. Moreover, the log has been separated from the tree, so it no longer carries out any biological processes, which is why it can be considered non-living.
Charu’s Argument— Charu says that a log of wood is living because earlier it was a part of a living tree and had all the characteristics of life. However, when the log is cut from the tree, it loses its living state and is considered non-living. Therefore, Charu’s argument is partially correct that the wood was once living but is now non-living.
Question- 6. What are the similarities and distinguishing features in the life cycles of a mosquito and a frog?
Answer- Similarities and Differences in the Life Cycles of Mosquito and Frog
Similarities—
- Both life cycles begin with an egg.
- Both life cycles have several stages during which significant changes occur in their body structure.
- The early stages of both life cycles are associated with water: the mosquito lives in water in the larval stage, and the frog lives in water as a tadpole.
Differences—
- The life cycle of a mosquito is short, whereas the life cycle of a frog is long.
- In the mosquito’s life cycle, the larva changes into a pupa and then into an adult mosquito, whereas in the frog’s life cycle, the tadpole develops directly into a frog.
- During its life cycle, a frog moves from water to land, whereas a mosquito develops into a flying insect that moves from water to land.
Question- 7. A plant is provided with all the conditions suitable for its growth (fig 10.9). Draw what you expect to see in the shoot and the root of the plant after one week. Write down the reasons.
Answer- If a plant is provided with all the suitable conditions required for its growth, then after one week we will observe the following changes:-
Shoot— The shoot will always grow upwards. It mainly grows in the direction of light.
- The length of the shoot will increase, and new leaves may also develop.
Root— The root will always grow downward. It grows in the direction of gravity.
- The length of the root will increase, and the roots will spread deeper into the soil.
Reason— The shoot grows upward because it needs light, whereas the roots grow downward because they spread in the soil to absorb water and nutrients.
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 set up seeds under three different conditions to study plant growth and their responses. Through these conditions, they want to find out the direction in which plant roots and shoots grow.
Their Objective—
- Tara and Vijay want to determine that plant roots always grow downward and shoots grow upward, no matter in which direction the seed is placed. This happens due to gravitropism.
- They also want to find out that shoots grow towards light, while roots spread downward into the soil. This process is called phototropism.
How They Found That They Were Right—
- First Condition— In the first condition, the seed is placed horizontally. If the root grows downward and the shoot grows upward, it shows that the effect of gravity determines the direction of plant growth.
- Second Condition— In the second condition, the seed is placed upside down. If the root again grows downward and the shoot grows upward, this further confirms gravitropism.
- Third Condition— In the third condition, the seed is placed upright. If the root grows downward and the shoot grows upward, it shows the combined effect of light and gravity.
If plant growth in all three conditions occurs as described above, then Tara and Vijay’s conclusion will be proven correct.
Question- 9. Design an experiment to check if temperature has an effect on seed germination.
Answer- Objective— To study the effect of temperature on seed germination.
Materials—
- Three places with different controlled temperatures
- Three separate pots
- Water, soil, cloth
- Thermometer
- Notebook and pen
Procedure- Preparation of Seeds—
- Equal amounts of soil were placed in three pots.
- The same type of seeds was sown in all the pots.
- All seeds were given the same amount of water.
Temperature-Controlled Conditions—
- The first pot was kept at room temperature.
- The second pot was kept in a warm place where the temperature was higher than normal.
- The third pot was kept in a refrigerator.
Observation—
- The seeds were observed daily to note whether they had germinated.
- The temperature was measured using a thermometer and recorded.
Results and Analysis—
- After 10–15 days, the number of germinated seeds and their growth at each temperature were analyzed.
- It was examined at which temperature the maximum and minimum number of seeds germinated.
- It was noted at which temperature seed germination occurred the fastest.
Conclusion— From this experiment, we can conclude which temperature is most suitable for seed germination and under which conditions germination is slow or fast.
