CHAPTER 5 :- THINGS AROUNDS US
Let's Try 1
Definitions (One or Two Words)
a. Cell: Basic unit of life
b. Respiration: Breakdown of food to release energy
c. Excretion: Waste removal
d. Reproduction: Producing offspring
e. Stimulus: Environmental trigger
Short Answer Questions
a. How do plants reproduce?
Plants reproduce through sexual reproduction (using flowers and seeds) or asexual reproduction (such as budding, vegetative propagation, or spore formation).
b. What is the life cycle of an organism?
The life cycle of an organism includes all stages of its development, from birth to maturity, reproduction, and eventual death. It varies across species, encompassing processes like growth and reproduction.
c. Plants also breathe in oxygen and release carbon dioxide like us. Then, why do we say that plants provide us oxygen?
Plants provide oxygen because during photosynthesis, they release more oxygen than they consume during respiration. This surplus oxygen is essential for other organisms to survive.
Differentiation Table
| Autotrophs | Heterotrophs |
|---|---|
| Produce their own food. | Depend on others for food. |
| Examples: Plants, algae. | Examples: Animals, humans. |
| Unicellular Organisms | Multicellular Organisms |
|---|---|
| Consist of a single cell. | Made up of multiple cells. |
| Examples: Amoeba, bacteria. | Examples: Humans, trees. |
Long Answer Questions
a. What are the three types of wastes produced by our body? How are they excreted?
The three types of wastes produced by our body are:
- Solid waste: Excreted through the digestive system as feces.
- Liquid waste: Excreted through the urinary system as urine.
- Gaseous waste: Excreted through the respiratory system as carbon dioxide.
These processes ensure the removal of toxic substances from the body.
b. How is excretion in plants different from that in animals?
Excretion in plants is passive and involves processes like releasing oxygen during photosynthesis and shedding leaves, bark, or other structures to eliminate waste. In animals, excretion is more complex, involving specialized organs like kidneys, lungs, and skin for the active removal of waste products like urine, sweat, and carbon dioxide.
c. What is stimulus? Explain the response to stimuli shown by plants and animals with the help of suitable examples.
A stimulus is any change in the environment that triggers a response. Animals respond to stimuli with immediate actions; for example, withdrawing a hand from a hot object. Plants also respond, though more slowly; for instance, the Mimosa plant folds its leaves when touched, and sunflowers turn toward sunlight.
d. Explain the different characteristics of living organisms with the help of a flow chart.
Flow Chart:
- Cellular Organization: Made up of one or more cells.
- Metabolism: Perform chemical processes like respiration.
- Growth: Increase in size or number of cells.
- Reproduction: Produce offspring to continue the species.
- Response to Stimuli: React to changes in the environment.
- Adaptation: Adjust to environmental conditions over time.
- Excretion: Remove waste products.
- Movement: Plants show growth-based movement, and animals move physically.
Answers:
a. Clouds are considered non-living because they do not perform essential life processes like breathing, growing biologically, or reproducing, even though they can move and grow in size.
b. A silk scarf is non-living because it is a manufactured product made from silk threads produced by silkworms, which are no longer alive.
c. An aeroplane is non-living as its movement and functioning are driven by human control and mechanical processes, not life activities.
d. Viruses are unique as they behave like living things only inside a host, where they reproduce, but act non-living outside the host.
e. The leather bag and wooden spoon are non-living but were once part of living organisms, while the polyester T-shirt and plastic toy are synthetic and never alive.
2. Long Answers:
a. Differences Between Living and Non-living Things:
| Living Things | Non-living Things |
|---|---|
| Show growth and reproduction. | Do not grow or reproduce. |
| Need food, air, and water. | Do not require these to exist. |
| Respond to stimuli. | Do not respond to stimuli. |
| Made up of cells. | Made of non-cellular materials. |
| Have a lifespan. | Do not have a lifespan. |
b. A seed appears non-living because it shows no visible life processes in its dormant state. However, when given water, air, and warmth, it germinates and becomes a living plant.
-----------------------------------------------Let's Try 3 ---------------------------------------------
1. Differentiation Table
| a. Biotic and Abiotic Components | Biotic | Abiotic |
|---|---|---|
| Definition | Living components of the environment. | Non-living components of the environment. |
| Examples | Plants, animals, fungi, bacteria. | Air, water, soil, sunlight, temperature. |
| b. Cold-blooded and Warm-blooded Animals | Cold-blooded | Warm-blooded |
|---|---|---|
| Definition | Animals whose body temperature changes with the environment. | Animals that maintain a constant body temperature. |
| Examples | Fish, amphibians, reptiles. | Birds, mammals. |
2. Short Answers
a. How do earthworms present in the soil enhance the quality of soil?
Earthworms improve soil quality by loosening it, allowing air and water to pass through. They also decompose organic matter into nutrients that plants can use.
b. How are plants dependent on air for survival?
Plants use carbon dioxide from the air for photosynthesis, which helps them make food. Oxygen from the air is also needed for their respiration.
c. What is the role of sunlight in the survival of biotic components in nature?
Sunlight provides energy for plants to carry out photosynthesis, which is the base of the food chain. Without sunlight, plants and animals would not survive.
3. Long Answers
a. Abiotic factors are non-living elements of the environment that influence living organisms. For example, sunlight provides energy for plants to perform photosynthesis, which is essential for the food chain. Water is another key abiotic factor, as it is necessary for the survival of all living beings, supporting processes like digestion and nutrient transport.
b. Soil interacts with biotic components by providing nutrients, water, and a place to live. Plants absorb minerals and water from the soil for growth. Microorganisms in the soil break down organic matter, releasing nutrients for plants. Animals like earthworms improve soil structure, making it fertile and helping plants grow.
0 Comments