Living Organisms and their Surroundings

1. Define-

a) Habitat- A place where an organism lives and grows is called habitat. The habitat must provide them food, shelter and climatic conditions so that it can easily survive, breed and flourish.

b) Adaptation- The special or specific characteristic which help the organisms to survive in an particular environment is called adaptation.

Habitat- Terrestrial , Aquatic

Terrestrial- Forest, Grassland, Coastal, Desert, Mountain

Aquatic-  Pond, lake, oceans, Swamps, rivers

Components of Environment

Environment consist of two main components. They are-

1) Biotic Components ( Living Components)

2) Abiotic Components (Physical Components)

Biotic Components

It constitutes the living parts of the environment. |It consist of  plants, Animals, Decomposers which are found around us.

Abiotic Components

Abiotic means non-living things. The soil, water and air constitute the abiotic components.

the climatic factors like Sunlight, temperature, rainfall, humidity, wind, etc are also a part of the abiotic components.

2. What are the adapting features that enables camel to live in a desert habitat.

Ans 1. Camels have long legs to keep the body away from the hot sand. 

2. They have large, padded feet that enables them to walk on soft sand.

3. It Can drink lots of water at a time. It doesn't sweat and passes very less urine to conserve water in its body. 

4. They have long eyelashes. That prevents sand from entering into their eyes.

5. They have hump that stores fat. This fat is used during starvation. when the fat gets used up the hump shrinks form the sides.

3. List the adaptation of desert plants.

Ans 1.Desert plants have wide, spreaded root system which goes deep into the soil in search of water. 

2. Leaves are modified into spines to reduce the loss of water from the leaves.

3. Stems are thick and fleshy to store  water.
4. Stems perform the function of leaves that is photosynthesis.
5. The stems of desert plant have a waxy coating that prevents the lose of water.

4. How do the biotic and abiotic components maintain balance in nature.
Ans  Biotic and abiotic components depend on each other-
1.The plants and animals develop adaptations that are suitable for the climate, light, water, temperature and air, showing that there is an interaction between the biotic and abiotic components in life.
2.The abiotic components supply nutrients to the plants. The plants prepare food for the animals.
3.Plants and animals when they die they get decomposed by microbe and add nutrients to the soil.
4.These nutrients are again absorbed by the plants and the cycle repeats again.
5.Thus the balance in nature is maintained.

5.What is the importance of the following Abiotic factors that are present in the habitat-
a) Temperature
b) Light 
c) Water
d) Air 
e) Soil

a) Temperature 
Most of the plants and animals grow in warm places but some need cold climate. eg tigers and elephants live in warm temperature, while polar bears live in cold temperature.
Palm trees, neem, peepal trees are found in hot region, while Pine trees are found in cold region.
Thus animals and plants can adapt in hot and cold regions.

b) Light
Green plants need light to make food and grow. Some animals don't come out in presence of light but some  prefer to come out to hunt prey at night. Earthworms, etc move away from light and stay in dark places.

c) Water
All living organisms need water for their survival. Cactus and camel are among the few plants and animals which can live without water or with little water for a long time.

d) Air
Animals require oxygen to live. They can't respire and produce energy if there is no oxygen. Plants require carbon dioxide to make food. The exchange of gases (carbon dioxide and oxygen) between plants and animals maintains their balance in nature.

e) Soil
It provides nutrients, water and mineral to the plants and shelter for animals.

6. What are the adapting features that are found in plants of the mountain regions?
Ans Plants such as pine and conifer are conical in shape that allow snow and water to slide of easily. They have sloping branches and leaves of some of these trees are needle-like. This help rainwater and snow to slide off easily. Some leaves have a  waxy coating.  They also have small leaves to avoid water lose and they grow near the soil to avoid uprooting by strong winds.

7. How do animals like yak, mountain goats and snow leopard adapt themselves to the mountain region?
Ans 1. Yaks- They have thick skin and long hair to keep them warm.
2. Mountain goats- They have strong hooves to move up and down on the rocky and sloppy mountain.
3. Snow leopard-  They have thick skin and fur to protect themselves from cold and have broad furry pads (Thick structure under the leg) or paws to walk on the snow.

8.What are the adapting features of a deer?
Ans 1. They have broad and strong teeth for chewing grass.
2. They have long, sharp ears to hear minute sounds that help them to be always alert.
3. They have long, strong legs to run away from predators.
4. Their eyes are on the side of their head which allows to look in all direction for danger.
5. The speed of the deer help to run away from predators.
6. The brown colour skin help to camouflage with the surroundings.

9. What are the adapting features of a lion which makes it a good predator?
Ans 1. They are fast.
2. They have long claws and sharp teeth. 
3. Eyes are in front of their face allowing it to have a correct idea of its prey and predators.
4. Brown colour of it skin helps it to camouflage when it hunts for its prey.

Adaptation for plants in grasslands

1. They have flexible stems which bend instead of breaking when the wind is strong.
2. They have strong roots to prevent uprooting by the winds.
3. They have narrow, thick leaves to reduce water loss from transpiration.
4. Some plants have deep penetrating roots to absorb as much water as possible.

Adaptation in aquatic plants (Hydro phytes) 
1. these are attached to mud at the bottom of the water body. Floating plants are exception.
2. Aquatic plants that float freely on water surface have adapted themselves for floating, Against decaying, water current, pressure, etc.
3. For floating they store air in different parts of the body (Stems, roots, leaves, etc)and have stomata on the upper surface which is exposed to air. eg Water Lily
4. For protection, the leaves are protected from decaying by a waxy coating to make it waterproof and non decayable eg tape grass.
5. For different purpose leaves are of different shapes to protect themselves from damage due to flow of water current.

Adaptation in aquatic animals
For Buoyancy
buoyancy in fishes and some insects is because of air bubbles in or on their body. 

Body scales
body is covered with scales and the scales are hard and rigid structures to protect the body and make the skin waterproof and the body is covered by slippery coating.

Body shape
The shape of fish is streamlined. The fins control the stability and underwater directional motion of fish.

Gills
Gills are capable of absorbing oxygen from the water flowing over the surface.

Adaptation of tropical rain forest
Adaptation of plants
Leaves on trees have grooves and special tips called "drip tips" that allow water to drip off easily and not collect on the leaves. thus, preventing rotting of leaves. To absorb maximum amount of sunlight as possible vegetation growing in lower levels have large leaves.

Animal life
Many rain forest animals use camouflage to escape from enemies. Some animals have become very specialised in their eating habits. They live in holes and trees. Eg parrot, monkey, macaw, insects, etc. 

10. Write about the adaptive features of the following-
a) Octopus and squid
b) Dolphin and whale 

a) Octopus and squid
1. They don't have streamlined body shape. When they move in water they make their body shape streamlined.
2. They have gills to help them use oxygen dissolved in water.
3. they stay deeper in the ocean near the sea bed and catch any prey that moves towards them

b) Dolphin and whale 
1. They have lungs to breathe. 
2. They stay inside water for a long time without breathing.
3. They come out to the surface from time to time to breathe in air.
4. They bring in air through nostrils or blowholes located on the upper part of the head.

11. Define acclimatisation.
Ans  Small changes that take place in an organism over a short period of time to overcome small problems due to changes in the surroundings is called acclimatisation.

12. Define-
a) Respiration
b) Breathing
c)Excretion
d) Stimulus
e) Response
f) Reproduction

a) Respiration
It is the process of breaking of food to carbon dioxide, water and energy in the presence of oxygen.

b) Breathing
1. It is the process of taking in oxygen rich air and giving out carbon dioxide rich air.
2. The process of taking oxygen is called inhalation.
3. The process of giving out of carbon dioxide is called exhalation.

c) Excretion
The process of removal of waste material from the organisms body is called excretion. 

d) Stimulus
Any change in the surrounding that make an organism respond to it is called stimulus.

e) Response
Reaction to a stimulus is called response.

f) Reproduction
The process of production of young one of its own kind is called reproduction.

13.What are the characteristic of living organisms?
Ans the characteristic of living organisms are all living organisms-
1. Respire
2. Move 
3. Grow
4. Respond to stimulus 
5. Reproduce
6. Excrete
7. They have definite lifespan (they grow, develop and become matured and dies)

14. Clouds exhibit growth and movement, still they are called non- living. Why?
Ans Clouds are called non-living because they don't show all the characteristics of a living organism.

15. How do plants get rid of their waste products?
Ans Plants excrete waste by-
1. The main waste product produced by plants are carbon dioxide (respiration), oxygen (photosynthesis) and water vapour. These waste products are given out through stomata.
2. Some plants store some of their waste products in the body parts in a way that they do not harm them.
3. Plants get rid of these waste by sheding of leaves, peeling of barks, falling of fruits.
4. Some plants remove their waste by secretion eg gum, raisin and latex (all are useful to humans).

16. Do plants give response to stimulus? Give two examples.
Ans Yes, plant respond to their stimulus. Eg The leaves of touch-me-not (mimosa plant) fold when someone touches it. 
Sunflower faces the Sun and changes its direction to the sun.

17. What are the different waste products which are produced in the body?
Ans 1. When proteins are broken down in the body. Ammonia, urea and uric acid is formed.
2. Carbon dioxide is produced as a waste product during digestion.
3. During digestion the undigested waste is removed as faeces and extra salt as sweat.

18. Write the adaptation of a frog.
Ans 1. It has webbed feet to climb and hold on plants.
2.  It has a long, sticky tongue to catch insects.
3.  It has strong eyesight and eats and insect which moves in front of it. 

Floating Aquatic plants
1. Plants float on the surface of water.
2. Roots are not fixed to the soil.
3. They have soft, hollow, light weighted stems having space filled with air.
4. They have a swollen petiole Eg Water Hyacinth, Water Lettuce 

Fixed Floating Aquatic plants
1. Roots are fixed on the soil below water.
2. Stems grow up to the surface of water.
3. Leaves and flowers flat on the surface of water.
4. They have long, flexible, stem so that it doesn't bread due to water current. They are also called a rooted floating plants. 
5.  They are partially submerged plants in the water. Eg Water Lily and Lotus

Submerged Aquatic plants
1. Roots of the plants are fixed in the soil.
2. All parts of the plant grow under water. 
3. They have needle-ribbon like highly divided leaves so that water can pass through them without obstruction. 
4. They are completely submerged in water. Eg Hydrilla, Vallisneria and Tapegrass  

 NUTRITION IN PLANTS

1. What is nutrition?

Ans The mode of taking food by an organism and its utilisation by the body.

2. Differentiate between autotrophic nutrition and heterotrophic nutrition.

Ans 1.The mode of nutrition in which organisms make food themselves from simple substances is called autotrophic nutrition.
2. The mode of nutrition in which organisms depend on other organisms for their food is called heterotrophic nutrition.

3. What are nutrients?
Ans The components of food that are necessary for our body are called nutrients. Carbohydrates, proteins, fats, vitamins and minerals are components of food.

4. What are the raw materials needed for photosynthesis?
Ans Sunlight, Carbon dioxide,  water and chlorophyll.

5. What is photosynthesis?
Ans The process by which green plants make their own food in the presence of sunlight using carbon dioxide and water with the help of chlorophyll is called photosynthesis. Carbohydrate and oxygen is formed. This process can be represented as an equation-

6. Explain photosynthesis with the help of diagram.

Ans 1. Carbon dioxide- It is obtained from air through tiny pores present underneath the leaves called stomata. Stomata is surrounded by guard cells which help in closing and opening the stomata.

2. Water- Water and minerals are absorbed by the roots of the plant and are transported to the leaves by the tubes in the stem(XYLEM).

3.Chlorophyll- Chlorophyll is a green pigment present in the leaf(FOOD FACTORY) which helps to trap sunlight.

4. Sunlight- Solar energy is used for the chemical reaction between carbon dioxide and water. The solar energy is converted to chemical energy in the process of photosynthesis. leaves store their food in the form of starch.

7. Describe the structure of a cell with the help of a diagram.

Ans 1. The bodies of living organisms are made up of tiny units called cells. The cell is enclosed by a thin outer boundary called cell membrane.

2. Most cells have a distinct centrally located spherical structure called the nucleus.

3. The nucleus is surrounded by a jelly like substance called cytoplasm.

8. What are variegated leaves? Give examples.  

Ans  Plants which have got pigments other than chlorophyll in large quantities are called variegated leaf plants. The colour pigments mask the chlorophyll present, hence they don't appear green. Still they take part in photosynthesis. Eg Croton, Coleus, etc

COLEUS

CROTON

9. What are algae? Is it an autotroph?

Ans Algae are slimy green patches in ponds or in other stagnant water bodies. They contain chlorophyll which gives them green colour and they prepare their own food by photosynthesis, hence they are autotrophs.

10. How do plants obtain nitrogen?

Ans 1.Soil has certain bacteria that convert gaseous nitrogen into a usable form and release it into the soil. These soluble form are absorbed by the plants along with water.

2. Farmers add fertilizers rich in nitrogen to fulfill the requirements of plants.

11. Define the following-

1. Parasites-Organisms that live in/on other organisms and derive readymade food from the host are called parasites. eg Cuscuta/Amarbel

2. Saprotrophs- Organisms which take food from dead or decaying matter are called saprotrophs. eg mushroom, fungus 

3. Symbiosis- The mode of relation in which two organisms live together for mutual benefit is called symbiosis. eg In organisms called Lichens, chlorophyll containing partner, which is an alga and a fungus live together. The fungus provides shelter, water and minerals to the alga and in return the alga provides food which it prepares by photosynthesis.

12. Explain the mode of nutrition in pitcher plants.

Ans The pitcher-like structure is the modified part of the leaf. The apex of the leaf forms a lid which can open and close the mouth of the pitcher there are hair which are directed downwards. When an insect lands in the pitcher. The lid closes and the trapped insect gets entangle into the hair. The insect is digested by the digestive juices secreted in the pitcher.

13. How does a saprotroph digest its food?

Ans Saprotrophs secrete digestive juices on the dead and decaying matter and convert it into a solution. Then they absorb the nutrients from it.

14. How is the symbiotic association between Rhizobium and Leguminous plants beneficial?

Ans Plants cannot take nitrogen in gaseous form. A bacteria called Rhizobium which is present in the root nodules of leguminous plants fixes it as it can convert gaseous nitrogen into a soluble form. This soluble nitrogen is taken by the leguminous plants and in return give food and shelter to the bacteria.

NUTRITION IN ANIMALS

1. What are the different parts of human digestive system?

Ans The Alimentary canal along with digestive glands is called digestive system. The human digestive system consists of the following organs-

ALIMENTARY CANAL

1. Buccal cavity/mouth

2. Oesophagus/food pipe

3. Stomach

4. Small intestine

5. Large intestine

6. Rectum

7. Anus

DIGESTIVE GLANDS

1. Salivary glands

2. Liver

3. Pancreas

2. Explain the different steps of nutrition in animals 

Ans 1. Ingestion

Process by which food is taken into the body of an organism

2. Digestion

The process of converting solid and complex food into simple and soluble form.

3. Absorption 

The process by which digested nutrients are absorbed by the blood vessels in the walls of the small intestine.

4. Assimilation

The process of utilizing absorbed nutrients by each and every cell of the body for energy, growth and development.

5. Egestion 

The process of removing undigested food material from the body in the form of faeces.

3. Write the functions of the following-

a) Tongue: It help us to taste food and in speaking. It mixes saliva with the food and helps in swallowing the food.

b) Saliva: Saliva makes the food soft and breaks down starch into sugars.

4. Draw a neat labeled  diagram of human digestive system and explain.

Ans 1. Mouth- The mouth contains tongue, teeth and salivary glands.

2. Oesophagus- Oesophagus is a muscular tube between the mouth and the stomach. The food is pushed down towards the stomach by the peristaltic movement (Contraction, relaxation) of the muscles of the food pipe.

3. Stomach- The stomach is a thick-walled bag. It receives food from the food pipe at one end and opens into the small intestine at the other. The inner lining of the stomach secretes mucus, hydrochloric acid and digestive juices. The mucus protects the inner lining of the stomach. The acid kills many bacteria that enters along with the food and makes the medium in the stomach acidic and helps the digestive juices to act. The digestive juices breaks down the proteins into simpler substances. 

4. Small intestine- The small intestine is highly coiled and is about 7.5 m long. It receives secretions form the liver and the pancreas and its walls also secretes juices.

5. Liver- The Liver is a reddish brown gland situated in the upper part of the abdomen on the right side. It is the largest gland in the body. It secretes bile juice that is stored in a sac called the gall bladder. The bile plays an important role in digestion of fats.

6. Pancreas- Pancreas is a large cream coloured gland located just below the stomach.The pancreatic juice acts on carbohydrates, fats and proteins and changes them into simpler forms.
The digestion of food is completed in the small intestine. The carbohydrates get broken into simple sugars such as glucose, fats into fatty acids and glycerol and proteins into amino acids. 

Absorption in small intestine
The digested food can now pass into the blood vessels in the walls of the small intestine which is called absorption. The inner wall of the small intestine have thousands of finger-like outgrowths called villi. The villi increase the surface area for absorption of the digested food. Each villus has a network of thin and small blood vessels close to its urface. The surface of the villi absorbs the digested food material.

Assimilation

The absorbed substance are transported via the blood vessels to different organs of the body where they are used to build complex substance such as the proteins required by the body is called assimilation. In the cells, glucose breaks down with the help of oxygen into carbon dioxide and water and energy is released.

Large Intestine

The food that remains undigested and unabsorbed materials enter into the large intestine. It is 1.5 m in length. It absorb water and some salts from the undigested food materials. Remaining waste goes to the Rectum and time to time is egested out through the Anus.

5. How does digestion of food take place in ruminants. Explain.

Ans. Grass-eating animals quickly swallow the grass and store it in a part of the stomach called Rumen. Here the food gets partially digested and is called cud. But later cud returns to the mouth in small lumps and the animal chews it. This is called rumination and these animals are callled ruminants.

Ruminants have a large sac-like structure called Caecum between the small intestine and large intestine. The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.

6. Explain the process of nutrition in amoeba.

Ans. Amoeba has a cell membrane, a rounded dense nucleus and many small bubble-like vacuoles in its cytoplasm. Amoeba constantly changes its shape and position. It pushes out one, ore more finger-like projections, called pseudopodia or false feet for movement and capture of food.

Amoeba feeds on small microscopic organisms. When it sensed food, it pushes out pseudopodia around the food particle and engulfs it. The food becomes trapped in a food vacuole. Digestive juices are secreted into the food vacuole which act on the food and breaks it into simpler substances. Gradually the digested food is absorbed. The absorbed substances are used for growth, maintenance and multiplication. the undigested residue of the food is expelled outside by the vacuole.