The Living Organisms - Characteristics and Habitats PDF

# The Living Organisms - Characteristics and Habitats ## Terms To Remember - **Habitat:** Natural place for an organism to live, survive, breed and flourish. - **Biotic Components:** All living components of a habitat. - **Abiotic Components:** All nonliving components of a habitat. - **Adaptation...

# The Living Organisms - Characteristics and Habitats ## Terms To Remember - **Habitat:** Natural place for an organism to live, survive, breed and flourish. - **Biotic Components:** All living components of a habitat. - **Abiotic Components:** All nonliving components of a habitat. - **Adaptation:** Features developed in an organism to survive in a particular environment. - **Nocturnal:** The animal which remains active during night. - **Hibernation:** Long winter sleep of some organisms. - **Xerophytes:** Desert plants. - **Succulent Plants:** Plants which store water in their spongy stems. - **Hydrophytes:** Aquatic plants of fresh water. ## Habitat All living organisms need a place to live in addition to food, water and air. A place where an organism lives is called its habitat. The habitat is a part of the total environment of the region. A habitat must provide to the organisms living there-in the following: - Food - Shelter - Favorable climatic conditions to survive, breed and flourish. ## Types of Habitat There are three main habitats in the biosphere: 1. **Terrestrial habitat or Land habitat:** Forest, Mountain, Grasslands, Desert, and Coastal regions. 2. **Aquatic habitat or Water habitat:** Sea, Lake, River, Pond. 3. **Aerial or Arboreal habitat (air or tree):** Tropical forests. ## Components of Habitat The two components of a habitat are: - Biotic component - Abiotic component ### Biotic component All living beings such as human beings, animals, plants and microorganisms are called the biotic components. Biotic component is also called living component. ### Abiotic component All non-living things, such as, soil, water bodies, atmosphere and meteorological factors such as sunlight, temperature, rainfall, wind speed etc. are called the abiotic component. Abiotic component is also called non-living component. ## Adaptation In Animals And Plants To Different Habitats The tendency of an organism to develop certain specific features which improve the chances of its survival in the environment in which it lives is known as adaptation. In response to a particular environment, an organism brings about certain changes in the structure and function of its body and makes it well suited to the environment. For example, Camel and Desert rat are adapted to the desert habitat. ## Adaptation in the Individuals Adaptation is of two types: 1. **Permanent adaptation:** Has a genetic basis and causes permanent changes in the individuals. For example, Camel is well adapted to desert environment and not to the water. A fish is well adapted to live in water. 2. **Temporary adaptation:** Is a short term adaptation, and is not inherited. For example, a bird adapted to live in the cage is a temporary adaptation. ## A Journey Through Different Habitats Different organisms adapted to live in different habitats. To survive in a particular habitat, the organism has to adapt itself to its climatic conditions. ## Some Terrestrial Habitats The plants and animals that live on land are said to live in terrestrial habitat. Some terrestrial habitats are, grassland, forests, deserts, mountains, etc. Let us discuss a few of these. ### Adaptation to Desert Habitat #### Desert Animals The climate of deserts is dry and hot. Deserts have very little vegetation. They provide little shelter to large animals from the sun. - Most animals which survive in deserts are insects, birds, reptiles, and smaller mammals. - Many animals living in deserts remain inactive during the day and become active during the night. This is just to prevent loss of water from their body. The animals that show such adaptation are called nocturnal. - Certain animals hide themselves in burrows with gelatinous secretions and sleep for eight to nine months in a year. This is called hibernation. - In summers, the cold-blooded animals like Lizards, Snakes, and Mosquitoes are more active during night. In winters they enjoy sun during the day and when cold, they become inactive for a certain long period. - The absence of sweat glands and concentration of urine are other physical adaptations in desert animals. #### Adaptation in Camel Camel is the only large animal that survives in desert conditions. Camel is also called “ship of the desert”. It is adapted to the desert conditions because of the following: - Its limbs contain large pads which help it to move on hot and slippery sand. - The hump of the camel is a reservoir of food in the form of fat. - It drinks a large quantity of water and stores it in water-cells, muscle and connective tissues. - It can live without drinking water for about two weeks. It excretes very little water in the form of urine. - It can adjust its internal temperature according to the surrounding air. It sweats profusely in the bright sun to maintain its body temperature. #### Desert Plants The plants that grow under very poor water conditions, such as, in deserts are called xerophytes. Plants like cacti are well adapted to hot and dry climates of deserts. Cacti plants can store water in their spongy stems. These are called succulent plants. The desert plants also show the following characteristics to survive in hot and dry climate. - Their leaves are reduced to scales or spines which reduce the loss of water by transpiration. - The leaves bear sunken stomata to reduce the rate of transpiration. - The thick cuticle found on the stem and leaves prevents water loss. ## Adaptation to Mountaineous Regions Mountaineous regions are generally very cold and windy. Snowfall is common during winters. There is a large variety of plants and animals living in mountainous regions. ### Mountain Plants/Trees The trees adapted to such cold snowy climate: - are cone-shaped and have sloping branches. - have needle-like leaves. These adaptations help the rainwater and snow to slide off easily. ### Mountain Animals The animals in these regions are usually white or light colored. This helps them to camouflage with the surroundings. This also helps them in thermal regulation. - They have thick skin or fur to protect them from cold. For example, Yaks have long hair. This keeps them warm. Snow leopard has thick fur over its whole body. Mountain goat has strong hooves which help it in running up the rocky slopes of mountains. ## Adaptation to Grasslands The Grasslands cover nearly one-fourth of the earth's land. The grasslands exist in every continent except Antartica. Tropical grasslands are hot throughout the year, whereas the temperate grasslands are hot in summer and very cold in winter. In grasslands, the rainfall is about 30 cm to 100 cm. As a result, here short grass grows. However, trees grow near streams/rivers. All grasslands have the following common features: - Plenty of grass as food. - Continuity and openness. - Lacking cover to hide from predators. Therefore, the type of animals living in grasslands around the world are similar. The animals are mostly plant-eating (Herbivorous), e.g., Deer, Horse etc. Temperate grasslands are home to many large herbivores such as, Bison, Zebras, Rhinoceroses, and Wild horses, and carnivores, like Lion, Wolves, Cheetahs, Leopards. Other animals of this region include Deer, Mice, Jack Rabbits, Snakes, Fox, Owls, Sparrows, Hawks etc. ### Adaptations in some animals living in grasslands are described below: #### Adaptation to Grassland in Herbivores Herbivores, such as Deer, Cow, Goat etc. living in grasslands have the following adaptations: - Strong teeth for chewing and cutting hard grass. - Long ears to follow the movements of predators. A predator is an animal which makes them its prey. - Long legs to run fast and save themselves from predators. #### Adaptation to Grassland in Carnivores Carnivores like Lion, Tiger, Hyena etc. are found in grasslands. They have the following general adaptations: - Sharp and long claws in their front legs to catch, hold and tear the body of their prey. - Light brown colour or patchy body. This helps them to hide in dry grass. - The eyes in front of the face help in locating their prey). - Long and strong canines (front teeth) help them in tearing the body of their prey. ## Aquatic Habitat The animals that live in water are said to live in aquatic habitat. Aquatic habitat includes both fresh water and marine water. Certain invertebrates are aquatic or semi-aquatic (amphibians). For example, Insects, Fishes, Whales, Turtles, Seals, Walrus, Dolphins etc. are well adapted to aquatic modes of life. ### Aquatic Adaptation in Animals and Plants The adaptive features for aquatic adaptation are: - Body of aquatic animals is compressed laterally to reduce friction. This allows swift passage in water while swimming. - Fins in fish and flippers in whale help in swimming. ## Adaptation to Oceans Most sea animals have streamlined bodies. Fish, Dolphins, Whales have streamlined bodies. Some sea animals such as Squids and Octopus do not have streamlined bodies. However, when they move in water, their bodies acquire streamlined shape. They stay deeper in the ocean near the seabed. ## Adaptation to Ponds, Lakes and Rivers Ponds and lakes of freshwater are called hydrophytes. They may be free floating, rooted and floating, or submerged. Some of these plants show adaptation for buoyancy in water and against decaying in water. - Lotus, Water lily, Hydrilla, Vallisneria and Spirogyra are common hydrophytes. - Some of the aquatic plants have their roots fixed into the soil under water. - Some aquatic plants float on water, whereas some other are completely submerged in water. - The stems of aquatic plants are long, hollow and light. The stems grow up to the surface of water. The leaves and flowers float on the surface of the water. #### Hydrophytes adapt themselves to water as follows: - In aquatic plants, roots are much reduced in size and their main function is to hold the plant in its place. - The stems may be reduced or long, slender, flexible and spongy. The air spaces in spongy stems make them buoyant, ## Characteristics of Living Beings All living organisms show some common features. ### All Living Beings Need Food If we don't take food for long, we may feel weak. If we don't drink water for long, we will feel thirsty. ## Living Beings Respire to Get Energy We cannot live without breathing. Close your nose/nostrils with your fingers for a while. Are you comfortable? No. When your nose is open you inhale (take-in) air and also exhale (throw out) air. The process of inhaling and exhaling air is called breathing. During breathing, oxygen is taken in and carbon dioxide, nitrogen and oxygen (unused part of the air) and water vapour are thrown out. Breathing is also called external respiration. Breathing thus helps in the movement of gases from outside to the body and from the body to outside. Breathing is fast when one is running, jumping or doing some other exercise. ## Living Organisms Breathe In Oxygen Breathing is fast when one is running, jumping or doing some other exercise. Living organisms breathe-in oxygen from the air during respiration. Carbon dioxide and water vapour produced in the process are breathe-out. Animals which live in water such as fish breathe in oxygen dissolved in water. A fish uses its gills for breathing. When in water, a frog breathes in oxygen dissolved in water through its skin. While on the land, it breathes through its lungs. ## Living Beings Excrete Body Wastes Most living beings eat food. During digestion and respiration some waste products are produced inside the body. These waste products are thrown out of the body in the form of urine, sweat, exhaled air and faecal matter. The process by which a living body throws out the waste products produced inside the body is called excretion. ## Living Beings Respond To Stimuli Living organisms can feel. As a result, all living organisms respond to stimuli such as temperature, touch, light, sound, smell etc. All living organisms respond to stimuli by moving towards or away from it. For example, if you happen to touch a hot object, you withdraw your hand. Here, higher temperature of the hot object is stimulus and the quick withdrawal of your hand is the response. ## Living Organisms Show Movement All living organisms move. The movement may occur in the whole body of the organism or only in certain parts of it. The movement of an organism, bodily from one place to another is called locomotion. Locomotion involves the whole body as in walking, running, swimming and flying. The change in the position of any part of the body with respect to its axis is called movement. For example, when you agree or disagree with some one, you shake your head. This shaking of head is called movement of head. For the movement, energy and coordination between different organ systems are required. All animals meet their energy requirements through nutrition and respiration. ## A plant remains fixed to its position but some of its parts can show movements. The movements of a plant in the direction of stimulus is called tropism. Some typical movements in a plant are: - Bending of a stem towards sunlight, *(phototropism)*. - Movement of roots vertically downwards towards the Earth, *(geotropism)*. - Opening and closing of guard cells of stomata to control water level in leaves *(hydrotropism)*. - Movement of a plant neither in the direction nor away from the stimulus is called nasticism. Bending and drooping of the leaves of touch-me-not plant on touching is an example of nasticism. - Flowering and seed germination in plants are regulated by the duration of light *(photoperiodism)*. - The leaves of exalis remain open during the day and fold up at night. ## The movements in plants are very slow. ## Living Things have Structure All living things are made of very small units called cells. Cells are the smallest structural and functional units of life. Cells were discovered by a British scientist Robert Hooke in 1665. All cells are generated from a single cell due to cell division. During growth of a living organism, the number of cells increases. Cells in any living organism are of different shapes and sizes and perform different functions. ## Living Things Reproduce All living beings produce young ones of their own kind, i.e., all living beings reproduce. Different organisms reproduce in different ways. For example, - Humans and animals such as cow, buffalo dog, cat etc. reproduce by giving birth to their babies. - Frogs, Snakes, Pigeons, Hen, Fish, and Birds reproduce by laying eggs. - Plants also reproduce. A mango seed produces mango plant. ## Living Beings Grow You must have seen a small plant growing into a tree in a few years' time. Growths is an irreversible change. A puppy grows into a dog. These are examples of growth. Growth is an increase in size and mass. All living beings grow on their own in their size and mass. ## Living Beings Have A Definite Life Span All living beings have a life span of a certain definite period, that is, each living organism is born, grows into adults, gets old and finally dies. Thus, each organism lives for a certain definite period of time. The duration of time for which a living organism lives is called its life span. Different living organisms have different life spans. The average life spans of some living organisms are shown below: | Animal | Life Span | |---|---| | Dog | 16-18 years | Lion | 20-25 years | Horse | 25-30 years | Elephant | 70-90 years | Ostrich | 45-50 years | Human Beings | 65-80 years | Squirrel | 8-9 years | Mouse | 2-3 years | Housefly | 1-4 months | Bacteria | 20 minutes | | Tortoise | 120-150 years | ## The Single Cell Organism Some living organisms consist of only a single cell. These are called single-celled living organisms. - Amoeba, Paramecium, Bacteria, and Yeast are single-celled living organisms. **Some single-celled organisms** - All living beings grow, have a definite life span, respond to stimuli, respire, reproduce, excrete and are made up of cells. - All living beings respond to stimuli by moving towards or away from it. - Living beings show a wide variation in their size, shape, food habits and in their place of living. - Cells are the smallest structural and functional unit of life.