Classification of Living Organisms PDF

# Classification of Living Organisms ## Students' Learning Outcomes After studying this chapter, the students will be able to: 1. Describe classification of organisms and its importance. 2. Classify the plants into two groups (monocots and dicots) and give an example of each group. 3. Compare the...

# Classification of Living Organisms ## Students' Learning Outcomes After studying this chapter, the students will be able to: 1. Describe classification of organisms and its importance. 2. Classify the plants into two groups (monocots and dicots) and give an example of each group. 3. Compare the structure of a monocot and dicot plant (with respect to their seeds, leaves and flowers). 4. Differentiate between vertebrates and invertebrates based on their characteristics. 5. Classify vertebrates into fish, amphibians, reptiles, birds and mammals on the basis of their characteristics. 6. Classify invertebrates into five groups (sponges, worms, insects, molluscs and echinoderms) on the basis of their characteristics. 7. Understand the concept of extinction and endangered species and the role of human actions in the loss of biodiversity. 8. Write some measures for conservation of endangered species. ## Classification of Organisms There are numerous types of organisms found on Earth. These organisms are different from each other. Some have a few similar characteristics. ### Activity 1.1 Write the names of organisms in their respective groups on the basis of similar characteristics: Guava, fowl, pigeon, mango, sparrow, snake, rose, crocodile, sunflower, lizard, cat, tiger, cow, tortoise, goat, and dove. For example, rose, fowl, snake and goat have been placed in separate groups. | Group 1 | Group 2 | Group 3 | Group 4 | | -------- | -------- | -------- | -------- | | Rose | Fowl | Snake | Goat | **Why did you put rose and mango in one group? Why did you put fowl and pigeon in another group?** You placed the organisms of similar characteristics in one group. For example, you made a group of flowering plants with mango, guava, rose and sunflower. You made another group of organisms of other similar characteristics. For example, you made a group of fowl, pigeon, dove and sparrow. All of them have the same characteristics. You have separated the organisms on the basis of similarities and differences. Thus, you have classified the organisms. **To put organisms into separate groups on the basis of similarities and differences is called classification.** ### Do You Know? As a wall is built of bricks stuck together, in the same manner, the body of organisms is built of cells stuck together. ### Importance of Classification Due to classification, we can determine the similarities and differences among organisms. ## Five Kingdom System The organisms have been divided into five kingdoms on the basis of similarities and differences. The names of kingdoms are: Monera, Protista, Fungi, Plantae, and Animalia: ### 1. Monera These organisms are made of one cell. Their structure is very simple. These include bacteria. Bacteria are found everywhere on Earth. Some bacteria can prepare their food. Many bacteria obtain food from other organisms and dead bodies. Some bacteria cause diseases in plants and animals. ### 2. Protista Most of them live in water. This kingdom includes Amoeba, Paramecium and Algae. Algae may consist of one or many cells. Algae are found in rivers, ponds and oceans. They have chlorophyll. ### 3. Fungi Some fungi are made of one cell. Many fungi are made up of more than one cell. Such fungi have filament-like bodies. Fungi need moisture for growth. They do not have chlorophyll. So, they cannot make their own food. They absorb food from the place where they live. Yeast is a microscopic fungi. Rhizopus is also called black bread mold. It grows on moist bread and fruits. The mushrooms are umbrella-like. They grow on piles of rotten matter. ### 4. Plantae These organisms are made of more than one cell. They are called plants. They have chlorophyll in their leaves. So, they are able to make their food by using the energy of the Sun. Due to chlorophyll, their leaves are green in color. ### 5. Animalia These organisms are also made of many cells. They are called animals. They do not have chlorophyll. So, they cannot make their food. They can move from one place to another. ### Point to Ponder! What is the difference between the paws of a hen and duck? ## Classification and Characteristics of Flowering Plants ### Activity 1.2 Take the seeds of wheat, rice, maize, pea, bean and gram. Find out in which seed there is one cotyledon and in which seed there are two cotyledons. Write your observations. ### Monocot Plants The flowering plants whose seeds have one cotyledon are called monocot plants. Sugarcane, wheat, rice, bamboo, and maize are examples of monocot plants. ### Dicot Plants The flowering plants whose seeds have two cotyledons are called dicot plants. Mango, guava, rose, and pea are examples of dicot plants. ### Activity 1.3 1. Observe the leaves of monocot and dicot plants. What is the arrangement of veins in these leaves? 2. Take the flowers of some monocot and dicot plants. Observe the flowers and count the number of floral leaves. The following are the main differences between monocot and dicot plants: | Part of Plant | Monocot Plant | Dicot Plant | | -------- | -------- | -------- | | Seed | | | | Leaf | | | | Flower | | | ### Activity 1.4 1. Paste leaves of monocot and dicot plants in a scrapbook. 2. Paste dried and preserved flowering and non-flowering plants in the scrapbook. ## Classification and Characteristics of Animals We have already studied in Grade 4 that animals have been divided into two main groups – vertebrates and invertebrates. ### Activity 1.5 Look at the pictures of a pigeon and a butterfly. What differences have you seen between them? Write your observations. ## Classification of Vertebrates The vertebrates are divided into five groups: fish, amphibians, reptiles, birds, and mammals. ### Fish Fish live in water. Both ends of their body are pointed. The middle part is broad and thick i.e., the body is boat-shaped. This body shape is most suitable to swim. They have scales on their skin. Fish breathe through gills. Fish have fins and tail which help to swim. Reproduction in fish takes place through eggs. Their body temperature depends on the temperature of their surroundings. ### Amphibians Amphibians can live on land and also in water. They respire through lungs and skin. Usually, their skin is moist and loose. They live on land but lay eggs in water. Their body temperature also depends on the temperature of their surroundings. Their development takes place in water. Frog, toad, salamander and newt are examples of amphibians. ### Reptiles Reptiles are called creeping animals. Their skin is thick, coarse, and dry which protect their body from external effects. Reproduction in these animals takes place through eggs. They lay eggs on land. Their body temperature also depends on the temperature of their surroundings. Lizard, crocodile, snake, and tortoise are examples of reptiles. ### Do You Know? 1. Dinosaurs were the largest reptiles of ancient times, but they have become extinct. 2. Compared to the amphibians, the reptiles flourished all over the world because they do not depend on water for reproduction. ### Point to Ponder! What is the difference between a toad and a frog? ### Birds The birds have feathers and beaks. Their bones are hollow, thus their weight is less. Along with lungs, they have air sacs. Birds can fly in the air. Some birds can swim in water, such as ducks. Some birds cannot fly and are called running birds, such as kiwi and ostrich. All birds lay eggs. The birds that live in water have webbed feet, such as ducks. Their body temperature does not depend on the external environment. Sparrow, pigeon, kiwi, rooster, dove, parrot, and ostrich are examples of birds. ### Do You Know? The largest flying bird is an eagle which lives on high trees or rocks. Humming bird is the smallest bird. Hawk is a hunter bird. Penguin is a bird that lives on snow. Woodpeckers live in the holes they make in a tree trunk. ### For Your Information 1. Birds have evolved from a generation of carnivore dinosaurs. 2. Birds have a different body temperature than reptiles. Their body temperature does not depend on the temperature of the external environment, so they remain active round the year. They show parental care. They make nests to live. They migrate from one place to another. ### Interesting Information A bird park is called 'Aviary.' There is a bird park in Islamabad at Lake View Park adjacent to Rawal Lake. This is the third in the world and the largest bird park of Pakistan. There are 280 types of birds here whose number is more than 4,000. ## Mammals They have fur or hair on their body. Mammals give birth to their young ones and feed them on milk. The body temperature of mammals does not depend on the temperature of the external environment. Horse, cow, goat, tiger, cat, and human are examples of mammals. ### Interesting Information 1. Polar bears live in snowy regions of the North Pole. Its body has a thick covering of fur. 2. Elephants live in hot climates so its body is not covered by a thick layer of hair or fur. 3. Platypus is a mammal. The female lays eggs and feeds milk to the young ones. 4. Kangaroo keeps its newborn babies in an external pouch on the belly. 5. Bat is a flying mammal. ### Interesting Information Among the vertebrates in the world, birds and mammals are the largest groups. What is the reason? The reason is that both show parental care. Such as you must have seen how hen and cats take care of their young ones. ### Activity 1.6 Paste pictures of different animals in the scrapbook. Divide them into vertebrates and invertebrates. Also write which of these animals are found in Pakistan. ## Classification of Invertebrates The major groups of invertebrates are sponges, worms, insects, molluscs, and echinoderms. ### 1. Sponges These are aquatic animals and most of them live in the ocean. They are of various colors. They usually remain attached to stones. The body is full of pores externally and canals internally. Water enters through the pores, and exits through a large pore. If any body part breaks, they can form it again. ### 2. Worms Worms are softbodied animals. Their body is round and cylindrical. They have no legs. The body of some worms is divided in segments, such as earthworms and tapeworms. The body of some worms are not divided in segments, such as flatworms and roundworms. ### 3. Insects The insects are invertebrates with jointed legs. Their body is segmented. The body is divided into three parts: head, thorax and abdomen. The number of legs is six, or three pairs. The external surface of the body is hard, which is called exoskeleton. The exoskeleton protects and supports the body. ### Do You Know? Stick insect looks like a stick and is green or brown in color. It is also known as walking stick. Leaf insect looks like a leaf. Both of these hide in the environment to remain hidden from the enemy. ### 4. Molluscs They are soft bodied animals. They live in ponds, lakes, rivers, oceans, and on land. They move freely or remain attached to anything. The body of some molluscs is covered with a shell, such as snail and oyster, whereas some are without a shell, such as octopus. ### For Your Information When a grain of salt or sand enters the body of an oyster (a mollusc), it forms a pearl around the grain. It takes years to form a pearl. ### 5. Echinoderms These animals are found only in the ocean. They do not have any head. The animals may be disc or star-shaped or a long one. The body has a spiny covering. ## Biodiversity As we have read in the previous class, the number of kinds of living things present at a particular place is called biodiversity. The type of plants and animals no longer found in this world are called extinct, such as dinosaurs. Many organisms that are very likely to become extinct in the near future are called endangered organisms, such as the Bengal tiger, rhinoceros, etc. There are many endangered animals in Pakistan, such as the snow leopard, green turtle, hawk, Indus dolphin, and markhor. ### Activity 1.7 Take a chart paper. Cut pictures of various plants and animals from old newspapers or magazines, and paste on the chart paper. You have placed all the organisms together in one place. What is it? This is biodiversity. ## Human Impact on Biodiversity The forests are being cut for cultivation and urbanization. The cutting of forests has destroyed the habitats of animals. Another human act of excessive hunting of animals has endangered animals. ### Do You Know? 1. Pine trees in Bunair (KPK), Juniper in Ziarat (Balochistan), and Mangrove at the seashores in Sindh are disappearing at a fast rate. 2. The Indus dolphin is blind but it can differentiate between light and the dark. Due to the construction of a dam at the Indus River, the dolphins have declined in number. Now they are found only between Jinnah and Kotri barrages. ## Conservation of Biodiversity For the conservation of biodiversity, trade of endangered animals has been regularized. To save the habitats, the number of game reserves has been increased. National parks have been made all over the world where endangered animals are kept. ### Do You Know? A game reserve (also known as a game park) is a large area of land where wild animals live safely. In some game reserves, animals are hunted in a controlled way.