Classification of living organisms

Everything in the world can be divided into three groups. some are living now others were once alive, and some were never alive.

Dividing them into groups help us to understand how all the different things ing the world fit into a pattern.

Scientists who study living organisms are called biologists. There is an estimated total of 8.7 million types of living organisms on the Earth. In order to study the huge diversity of living organisms, biologists placed them into groups

Classification of living organisms:

The sorting of living organisms into groups based on their similarities and common characteristics is called classification. Biologists have classified all living organisms into five groups called kingdoms.

•Protist kingdom:algae and protozoa

•Monera Kingdom:bacteria and blue-green algae

•Animal kingdom

•Plant Kingdom

Fungi :moulds,mushrooms,

toadstool, and yeast

Monera:

The organisms in this kingdom are the simplest cell structure. They all are unicellular organisms. They include bacteria and blue-green algae.

Bacteria are very important because many of them break down dead animals and plants. Other bacteria are used to make cheese, yoghurt, and antibiotics. Blue-green algae recycle nutrients in the environment and food chain. They are food to many aquatic animals.

Some of them produce toxins which can sicken people.

Protist:

The protist kingdom includes organisms that have a very simple structures Most of them are unicellular and live in water, either freshwater or seawater Eg Protozoa and algae. They have chlorophyll and like plants they can make their own food. However, they do not have roots, stems or leaves.

Fungi:

The organisms in this kingdom include mushrooms, toadstool, bread moulds, and yeast. They are similar to plants, but they do not have chlorophyll and cannot make their own food. They obtain nutrients from other sources. They do this by growing on things they can use as a source of nutrients, such as dead plants or animals.

Plants

These multicellular organisms contain green substance called chlorophyll. This substance can absorb energy from Sunlight. The plant then uses this energy to make food.

Plants cover much of the surface of Earth. They vary in shapes and sizes. Plants include familiar types such as trees, herbs, bushes. grasses, vines, ferns, mosses, and conifers.

In order to study plants, scientists have divided plants into two major groups.

These plants are classified depending on whether they have flowers.

Mosses

Mosses are small plants which need damp places to live They do not have a transport system for water. They reproduce by making spores, they do not. moke seeds.

Mosses do not have true leaves and stems

Ferns

Ferns are bigger plants than mosses. They have stems, leaves and roots and have transport system for water They reproduce by making spores they do not make seeds

Conifers are usually evergreen-they have thin, needle-like leaves. They have a transport system, Conifers produce seeds which are formed inside the cone.

Flowering Plants

They are the most advanced group in the plant kingdom. They produce flower and fruits. The seeds of flowering plants are enclosed in fruits or flowers.

They have roots, stems, and leaves. The examples of flowering plants are rose, lotus, and sunflower.

Flowering plants are further divided into two major groups based on their seed structure, monocotyledons or monocot, and dicotyledons or dicot.

Peas, beans, chickpeas, peanuts, mint, tomatoes, rose, sunflower, grapes, and potatoes are examples of dicotyledonous plants.

Wheat, maize, rice, sugarcane, banana, ginger, onions, and grass are examples of monocotyledonous plants.

Differences between Monocots and Dicots

Seed

The seed of a monocot plant has only one cotyledon (seed leaf), while dicots have two cotyledons (seed leaves), Cotyledons provide food to a germinating plant

Stem

Stems have a transport system called the vascular system which transports food and water to all parts of the plant. Stems consist of two tubes. The tubes that carry water in the plant are called xylem and the tubes which carry food are called phloem

The xylem and phloem are very well organised in the stems of dicot plant, in the form of a ring. The xylem and phloem are scattered throughout the stem of g. monocot plant.

Leaf

All leaves have a network of veins. The leaves of a monocot plant have parallel veins while the leaves of a dicot plant have web-like veins.

Flower

A monocot flower has three petals, or a number which is divisible by three. A dicot flower has a number of petals that can be divided by four or five

Roots

The underground part of the plant makes up the roots. Monocots have fibrous roots, while dicots have taproots

The Animal Kingdom

The organisms in the animal kingdom eat other animals and plants to obtain energy for life processes. There are different types of animals, all are multicellular, some live on land, others live in water and yet others can fly Animals can be classified into two main groups.

The invertebrates

Invertebrates come in all shapes and sizes. Many of them have soft bodies. They may have shells inside or outside their bodies or a tough external skeleton on the outside of the body None of the invertebrates have a bony skeleton with a backbone.

The invertebrates can be divided into the following main groups:

Sponges

Sponges are the simplest form of animals. They do not have a nervous systern but they possess an internal skeleton. They cannot move on their own and most of them live on the sea floor. Their bodies are full of pores and canals. Water flows through pores and canals in their body. The water contains the oxygen and nourishment they need to survive.

Echinoderms

They all have star- like appearances.All are marine animals and possess a very unique water vascular system that not only allows them to transport food and water in their bodies, but also helps them in movement.

Insects

Insects have segmented bodies and a hard external skeleton. All adult insects have three body parts a head, a thorax, and an abdomen. Most insects have three pairs of legs joined to their thorax and two feelers or antennae. These are used for smelling and feeling.

Worm

They have soft, long, tube-like bodies divided into segments They do not have arms or legs. Some worms are microscopically small while others can grow much longer. Many worms have sense organs to detect chemical changes in their environments, and some have light-sensing organs. Worms live in various habitats. Some are parasites and live in the bodies of other animals. Some worms are decomposers, and others are predators.

Mollusc

Mollusc, means "soft-bodied". Most of them are marine, They also occur in freshwater and on land. Snails, squid and octopi all have very muscular bodies and a shell either inside or outside their bodies.

The vertebrates

Vertebrates have a hard, bony internal skeleton inside their bodies. This gives them support, protects the delicate organs inside the body and helps them move about. They all have a backbone - made up of lots of little bones - which supports the body, allows it to move and protects the delicate spinal cord.Vertebrates are more easily recognised as they include animals we all know in our daily lives. The vertebrate group.contains fishes, amphibians, reptiles, birds, and mammals.

Common characteristics used in classifying vertebrates are:

•Their habitat

•How they move

•Their body surfaces

•Type of respiration

•Reproduction method

Fish

•Habitat: Live in water

•Body shape: Streamlined Most fish have skin covered with scales

•Movement: Tail and fins to help them to swim

•Breathing: All fish breathe through gills

•Reproduction: Mostly they lay eggs without shells

Example:goldfish,rohu and trout

AMPHIBIANS

•Habitat: Spend part of its life in water and part of its life on land. When amphibians are young, they live in the water

•Body: Is covered with moist skin

•Movement: Have four limbs to jump on land and swim in water.

•Breathing: Adults breathe through lungs to survive on land.Young ones breathe through gills

•Reproduction: Lay eggs without shells in water

Example frogs,toads and newts

REPTILES

Habitat: Live on land and in water.

Body: They have dry, scaly skin.

Movement: Have four limbs and tail to crawl on land and swim in water.

Breathing: Use lungs

Reproduction: Most lay eggs with thick shells.

Example lizards,snakes and turtles

BIRDS

Habitat: Live on land.

Body: Birds are the only animals with feathers.

Movement: Have wings to fly but not all birds can fly.

Breathing: Use lungs,

Reproduction: Lay eggs with shells.

Examples eagles,pigeons and parrots

MAMMALS

Habitat: Most live on land, some like dolphins and whales live in water.

Body: covered with fur and hair

Movement: Have four limbs to walk and run

Breathing: use lungs.

Reproduction: give birth to babies and feed them on milk.

Examples cats,dogs and horses

Extinct and endangered species

Maintaining the physical conditions and biodiversity in an ecosystem is important for life on Earth. Biodiversity is the variety of all the different species of organisms on Earth, or within an ecosystem.

Threats to biodiversity

In modern times, human activities like deforestation, hunting and pollution disturb the balance in the nature, changing environmental conditions that cause imbalance in the biotic and abiotic factors. This imbalance leads to loss of many species.Biodiversity is lost when species become extinct, Extinction is the disappearance of species when the lost of its members dies.

Species in danger of becoming extinct in near future are colled endangered species. For example, Markhor the national animal, and Mountain Weasel that live in the higher altitudes, mainly Kashmir and Balochistan.

In Pakistan, Ziarat has largest remaining juniper forestin the world. These are now in danger of disappearing forever.

The Balochistan, forest dormouse is found in juniper forest, however, deforestation has caused a decrease in their population, Forest Dormouse are endangered species of Pakistan.

Each of you can show care and conserve endangered species:

By Saying No

• to capture or collect wildlife

• to buy products made from endangered animals(such as furs, ivory or shells of turtles).

•to littering.

•to use plastic bags when it is unnecessary.

By Doing

• reforestation

• controlling pollution through education and invention of environmentally friendly products.

•conserving ecosystems

•Using technology to create sustainable food sources

Facts

•There are more than one million different kinds of animals and more than 350,000 kinds of plants.

•Monocots are not usually woody. The flowers are usually green or brown

•Dicots are often woody They often have very brightly coloured and scented flowers.