Exploring Biology Topics can reveal the incredible complexity and interconnectedness of living systems.
The Forest Ecosystem; Components, Types and Examples
A forest is a large area of land covered mainly with trees, and other plants. All the forests do not have similar kinds of trees and other plants. Due to different climates and soils, there are variations in the types of trees and other plants found in various forests. Some of the common trees found in the forests in our country are : Sal, Teak, Sheesham (Indian Rosewood), Neem, Palash, Semal, Bamboo, Fig, Khair, Eucalyptus, Kikar, Arjuna, Banyan and Peepal. There are several other trees, shrubs, herbs and grasses in the forest.
Some of the forest trees are also covered with different types of creepers and climbers. No one grows trees in the natural forests. The natural forest trees grow on their own. This happens as follows : In nature, the trees produce enough seeds. These seeds fall on the forest floor (or forest ground). The forest floor provides favourable conditions (nutrients, water, warmth, etc.) for these seeds to germinate into seedlings and saplings (A young, slender tree is called a sapling). Some of these saplings grow into big trees. The shrubs and herbs also grow in the forest on their own in a similar way.
In addition to the various types of trees and other plants, the forest also has a wide variety of animals. The type of animals also differ from forest to forest. Some of the common animals which are found in forests in our country are : Monkeys, Boar (Pig), Jackal, Bison, Elephants, Tigers, Lions, Deer, Rabbit, Ape, Porcupine, Squirrel, Peacock, Toucan, Frog, Bat, Owl, Rats, Snakes, Butterflies, Insects, Spiders, Ants, Honeybees, and various other small animals. The insects, butterflies, honeybees, and birds help the flowering plants of the forest in pollination. The forest also contains decomposer organisms (or micro-organisms) such as bacteria and fungi. The fungi found in forest are mushrooms, toadstools and puffballs, etc.
The forest is a big habitat. The forest provides a home for many plants, animals and decomposer organisms. A forest acts as the purifier of air and water. The forest acts as a purifier of air because the leaves of its trees and plants clean the air by trapping dust from the air. It also puts oxygen in air. The forest acts as purifier of water because its trees may suck dirty water from the soil through their roots and make pure water available as rain (through the water cycle).
The living organisms in a forest are plants, animals and decomposers. The non-living environment in a forest consists of soil, water and air. We will now describe the living organisms of a forest in somewhat detail. The non-living environment of a forest provides nutrients, water and carbon dioxide for the growth of plants.
(i) PLANTS. A forest has many green plants (The term ‘plants’ also includes ‘trees’ of the forest). The green plants produce food by photosynthesis (by absorbing nutrients and water from soil, and carbon dioxide from air). So, the plants are called producers (of food). The green plants are also called autotrophs (because they make their own food). The green plants provide food to all the animals in the forest, directly or indirectly.
(ii) ANIMALS. A forest has also many animals. The animals are called consumers (of food). The animals in the forest may be herbivores (plant eating) or carnivores (flesh eating). All the animals of the forest, whether herbivores or carnivores, depend on plants for food, directly or indirectly. The animals are also called heterotrophs (because they depend on other organisms for food).
(iii) DECOMPOSERS. The living organisms such as certain bacteria, and fungi (mushrooms and toadstools, etc.) which live and feed on dead plants and animals are called saprotrophs. Saprotrophs are commonly known as ‘decomposer organisms’ or just ‘decomposers’. The decomposers play a very important role in sustaining the forests. So, we will now describe the importance of decomposers in a forest in detail.
The plants and animals do not live for ever. After a certain period, the plants and animals die. The micro-organisms which break down the dead parts of plants and dead bodies of animals into simple substances such as mineral salts (or nutrients), carbon dioxide and water, which can be re-used by the plants, are called decomposers.
The micro-organisms such as bacteria and fungi are decomposers (see Figure). Bacteria and fungi are nongreen organisms which cannot make their own food. They obtain their food from the dead parts of plants and dead bodies of animals. During the process of obtaining food, the bacteria and fungi decompose the matter present in the dead plants and animals into mineral salts, carbon dioxide and water. The mineral salts thus formed are called nutrients (for plants). The mineral salts (or nutrients) formed in this way mix with the soil of the forest.
They make the soil fertile. These nutrients in the soil can be used again by the plants for their growth (see Figure) (The carbon dioxide and water formed by the decomposition of dead organisms are also used by the plants). Besides feeding on dead plants and animals, decomposers also feed on animal wastes (like animal dung or droppings). The decomposers break down the animal waste into mineral salts which go into the soil as nutrients for plants (see Figure).
The importance of decomposers (or micro-organisms) such as bacteria and fungi in the forest is that:
(i) decomposers return the nutrients present in the dead plants, dead animals, and animal wastes to the soil (so that they can be re-used for the growth of plants). In this way, decomposers help in maintaining the supply of nutrients to the growing plants in the forest.
(ii) by carrying out decomposition, decomposers prevent the dead plants, dead animals, and animal wastes from piling up in the forest.
Actually, when decomposers (like bacteria and fungi) feed on dead plant parts, dead animals, and animal wastes (like animal dung and droppings), they convert them into a dark coloured substance called humus (khaad mitti). This humus contains the mineral salts (which are plant nutrients). When this humus mixes with forest soil, the soil gets nutrients. From the soil, these nutrients are again absorbed by the roots of living plants. So, the importance of humus to the soil is that it provides nutrients for the growth of plants.
SCAVENGERS. There are some animals which eat dead bodies of other animals. Those animals which eat the dead animals are called scavengers. Vultures, crows, jackals and hyena eat the dead animals, so vultures, crows, jackals and hyena are scavengers (see Figure). Scavenger is called murdar khor in Hindi. Some insects, ants, beetles, termite, woodlouse, maggot, millipedes, and earthworm also eat dead animals, so they are also scavengers. Scavengers are a kind of cleansing agents of the environment. Scavengers eat up the dead bodies of animals and help in keeping forest environment clean. Without scavengers, dead bodies of forest animals could not be got rid of quickly. Please note that scavengers are not decomposers. They do not break down dead animals into simple substances which can be re-used by the plants. From the above discussion we conclude that when an animal dies in a forest, then the dead animal becomes food for vultures, crows, jackals, hyena, some insects and beetles, etc.
Why There is No Waste in a Forest
When the animals die in a forest, they are eaten up by some other animals called scavengers (such as vultures, crows, etc.). The decomposer organisms (bacteria and fungi) decompose the dead plant material, dead animals and animal wastes present in the forest into mineral salts (in the form of humus), water and carbon dioxide, which go into soil and air (and hence recycled for the growth of plants). Since dead animals are eaten up, and the materials present in dead plants, dead animals and animal wastes are recycled, therefore, there is no waste left in a forest.