[Biology Class Notes] on Ecosystem Pdf

An ecosystem is the basic functional unit of an environment where organisms interact with each other (living and nonliving), both necessary for the maintenance of life on earth. It includes plants, animals, microorganisms, and all other living things along with their nonliving environment, which includes soil, land, air, water, dust, and other parts of nature. 

If ecology has to be studied in detail, the basic unit starts from the Ecosystem. The study of the Ecosystem deals with how organisms living together interact with each other and how energy flows through the chain of organisms in the Ecosystem. It also studies how an organism lives in a relationship that is harmful or benefitted by one another to live in a sustainable manner. 

It is seen in nature that the Ecosystem can be as large or  small. It depends on the number of abiotic components available in the environment. The ecosystem in the north or south poles does not have much flora and fauna as compared to a tropical climate like a forest due to the extreme climate the animals are subjected to. Only organisms that are resistant to such an environment will be able to make up the Ecosystem. Overall, it is understood that different ecosystems combined would make up the biosphere.

Types of Ecosystem

In ecology, ecosystems are classified into different types based on the region or on the basis of the environment like land or water. It can also be grouped based on the amount of energy the Ecosystem consumes.

 Classification in basic ecosystem are :

1. Terrestrial Ecosystem

2. Aquatic Ecosystem

All other types will fall on either of these ecosystems and hence can be subcategorized into different types. 

Terrestrial Ecosystem

These ecosystems can only be found on land. Different landforms will have different ecosystems based on the climate, temperature, types of organisms residing, the food chain, energy flow, and other factors. This Ecosystem has a relative scarcity of water percentage than the aquatic Ecosystem, and also there is better availability of sunlight as the major source of energy. Types of terrestrial ecosystems are: 

• Forest Ecosystem: These ecosystems are a densely packed environment of various flora and fauna. It has the highest number of organisms living per square km. It is important to conserve this ecosystem as many rare species of the earth are found here. Most of the oxygen in the world is supplied by the forests.

• Desert Ecosystem: Deserts are defined as ecosystems that receive rainfall of less than 25cm indicating extreme climate. Even in harsh temperatures, there are organisms that have resistance towards high temperatures and plants that require very little water to survive, having modified their leaves and stem to conserve water. Camels, rattlesnakes, and cacti are a few examples. 

• Mountain Ecosystem: Mountains are regions of high altitude above sea level with scattered vegetation. It also has an extreme climate, and animals of these regions have developed thick fur on the skin to survive the cold climate.

• Grassland Ecosystem: It mainly includes shrubs, herbs, and few trees which are not as dense as the forests. These basically include grazing animals, insectivores, herbivores. The temperatures are not too extreme in these ecosystems. There are two main forms: The savannas and prairies. The savannas are the tropical grasslands. It dries seasonally with many predators and grazers. The prairies are temperate grassland, which lack large shrubs and trees.

 

Aquatic Ecosystem

The aquatic ecosystem consists mainly of animals and organisms that stay in the water bodies, such as lakes, oceans and seas. Amphibians, fish, sea creatures all come under this ecosystem. Since water is in abundance, organisms survive using the oxygen dissolved in water. This ecosystem is much larger than the terrestrial ecosystem as it acquires a greater part of the earth. The two types of aquatic ecosystems are: 

• Marine Ecosystem: It includes all the oceans and seas and constitutes about 71% of the earth’s surface. About 97% of the water on earth falls under this category. Sharks, whales, dolphins, seals, walrus, and many more come under this ecosystem.

• Freshwater Ecosystem: It includes all the rivers, lakes, ponds, and water bodies that are not salted. This accounts for 0.8% of earth’s water and 0.009% of total water present on earth. There are three types of this ecosystem lotic system where the water is fast-moving, e.g., rivers. The lentic system where the water remains stagnant, e.g., ponds and lakes. The wetlands where the soil remains saturated for most of the time period.

Structure of the Ecosystem

The structure of an ecosystem refers to the explanation of living beings and the physical features of the environment in which the organisms live. 

Components of the Ecosystem 

The ecosystem has two components associated with it mentioned below: 

1. Abiotic component 

2. Biotic component

Abiotic Component

This basically involves inorganic minerals, calcium, phosphorus & iron. It also includes soil, water, land & solar radiation. It is further divided into climatic factors and edaphic factors which include rain, light, temperature, and wind, soil, pH, minerals, and topography.

Biotic Component

The biotic component consists of all the living organisms in the ecosystem. It can be classified as Autotrophic organisms that produce their own food and heterotrophic organisms which depend on other organisms for food. This classification is based on nutritional requirements of the organism. 

• Producers: These are the organisms in the ecosystem that generate the food and energy with the help of sunlight, oxygen, and all other abiotic components. The main producers of the ecosystem are the plants.

• Consumers: These are the organisms that take their nutrition from the food that is made by the producers. 

• Primary Consumers: These organisms feed directly from the producers. They are herbivorous animals like deer, rabbit, cow, buffalo, and giraffes.

• Secondary Consumers: These
  organisms feed on the primary consumers for their nutrition. These are carnivorous and omnivorous animals like crows, dogs, cats, snakes.

• Tertiary Consumers: These organisms feed on secondary consumers. These are only carnivores where they only consume meat usually by preying on prey. Eg., lion, tiger, cheetah

• Quaternary Consumers: These organisms feed on the tertiary consumers for their nutrition. Eg; Eagle, which consumes a snake that consumes a frog that consumes a fly.

Decomposers

These organisms break down dead matter and gain their nutrition, and the decomposed material returns back to the land, which will again be utilized by the producers to produce more food.

The Function of the Ecosystem 

The primary function of any ecosystem is the exchange of energy from one life form to others, which eventually runs in a circle and sustains the entire life of the planet. Without the ecosystems maintaining balance, there would not have been any life form existing on earth.

Important Ecological Concepts

The study of the Ecosystem involves understanding energy flow in the Ecosystem, the various relationships between two organisms, following commensalism, parasitism, mutualism, predation, and various symbiotic relationships exist in an ecosystem. Biogeochemical cycles and limiting factor complexes, the evolution of ecosystems, and the science of population in ecosystems are various important ecological concepts that come under the study of ecology.

 

 Ecosystem

Ecosystem can be defined as the main functional unit that exists in an environment where there is an intersection between all the organisms that are living in the environment which is required for balancing life on earth. Ecosystems are large in structure and have hundreds of animals and plants which live in a balance or it can be something small too. In harsh areas like the North and South poles, ecosystems are simpler in structure and have very few organisms which dwell in such areas. The ecosystems have all the components like plants, animals, microbes and many other living beings which live with non-living components like soil, land, water, air and other components of nature. When we study ecology, we start with studying the ecosystem which deals with the relationships between animals and how the transfer of energy occurs between these animals. We also learn about food chains and food webs. Ecosystems can be either small or large depending on the biotic and abiotic components present in the system. Ecosystems of harsh climate are usually smaller as there are lesser species and abiotic components too whereas the ecosystems of tropical climate will comparatively have a larger number of flora and fauna. We must remember that all the different types of ecosystems form the biosphere.

Some organisms are found in multiple and different ecosystems around the earth which share different relationships with other or similar organisms. There are ecosystems which help species mutually benefit each other be it in getting shelter, protection or food. This relationship is called mutualism. To learn more about the ecosystem, log in or sign up to where you can download free notes and revision notes too.