Ecosystem

Module 2-ECOSYSTEM 

28. Ecosystem

Ecosystem is the unit of ecology in which communities of organisms are interacting with each other and with their physical environment. It is the smallest unit of biosphere which has all the characteristics required for existence of life. 

An ecosystem consists of biotic and abiotic components and it exist by the following function-nutrient cycling, energy flow, mutual interactions and homeostasis

29. Types of ecosystem

Natural ecosystem

In natural ecosystem, all its functions are happened without any human intervention. Examples are Forest, grass land, desert, river, lake, pond, ocean, estuary etc.

Artificial ecosystem

Artificial ecosystem required to be maintained by human being for its survival. Examples are artificial ponds, garden, well, agricultural land, aquarium etc.

 Forest ecosystem

A forest ecosystem consist of several plants, animals and microorganisms that live in coordination with the abiotic factors of the environment.

Grass land ecosystem

In a grass land ecosystem, the vegetation is dominated by grasses and herbs.

Desert ecosystem

These are regions with very little rainfall and the temperature is high.

Aquatic ecosystem

Aquatic ecosystems present in a body of water. These can be further divide into two types, namely:

 

1)  Fresh water ecosystem

2)  Marine water ecosystem

Fresh water ecosystem

It is an aquatic ecosystem that includes lakes, ponds,

rivers, streams and wetlands

Marine water ecosystem

It includes seas and oceans. These have a larger salt

content and greater biodiversity in comparison to the

fresh water ecosystem

30. Difference- Natural and artificial ecosystem 

Explain the characteristics of an ecosystem
31.  Structure of an ecosystem

The components of the structure of an ecosystem are shown in the diagram.

The structure of an ecosystem has two major components

1. Abiotic components
2. Biotic components

Abiotic components

They are the non-living components of ecosystem and includes physical factors such as soil, sun light,  water, various organic substances like carbohydrates, proteins, lipids, methane, coal, enzymes etc. and various inorganic substances like hydrogen,  nitrogen,  potassium,  phosphorus etc.

Biotic components

It is the living components of the ecosystem. Examples are plants, animals, birds, human being, bacteria etc.
Biotic components can be divided as
1. Autotrophs
2. Heterotrophs
3. Saprotrophs

Autotrophs

Autotroph or Producer is an organism that produces complex organic substances like carbohydrates, fats and proteins using simple inorganic substances like carbon dioxide and energy from sunlight. This is required for other living beings like heterotrophs and saprotrophs for their food and energy needs. Examples are plants on land and algae in water.

Heterotrophs

A Heterotroph or consumer is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter.
Heterotrophic living organisms include all animals and fungi, human being, some bacteria and protists and many parasitic plants.
Heterotrophs include Herbivores, Carnivores and Omnivores

Herbivores

Herbivores are primary consumers which directly depend autotrophs for their food. Examples are cattle, deer, horse, rabbit, parrot etc.

Carnivores

Carnivores are secondary or tertiary consumers which depend herbivores or other carnivores for their food. Examples are: tiger, lion, hawk, eagle, snake, frog etc.

Omnivores

Omnivores are those living beings which eat both autotrophs and herbivores. Examples are human being, crow, pig etc.

Saprotrophs

Saprotrophs are living organisms that derive their nutrition from the dead and decaying organic matter. As they derive nutrition from dead matter, they are often termed as decomposers or Detrivores. Fungi and few other bacteria are good example of saprotrophs.

32.  Function of ecosystem

Ecosystems exist through the following functions:

1.    Mutual interaction
2.    Nutrient cycling
3.    Energy flow
4.    Homeostasis

Interaction

Ecosystem cannot survive without interactions between its components. Biotic communities in the ecosystem are getting their food and energy from the abiotic components like sunlight, water, soil, temperature and various organic and inorganic substances. At the same time, the nutrients for plants are returned to the soil through the dead bodies and faecal matters of living beings. When plants use carbon dioxide for photosynthesis and return the oxygen to the atmosphere, living beings use this oxygen for their respiration. Biotic communities are interacting with each other by eating and by being eaten up. Decomposers are working as cleaning agents by decaying animal wastes and faecal matters. Such a way an ecosystem exists through mutual interactions between its various components.

Nutrient cycling

In an ecosystem nutrients like organic compounds and minerals are cycled through its various components and returned to its origin. Autotrophs extract minerals from the soil and by the process of photosynthesis convert it into organic compounds and also some are stored in its structure. These nutrients transferred to the heterotrophs when they eat it. At the same time these nutrients returned to the soil, when decomposers decay the dead matters of plants and animals and their faecal matters. Such a way nutrient cycling is happened in an ecosystem.

Energy flow

The sun is the ultimate source of energy. In an ecosystem, the light and heat energy from the sun is converted into chemical energy i.e. nutrients by the autotrophs and then it is transferred to the heterotrophs as they consume it. It is noted that only a small amount of energy is transferred from one trophic level to another and the remaining is lost as heat to the atmosphere. Finally this energy will reach into the saprotrophs also. This way energy from the sun is flowing through the biotic components and some reach into the atmosphere.

Homeostasis

Ecosystem maintains a functional balance between its various components. This phenomenon is known as homeostasis.  For example , it is sometimes claimed that when atmospheric carbon dioxide levels rise , certain plants may able to grow better and thus act to remove more carbon dioxide from the atmosphere. Same way, in an agricultural land, when the rat population increases, the snake population also increases. But at a certain stage when rat population decreases, the snake population also reduces. Again as the snake population reduces, the rat population

33. Components of ecosystem

Refer Answer Above