What are Biotic Factors? : Definition, types, examples

What are Biotic Factors?

Those factors of the ecosystem that have life are called biotic factors. An ecosystem is formed both by biotic and abiotic factors. Both biotic and abiotic factors are related have interact with one another. To know in detail about abiotic factors, read our article - Abiotic factors. 

The interaction between biotic factors may be positive or negative. Positive interaction is harmful. These interactions the life of the ecosystem. The relation between biotic is divided into two categories.

(A) Intraspecific relations

The relations which are found among the members of same species are called intraspecific relations. These relations may be co-operative and non co-operative relations are useful while non co-operative relations are harmful for the members of the species.

1. Intraspecific co-operative relations: These relations are among the members of same species. These may be of following kind:

 ➤  Colonization: When the members of a species live together in group and share different activities, such grouping is called colony and its formation is called colonization. Their colony is permanent colonization starts from phylum Protozoa. Honey bees, ants, wasp and termite are also colonial animals.

 ➤  Aggregation: Aggregation is also like the colonization but it is not permanent. The members of a species from temporary group for a purpose, after solving the purpose group is break off. A bison may not face alone to the wolf so bison go in groups for grazing. A wolf does not attack easily on the groups of bison. In the groups of bison healthy males remain outside then other males and in the centre females and young calf are present.

 ➤  Society formation: When the group of members of one species more than one kind of members are found and they perform different function, such colony is called society. Society formation generally found in insects are ants, honey bees, wasps, and termites. These insects are called social insect. In the society of honey bee three kinds members are found, these are queen, drone and workers. Queen is fertile females, drone are fertile males and workers are sterile females.


2. Intraspecific non co-operative relations: The relations which are harmful among the members of a species are called intraspecific non co-operative relations which are as follows:

 ➤  Competition: The needs of all members of a species are same. If the resources are limited then competition starts among the members to fulfill their requirements. This competition may be for food, space and sex. In competition healthy members get benefits while week and old members suffer. In comparison of herbivores there is more competition in carnivores for food.

 ➤  Definite hostility: Almost in all species members, some hostility can be seen in their natural. In some species this hostility is quite clear as a lion does not tolerate the presence of other lion in its territory, similarly dog have hostile attitude to other members of its species. If the honey bee of other hive comes in the hive then it is expelled out by the soldier bees of that hive.

(B) Interspecific Relations

Relations which are found the members of different species are called interspecific relations. These relations may be co-operative and non co-operative types.

1. Interspecific co-operative relations: The relations between the members of different species are useful to each other, such relations are called interspecific relations, which may be of following types:


Symbiosis

When the members of two different species live together for food, shelter and locomotion, their relation is called symbiosis and the members which form symbiosis are called symbiont.

There are two categories of symbiosis, which are termed as-

1. Mutualism
2. Commensalism

(i) Mutualism: The interspecific relation in which members of both species are useful to each other is called mutualism. 

On the basis of degree of intimacy between the members, mutualism is of two types:

(a) Obligatory mutualism: In this relation both members have deep intimacy to each other and they completely depend on each other. In obligatory mutualism life of both members is not possible after separation. There are following common examples of obligatory mutualism.

• Nitrogen fixing bacteria: Rhizobium is a common nitrogen fixing bacteria. It is found in the roots of the legumes (family leguminoceae) in symbiotic form. It converts free nitrogen of atmosphere into nitrate for plants and takes food from plant roots.
• Termite and unicellular protozoan: Termites feed on cellulose but it cannot digest cellulose itself, for its digestion a unicellular flagellate protozoan Trichonympha is present in its intestine. This protozoan take its food from termite intestine.
• Sea anemone and hermit crab: Sea anemone is a coelenterate and hermit crab is an atrhopod. Hermit crab carries sea anemone to different places for food collection and it also gets its food through sea anemone.
• Hydra and zoochlorella algae: In the body wall of Hydra viridis, Zoochlorella algae is found, by its presence this Hydra photosynthesis and Hydra carries it in light, both share the food produced in photosynthesis.

(b) Facultative mutualism: In this relation both members are beneficial to each other but these do not have deep intimacy, on separation their life is possible. The common example of facultative mutualism are as follows:

1. On the skin of cow and buffalo many parasitic insects are present which cause harm to the animal. Some birds and crow and buffalo get relief.
2. Crocodile mainly feed on fishes. The pieces of fishes are discomfort. The crocodile lay down at the river bank to open the mouth. Carnivorous birds take out fish pieces by which birds get food and crocodile get comfort.

Read More: What are Abiotic Factor

(ii) Commensalism: The relation between two organism in which one gets benefit and other neither get benefit nor loss, such relation is called commensalism.

Some Example of commonsalism are as follows:

1. Shark is dominant fish of its territory. In its territory Echineis (sucking fish) is also found. It is a weak fish and its several enemies are present around it, to protect itself, it attaches under the snout of shark. When a commensal attaches to the outer surface of other organism then it is called ectocommensal. Sometime echinics also attaches to turtles.

2. Pinnotherm ostrium : (crab) is found attached to the mantle cavity of oyster for protection. It is the example of endocommensal. Epiphytic plants are also examples of commensal.

3. Interspecific non co-operative relations: The relation between the member of two species which is harmful at least stone member of species called interspecific non co-operative relation. Such relations are as follows:

(i) Predation: Some animals are carnivores, they feed on others animals by killing them, this tendency of feeding is called predation. The animal which kills other for food is called predator and the animal which is killed is called prey. In this relation prey has to loss its life. There are so many predatory animals as cat feeds on rat, lion and tiger feed on cow, buffalo, deer, sheep, goat etc. Eagle feeds on snake.

(ii) Antibiosis: When the secretion of one organism is harmful for others, such relation is termed as antibiosis. Antibiosis is also termed as ammensalism. There are many example of antibiosis in plant and animal kingdom as:

• Microcystis is a blue green algae which is found is ponds. It secretes hydroxylamine poisonous substance. By the presence of this substance many fish or die. If any drinks this water either it fall ill or die.
• In 1957 Abbot and Ballentiae noticed that Gymnodinium veneficium, at dinoflgaellate secretes a toxic substance that causes the death of fishes by effecting their nervous and muscular system.
• From certain organisms antibiotic medicines are obtained which cause death of bacteria.
• Many insects secrete poisonous substance, when they bite man to discharge this substance in the body of man, it causes irritation and swelling. Scorpion bite may causes death of may.
• Poison of snake is also harmful for man and other animals.

(iii) Parasitism: The organism which depends on other organism for its living is called parasite and to whom it depends is called host. The relation of parasite and host is called parasitism. In this relation of parasite gets benefit and host gets loss. 

When parasite gets its need from outer body parts of host, it is called electroparasite as bedbug, louse, and many skin fungi, when parasite fulfills its need from internal body parts of host, it is called endoparasite as Ascaris, Plasmodium species. Fasciola and Trypanosoma etc.