There are different types of interactions in the biotic community. It can be positive, negative or neutral. In the positive interactions one of the species helps the other in one way or other. In the negative interactions one of the species harms the other in one way or other. The other species is harmed or benefitted or unaffected. In the neutral interaction the species is neither harmed nor benefitted.
The predation is defined as an interaction between the members of different species in this one member catches the prey and kills them. They are known as predators. The majority of them are animals which are mainly carnivorous. The herbivorous animals can also act as a predator. They remove the plants as well as seeds. There are few plants which also act as predators and are known as insectivorous plants. These include drosera and utricularia. Their role is interchangeable that means the predators can act preys and vice a versa. For example, frog feeds for snakes and the snakes feed for eagle. The predators have strength, agility, tearing ability to capture and eat the prey. The population of predator is small. The preys are larger in number and cannot be eliminated. The prey has a high reproductive ability. If there are no predators the population of the prey will increase at such a rate that it will cross the carrying capacity of environment. The species go under degeneration. The predator keeps the population under check. The prey maintains its optimum activity as the sick individuals are removed by predators.
The control of weeds and pests depend upon the predator prey relationship. An opuntia is a serious weed which occurs in Australia. Its natural herbivore known as cactoblastis has brought under control by it. The menace of red locust was controlled by the mynah of India. The pests like aphids are controlled by the beetles and insects. They are also controlled by the birds. The simple predation includes tiger and deer. The frogs and insects, owls and rats, sea snakes and eggs are the examples of simple predation. The relationship between the land snake and mice is a complex one. The woodpecker not only digs hole in their nest but also feeds on the red ants. The eggs and young ones are not harmed in this process.
The scavenging is defined as the process of feeding on the flesh of animals which die naturally or are killed by the other animal. The animal which feed on the dead flesh is called scavenger. Vultures are the main animals which act as a scavenger. The animals such as crows and ants are omnivorous. They feed on the dead and decayed bodies. The lion is followed by the jackal and hyenas. They eat the flesh on the body of animal. They also act as a predator. It is difficult for them to capture the larger animals like the zebra etc. The scavenging is very helpful in cleaning the environment. It acts on the dead bodies and prevents the wastage.
The parasitism is defined as the process in which two organisms of different species are present and in which one of the organism acts as a parasite and the other organism acts as a host. The food is obtained from the host. The parasite spends a part or their full life in the body of host. There are different types of parasites available on our planet. There are ecto and endo parasites. The ecto parasites occur on the body surface of host and the endo parasites occur inside the body of host. They can be intracellular or extracellular. They can be tissue parasites, gut parasites and the body fluid parasite. The ecto parasites suck blood, juice etc. There are also temporary and permanent parasites. The temporary parasites occur in the host for some part of their life. It includes the female mosquitoes and bed bugs. The permanent parasites occur in the host for whole of their life. It includes the ascaris and lice. They are also known as the intermittent parasites. There are holo parasites and hemi parasites in which the holo parasites depend completely on the host for their requirements. It includes rafflesia and cuscuta. The cuscuta receives the flower inducing hormone from host. It can be a short day plant or long day plant. The host can also be a short day or long day. The hemi parasites do not depend completely on the host for their requirements. They make themselves rest of their food. There are certain parasites which occur in the plant and are known as the phyto parasites. They can be stem or root parasites. The stem parasites occur in the region of stem of plant. It includes viscum and aphids. The root parasites occur in the region of root of plant. It includes the rafflesia and root nematodes. The pathogenic parasites are those which harm the host and include the corny bacterium, mycobacterium, vibrio, rusts and smuts, fungal and the ring worm disease. The non pathogenic parasites are those which do not harm the host cell. The host cells provide food and nutrition and they are spared. It includes the entamoeba coli. There is a hyper parasite which resides on the other parasite. It includes the bacterial virus and the powdery mildew.
The parasite infects the host through skin, direct contact with the person who is infected; enter the human body through insect bite, cyst or egg swallowing. They can be ascaris or tape worm. It also includes the kala azar and tse tse fly. There are certain general features of the parasites. They are anaerobic and have resistant eggs which provide the safety. It helps in the safe transfer of off springs. They lose some of their organs and divide at a faster rate. They have adhesive organs.
The amensalism is defined as the process in which two organisms of different species are present and in which one organism do not allow the other organism to survive. This mode of inhibition occurs with the use of allochemics. For example, the growth of staphylococcus is inhibited by the use of penicillin. There are the smoother crops which are barley, sorghum and sunflower. They do not allow the weed to grow near them. The black nut has roots which form a chemical called the juglone. The growth of wheat is inhibited by the convolvulus. The juglone is toxic to apple and tomato. The plant known as grevillea does not allow its seedlings to grow nearby by secreting an allo chemical by its roots.
The commensalism is defined as the process in which two organisms of different species are present and in which one organism is benefitted while the other one acts as a neutral organism. It is neither harmed and nor benefitted. It includes the pilot fish. It is present along with the shark. It detaches itself from the fish some times. The sucker fish is also attached to the shark and gets detach from the shark when it feeds on the food. The lions are followed by the jackals and the fox follows the seal to obtain food. There are small plants which grow on the larger plants for only space and are known as epiphytes. They do not depend upon the nutrition. The seeds and fruits of the plants are dispersed by the animals which are present on their fur. The commensal can be harmful or non harmful. In the human intestine E.Coli is present which acts on the undigested food and also keep an eye on the putrefying bacteria. They also release some vitamins. The sea anemone is solitary and the hermit crab is a free swimming organism. The sea anemone uses the shell of snail as their temporary home. The sea anemone is able to get more food when it is in combination with the snail. The hermit crab also gets the protection from the sea anemone as it bears the stinging cells.
The protocooperation is defined as the process in which two organisms of different species are present and in which both the organisms are mutually benefitted and they can live independently. It includes the red and yellow billed ox pecker. They form a protocooperation with the rhinoceros. The birds feed on the parasites present on the skin of rhinoceroes and relieve him of the parasites. Similarly, the crocodile bird goes inside the mouth of crocodile and removes the leeches.
The symbiosis is defined as the process in which two organisms of different species are present and in which both the organisms are benefitted and they cannot live independently. It is also known as the mutualism. A de Bary defined symbiosis as an interaction between organisms of different species which can be positive or negative. The negative interactions include parasitism and predation. The rest of them are positive interactions. There are many examples of symbiosis. There is a lichen planus which is formed by the combination of alga and a fungus. The fungus is a main part body of lichen planus. The fixation, water and minerals, shelter is provided by the alga. The food is manufactured for the lichen as well as for themselves. So, the lichen is able to survive under the extreme conditions. The nitrogen fixation is also included. It occurs in the root nodules of legumes, leaf nodules of ardisia, roots of the cycas etc. In legumes it is carried out by the rhizobium bacteria. They live freely and are not able to fix the nitrogen. The root nodules help in the nitrogen fixation. The food and shelter to the bacteria is provided by the legume. Both the bacteria and legume are benefitted. The nitrogen fixing blue green alga is also known as anabaena. It occurs in association with the azolla. The cycas also shows the similar association. The symbiotic association is also seen in the mycorrhizae. In this a fungus and root are involved. The shelter and the food to fungus is provided by root. The fungi play a role in the absorption of water and minerals. It also prevents from other disease causing fungi. The termites act on the wood and are devoid of the enzymes which digest the food. They have a cellulose digesting flagellates. The flagellates cannot survive their own. If there are no flagellates the termites are not able to survive and the newly formed termites receive the flagellates from the old termites. The ruminant mammals have flagellates along with the bacteria. These help in the cellulose digestion. The microorganism requires food, shelter and help in the digestion of cellulose.
The competition is defined as the process in which the organism fights for the same resources. It can be intra specific or inter specific. The competition between the organisms of the same species is referred as an intra specific competition. This type of competition is very severe as the organism of the same species has same requirement for food, water, shelter and light etc. The completion between the organisms of the different species is refereed as an inter specific competition. The intra specific competition keeps a close check on the size of population. It decreases the birth and survival rate. The organism in this group has similar characteristics and establishes their own territory. The plants of the same species can grow only when they are shaped properly. The population belongs to the similar trophic level. They compete for the same natural resources. For example, in forests the different types of tress and vegetations compete for water, sunlight and other similar resources. The carnivorous animals compete for the similar prey. The individuals of different species have no such common interest. They prove their superiority and inferiority to survive. If the resources are few the superior individuals outperform the inferior individuals.
The Gause Hypothesis is also known as the principle of competitive exclusion. It states that out of the two species which grow together one is eliminated and the other one survives. At few occasions more than one species can survive. The species which compete they coexist due to their specializations. The Darwin discovered around 14 finches of species in the Galapagos Islands. They all have different feeding habits. The Serengeti plains have around 20 species of antelopes in the same area. There are many plants which can grow by their roots which are of different lengths.
The mimicry is defined as the process of resemblance of organism to the other organism or with the other object so that they can be concealed or protected as the time demands. Mimic is an organism which exhibits the mimicry. The model is defined as an object which resembles a mimic. In this type the color, form, pattern and scent of an organism resemble to the other organism or the surrounding objects. It helps the organism to protect it from predator and help in the easy trapping of prey. It also helps to secure pollination in the orchid. The prey develops a mimicry which is known as the protective mimicry. The predator develops a mimicry which is known as the aggressive mimicry. The protective mimicry is of different types. It can be concealing or warning. In concealing type the organism resembles the surroundings so that they cannot be detected easily. It includes the stick insect, larva of moth and the leaf insect. These different types of organism resemble the twigs and green leaf. In the warning type the organism resembles the poisonous organisms. It includes the palatable butterfly and non palatable butterfly. There is another type of mimicry which is known as the Batesian mimicry. In this an edible species resemble a non edible species. When the non edible species resemble each other it is referred as the Mullerian mimicry. This mimicry which is discussed above is included in the protective mimicry. The aggressive mimicry is of different types. It can be concealing and alluring. In concealing type the predator resembles the surroundings so that they cannot be detected easily. They hide and strike suddenly. It includes the praying mantis. In alluring type the predator attracts the prey by resembling an object which is liked by the prey. It includes the mouth of African lizard which resembles a flower. The spider also resembles an orchid flower.