All animals, plants and microbes in a biological community interact with each other. These interactions may be beneficial, detrimental or neutral to one of the species or both.
Types of interaction
Predation
\displaystyle \small \bullet It is an interspecific interaction where one animal kills and consumes the other weaker animal.
\displaystyle \small \bullet Roles of Predators
\displaystyle \small \circ Transfer energy from plants to higher trophic levels
\displaystyle \small \circ Control Prey population. E.g. Prickly pear cactus - moth
\displaystyle \small \circ Biological control of Agricultural pest
\displaystyle \small \circ Maintain species diversity by reducing intensity of competition among competing prey species
\displaystyle \small \bullet Over exploitation of prey by the predators results in extinction of prey and predator.
\displaystyle \small \bullet Defense to lessen impact of predation
\displaystyle \small \bullet Ex: Insects and frog – camouflage, Monarch butterfly – poisonous
Competition
\displaystyle \small \bullet It is a process in which fitness of one species (‘r’ value) is significantly lower in the presence of another species.
\displaystyle \small \bullet Interspecific competition is a potent force in organic evolution.
\displaystyle \small \bullet Competition occurs when closely related species compete for the same limited resources.
\displaystyle \small \bullet Unrelated species can also compete for the resource. E.g. Flamingos and fishes in some shallow South American lakes compete for zooplankton.
\displaystyle \small \bullet Competition occurs in abundant resources also. E.g. In interference competition, the feeding efficiency of one species is reduced due to the interfering and inhibitory presence of other species, even if resources are abundant.
\displaystyle \small \bullet Evidence for competition
Competitive release: species distribution restricted to small areas due to competitively superior species.
Resource partition: Two competing species avoid competition by different feeding and foraging patterns - Mc Arthur (Ex. warblers foraging activities)
Gause’s Competition Exclusion Principle
“Two closely related species competing for same resources cannot coexist as the competitively inferior one will be eliminated.”
Parasitism
\displaystyle \small \bullet It is the interaction where one species (parasite) depends on the other species (host) for food and shelter, host is harmed.
\displaystyle \small \bullet Adaptations of parasites
\displaystyle \small \circ Loss of sense organs
\displaystyle \small \circ Presence of adhesive organs or suckers to cling on to the host
\displaystyle \small \circ Loss of digestive system.
\displaystyle \small \circ High reproductive capacity etc.
\displaystyle \small \bullet Types of parasites
Ectoparasites
\displaystyle \small \circ Parasites that feed on the external surface of host.
\displaystyle \small \circ Ex: Lice on humans
\displaystyle \small \circ Ticks on dogs
\displaystyle \small \circ Ectoparasitic Copepods on many marine fishes.
\displaystyle \small \circ Cuscuta plant on hedge plants. - Cuscuta has no chlorophyll and leaves. It derives its nutrition from the host plant.
\displaystyle \small \circ Female mosquito is not considered a parasite, because it needs our blood only for reproduction, not as food.
Endoparasites
\displaystyle \small \circ Parasites that live inside the host body at different sites (liver, kidney, lungs, RBC etc).
\displaystyle \small \circ The life cycles of endoparasites are more complex.
\displaystyle \small \circ They have simple morphological and anatomical features and high reproductive potential.
\displaystyle \small \circ Ex: nematodes, tapeworms, helminthes, Plasmodium etc.
Brood parasitism in birds
\displaystyle \small \circ Here, the parasitic birds lay eggs in the nest of its host and lets the host incubate them.
\displaystyle \small \circ During the course of evolution, the eggs of the parasitic bird have evolved to resemble the host’s egg in size and colour to reduce the chances of the host bird detecting the foreign eggs and ejecting them from nest.
\displaystyle \small \circ E.g. Brood parasitism between cuckoo and crow.
Commensalism
\displaystyle \small \bullet Interaction in which one interacting individual is benefited whereas other is neither benefited nor harmed.
\displaystyle \small \bullet Orchid (+) growing as epiphyte on a mango branch (0).
\displaystyle \small \bullet Barnacles (+) growing on the back of a whale (0).
\displaystyle \small \bullet Cattle egret (+) and grazing cattle (0). The egrets forage close to where the cattle are grazing. As the cattle move on the vegetation, insects come out. Otherwise it is difficult for the egrets to find and catch the insects.
\displaystyle \small \bullet Sea anemone (0) and clown fish (+). Stinging tentacles of sea anemone gives protection to fish from predators.
Mutualism
\displaystyle \small \bullet It is interaction in which both the interacting species are benefited.
\displaystyle \small \bullet Lichen: It is a mutualistic relationship between a fungus and photosynthesizing algae or cyanobacteria.
\displaystyle \small \bullet Mycorrhizae: Associations between fungi and the roots of higher plants. The fungi help the plant in the absorption of essential nutrients from the soil while the plant provides the fungi with carbohydrates.
\displaystyle \small \bullet Mutualism b/w plant and animal through pollination and seed dispersion
Fig trees and wasps. The fig species is pollinated only by its ‘partner’ wasp species and no other species. The female wasp pollinates the fig inflorescence while searching for suitable egg-laying sites in fruits. The fig offers the wasp some developing seeds, as food for the wasp larvae.
\displaystyle \small \bullet ‘Sexual deceit’ of Ophrys (Mediterranean orchid). One petal of its flower resembles female bee in size, colour and markings. So male bee ‘pseudocopulates’ with the flower and is dusted with pollen. When this bee ‘pseudocopulates’ with another flower, it transfers pollen to it. If the female bee’s colour patterns change slightly during evolution, pollination success will be reduced unless the orchid flower co-evolves to maintain the resemblance of its petal to the female bee.
Amensalism
\displaystyle \small \bullet Interaction between two different species, in which one species is harmed and the other species is neither harmed nor benefited.
\displaystyle \small \bullet E.g.: Bacterial culture, after few days fungus growth will be there on it like Pencillium and its secretions of chemical will kill bacteria, but no benefits to fungi.
Types of interaction
Predation
\displaystyle \small \bullet It is an interspecific interaction where one animal kills and consumes the other weaker animal.
\displaystyle \small \bullet Roles of Predators
\displaystyle \small \circ Transfer energy from plants to higher trophic levels
\displaystyle \small \circ Control Prey population. E.g. Prickly pear cactus - moth
\displaystyle \small \circ Biological control of Agricultural pest
\displaystyle \small \circ Maintain species diversity by reducing intensity of competition among competing prey species
\displaystyle \small \bullet Over exploitation of prey by the predators results in extinction of prey and predator.
\displaystyle \small \bullet Defense to lessen impact of predation
\displaystyle \small \bullet Ex: Insects and frog – camouflage, Monarch butterfly – poisonous
Competition
\displaystyle \small \bullet It is a process in which fitness of one species (‘r’ value) is significantly lower in the presence of another species.
\displaystyle \small \bullet Interspecific competition is a potent force in organic evolution.
\displaystyle \small \bullet Competition occurs when closely related species compete for the same limited resources.
\displaystyle \small \bullet Unrelated species can also compete for the resource. E.g. Flamingos and fishes in some shallow South American lakes compete for zooplankton.
\displaystyle \small \bullet Competition occurs in abundant resources also. E.g. In interference competition, the feeding efficiency of one species is reduced due to the interfering and inhibitory presence of other species, even if resources are abundant.
\displaystyle \small \bullet Evidence for competition
Competitive release: species distribution restricted to small areas due to competitively superior species.
Resource partition: Two competing species avoid competition by different feeding and foraging patterns - Mc Arthur (Ex. warblers foraging activities)
Gause’s Competition Exclusion Principle
“Two closely related species competing for same resources cannot coexist as the competitively inferior one will be eliminated.”
Parasitism
\displaystyle \small \bullet It is the interaction where one species (parasite) depends on the other species (host) for food and shelter, host is harmed.
\displaystyle \small \bullet Adaptations of parasites
\displaystyle \small \circ Loss of sense organs
\displaystyle \small \circ Presence of adhesive organs or suckers to cling on to the host
\displaystyle \small \circ Loss of digestive system.
\displaystyle \small \circ High reproductive capacity etc.
\displaystyle \small \bullet Types of parasites
Ectoparasites
\displaystyle \small \circ Parasites that feed on the external surface of host.
\displaystyle \small \circ Ex: Lice on humans
\displaystyle \small \circ Ticks on dogs
\displaystyle \small \circ Ectoparasitic Copepods on many marine fishes.
\displaystyle \small \circ Cuscuta plant on hedge plants. - Cuscuta has no chlorophyll and leaves. It derives its nutrition from the host plant.
\displaystyle \small \circ Female mosquito is not considered a parasite, because it needs our blood only for reproduction, not as food.
Endoparasites
\displaystyle \small \circ Parasites that live inside the host body at different sites (liver, kidney, lungs, RBC etc).
\displaystyle \small \circ The life cycles of endoparasites are more complex.
\displaystyle \small \circ They have simple morphological and anatomical features and high reproductive potential.
\displaystyle \small \circ Ex: nematodes, tapeworms, helminthes, Plasmodium etc.
Brood parasitism in birds
\displaystyle \small \circ Here, the parasitic birds lay eggs in the nest of its host and lets the host incubate them.
\displaystyle \small \circ During the course of evolution, the eggs of the parasitic bird have evolved to resemble the host’s egg in size and colour to reduce the chances of the host bird detecting the foreign eggs and ejecting them from nest.
\displaystyle \small \circ E.g. Brood parasitism between cuckoo and crow.
Commensalism
\displaystyle \small \bullet Interaction in which one interacting individual is benefited whereas other is neither benefited nor harmed.
\displaystyle \small \bullet Orchid (+) growing as epiphyte on a mango branch (0).
\displaystyle \small \bullet Barnacles (+) growing on the back of a whale (0).
\displaystyle \small \bullet Cattle egret (+) and grazing cattle (0). The egrets forage close to where the cattle are grazing. As the cattle move on the vegetation, insects come out. Otherwise it is difficult for the egrets to find and catch the insects.
\displaystyle \small \bullet Sea anemone (0) and clown fish (+). Stinging tentacles of sea anemone gives protection to fish from predators.
Mutualism
\displaystyle \small \bullet It is interaction in which both the interacting species are benefited.
\displaystyle \small \bullet Lichen: It is a mutualistic relationship between a fungus and photosynthesizing algae or cyanobacteria.
\displaystyle \small \bullet Mycorrhizae: Associations between fungi and the roots of higher plants. The fungi help the plant in the absorption of essential nutrients from the soil while the plant provides the fungi with carbohydrates.
\displaystyle \small \bullet Mutualism b/w plant and animal through pollination and seed dispersion
Fig trees and wasps. The fig species is pollinated only by its ‘partner’ wasp species and no other species. The female wasp pollinates the fig inflorescence while searching for suitable egg-laying sites in fruits. The fig offers the wasp some developing seeds, as food for the wasp larvae.
\displaystyle \small \bullet ‘Sexual deceit’ of Ophrys (Mediterranean orchid). One petal of its flower resembles female bee in size, colour and markings. So male bee ‘pseudocopulates’ with the flower and is dusted with pollen. When this bee ‘pseudocopulates’ with another flower, it transfers pollen to it. If the female bee’s colour patterns change slightly during evolution, pollination success will be reduced unless the orchid flower co-evolves to maintain the resemblance of its petal to the female bee.
Amensalism
\displaystyle \small \bullet Interaction between two different species, in which one species is harmed and the other species is neither harmed nor benefited.
\displaystyle \small \bullet E.g.: Bacterial culture, after few days fungus growth will be there on it like Pencillium and its secretions of chemical will kill bacteria, but no benefits to fungi.
0 Comments