NAVODAYA VIDYALAY, WAHAR A, Ray of Say eS = BIOLOGY INVESTIGATORY PROJECT POPULATION INTERACTION 2016-17 PREPARED By: Guided By: MA.SIDDHESH KISHOR SAIGAONKAR MR.D.M. TAKALE (sir) 12™ SCIENCE (PGT-BIOLOGY)CERTIFICATE This is to certify that the project entitled by Ma.Siddhesh Kishor Saigaonkar is record of work by the candidate during academic year 2016-17 as a part of practical work prescribed by CBSE for class xu? (science). This is also to certify that the project presented is the independent work of candidate BOARD ROLL NO.: DATE: Mr.D.M.TAKALE MR. P.K. NARAYANAN PGT-BIOLOGY PRINCIPAL (JNV,RAIGAD) EXTERNAL EXAMINORAcknowledgement l express my deep and heartfelt sense of gratitude towards my guide Mr.D. M. Takle and Mr. Vivek Patil for providing timely help and suggestions in carrying out this project l express my deep and heartfelt sense of gratitude towards my respected principal Mr.P.K.Narayanan. | also express my sincerest thanks to all staff members of my school, JAWAHAR NAVODAYA VIDYALAYA,NIZAMPUR,RAIGAD for providing me essential help every time. At last | thank all my friends who have rendered their willing cooperation and service in a variety of way to bring out this project Ma. Siddhesh Kishor Saigaonkar XII" ScienceINDEX > Introduction » Important interaction between two species * Population interaction influence abundance © Mutualism « Competation © Predation e Parastism e Commensalism e Amenalism(allopathy) e Symbiosis » OBSERVATION OF SOME INTERACTIONS IN OUR LOCALITIES > ReferanceIntroduction POPULATION INTERACTION Biological interactions are the effects that the organisms in a community have on one another. In the natural world no organism exists in absolute isolation, and thus every organism must interact with the environment and other organisms. An organism's interactions with its environment are fundamental to the survival of that organism and the functioning of the ecosystem as a whole. In Ecology, biological interactions can involve individuals of the same species (intraspecific interactions) or individuals of different species (interspecific interactions). These can be further classified by either the mechanism of the interaction or the strength, duration and direction of their effects. Species may interact once in a generation (e.g. pollination) or live completely within another (e.g. endosymbiosis). Effects range from consumption of another individual (predation, herbivory, or cannibalism), to mutual benefit (mutualism). Interactions need not be direct; individuals may affect each other indirectly through intermediaries such as shared resources or common enemies.IMPORTANT INTERACTIONS BETWEEN TWO SPECIES By comparing populations living alone and together, several types of interactions can be identified. * COMMENSALISM (+/o) * MUTUALISM (+/+) ® COMPETITION (-/-) © PARASITISM (+/-) * PREDATION (+/-) * ALLELOPATHY(+/-)POPULATION INTERACTIONS INFLUENCE ABUNDANCE + When populations of different species interact, the effects on one on the other may be positive (+), negative (-) or neutral (0). Species A Table 1.: Population Interactions Species B + Name of Interaction Mutualism Competition Predation Parasitism Commensalism AmensalismMUTUALISM * Mutualism is a type of symbiosis in which populations interact to the benefit of both species. * Mutualism may be obligate (necessary for survival of one or both species) or facultative (one species may survive in the absence of other). MUTUALISM SYMBIOTIC NITROGEN FIXERS « Although free nitrogen is about 80% of the atmosphere, plants are unable to use it until it is “fixed” into ammonia and converted to nitrates by bacteria. * A common example of this mutualism between plants and nitrogen fixing bacteria is found in the roots of leguminous plants. King NitrogenCOMPETITION ® Mutual use of a limited resource by populations of two or more species. e Each individual adversely affect another in the quest for food (nutrients), living space, or other common needs. e Individuals harm one another is attempting to gaina resource. Categories of Competition * When competition is between individuals of: same species (intraspecific) different species (interspecific) * When a resource is in short supply that used by one thus not available to the other (exploitation). » When an action or substance produced by one is directly harmful to the other (interference).PREDATION Predation comprises of organism which are; +Classic or “true” predators: most commonly thought of predators including, sharks, cheetahs, bears etc. These predators kill their prey soon after catching it, normally consuming it all. *Grazers: can be considered a predator by the same definition but consume only part of a prey organism. PREDATION *Most of the predatory organism are animals but there are some plants, like Nephenthes, Drosera etc. which consume insects for their food. They are also known as Insectivorous plants *These plants are adapted in remarkable ways to attract,catch and digest their victims. Their foliar appendage produce proteolytic enzymes for digestion of insectsPARASITISM *Parasites are divided into two groups: endoparasites and ectoparasites. *Endoparasites are parasites that live inside the body of the host e.g. Trypanosoma -Ectoparasites are parasites that live on the outer surface of the host and generally attach themselves during feeding e.g. Ticks, Mites PARASITISM *Ectoparasites develop some clinging organs like hooks, suckers to get attached with the body of host. «Some plants like cuscuta have certain specialized absorbing structures called haustoria to attain food.COMMENSALISM *Commensalism is an association between two organisms in which one benefits and the other derives neither benefit nor harm +In commensalism species involved live together without entering into any kind of physiological exchange COMMENSALISM EPIPHYTE * An epiphyte is a plant that grows upon another plant. Growing on another plant gives the epiphyte better access to sunlight and moisture, ® They differ from lianas in that they are not rooted into the soil © They have specialized roots to absorb moisture and nutrients from humid air to prepare food so, they are not dependent on the supporting species » Eg. : Orchid speciesALLELOPATHY -Allelopathy is a biological phenomenon by which an organism produces one or more biochemical's that influence the growth, survival, and reproduction of other organisms. These biochemical's are known as allelochemicals and can have beneficial (positive allelopathy) or detrimental (negative allelopathy) effects on the target organisms. »plant allelopathy is used as a means of survival in nature, reducing competition from plants nearby. Figure 1, Possible pathways for release of allelochemicals into the environment.The term symbiosis (Greek: living together) can be used to describe various degrees of close relationship between organisms of different species. Sometimes it is used only for cases where both organisms benefit; sometimes it is used more generally to describe all varieties of relatively tight relationships, i.e. even parasitism, but not predation. Some even go so far as to use it to describe predation. It can be used to describe relationships where one organism lives on or in another, or it can be used to describe cases where organisms are related by mutual stereotypic behaviours .OBSERVATION OF SOME INTERACTIONS IN OUR LOCALITIES “> The dog is a classic example of a domestic animal that likely traveled a commensal pathway into domestication. Pollination in which nectar or pollen (food resources) are traded for palien dispersal (a service) or ant protection of aphids, where the aphids trade sugar-rich honeydew (a by-product of their mode of feeding on plant sap) in return for defense against predators such as ladybugs. Common clownfish (Amphiprian ocellaris) in their Ritteri sea anemone (Heteractis magnifica) home. Both the fish and anemone benefit from this relationship, a case of mutualistic symbiosis. Common Cuckoo chick ejects eggs of Reed Warbler out of the nest.lt is type of brood paracitism. agricultural varieties of maize provide food for humans and are unable to reproduce without human intervention because the leafy sheath does not fall open, and the seedhead does not shatter to scatter the seeds naturally, cheetahs and lions since both species feed on similar prey, they are negatively impacted by the presence of the other because they will have less food, however they still persist together. REFERANCE > NCERT TEXTBOOK CLASS 12™ >» BIOLOGY TODAY(mtg publication) ® BIOLOGICAL SCIENCE (Cambridge edition)