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TYPES OF RELATIONS AMONG ORGANISM 
GAYATHRI. A.T 
NATURAL SCIENCE
 Different types of relations found among 
organisms. 
 Relationships ensures food and space among 
organism. 
 These relationship is known as interaction. 
 On the basis of benefits and harmful effects – 
two types of interaction. 
 Positive interaction & Negative interaction.
 Beneficial for one interacting partner 
 Other partner is not harmed or both of them 
benefited 
 Includes Mutualism and Commensalism
 Interaction between two living organisms of 
different species 
 Both partners are benefited 
 Examples 
 Crocodiles and plover bird 
 Ants and Aphids 
 Flower and Butterfly 
 Honey Bee and Flower
 ANTS & APHIDS 
 Ants : feed on the sugary honeydew left 
behind by aphids. 
 Aphids : protection provided by ants from 
predators and parasites.
 
 CROCODILE & 
 PLOVER BIRD 
 Crocodile : gets mouth cleaned from food 
residues 
 Plover Bird : gets food residues from teeth
 One of the partner is benefited 
 Other partner neither benefited nor harmed 
 Examples 
 Shark and Remora ( Sucker Fish ) 
Vanda and Mango tree 
 Anemone fishes or clown fishes & Sea 
anemone
 CLOWN FISH 
 & 
SEA ANEMONE 
 Clown fish : live amid the tentacles of the 
anemones which protects them from 
predators. 
 Sea anemone : neither benefited nor harmed
 SHARK 
 & 
 SUCKER FISH 
 Sucker fish : gets free food and transport 
 Shark : neither benefited nor harmed
 One interacting partner is harmed 
 Sometimes both partners are harmed 
 Includes 
Predation 
Parasitism 
Competition
 Direct food relationship between two 
partners 
 One partner captures and feed on other 
partner. 
 Partner that captures and feed : Predator 
 Partner that is eaten : Prey 
 Examples 
 Tiger & Deer 
 Whale & small fishes 
 Humans & other organisms
 TIGER 
 & 
 DEER 
 Tiger : eats deer and gets food 
 Deer : killed by tiger
 WHALE 
 & 
 SMALL FISHES 
 Whale : feed on small fishes & gets food 
 Small fishes : killed by Whale
 One partner is benefited and other is harmed. 
 Partner those gets benefits : Parasites 
 Partners those gets harmed : Host 
 Parasites get food & shelter from the host 
 Examples 
Tape worm and humans 
Leech and pig 
Mosquito and humans
 TAPE WORM 
 & 
 HUMANS 
 Tape worm : lives on intestine of humans & 
feed on them 
 Humans : Diarrhea ,Abdominal pain, Hunger or 
loss of appetite, Fatigue, Weight loss, Vitamin and 
mineral deficiencies
 MOSQUITO 
 & 
 HUMANS 
 Mosquito : feeds on blood of humans 
 Humans : gets various diseases transmitted 
by mosquito such as Dengue
 Here organisms competes for resources like 
water, nutrients, light and space 
 occurs when resources are not sufficient for all 
individuals 
 Individuals harm one another in trying to obtain 
it. 
 Examples 
 Fishes inside an aquarium competing for food 
and space. 
Hyena and Lion competing for territory 
 An Eagle and a Hawk competing for a prey.
 Fishes inside an aquarium competing for 
food and space.
 Hyena and Lion competing for territory
 An Eagle and a Hawk competing for a prey.
 Animal interactions play a vital role in the 
ecological balance 
 Animal interactions are part of food chain and 
food web 
 The energy flow in an ecosystem occurs through 
animal relationships 
 Thus different types of animal interactions play 
their magnificent role in an ecosystem
 ENVIRONMENTAL BIOLOGY & ECOLOGY 
Vijayakumaran Nair 
Academica Publications (2008) 
 Science textbook, Std : VIII, SCERT 
 www.en.encyclopedia.com 
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