SUBMITTED BY,

VIDYA P.PILLAI B.Ed, IInd SEMNATURAL SCIENCE N. S. S. TRAINING COLLEGE PANDALAM

SUBMITTED TO,

Dr. PADMA PRIYAOPTIONAL IN CHARGENATURAL SCIENCEN. S. S. TRAINING COLLEGE PANDALAM

CONTENTBLOCK – AN ADDRESS FOR LIVING BEINGS

TOPIC – BIOLOGICAL INTERACTIONS

Achu, next week i have to present a seminar on different types of relation among organisms. But i don’t know anything about the topic. Can you help me please ?

Yes of course, You don’t worry. I will help you.

Oh, Thank you

Ammu, different types of relations are found among organisms of various types. You know the purpose behind that ?

Ammu and Achu were discussing about different types of relations among organisms.

Yes, you are right. An animal has to depend on other organisms in the habitat for food, shelter, reproduction and other needs. This type of relations exist among organisms are known as biological interactions.

Which are the different types of biological interactions?

Yes, these relationships are useful for ensuring food and space for living.

The interactions may be of two types interspecific or intraspecific. If the interaction is among the individual of same species it is called intraspecific interaction. So, can you explain what is interspecific interaction?.

Yes, you are right. On the basis of benefits and harmful effects of organisms, the interactions can be categorized in to two namely positive interaction and negative interaction.

If the interaction is among the individuals of different species, it is called interspecific interaction. Am I right?

What is this positive interaction?

It is the interaction in which one interacting species helps the other either one way or on reciprocal terms.

Oh! Which are the different types of positive interactions?

Mutualism and commensalism are the different types of positive interactions.

What is this Mutualism?

I will show you a video, you should observe that and try to find out how the organisms helps each other ?

Monarch butterfly (Danaus plexippus) feeding on flowers. 1080p HD..mp4

Ok Ammu. Then what is Commensalism?

In this video plant helps butterfly by giving honey and butterfly helps plant by pollination.

Yes, you are right. So that is Mutualism. Here the two organisms are benefited.

I will show you a picture and try to find out what is Commensalism?

VANDA AND MANGO TREE

Yes, in Commensalism one is benefited and the other is neither benefited nor harmed.

Here vanda is benefited by getting a support on mango tree and mango tree is neither benefited nor harmed.

So Achu, What about negative interactions.

I will show you one more example for commensalism. It is a video of shark and sucker fish.

Oh! Who is benifited here and how?

Here sucker fish attaches itself to shark to move about in search of food and thus it is benifited. shark is neither benifited nor harmed..

Remoras, Cobias & Rainbow Runners - Reef Life of the Andaman - Part 22(27s714ms - 01m10s442ms).mp4

So Achu, What about negative interactions..

In negative interactions, one interacting species is harmed. The other may be harmed, benefited or unaffected..

Which are the different types of negative interactions.

Predation, Parasitism and Competition are the different types of negative interactions.

I know about Predation. Animals that secure their food by killing other animals are known as predatory animals and this mode of feeding is termed Predation.

Yes, here one is benefited and the other is harmed. The organism which is benefited is the Predator and one who killed is the Prey.

Yes, I will show you a video on how eagle catches its prey, the fish.

For example eagle and fish. Here eagle is the predator and fish is the prey.

Eagle Catches Fish - High speed Video.mp4

That means in predation, the predator is larger than the prey and in parasitism the parasite is smaller than the host.

In parasitism, one is benefited and the other is harmed. The organism which is benefited is the parasite and one who harmed is the host.

What about parasitism and competition.

Yes, this picture is an example for Parasitism.

LORANTHUS AND MANGO TREE

Here, mango tree is the host and loranthus is the parasite. So loranthus is benifited and mango tree is harmed.

In competition, both organisms suffer first. But the organism which win is benefited. For example crops and weeds.

CROPS AND WEEDS

Ammu, now are you familiar with your seminar topic.

Yes Achu. Now I am very confident to present my seminar.

Now can you consolidate the topic.

Yes, of course

CONSOLIDATION

Different types of relationships are found among organisms of various types.

The relationships can be categorized in to two, namely positive and negative interactions.

In positive interaction one interacting species helps the other either one way or on reciprocal terms.

In negative interactions , one interacting species is harmed. The other may be harmed, benifited or unaffected.

Mutualism and commensalism are the two types of positive interactions.

Predation, parasitism and competition are the different types of negative interactions.

REVIEW• What is positive interaction?• What is commensalism?• Give an example for predation?• What is parasitism?

THANK YOU