CHAPTER 4:INTERACTION

BETWEEN LIVING ORGANISMS

INTERACTION BETWEEN

ORGANISMS

Prey predator Competition Symbiosis

Commensalism Parasitism Mutualism

Prey-predatorA relationship where an animal captures andeat other animals.

Rat is the victim(prey)

Snake eats and kills rat

(predator)

OwlRat(Predator)(Prey)

Frog(Predator)

Insects(Prey)

Predator Prey

Owl

Tiger

Frog

Rat

Goat/deer

Insect

CompetitionCompetition is a relationship where organisms compete with each other for food, light, water, shelter, mate or minerals.

Compete for food Compete for light

This is Intra-specific competition.

Competition among organisms of the same species.

This is Inter-specific competition.

Competition among organisms of different species.

INTERACTION BETWEEN

ORGANISMS

Prey predator Competition Symbiosis

Commensalism Parasitism Mutualism

Organismslive together

CommensalismCommensalism Commensalism is a relationship between two Commensalism is a relationship between two

organisms.organisms. The commensal benefits from the host.The commensal benefits from the host.

Commensalism (+,0)Commensalism (+,0)

Remora fish

Gets- free transport- feeds on food scraps left by sharkShark

-not receive any benefits or harm

Commensalism (+,0)Commensalism (+,0)

Bird’s nest fern -Grows on a tree-To obtain sunlight

Tree-not receive any benefits or harm

bb

Barnacles - gets shelter

Mussels- Not affected

INTERACTION BETWEEN

ORGANISMS

Prey predator Competition Symbiosis

Commensalism Parasitism Mutualism

Organismslive together

MutualismMutualism

Mutualism is an interaction that benefitsMutualism is an interaction that benefits

both organisms. (+,+)both organisms. (+,+)

Mutualism (+,+)Mutualism (+,+)Lichen consists of fungi and algae living together.

Algae - produce food

Fungi- Provide shelter

Mutualism (+,+)Mutualism (+,+)

Nodule(contain Nitrogen fixingbacteria)

- Plant needs nitrogen- But it must be changed to nitrates first.- Nitrogen-fixing bacteria change nitrogen to nitrates Peanut plant root

-Provide shelter and food bacteria

INTERACTION BETWEEN

ORGANISMS

Prey predator Competition Symbiosis

Commensalism Parasitism Mutualism

Organismslive together

Parasitism (+,-)

Parasitism is an interaction that benefits the parasites.

On the other hand, the host is harmed by the parasites.

Parasitism (+,-)Parasitism (+,-)

Tapeworm

- A parasite- Live in human intestine- Obtain food and shelter from human

Host (Human)-Loses weight-Becomes weak

Parasitism (+,-)Parasitism (+,-)

Wood fungus

- Obtains food and shelter from tree

Host (Tree)-Is weakened and may die

Parasitism (+,-)Parasitism (+,-)

Rafflesia

- Obtains food and shelter from tree

Host (Tree)-Is weakened and may die

InteractionInteraction EffectsEffects

Prey-predatorPrey-predator + (predator)+ (predator)

- (prey)- (prey)

CompetitionCompetition + (stronger organism)+ (stronger organism)

- (weaker organism)- (weaker organism)

CommensalismCommensalism + (the commensal)+ (the commensal)

0 (the host)0 (the host)

MutualismMutualism +,+ (both organisms)+,+ (both organisms)

ParasitismParasitism + (the parasite)+ (the parasite)

- (the host)- (the host)

Symbiosis(“Living together’’)

Indicator :+ benefits - harm 0 not affected (neither benefit nor harm)

Biological controlBiological control

Attack,destroyThe fruits

Oil palm plantation

versusversus

Biological controlPesticide

Which method is better to kill Which method is better to kill the pests and save the pests and save

environment?environment?

Biological controlBiological control

kill

- A method of - A method of using living things using living things to to killkill the the pestspests..- Use - Use prey-predatorprey-predator relationship relationship..

Biological controlBiological control

Aphids (insects)

- destroy the plant

Ladybird

- eat aphids -to save the plant

Biological control has many advantages as compared to using pesticides.

Some of them are :

a. does not pollute the environment b. does not kill other pests because natural enemies are used c. is cheap and safe to use.

Biological control