This document discusses different types of interactions between living organisms: prey-predator relationships, competition, and symbiotic relationships including commensalism, mutualism, and parasitism. It provides examples for each type of interaction: prey-predator examples include owls and rats; competition examples include competing for food or light; commensalism examples include remora fish and sharks; mutualism examples include lichen and nitrogen-fixing bacteria and plants; and parasitism examples include tapeworms and humans. The document also notes the effects of each interaction type on the organisms involved and discusses biological control as an alternative to pesticides in agriculture.

1. CHAPTER 4:
INTERACTION
BETWEEN LIVING
ORGANISMS

2. INTERACTION
BETWEEN
ORGANISMS
Prey predator Competition Symbiosis
Commensalism ParasitismMutualism

3. Prey-predator
A relationship where an animal captures and
eat other animals.
Rat is the victim
(prey)
Snake eats and
kills rat
(predator)

4. Owl
Rat(Predator)
(Prey)
Frog
(Predator)
Insects
(Prey)

5. Predator Prey
Owl
Tiger
Frog
Rat
Goat/deer
Insect

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

7. This is Intra-specific competition.
Competition among organisms of the same species.

8. This is Inter-specific competition.
Competition among organisms of different species.

9. INTERACTION
BETWEEN
ORGANISMS
Prey predator Competition Symbiosis
Commensalism ParasitismMutualism
Organisms
live together

10. Commensalism
 Commensalism is a relationship between two
organisms.
 The commensal benefits from the host.

11. Commensalism (+,0)
Remora fish
Gets
- free transport
- feeds on food
scraps left by sharkShark
-not receive any
benefits or harm

12. Commensalism (+,0)
Bird’s nest fern
-Grows on a tree
-To obtain sunlight
Tree
-not receive any
benefits or harm

13. b
Barnacles
- gets shelter
Mussels
- Not affected

14. INTERACTION
BETWEEN
ORGANISMS
Prey predator Competition Symbiosis
Commensalism ParasitismMutualism
Organisms
live together

15. Mutualism
Mutualism is an interaction that benefits
both organisms. (+,+)

16. Mutualism (+,+)
Lichen consists of fungi and algae living together.
Algae
- produce food
Fungi
- Provide shelter

17. Mutualism (+,+)
Nodule
(contain
Nitrogen fixing
bacteria)
- 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

18. INTERACTION
BETWEEN
ORGANISMS
Prey predator Competition Symbiosis
Commensalism ParasitismMutualism
Organisms
live together

19. Parasitism (+,-)
 Parasitism is an interaction that benefits the
parasites.
 On the other hand, the host is harmed by the
parasites.

20. Parasitism (+,-)
Tapeworm
- A parasite
- Live in human intestine
- Obtain food and shelter
from human
Host (Human)
-Loses weight
-Becomes weak

21. Parasitism (+,-)
Wood fungus
- Obtains food and
shelter from tree
Host (Tree)
-Is weakened and
may die

22. Parasitism (+,-)
Rafflesia
- Obtains food and
shelter from tree
Host (Tree)
-Is weakened and
may die

23. Interaction Effects
Prey-predator + (predator)
- (prey)
Competition + (stronger organism)
- (weaker organism)
Commensalism + (the commensal)
0 (the host)
Mutualism +,+ (both organisms)
Parasitism + (the parasite)
- (the host)
Symbiosis
(“Living
together’’)
Indicator :
+  benefits - harm 0  not affected (neither benefit nor harm)

24. Biological control
Attack,destroy
The fruits
Oil palm plantation

25. versus
Biological control
Pesticide
Which method is better to kill
the pests and save
environment?

26. Biological control
kill
- A method of using living things to kill the pests.
- Use prey-predator relationship.

27. Biological control
Aphids (insects)
- destroy the plant
Ladybird
- eat aphids
-to save the plant

28. 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