1. Energy Flow and Relationships
in an Ecosystem:
How do we live together?

3. Reminder… food chains ALWAYS begin with producers
food chain - a diagram that shows how energy flows from one organism to another
food chains ALWAYS begin with producers

5. Food Web [ALL food chains together]
a diagram that shows ALL the feeding relationships in an ecosystem
most consumers EAT a variety of foods and can be EATEN BY a variety of other consumers
[ALL food chains together]

6. Food Web

7. Interactions in an Ecosystem
Organisms in an ecosystem interact in many ways

8. Interaction between Organisms
competition - when organisms try to use the same resources (such as food)
occurs within a population AND between populations

9. Competition
hyenas and lions compete for the meat of the dead buffalo

10. Interaction between Organisms
predation – when an organism kills and eats another organism (prey) X X

11. Predation
the lion is the predator and the zebra is the prey

12. Interaction between Organisms: Symbiotic Relationships
Symbiosis: Any close relationship between species: can be positive or negative
Mutualism: both species benefit (+, +)
Commensalism: one species benefits, the other is not affected (+, 0)
Parasitism: one organism benefits, but the other is harmed (+, -)

13. Symbiosis = Close Interaction between Organisms
mutualism - relationship between two species in which both species benefit

14. Mutualism The oxpecker bird eats ticks off the impala.
The impala gets rid of parasites.
(+,+)

15. Mutualism: The lichen is an algae or cyanobacteria
living with a fungus

16. Lichen Structure
Fungus: Provides protection and water storage (hyphae hold a lot of water) for the algae
Algae: Provides food through photosynthesis for the fungus

17. Mutualism (+, +)
The cleaner wrass gets food; the moray eel gets rid of mouth parasites.
The clown fish gets protection;
the sea anemone
gets scraps of food from the clownfish
The bee gets nectar;
the flower gets pollen
moved to the next flower.

18. Symbiosis = Close Interaction between Organisms
commensalism - a relationship in which one organism benefits and the other is unaffected

19. Commensalism
The remora eats food scraps that the shark would not eat; the shark is not affected in any way.

20. Commensalism
The rhino + the egret: as the rhino walks, insects in the grass are disturbed. The egret swoops down and eats. The rhino is not affected in any way.
The tree + the epiphyte: The
epiphyte grows on a branch on
a tree. The epiphyte gets more
sunlight. The tree in not
affected in any way.

21. Symbiosis = Close Interaction between Organisms
parasitism - one species, the parasite, lives in/on and benefits from the host species. The host is harmed.

22. Parasitism
The wasp larvae live on and feed off the caterpillar. The caterpillar loses nutrients.

23. Parasitism A tick sucks the blood from a dog or
other animal. The tick gets food.
The dog or other animal is harmed.
A tapeworm lives in the intestine of another animal. The tapeworm gets food. The other animal loses nutrients.
Trypanosomiasis (African Sleeping
Sickness): This disease is caused by a protist that lives in the brain. The protist gets food. The infected person gets sick.

24. Summary: Types of Interactions
Competition
Predation…………..
Symbiotic Relationships......
1) Mutualism
2) Commensalism…
3) Parasitism……….