1. Community Interactions

2. Niche and Habitat Habitat is where an organism lives
can be thought of as an organisms address
Niche is all the interactions and relationships an organism has with its surroundings (environment)
Can be thought of as an organisms ‘profession’ or job

3. Types of Interactions, cont’
Symbiotic relationship: a relationship in which two organisms closely interact
Main types of symbiotic relationships are parasitism, commensalism, mutualism predation

4. Symbiotic Relationships
Parasitism: one organism benefits from the relationship and the other is harmed
Ex: a tick and a dog,
a tapeworm and a
moose
Mistletoe on a tree
Wasp larva on a
Tomato hornworm
Brood parasitism: one organism lays it’s eggs in another species nest (usually birds, some fish and insects)

5. Symbiotic Relationships
Mutualism: both organisms benefit or are helped
Ex. Humans and our ‘good’ intestinal bacteria
We give them a warm, safe place to live, they help us digest and process Vitamin K (important for blood clotting)
Lichen (Algae and Fungus)
Algae photosynthesizes
(makes energy), fungus provides
structure 

6. Symbiotic Relationships
Commensalism: one organism benefits, the other is not helped or harmed
Ex: Shark and remora
Remora attaches itself to shark, or swims right behind it and eats food scraps. Shark is just eating and swimming like it would normally be

7. Predator-Prey is when one animal (predator) eats another (prey)
BUT….there is so many other ways that organisms can interact with eachother…
Let’s see what they are!

8. Competition occurs when two organisms rely on the same resources to survive
Ex: hyenas and vultures
fighting over a carcass
two plants competing for
water or sunlight, or space

9. More interactions
Many organisms have mechanisms to avoid being eaten or to avoid competition.
Some ways to avoid predation are: camouflage, chemical defenses, and mimicry

10. Camouflage
Body coloration that allows an animal to blend in with it’s surroundings
If you blend in with your surroundings, then you have less of a chance of being spotted!

11. Chemical Defenses
Many plants and animals use chemicals to repel predators
Ex: Skunks spray, many insects spray acid when threatened, and some plants produce bitter tasting (or even poisonous) compounds

12. Aposematic Coloration
Some animals have bright coloration to warn potential predators that they are dangerous or toxic.

13. Aposematic Coloration

14. Mimicry Batesian Mimicry
…is when a harmless animal looks like another animal that causes harm
If an animal isn’t toxic to predators, why not look like an animal that is?
A coral snake, which produces an very potent neurotoxin, and a harmless milk snake
A stinging wasp and a harmless fly
Henry
Walter
Bates

15. Mimicry, cont’ Müllerian Mimicry
This is when two or more dangerous or distasteful species exhibit similar colorations
Both species can benefit from the losses of the others
Ex: Monarch and Viceroy butterflies!
Stinging insects
Paper wasp
Honey bee
Yellow jacket
Fritz Muller

16. Aggressive Mimicry
…is when predators are disguised to better ambush their unsuspecting prey
Some predators have turned the tables and display camouflage or resemble other organisms or even non-living things!
This anglerfish lures
in unsuspecting prey

17. Plant Defenses
In addition to physical deterrents (thorns, hairs), some plants produce bad tasting or harmful chemicals to steer away foraging animals.
Some plants produce chemicals that are not only toxic to animals, but also to other plants!
This is called allelopathy.
Allelopathic plants ensure that they won’t have much competition for water, sunlight, space, etc. by killing off the other plants!

18. So, to sum it all up….
There are many more interactions going on in a community than just feeding relationships
Organisms can help, harm or trick each other.
“When one tugs at a single thing in nature, he finds it attached to the rest of the world.” 
--John Muir