COMMUNITIES

HOW DO COMMUNITIES OF ORGANISMS INTERACT WITH

EACH OTHER?

Communities

Definition

• groups of different populations of organisms living together in the same place at the same time

• Communities interact through competition, predation, and symbiotic relationships

What must all organisms in a community have?

• Habitat – Where the organism lives. – Ex. Bird lives in the nest of a tree.

• Niche - The organism’s role in the community.– Ex. Scavenger, Predator, Prey

Watch the video clip and note the types of relationships that

exist in communities• http://www.youtube.com/watch?v=D1aRS

eT-mQE

NOT ENOUGH FOR ALL

• Hey hey hey I see some nice fruits on that tree but it looks like those finches bird are also have their eyes on it. I don’t even think there are enough for our little blue jay flock let alone them. LET’S GET IT!

1-COMPETITION: FIGHT FOR RESOURCES

• INTRASPECIFIC- competition within the SAME species

• INTERSPECIFIC- competition among different species

HIDE OR I WILL GET YOU

• I AM ALWAYS IN FEAR OF THAT JAGUAR COMING OUT OF THE BLUE TO KILL ME FOR FOOD, BUT I HAVE TO LOOK FOR SOMETHING TO EAT… A HYENA GETS HUNGRY TOO!!

2-PREDATION

• PREDATOR- PREY RELATIONSHIP

Organisms in a community must interact in a predator-prey relationship to obtain food for survival.

Predator/prey relationships are also a

means of population control in communities

Predator/Prey GraphPredator/prey relationship can control populations

3-SYMBIOTIC RELATIONSHIPS

SYMBIOSIS: CLOSE ECOLOGICAL RELATIONSHIP BETWEEN TWO OR MORE ORGANISMS OF A DIFFERENT SPECIES

YOU ARE MY FRIEND…AREN’T YOU?

• I FEEL THAT OUR FRIENDSHIP IS AN EQUAL PARTNERSHIP. YOU HELP ME WHEN I NEED IT AND LIKEWISE I HELP YOU. THIS RELATIONSHIP IS GREAT…WE ARE IN SYMBIOSIS

MUTUALISM RELATIONSHIP

• BOTH ORGANISMS BENEFIT FROM THE RELATIONSHIP– BACTERIA IN OUR STOMACH BACTERIA

HELPS US DIGEST FOOD, BACTERIA HAS A HOME

– ANTS LIVING ON APHIDS(PLANT) ANTS FEED ON SUGARY APHID, ANTS PROTECT THE PLANT

SOMETIMES I FEEL USED

• YOU KNOW, WE ARE GOOD FRIENDS, BUT SOMETIMES I FEEL LIKE YOU ARE ASKING ME TO HELP YOU OUT ALL THE TIME…TESTS, HW, PROJECTS. I AM GETTING QUITE SICK OF IT AND FEEL HURT BY IT

PARASITISM RELATIONSHIP

• ONE ORGANISM BENEFITS THE OTHER IS HARMED– Virus infects a cell– Fleas on a dog– Mosquito bites us

I REALLY DON’T CARE, IT DOESN’T BOTHER ME

• YOU CAN COPY MY WORK ALL YOU WANT, AS ALONG AS WE BOTH GET THE SAME GRADE

COMMENSALISM RELATIONSHIP

• ONE ORGANISM BENEFITS THE OTHER IS NOT HARMED

– BARNACLES ON A WHALE’S BODY– REMORA FISH ATTACHES ITSELF TO A

SHARK

WRITING RELATIONSHIPS IN SHORTHAND

• MUTUALISM ( +/+ )

• PARASITISM (+/ -)

• COMMENSALISM ( +/ 0)