POPULATION POPULATION INTERACTIONSINTERACTIONS

How orgs interact in an How orgs interact in an ecosystem!ecosystem!

What role are you up for?What role are you up for?

What does it mean to have a What does it mean to have a rolerole in an ecosystem? in an ecosystem?

NICHE:NICHE:THE THE ROLEROLE AN ORGANISM PLAYS IN ITS AN ORGANISM PLAYS IN ITS

ECOSYSTEMECOSYSTEMONLY ONLY ONEONE SPECIES CAN SPECIES CAN OCCUPYOCCUPY A A

NICHENICHE AT A TIME AT A TIMELEADS TO COMPETITION IF MORE LEADS TO COMPETITION IF MORE THAN ONE SPECIES WANTS ROLETHAN ONE SPECIES WANTS ROLE

SIMILARSIMILAR SPECIES CAN SPECIES CAN COEXISTCOEXIST AS AS LONG AS THEY HAVE LONG AS THEY HAVE DIFFERENTDIFFERENT NICHESNICHES!!EX:EX: p102 in RB – WARBLERS! p102 in RB – WARBLERS!

HOW CAN I REMEMBER THAT HOW CAN I REMEMBER THAT “NICHE” MEANS ROLE AND “NICHE” MEANS ROLE AND NOTNOT SPACE?SPACE?

THINK OF A PLAY!THINK OF A PLAY!EVERY ROLE NEEDS TO BE FILLED EVERY ROLE NEEDS TO BE FILLED

IN ORDER FOR THE PLAY TO IN ORDER FOR THE PLAY TO WORK!WORK!

IF MORE THAN TWO PEEPS WANT IF MORE THAN TWO PEEPS WANT A ROLE, THERE IS COMPETITION A ROLE, THERE IS COMPETITION AND THE BEST WINS!AND THE BEST WINS!

What are the relationships in an What are the relationships in an ecosystem?ecosystem?

FOOD CHAINSFOOD CHAINSIllustrate relationships between Illustrate relationships between

predators and preypredators and preySpecific orgs are includedSpecific orgs are includedLet’s take a look!Let’s take a look!

What are the relationships in What are the relationships in an ecosystem?an ecosystem?

What are the relationships in an What are the relationships in an ecosystem?ecosystem?

Niches defined by how obtain foodNiches defined by how obtain foodAutotrophs (Producers):Autotrophs (Producers):

Make own food (grass)Make own food (grass)Heterotrophs (Consumers):Heterotrophs (Consumers):

Herbivores:Herbivores: Eat plants (Eat plants (grasshoppergrasshopper))Carnivores:Carnivores: Eat animals ( Eat animals (snakesnake))Omnivores:Omnivores: Eat plants and animals Eat plants and animals

(humans)(humans)Scavengers:Scavengers: Eat dead things; life’s Eat dead things; life’s

clean-up crew! (vultures)clean-up crew! (vultures)Decomposers:Decomposers: life’s recyclers life’s recyclers ((

bacteria and fungibacteria and fungi))

What are the relationships in an What are the relationships in an ecosystem?ecosystem?Symbiotic relationshipsSymbiotic relationships

When orgs live in REALLY close quartersWhen orgs live in REALLY close quartersParasitism:Parasitism:

Live offLive off other orgs but don’t kill them other orgs but don’t kill them (some worms, ticks, fleas)(some worms, ticks, fleas)

Mutualism:Mutualism:Orgs that Orgs that both benefitboth benefit (Clownfish and (Clownfish and

sea anemone)sea anemone)Commensalism:Commensalism:

One org benefits, other neither One org benefits, other neither harmed or benefitted harmed or benefitted (Whale and (Whale and barnacles)barnacles)

What are the relationships in What are the relationships in an ecosystem?an ecosystem?

FOOD WEBS:FOOD WEBS: All All food chainsfood chains

in an in an ecosystem are ecosystem are illustrated in a illustrated in a food webfood web

How many How many food chains food chains can you make can you make from this food from this food web?web?

Let’s talk energy! The fuel of Let’s talk energy! The fuel of life!life!

Ask yourself:Ask yourself: Where does our ultimate Where does our ultimate source of source of energyenergy come from? come from? The sun of course!The sun of course!

Ask yourself:Ask yourself: Which orgs can harness Which orgs can harness sun’s sun’s energyenergy and make food? and make food? Plants of course!Plants of course!

Ask yourself:Ask yourself: What happens to the plant’s What happens to the plant’s energyenergy when a when a herbivoreherbivore eats it? eats it?

Ask yourself: Ask yourself: What happens to the What happens to the herbivore’sherbivore’s energyenergy when a when a carnivorecarnivore eats eats it?it?

Ask yourself:Ask yourself: What happens to the What happens to the carnivore’scarnivore’s energyenergy when another when another carnivorecarnivore eats it? eats it?

What happens to What happens to energyenergy in an in an ecosystem?ecosystem?

Every organism uses energy to Every organism uses energy to carry out life processescarry out life processes

If an organism is eaten, it will If an organism is eaten, it will give less energy to the give less energy to the predatorpredator

THEREFORE, THEREFORE, ENERGY ENERGY DECREASES AS YOU MOVE UP A DECREASES AS YOU MOVE UP A FOOD CHAIN!FOOD CHAIN!

WE USE AN WE USE AN ENERGY PYRAMIDENERGY PYRAMID TO SHOW THIS!TO SHOW THIS!

ENERGY PYRAMIDENERGY PYRAMID

ENERGY PYRAMIDENERGY PYRAMID

ENERGY PYRAMIDENERGY PYRAMID

ENERGY PYRAMIDENERGY PYRAMID

ENERGY PYRAMIDENERGY PYRAMID

RECYCLING NUTRIENTSRECYCLING NUTRIENTSDecomposersDecomposers extract what little extract what little

nutrients are leftnutrients are leftThey return raw materials They return raw materials

(nitrogen) back to soil(nitrogen) back to soilOther orgs continually recycling Other orgs continually recycling

carbon dioxide, oxygen, and carbon dioxide, oxygen, and nitrogennitrogen

ENERGY IS ENERGY IS NEVERNEVER RECYCLED! RECYCLED!Let’s look at p107 and p108 in RB!Let’s look at p107 and p108 in RB!