Ecosystems

Relationships and Populations

Biotic Factors

ECOSYSTEM

Abiotic Factors

Biotic and Abiotic Factors

(Living and Non-Living)

NichePart of the environment that

an organism usesROLE + HABITAT

Bay-Breasted WarblerFeeds in the middlepart of the tree

Yellow-Rumped WarblerFeeds in the lower part of the tree andat the bases of the middle branches

Cape May WarblerFeeds at the tips of branchesnear the top of the tree

Spruce tree

Warbler Niche

Community interactions

Competition individuals or species trying to use the same limited

resource

Competition competitive exclusion principle – 2 species

cannot occupy the same niche in the same habitat at the same time

Predator/Prey - +/- -the predator catches the prey- One organism captures and kills

another

http://inspectorgadget.files.wordpress.com/2007/12/tiger.jpg

http://www.wallpaperbase.com/wallpapers/animals/tigers/tiger_6.jpg

Two species living closely together

http://sugarmtnfarm.com/blog/uploaded_images/ClownInBubbleAnemone200511-780236.jpg

Symbiosis

Symbiosi

s a.Mutualism - +/+

both species benefit

Symbiosisb. commensalism

- +/0

– one benefits, the other is not helped nor

harmed Example – a bird’s nest

in a tree OR barnacles on whales

Symbiosi

s c. Parasitism - +/- one species benefits (parasite), one is harmed

(host)

Ecological Succession – natural

progression of an environment 1. primary succession – starting where there is no soil

http://www.v-liz.com/galapagos/isabela/puntam~1/lavacac-.jpg

2. secondary succession – where there was a community, but it has been removed

Climax Community – last stage of succession, ecosystem has reached equilibrium

Important characteristics of populations

•geographic distribution – the area inhabited by a

population•density –

number of individuals per unit area•growth rate –

depends on birth rate and death rate

low density high density

•density – number of individuals per unit area

Exponential growthideal conditionsunlimited resources

Growth rate of bacteria•some bacteria can divide every 20 minutes•first 20 minutes – there will be two bacteria•in one hour - there will be 64 bacteria•in one day – there would be:

4,720, 000,000,000,000,000,000

or 4.72 x 1021

Logistic growthas resources become limited•growth rate slows or stops•carrying capacity is reached

•Carrying Capacity – maximum population size an area can support

Num

ber o

f Yea

st C

ells

Time (hours)

Carrying capacity

Logistic Growth – S shaped curve, levels off at the Carrying Capacity

Limiting factors nutrient space carbon dioxide level

density-dependent – competition, predation, disease, parasitism

density-independent – weather, human activities, seasonal cycles

Populations are dependent on Predator/Prey Relationships

Age-structure diagram shows number or percentage at each age