Ecology

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Ecology . AP Biology 2010. Use textbook to: Compare/Contrast Chaparral and Savannah Biomes. Temperature Rainfall Geographic Locations General types of plants/animals (ex. Pine forest) Special adaptations. Freshwater Aquatic Biomes. Zones: photic/aphotic; temperature - PowerPoint PPT Presentation

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Ecology

AP Biology 2010

Use textbook to: Compare/Contrast Chaparral and Savannah Biomes

• Temperature• Rainfall• Geographic Locations• General types of plants/animals (ex. Pine

forest)• Special adaptations

Freshwater Aquatic BiomesZones: photic/aphotic; temperature

Oligotrophic versus Eutrophic lakes

Cultural Eutrophication

Input of nitrogen and phosphorous

Algal blooms followed by fish-kills

Marine BiomesZones: intertidal, neritic, oceanic/pelagic, benthic

Intertidal zone

Nertitic zone

Oceanic/pelgic zone

Benthic Zone

How might we expect global climate changeto alter world biomes?

Population EcologyDemography – Life tables & survivorship curves

Human Population Survivorship Curves

Life Histories

Semelparity: One-time reproduction

Iteroparity: repeated reproduction

Driving factor: how many offspring survive to reproduce – determines how many offspring; parental investment

Basic factors Affecting Population Size

• Number/Age of females• Fertility rate of females• Death rates of females

Purple: 7-8; bottom blue:0-1

World fertility rates

Population GrowthIn a restricted environment without immigration/emmigration:

Change in pop. Size = Births - Deaths for a time interval

N = B-Dt

b/d= per capita rateNt

= bN-dN

r=b-d Nt = rN OR

dNdt

= rN

Intrinsic rate of increase: rmax : exponential growth

Exponential Population Growth

Logistic GrowthK = carrying capacity

dN= rmaxN( K-N

K ) dt

Compare/Contrast

• Tundra/Desert• Rainforest/Temperate deciduous forest

Geographic locations,Rainfall, temperature, unique adaptations, overall types of plants/animals

Natural Populations have Limits to Growth• Negative Feedback - intrinsic/extrinsic

• Density dependent factors: predation, disease

K – selection life history traits or r-selected life history traits

Community Ecology• Species Richness – Biodiversity• Historical theories: Gleason’s Individualistic hypothesis

versus Clements Interactive hypothesis• Modern theories:

– Erlich’s Rivet Theory – tight association– Walker’s Redundancy Model – loose web

Competition

• Interspecific – Competitive Exclusion Principle• Ecological niche• Resource partitioning

Ecological Niche

Sum of a species use of abiotic and biotic resources in an environment.

Reflect and write a paragraph on the following statement: Humans are responsible for all major ecological issues.

Ecological Interactions

• Competition: inter and intra- specific• Predator/Prey: camoflauge, mullerian,

batesian mimicry• Mutualism• Commensalism• Parasitism

Batesian Mimicry

Primary Succession

Secondary Succession

Dominant versus Keystone species

• Dominant: highest abundance• Keystone species: disproportional importance

for abundance. Removal Experiments

Trophic Organization

Primary production - amount of light energy converted to chemical energy (glucose) by autotrophs

Net primary production – what is available to next trophic levels: Primary-R

Secondary production

Bioaccumulation of Toxins in Food Chain:

Ex. Mercury (methylmercury)

Mercury in Tuna Sushi Higher at Restaurants than Groceries

Nitrogen fixation: Endocrine disrupters and flavonoid signallingJennifer E. Fox1,2, Marta Starcevic1, Kelvin Y. Kow1, Matthew E. Burow1,3

& John A. McLachlan1,3Top of page

AbstractNitrogen fixation is a symbiotic process initiated by chemical signals from

legumes that are recognized by soil bacteria. Here we show that some endocrine-disrupting chemicals (EDCs)1, 2, 3, so called because of their

effect on hormone-signalling pathways in animal cells, also interfere with the symbiotic signalling that leads to nitrogen fixation. Our results raise the

possibility that these phytochemically activated pathways may have features in common with hormonal signalling in vertebrates, thereby extending the

biological and ecological impact of EDCs.

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