Ch 2: Ecosystem

ESSMs. Wilson

9/12

2.1 4 Types of Population Interactions

• Competition• Predation• Parasitism• Mutualism

Competition

• Intraspecific– More species of the same size, more competition

there is• Interspecific– Niches overlap– Better competitors suffer less

– Figure 2.8 \/

Predation

• Negative feedback loop• Give me an example…

Parasitism

• Ectoparasites

• Endoparasites

Mutualism

• Both benefit• Example: zooanthellae

2.2 Abiotic Ecosystems• Marine

– Salinity– pH– Temperature– Dissolved oxygen– waves

• Freshwater– Turbidity– Flow velocity– pH– Temp– Dissolved oxygen

• Terrestrial– Temp– Light intensity– Wind– Particle size– Slope– Soil moisture– Drainage– Mineral content

• Around here?

• Figure 2.11 \/

How to measure each• Light: light meter• Temp: electric thermometer (why not mercury?)• pH: pH meter• Wind: anemometer• Particle size: ruler or sifter• Dissolved oxygen and wave action (inversely proportional)• Slope: clinometer [tan(degree read)*100• Soil moisture: weight after heated• Mineral content: LOI test (mass lost)• Flow velocity: surface or flow meter• Salinity: electric conductor (ppt)• Turbidity: secchi disk

2.3 Biotic Components of Ecosystems

• Dichotomous Key – ex: bats in Costa Rica• Often times subjective• % cover – immobile organisms

Lincoln Index

• Collecting and marking – Capture-mark-release-recapture

• N=n1*n2/m

Quadrats• Limit sampling area – random is best• Stratified random sampling with 2 different habitats• Put them at set distances (transecting)

– Systematic sampling– Continuous sampling: across entire transect

• Population density: # individuals of each sp. per unit area– #sp/total area

• Percentage frequency: % of total quadrat number sp. is present in• Estimating biomass

– Does not include water– Take 1 area’s mass, then multiply to estimate

– KIVA: pg 33 philosophy

Diversity and Simpson’s diversity index

• Diversity is not an old wooden ship.• Diversity: # diff. sp & # ind. of each sp.• High D – stable and ancient• Low D – pollution, recent colonization• Equation (don’t need to memorize but need to know what the symbols

are):

D=[N(N-1)]/[Ʃn(n-1)]

– D=diversity index– N=total number of all sp. found– n=number of ind. of a particular sp.– Ʃ=sum

2.4 Biomes

• Many ecosystems within same climate• What controls climate?

Homework:

• Each person select a biome and research it• Climate: temp, precipitation and insulation

Atmospheric Circulation

What are the green areas?

Tropical Rainforest

• Rains daily – very humid– Creates cumulus clouds

• Temp around 80 degrees F• Common organisms: Gorillas, orangutan, spider

monkey, whiptail lizard, toucans, collared aracari, rufous, motmot, cicada, pleasing fungus beetle, wasp, Bullet ant, walking stick, dart frog, coatimundi, Leaf frog, butterfly, collared peccary

• Sources: www.marietta.edu and www.bioexpedition.com

What are the red areas?

Desert

• Cold desert:– Soil produces insensitive plants– Receives a lot of snow, melt is stored in soil– Winter temp averages 2-4 degrees C– Summer temp averages 20-26 degrees C– Organisms: jack rabbits, kangaroo rats, mice and

squirrels– Ex: Utah region

What are the dark brown areas?

Tundra

• Marine biome rich in nutrients from land locked in ice

• Organisms: polar bear, sea lion, penguins, fish, birds, plankton

• Ex: North Pole

What are the green areas?

Temperate Forest

• Precipitation: 20cm-200cm in form of snow• Temp averages -5 – 15 degrees C• Organisms: firs, pines, spruces, hemlock,

lichen, moss, birch, deer, snowshoe hare, porcupine, bobcat, lynx, fox, and elk

• Large threat: exploration and development of oil and natural gas

What are the yellow areas?

Grasslands

• Temp: stays relatively warm year round– Winter: long and dry (~4 inches)– Summer: very wet (25 inches)

• Organisms: Plants adapted to much water, (marsh) deer, large cats, ungulates, kangaroo – all adapted to long/fast travel

• One of the most studied climates• Ex: African Savanna or South America (mostly

flooded) Australia’s “bush”/“the scrub”

2.5 Function of Ecosystems