Transcript Chapter 3 The Biosphere & 4.2 What shapes an Ecosystem

Chapter 3 The Biosphere
3.1 What is ecology?
Ecology: scientific study of interactions
among & betwn org & env’t
– Ernst Haeckel (1866)-oikos: “house”
– Largest “house”: Biosphere:
Life Layer: land, water, & atmo, supports life
8 Km atm to 11Km below ocean
Levels of Organization
Biome: eco w/
same climate
& dominate
community
All org in
area w/
env’t
Diff pop in
same area
Grp of same
organism
(species) in 1 area
1 organism
Ecological Research
Observation: 1st step in designing
experiment/model
Experimentation: test hypo
– artificial env’t in lab or natural env’t
Model: use computer/formula to study
– for studies over time or large spacial scale
global warming
– for ethical reasons Ex: use of mice
3.2 Energy Flow
Sunlight: main NRG source for life
Autotrophs: (producers) produce food
using E from env’t
Photosynthesis: plants/algae convert
sunlight E into food NRG (Carbs)
• 6CO2 + 6H2OC6H12O6 + 6O2
Autotroph (cont)
Chemosynthesis: bacteria convert
chemical NRG into carb NRG
Heterotroph-Consumer: eat food
for NRG
Herbivore: plant
eaters
Carnivore:
animal
eaters
Omnivore:
eat plants &
animals
Heterotrophs (cont)
Detrivore: feed on
remains/dead
matter
Decomposer:
breakdown organic
matter
Food Chain
One-way stepwise flow of NRG
Food Web
More complex feeding relationships
(many food chains)
Trophic Levels
NRG steps from sun, producers = 1st
level
l
Energy Pyramid
Rule of 10%-decrease amt of NRG at
each trophic level
Biomass Pyramid
Amount of living organic tissue/level
Pyramid of Numbers
# of indiv org at each level
3.3 Cycles of Matter (within/betwn
ecosystems)
Biogeochemical cycles: forms of matter
– connects biology, geological and chemical
aspects of the biosphere
Continuous Cycle Never stops
Water Cycle
Precipitation/condensation (dew)
Evaportation/transpiration (plant evap)
Condensation
Preciprain
Transpiration
(evap from
plants)
Carbon Cycle
• CO2 to producer w/photosyn (sugar)
• Consumer eats prod w/C (carbs)
• Cellular respir breaks down food
– C released back into eco as CO2
Nitrogen Cycle
Org require N for Amino Acid for proteins
N2 (gas) abundant in atmo
N-fixing-bacteria (on legume root) turn
N2 into ammonia (useable by plants)
Decomposers return N2 to atmo
Limiting Nutrient
Scarce nutrient, cycles slowly thru sys
– Ex: Algae Bloom:
growth removes O2
causing other org to die
4.2 What shapes an Ecosystem?
Biotic Factors: living (plants/anmls)
Abiotic Factors: physical (temp, precip)
– Both influence survival, growth, &
productivity in habitat (area where org
lives)
Niche
Role in community, “occupation”
– Depends on abiotic & biotic factors
– One species/niche (competitive
exclusion principle)
– Includes: food it eats, how it eats, when
& how it reproduces
Community Interactions
1. Competition: Struggle btw org for
limited resources (food, water)
Community Interaction
2. Predation: 1 org hunts/kills for food
– Predator/Prey
Community Interaction
3. Symbiosis: 2 species close together
– Mutualism: Both benefit (win-win)
– Commensalism: 1 benefits/
other not helped/harmed
– Parasitism: 1 (helped) lives in/on another
(harmed)
– Ex: Aphids & tapeworm
Ecological Succession
Predicatable changes in ecosystem
Primary Succession: w/no soil
Pioneer species (1st species): Lichens &
mosses break rock to soil
2. Secondary Succession: disturbance w/o
removing soil
Ex: Fire, tornado, hurricanes