ecosystems: structure & function
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Ecosystems: Structure & Function. Biology 391 Ch. 24. What is going on in this picture? Can you explain all of the arrows? What do you think each represents? How does this define ecology? Hints: Nutrients, energy, biomass, abiotic, biotic. 24.1 Abiotic Factors. Examples? - PowerPoint PPT PresentationTRANSCRIPT
Biology 391Ch. 24
Ecosystems:Structure &
Function
What is going on in this picture?
Can you explain all of the arrows?
What do you think each represents?
• How does this define ecology?• Hints:
Nutrients, energy, biomass, abiotic,
biotic
24.1 Abiotic Factors
• Examples?• Abiotic affects biotic
– Distribution, adaptations, etc.– Trade-off adaptation to live in one envi.
Usually means exclusion for another• Biotic can affect abiotic
– EX: Soil development by lichens
All life on Earth is interconnected.
All life interacts with the nonliving
environment.
ECOSYSTEMSA. ABIOTIC
1. Includes: Water, air, temperature, soil, light levels, precipitation, salinity, pH
2. Sets tolerance limits for populations and communities3. Some are limiting factors that structure the abundance
of populations
B. BIOTIC – trophic structure1. Producers, consumers, decomposers in a food chain, web and pyramid2. Interactions lead to transfer of energy and biomass
ENERGYSUN Autotrophs Heterotrophs (producers) (consumers)
• Autotrophs- plants, algae, phytoplankton
• Heterotrophs- – Herbivores- eat plants– Carnivores- eat meat– Omnivores- eat meat or plants– Scavengers- eat dead material – Decomposers- final breakdown of dead material- returning
nutrients to soil/water
Energy Pyramid
• Shows transfer of energy through trophic levels (who eats what)
Producers primary consumers secondary consumers tertiary consumers, etc.
• 10% Rule– Only 10% of the energy in the previous trophic level is passed
on
• Biomass– Total quantity of living matter at each trophic level
Where does the 90% go? What law is this?
Relationships in Ecosystems• What is a niche?• Predation
– Predator/prey• Competition
– **Competitive Exclusion Principle• Symbiosis
– Mutualism– Parasitism– Commensalism
Ecosystem Dynamics – nutrient cycles
Nitrogen Cycle
What gases compose air?
Nitrogen is NOT usable by plants & animals
Must change molecular forms (nitrogen fixation)
Ammonia & nitrate preferred by plants
Decay & denitrification return N2 to air
Limiting Factors• Abiotic factors that limit the population• Examples?
Population Dynamics• Carrying capacity• Exponential growth vs.
Logistic growth• Boom-bust cycle• Predator-prey cycle
http://desip.igc.org/mapanim.htmlhttp://www.poodwaddle.com/clocks2.htm
Recap• Can an herbivore be a secondary consumer?
Secondary trophic level? Why/why not?• How many trophic levels typically exist in a food
web? Explain.• Why could the Earth support more people if we all
ate at lower trophic levels?• List 3 abiotic factors and describe how each can
act as a limiting factor.• What is the relationship between K and limiting
factors?
Chapter 25
• Biomes– Types of ecosystems usually defined by the
most conspicuous vegetation• Tropical rain forest• Savanna• Deserts• Temperate grasslands• Temperate deciduous forests• Taiga• Tundra
Aquatic Biome
• Vertical zones– Photic zone– Aphotic zone
• Benthic and abyssal zones can be within here
• Horizontal zones– Intertidal zone– Neritic zone– Oceanic zone