Post on 01-Jan-2016
Basic Ecology
Study of the interactions among ecosystem residents and their environment
Residents……individuals…populations…communities
Ecology – the basics
Niche……the role or function of a population within its ecosystem
Study of the interactions among ecosystem residents and their environment
Ecology – the basics
Abiotic components……air…water…soil…temperature
Habitat……the local environment of a population, biotic and abiotic
Fundamental concerns:
…flows through ecosystems; not recycled
Ecology – the basics
Fixed by producers, harvested by consumers & detritivores
Used for respiration, tissue maintenance & reproduction
Some is lost with each transformation
Transformed, stored and transferred
The trophic pyramid of a terrestrial ecosystem
1-10% energy transformation
efficiencies
Fundamental concerns:
Ecology – the basics
…cycles within ecosystems.
Assembled by producers, harvested by consumers, reused by producers
Reservoirs: GTTransfers: GT/yr
Compartments: GT Transfers: GT/yr
Compartments: MTTransfers: MT/yr
Compartments: MTTransfers: MT/yr
A Food Web (Trophic Web) illustrates energy and nutrient transactions in an ecosystem
Ecosystems are dependent on their primary producers
soil nutrients
Limits to Primary Production
Light
Water
Nutrients
Temperature
On land, the most favorable combination of these assets is found in tropical rainforests
!!Tropical rainforest litter residence time is very low!!
Essentia
lly
free r
esource
s
The effect of climate on organic decomposition
temperate forest floor tropical rainforest floor
over comparable time periods
GPP – R = NPP
Gross Primary Production – Respiration = Net Primary Production
NPP is higher in tropical
rainforests than other forest ecosystems
Energy Budget
Energy available for consumer trophic levels depends on…
…NPP*efficiency of transfer(s) (5-20%)* assimilation efficiency(ies)
= assimilated/ingested
…depends on type of ingested material
e.g. wood: 15%; seeds/animal tissues: 90%
Energy Budget
Consumer production…
=assimilated energy – respiration – excretion
Net Production Efficiency = production/assimilation
…depends on the animal
bird: 1%; sedentary cold-blooded: 75%
O (organic) Horizon
A Horizon
Zone of Leaching
B Horizon
Zone of Accumulation
C Horizon
Partially decomposed parent material
Soils develop from above and below
organic
mineral
provide primary producers with…
…water
…mineral nutrients
…anchorage
Soils
Soil Texture Classification
Soil particle size classes
<0.002 mm clay0.002-0.05 mm silt0.05-2 mm sand
% c
lay %
silt
% sand
Some Soil Properties Influenced by Soil TextureTexture Class
Soil Property Sand Silt Loam Clay
Aeration excellent good poor
Drainage excellent good poor
Tillage easy moderate difficult
Spring Warming rapid moderate slow
Water holding low moderate high
Cation Exchange low moderate high
Soil Weathering in Tropical Rainforests
Laterization
–wet warm climates
– clay particles broken down
– silica leached downward
– iron & aluminum oxides retained
– low nutrient holding capacity
– low organic content