BIOL150 Lecture Notes - Lecture 4: Primary Production, Detritivore, Heterotroph
2 May 2018
School
Department
Course
Professor
Ecosystem Ecology
• Ecosystems - multiple communities, and their chemical and physical environments
• Primary components of ecosystems
o abiotic environment - including light, temperature, water and nutrient
availability
o primary producers - autotrophs, make their own food
o consumers (heterotrophs) - eat autotrophs and other heterotrophs
o Detritivores and decomposers - heterotrophs that get energy from dead
material. Recyclers
• Two main processes in in ecosystems
o Energy flow
o Chemical cycling
• Positive feedback - X produces changes in Y which in turn produces more of X
• Negative feedback - X produces changes in Y which results in less X
• Homeorhesis - ecosystems tend toward a particular trajectory instead of a set point
• Resistance - ability of system to remain the same under forces of disturbance
• Resilience - measure of how quickly an ecosystem recovers following a disturbance
• Resistance and resilience often inversely related
• Going from tropics to tundra, resistance decreases, resilience increases
• Niche breadth increases from tropics to tundra
o specialists (small niche) - cannot cope with wide range of conditions but very
little competition
o generalist (large niche) - can cope with wide range of conditions, but lots of
competition
• Ecosystems with more generalists = more resilient b/c organisms can tolerate more
change
• Gross primary productivity - rate of energy fixation per unit area and time
• Net primary productivity = Gross primary productivity (GPP)- Respiration (R) by
autotrophs
o It is a rate e.g kg/meter square/year
• Standing Crop Biomass - g/unit area
find more resources at oneclass.com
find more resources at oneclass.com
