Day 21 Ecosystems and Communities
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Transcript of Day 21 Ecosystems and Communities
We only have 2 classes left!
• Today – teacher evaluations, Homework CH 15
• Thursday – Turkey Day, no class
• Tue Dec 2nd – Finish Chapter 15
• Thur Dec 4th – Chapter 16
• Final – Dec 11th – CBT, will be open from noon to 7pm.
• Any makeup exams for excused absences will be Dec 8th – 10th, in the CBT, by appointment only
Chapter 15: Ecosystems and Communities
Organisms and their environments
by Mark Manteuffel, St. Louis Community College
15.1 What are ecosystems?
A community of biological organisms plus the non-living components with which the organisms interact.
Biomes What is the average temperature?
What is the average rainfall (or other precipitation)?
Is the temperature relatively constant or does it vary seasonally?
Is the rainfall relatively constant or does it vary seasonally?
Biomes Temperature and precipitation dictate:
• Primary productivity levels
the amount of organic matter produced
The numbers and types of primary producers:
• are the chief determinants of the amount and breadth of other life in the region.
Why do beach communities have milder weather than more inland communities?
Water’s capacity to absorb and hold heat
Beaches on the east coast of the United States have warmer water than west coast beaches at the same latitudes.
Why?
Chains or Webs?
Food chain
• Pathway from photosynthetic producers through the various levels of animals
Food web
• Involve harvesting energy from multiple stops in the food chain
In humans, why is vegetarianism more energetically efficient than meat-eating?
The 10% rule in application
Chemical Reservoirs Each chemical is stored in a non-living part of the
environment.
Organisms acquire the chemical from the reservoir.
The chemical cycles through the food chain.
Eventually, the chemical is returned to the reservoir.
Global CO2 levels are rising in general, but they
also exhibit a sharp rise and fall within each year.
Why?
Finally - Evaluations
• I need someone to volunteer to do the survey for this class.
• Be honest – what can I do to improve (seriously, besides just giving away grades like skittles)
• www.ratemyprofessor.com is the best way to let future students know what’s good or bad.
What to note -
• Did you like the technology for the class?
• Was I helpful or caring or a big nasty jerk?
• What did you think of the videos?
• Do you like that I post everything online?
• Do you think the material was too easy or too hard?
• What did you think of lecture versus lab?
• Would you take me again for a class?