3.1 Organisms, their Physical Environment, and Communities
1. Identify abiotic factors affecting organisms in their environment.
2. Describe habitat requirements of local species.
3. Define the composition of biological communities
4. Describe the effect of changing abiotic factors on the regional or geographic distribution of species.
Readings: 15: 393-400: 4: 81-86, 101-103
temperate forest grassland kelp forest (marine) coral reef (marine)
Kelp forests (occur in temperate zones)
Coral reefs (occur in tropic zones)- poor nutrients in the water
Desert- unpredictability of the weather causes an area to be a desert
Physical Characteristics of an Environment = Abiotic (non-living) Conditions
1. Sunlight –light intensity
- light wavelength
- duration of light
3. pH of soil
4. pressure (particularly in ocean)
6. inorganic compounds –could be harmful to some organisms
-some needed for organisms’ growth
Can you think of some other abiotic factors that could affect the distribution or abundance of organisms? Variation in abiotic conditions within one location
Daily – light intensity (weather, time of day)
- temperature (cooler at night)
Seasonally –precipitation (e.g. rainy vs. dry season)
-precipitation (e.g. snow vs. rain)
-duration of light due to angle sunlight hits the earth
An example of variation in abiotic conditions in Kamloops, BC:
Kamloops Climatic Data (monthly averages for a 30 year period)
Statistic Units Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average
Temperature C -4.8 -0.6 4.5 9.4 14.0 18.3 20.8 20.3 14.9 8.5 1.7 -3.3 8.64
Mean Value C -1.3 3.4 10.2 16.2 21.1 25.4 28.3 27.8 21.7 14.0 5.3 0.0 14.34
Mean Value C -8.4 -4.8 -1.3 2.5 6.9 11.1 13.2 12.8 8.1 3.0 -2.0 -6.6 2.88
Precipitation mm 26.1 13.8 9.6 14.8 21.8 28.6 27.9 30.2 27.6 14.4 22.0 32.6 22.45
Mean Monthly Value
Snowfall cm 27.5 11.9 3.1 0.3 0.0 0.0 0.0 0.0 0.0 0.2 12.1 31.0 7.17
Mean Monthly Value
Questions: What is the range of temperatures that an organism living in Kamloops must be able to tolerate?
Beside sunlight, what other abiotic factors are necessary for plants?
Temp and water availability. As temp gets lower, plants/trees reduce surface area by losing leaves
How does an amphibian such as Spea intermontana tolerate
Tolerance of Abiotic Conditions extreme temperatures and low precipitations?
Gradient: concentration/ levels of severity
Plants: Seeds can handle more adverse environments. They are built with reserve in their coat so they don’t need to be
active, they are dormant Animals: Adults can endure more adverse environments because they have more defenses (such as fat)
Many abiotic factors vary over time; organisms living in a particular environment will be exposed to and must be able to
tolerate the extremes of each abiotic factor in their environment.
Organisms thrive and reproduce within their optimum range of each factor; they become stressed at the extremes of
their range of tolerance. Few individuals survive the extremes for a sustained period of time; if a factor occurs beyond
their range of tolerance, organisms will die.
Mountain pine beetles
The mountain pine beetle (Dendroctonus ponderosae) lay their eggs under the bark of coniferous trees, particularly
lodgepole pines (Pinus contorta) common in Kamloops. The larvae chew tunnels in the wood and leave beh