1. An Introduction to Ecology and the Biosphere
Chapter 50
An Introduction to Ecology and the Biosphere

2. LE 50-3a
Organismal ecology

3. LE 50-3b
Population ecology

4. LE 50-3c
Community ecology

5. LE 50-3d
Ecosystem ecology

6. Rachel Carson – Silent Spring

7. Biotic Factors
Biotic factors that affect the distribution of organisms may include:
Interactions with other species
Predation
Competition

8. Abiotic Factors Abiotic factors affecting distribution of organisms:
Temperature
Water
Sunlight
Wind
Rocks and soil

9. Sunlight Light intensity and quality affects photosynthesis
Light is also important to development and behavior of organisms sensitive to photoperiod

10. Wind
Wind amplifies effects of temperature by increasing heat loss from evaporation and convection
Wind can change morphology of plants

11. Rocks and Soil
Many characteristics of soil limit distribution of plants and thus the animals that feed upon them:
Physical structure pH
Mineral composition

12. Climate
Four major abiotic components of climate: temperature, water, sunlight, and wind
Climate is the prevailing weather in an area

13. LE 50-10a
North Pole
60°N
Low angle of incoming sunlight
30°N
Tropic of
Cancer
Sunlight directly overhead at equinoxes
0° (equator)
Tropic of
Capricorn
30°S
Low angle of incoming sunlight
60°S
South Pole
Atmosphere

14. LE 50-10b
March equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness.
60°N
30°N
June solstice: Northern Hemisphere tilts toward sun; summer begins in Northern Hemisphere; winter begins in Southern Hemisphere.
0° (equator)
30°S
December solstice: Northern Hemisphere tilts away from sun; winter begins in Northern Hemisphere; summer begins in Southern Hemisphere.
Constant tilt
of 23.5°
September equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness.

15. Wind direction East Pacific Ocean Sierra Nevada Coast Range
LE 50-12
Wind
direction
East
Pacific
Ocean
Sierra
Nevada
Coast
Range

16. LE 50-13 Winter Spring Autumn Thermocline Summer O2 (mg/L) O2 (mg/L) 44 8 12 4 8 12
Lake depth (m)
Lake depth (m) 8 8 16 16 0° 4° 2° 4° 24 4° 4° 24 4° 4° 4° 4°
4°C
4°C
O2 concentration
High (>8 mg/L)
Medium (4–8 mg/L)
Low (<4 mg/L)
O2 (mg/L)
O2 (mg/L) 4 8 12 4 8 12
Lake depth (m)
Lake depth (m) 8 4°
22° 8 4°
20° 4°
18° 16 4° 8° 4° 6° 16 5° 24
4°C
4°C 24
Autumn
Thermocline
Summer

17. Aquatic biomes account for the largest part of the biosphere in terms of area
They can contain fresh water or salt water
Oceans cover about 75% of Earth’s surface and have an enormous impact on the biosphere

18. Littoral zone Limnetic zone Photic zone Pelagic zone Benthic zone
LE 50-16a
Littoral
zone
Limnetic
zone
Photic
zone
Pelagic
zone
Benthic
zone
Aphotic
zone
Zonation in a lake

19. (deepest regions of ocean floor)
LE 50-16b
Intertidal zone
Neritic zone
Oceanic zone
Photic zone
200 m
Continental
shelf
Pelagic
zone
Benthic
zone
Aphotic
zone
2,500–6,000 m
Abyssal zone
(deepest regions of ocean floor)
Marine zonation

20. Oligotrophic or Eutrophic?

22. Intertidal zone - Oregon

23. Pelagic – open ocean

24. Coral Reef – Red Sea

25. Deep Sea Hydrothermal vent – tube worms

26. Annual mean temperature (°C)
LE 50-18
Desert
Temperate grassland
Tropical forest 30
Temperate
broadleaf
forest 15
Annual mean temperature (°C)
Coniferous
forest
Arctic and
alpine
tundra
–15
100
200
300
400
Annual mean precipitation (cm)

27. LE 50-19 30°N Tropic of Cancer Equator Tropic of Capricorn 30°S
Chaparral
Key
Tundra
Temperate grassland
High mountains
Tropical forest
Temperate broadleaf forest
Polar ice
Savanna
Coniferous forest
Desert