1. Ecosystems and Communities
Chapter 4

2. The Role of Climate What is Climate?
Weather  day-to-day condition of Earth’s atmosphere at a particular time and place
Climate  average year-after-year conditions of temperature and precipitation in a particular region

3. Climate Many factors affect climate:
trapping of heat by the atmosphere
latitude
transport of heat by winds and ocean currents
amount of precipitation
shape and elevation of land masses

4. Climate The energy of sunlight creates winds and ocean current
Solar energy and certain gases affect Earth’s temperature

5. Greenhouse Effect
Atmospheric gases trap heat energy and maintain Earth’s temperature range
Carbon dioxide
methane
water vapor

6. Greenhouse Effect
Solar energy enters atmosphere and bounces off Earth’s surface
Gases trap heat energy in atmosphere
Without gases, Earth would be 30°C cooler

7. Greenhouse Effect Sunlight Some heat escapes into space Greenhouse
gases trap
some heat
Atmosphere
Earth’s surface

8. Effect of Latitude on Climate
Earth is tilted on its axis 23.5°
The sun strikes the Earth at different angles depending on latitude and season
Creates three climate zones

10. Effect of Latitude on Climate
Polar – sun hits Earth at low angle, very cold
Temperate – sun’s angle varies with season, cold in winter, hot in summer
Tropical – direct sun all year, hot

11. Effect of Latitude on Climate
90°N North Pole
Sunlight
66.5°N
Arctic circle
Sunlight
Tropic of Cancer
23.5°N
Equator
Most direct sunlight 0°
Tropic of Capricorn
23.5°S
Sunlight
Arctic circle
66.5°S
Sunlight
90°S South Pole

12. Heat Transport in Biosphere
Solar energy heats air near equator
Air rises at equator, sinks near the poles
Creates wind currents

13. Wind Cells

14. Heat Transport in Biosphere
Similar patterns of heating and cooling in Earth’s oceans
ocean currents transport heat energy within biosphere
surface ocean currents warm or cool the air above them, thus affecting the weather and climate of nearby landmasses

15. Ocean Currents

16. What shapes an ecosystem?
Biotic and Abiotic Factors
Biotic Factors  living things that affect an organism
biotic factors affecting bullfrog: plants it eats, birds that might eat it, other species that compete for food or space

17. What shapes an ecosystem?
Abiotic Factors  physical, or nonliving factors that affect organisms
bullfrog affected by availability of water and temperature of air
Habitat includes both biotic and abiotic factors

18. Biotic and Abiotic Factors
ECOSYSTEM
Abiotic Factors

19. Niche An organism’s niche includes: Place in food web
Range of temperatures organism needs to survive
Type of food it eats
How it obtains food
Other species that use it as food
Physical conditions necessary for survival
When and how it reproduces

20. Niche Two species cannot share the same niche in the same habitat.
Different species can occupy similar niches.
Ex - three species of warblers live in the same spruce trees but feed at different elevations and in different part of the trees

21. Warbler Niches Cape May Warbler Feeds at the tips of branches
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Spruce tree

22. Community Interactions
Competition  same or different species attempt to use an ecological resource in the same place at the same time
resource = necessity of life (water, nutrients, light, food, space)

23. Community Interactions
Competitive Exclusion Principle - no two species can occupy the same niche in the same habitat at the same time
Direct competition in nature often results in winner and loser – losing organism fails to survive

24. Community Interactions
Predation - one organism captures and feeds on another organism
Predator – the one killing and eating
Prey – the food

25. Symbiosis When two species live close together. Three types:
Parasitism – one is harmed (host), one benefits (parasite)
Mutualism – both benefit
Commensalism – one is neutral, one benefits

26. Mutualism
Parasitism
Commensalism

27. Ecological Succession
Ecosystem constantly changing due to natural and human disturbances
older organisms die out and new organisms move in, causing further changes in the community

28. Ecological Succession
Primary succession – occurs in areas where no soil exists
Ex – new rock created by volcano, rock exposed when glaciers melt
Pioneer species – first to populate new land
Usually lichens (algae and fungus) that can break up rock to begin soil formation

29. Lichen on Rock

30. Ecological Succession
Secondary Succession – occurs when community is destroyed or altered but soil is still there
Ex – fire, clear cutting
Regrows to mature, stable community called climax community

31. Forest Fire Regrowth