1. Communities, Ecosystems and Biomes
Chapter 3
Communities, Ecosystems and Biomes

2. Essential Questions
How do unfavorable abiotic and biotic factors affect species?
How do ranges of tolerance affect the distribution of organisms?
What are the stages of primary and secondary succession?

3. Community Ecology
Limiting factors—sunlight, climate, temperature, water, nutrients, fire, soil chemistry, space
Biotic limiting factors—non-native or invasive species, competition, plants and animals

4. Range of tolerance
Upper and lower limit that define the condition in which an organism can survive
Tolerance—ability of an organism to survive when subjected to abiotic factors or biotic factors
Trout tolerate a specific range of temperatures—9 degrees Celsius to 25 degrees Celsius, the greatest number of trout live in the optimum zone (temperature) for the best survival, Temperature would be considered the limiting factor.

5. Ecological succession
Progression of change in an ecosystem over time because of changes in biotic and abiotic factors.
Primary succession—no soil present, only rock
Pioneer species breaks down the rock—lichen (makes an acid that breaks down the rock)
Stages of primary succession
Lichen grow on rocks, break it into soil
Small plants such as grasses and herbs
Perennials
Shrubs, small trees and large trees
Ends with climax community

6. Secondary succession
Natural disasters—deforestation, floods, fires (there is soil)
Stages—grasses as pioneer species
Ends with climax community

7. Threats to Ecosystems
Pollution, global warming, and sedimentation—could kill 30 percent of the existing coral reefs in the next 30 years.
Deforestation and coral reefs

8. Sample question
The number of pythons found throughout Everglades National Park has increased in recent years. These huge snakes are not native to Florida and are believed to have been released into the wild by pet owners. Wildlife biologists have initiated attempts to capture and remove these pythons. Which statement best explains the biologists’ reason for removing these pythons from the Everglades? A. The pythons could upset the territorial boundaries of native organisms. B. The pythons could adapt to overcome diseases common to native snakes. C. The pythons could prey on native organisms and cause native populations to decline. D. The pythons could begin to interbreed with native snakes and produce a more successful species.

9. Sample question
Which of the following best explains the difference in the amount of available energy in the trophic levels of the desert ecosystem?
A. There is less energy available in the producers because their tissues are less dense than
those at higher trophic levels.
B. There is more energy available in the second trophic level because less energy is needed
for hunting compared to the higher trophic levels.
C. There is more available energy in the birds of prey because they have greater muscle
mass for storing energy than organisms in lower trophic levels have.
D. There is less available energy in the fourth trophic level because of the loss of energy
through metabolism in each of the lower trophic levels.

10. Essential Questions
How is latitude related to the three major climate zones?
What are the major abiotic factors that determine the location of a terrestrial biome?
How are the terrestrial biomes distinguished based on climate and biotic factors?

11. 3 major climate zones

12. Section 2
Weather—the condition of the atmosphere at a specific place and time
Climate—average weather conditions in an area including temperature and precipitation
Sunlight strikes Earth more directly at the equator than at the poles

13. Temperature and precipitation determine characteristics of terrestrial biomes
Tundra—treeless biome with layer of permanently frozen soil below the surface called permafrost with cycles of freezing and thawing
Boreal forest—south of tundra—broad band of dense evergreen forest (Northern coniferous forest) also called Taiga
Temperate forest—mostly broadleaf , deciduous trees, 4 seasons, in spring new growing season
Temperate woodland and shrub land—less annual rainfall than temperate forest
Temperate grassland—fertile ground, thick grasses, drought, grazing animals and fire keep trees from growing
Perennial grasses have underground stems and buds
Desert—area which annual rate of evaporation exceeds rate of precipitation
Tropical savanna—grasses and scattered trees, less precipitation than other tropical areas
Tropical seasonal forest (tropical dry forest)—resembles the temperate forest during dry season
Tropical rain forest—warm temperature and large amounts of rainfall, broad leaf trees
Polar regions—cold all year with thick layer of ice

14. Section 3 Essential Questions
What are the major abiotic factors that determine aquatic ecosystems?
What are transitional aquatic ecosystems and why are they important?

15. Section 3
Abiotic factors that determine aquatic ecosystems are flow, depth, distance from shore, salinity (salt content) and latitude.
3 major categories of aquatic biomes
Freshwater—ponds, lakes, rivers and wetlands
Transitional—between freshwater and marine (estuaries); wetlands—marshes, swamps and bogs
Marine—saltwater

17. Freshwater Ponds, lakes, streams and rivers
Sediments—material that is deposited by water, wind or glaciers
As the slope levels, the speed of the water flows decreases and sediments are deposited in the form of silt, mud and sand.
Rivers and streams—Life here has the ability to withstand the constant water current.
Lakes and ponds—standing water

18. Zones of lakes and ponds
Littoral zone—closest to shore, shallow, sunlight reaches bottom
Many producers (plants and algae), frogs, turtles, worms, crustaceans, insect larvae and fish
Limnetic zone—open water
Plankton—free floating photosynthetic organisms
Many fish live in limnetic zone!
Profundal zone—minimal light, deepest zones, colder, lower oxygen; limited species live in this harsh environment

19. Lakes
Oligotrophic—nutrient-poor lakes found in mountains, small amounts of organic matter and nutrients
Eutrophic—nutrient-rich lakes

20. Transitional aquatic ecosystems
High level of diversity, nursery ground for many species of crustaceans, insects, fish, birds
Wetlands—marshes, swamps, bogs
Estuaries—ecosystem that is formed where freshwater from river or stream merges with saltwater from the ocean
Tropical estuary—mangrove trees are the dominant salt-tolerant plants
Salt marshes—salt-dominant grasses and sea grasses

21. Marine ecosystems
Intertidal zone—where ocean meets land, organisms must be adapted to daily tides, alternating between being submerged and exposed to air.
Open ocean—contains photic and aphotic zones
Pelagic--area of the ocean outside of coastal areas, and where you’ll find some of the biggest marine life species. (The sea floor is not included in the pelagic zone.)
Abyssal—deepest regions of the ocean, cold, organisms depend on material that drifts from zones above.
Benthic—ocean floor contains sand, silt and dead organisms; diversity depends upon depth, light and temperature. Hydrothermal vents spew hydrogen sulfide and other minerals, chemosynthetic organisms present
Photic—light penetrates so many autotrophs and many other organisms live in the photic zone
Aphotic—constant darkness, cold,
Coastal and coral reef—most diverse aquatic ecosystems, found in warm, shallow marine waters, form natural barriers along continents that protect shorelines from erosion, sensitive to changes in the environment