1. COMMUNITIES AND BIOMES

2. Ch. 3.1: Communities What is a community?
all the interacting biotic factors in an area; all the different species
How is a community different than an ecosystem?
Focuses on biotic AND abiotic factors in an area
What are some limiting factors that may have an effect on the living organisms in this desert community?

3. Limiting Factors Sunlight Temperature Water Soil nutrients/chemistry
# of other individuals (shelter/food/protection)
Food source

4. What is tolerance?
Ability of an organism to withstand fluctuations of biotic and abiotic factors
What temperature range would you want to stay within for optimal plant growth?
What is the temperature range you need to stay within to ensure the plants survive? (This is the range of tolerance)

5. Succession It is a process
By definition: orderly changes & species replacement of communities in ecosystems
You determine the type of succession by looking at the starting point

6. Ask yourself  What was there before?
Succession
The steps of primary and secondary succession are identical with the exception of how they begin.
Ask yourself  What was there before?
Absolutely nothing.
Primary Succession
Colonization of barren land (NEW land w/ no soil)
Things used to be there, but are gone.
Secondary Succession
Soil is already present
There were living organisms on the land before

7. Primary Succession = colonization of barren land by communities of organisms
1. New land is formed
3. Decayed pioneer species build up and create soil
Lava flow, lichen (algae & fungus), a Galapagos island
2. Pioneer species (ex. lichens) take hold
4. Once soil is formed, is the same as secondary succession

8. Secondary Succession
Sequence of changes after an existing community is destroyed/damaged/abandoned
Mount St. Helens

9. Once soil has been established…
Succession follows the same pattern (whether it started as primary or secondary)
Goes through a series of changes until a stable, climax community is reached

10. The Indiana Dunes are an example of primary succession

11. Biomes
Ch. 3, Sec. 2

12. What’s a Biome?
Large group of ecosystems that share the same type of climax community

13. Aquatic Biomes Approx. 75% of Earth’s surface is covered by water
Mostly salt water

14. 1. Marine Biomes = oceans, can be very shallow (surface of ocean) or very deep (bottom of ocean)
Photic Zone = portion of marine biome that is shallow enough for sunlight to penetrate
Aphotic Zone = deep water that never receives sunlight

15. 2. Estuaries = mixture of freshwater & ocean water; where rivers meet the ocean
Sea grass, mangroves

16. 3. Intertidal Zone = portion of shoreline between high and low tide

17. 4. Freshwater Biomes = lakes, ponds, rivers
Lake Victoria, Amazon river

18. Terrestrial Biomes

19. Rainfall varies from biome to biome, resulting in different adaptations in species

20. Tundra Cold temperatures Low precipitation (less than 100cm/year)
Layer of permafrost, only plants with shallow roots can grow
Short growing season

21. Taiga
Cold, more precipitation than tundra
Characteristic species of plant: conifers (trees that produce cones)
Soil has poor minerals

22. Less than 25cm of annual rainfall
Desert
Less than 25cm of annual rainfall
Tend to be very warm, but can be very cold as well
Adaptations for living in the desert
Plants = spine, waxy coating, toxins
Animals = nocturnal activity, venom, require less water
Kangaroo rat, cactus, rattlesnake

23. Grassland (prairies and savannas) 25-75cm of rainfall
Grasses are predominant species
Soil is rich in nutrients
Supports trees and shrubs
Usually near bodies of water
Many grazing herbivores
Prairie, Savannah, Steppe

24. Temperate Forests
Trees lose their leaves each year
Precipitation of cm /year

25. High level of precipitation Warmer temperature
Rain Forests
High level of precipitation
Warmer temperature
High level of biodiversity found in tropical & temperate (moderate climate) areas
Jaguar, poison dart frog, sloth

26. Practice
How are organisms in the photic zone and aphotic zone interdependent?
(Hint: Think about what grows in the photic zone, what supports the base of ecological pyramids? What happens if a population of one species grows out of control?)