1. Communities and Biomes
Biology I

2. Community Ecology: Lesson Objectives
Recognize how unfavorable abiotic and biotic factors affect a species.
Describe how ranges of intolerance affect the distribution of organisms.
Sequences the stages of primary and secondary succession.

3. Main Ideas
All living organisms are limited by factors in the environment.
Ecosystems on land are grouped into biomes primarily based on the plant communities within them.
Aquatic ecosystems are grouped based on abiotic factors such as water flow, depth, distance from shore, salinity, and latitude.

4. Communities
A group of interacting populations that occupy the same area at the same time.
Not every community contains the same variety
Ex. Urban vs. rural, desert vs. artic
Most organisms are adapted to maintain homeostasis in their native environment.

5. Limiting Factors
Environmental factors (biotic or abiotic) that affect an organism’s population, reproduction, distribution, or ability to survive in its environment
Factors that limit one population in a community may also have an indirect effect on another population.
Abiotic (non-living) factors
Sunlight, temperature, climate, water, food, soil, space, fire
Biotic (living) factors
Plants and animals

6. Range of Tolerance
The ability of any organism to survive when subjected to abiotic or biotic factors is called tolerance.
Each organism has an upper and lower limit to what they can tolerate.

7. Ecological Succession
Ecosystems are constantly changing.
Succession is the orderly, natural changes and species replacements that take place in the communities of an ecosystem over time.
Occurs in stages: different species at different stages create conditions that are suitable for some organisms and not for others.
Can take decades to centuries

8. Primary Succession
The colonization of new land that is exposed by avalanches, volcanoes, or glaciers by pioneer organisms.
Establishment of a community in an area of exposed rock that does not have any topsoil.
Lichens (combo of fungus and algae) and some mosses are among the first organisms to appear because they can grow on rock.

9. Primary Succession Pioneer species are the first species in an area.
As pioneer species die, their decaying organic materials, along with bits of sediment from the rocks, make up the first stage of soil development.
Eventually enough soil will be present so that trees and shrubs can grow.
Primary succession eventually slows down and the community becomes fairly stable.

10. Secondary Succession
A stable, mature community that undergoes little or no change in species is called a climax community.
Eventually, things will begin to change.
Secondary succession refers to the sequence of community changes that take place after a community is disrupted by natural disasters or human actions.
Happens in areas that previously contained life.
Takes less time than primary succession

11. Terrestrial Biomes: Lesson Objectives
Relate latitude and the 3 major climate zones.
Describe the major abiotic factors that determine the location of a terrestrial biome.
Distinguish among terrestrial biomes based on climate and biotic factors.

12. Effects of Latitude and Climate
You are affected by weather and climate.
Weather is the condition of the atmosphere at a specific place and time.
The distance of any point on the surface of Earth north or south from the equator is latitude.
Light from the sun strikes Earth more directly at the equator than at the poles.

13. Effects of Latitude and Climate
Earth’s surface is heated differently in different areas.
The average weather conditions in an area, including temperature and precipitation, describe the area’s climate.
Latitude has an effect on climate, as well as elevation, landmasses, and ocean currents.

14. Major Land Biomes Biomes are classified by: Their plant life
Temperature
Precipitation
Animal species

15. Tundra Average precipitation: 15-25 cm/year
Temperature range:-34°C-12°C
Plants: short grasses, shrubs
Animals: caribou, polar bears, birds, insects, wolves, salmon, trout
Location: south of the polar ice caps in the Northern Hemisphere, North/South pole
Abiotic factors: soggy summers; permafrost; cold and dark much of the year

16. Taiga Boreal forest Average precipitation: 30-84 cm/year
Temperature range: -54°C – 21°C
Plants: spruce and fir trees (conifers), few deciduous trees, small shrubs
Animals: birds, moose, beavers, deer, wolverines, mountain lions
Location: Northern part of North America, Europe, and Asia
Abiotic factors: summers are short and moist; winters are long, cold, and dry

17. Temperate Forest Average precipitation: 75-150 cm/year
Temperature range:-30°C-30°C
Plants: oak, beech, and maple trees, shrubs
Animals: squirrels, rabbits, skunks, birds, deer, foxes, black bears
Location: South of the boreal forests in eastern North America, eastern Asia, Australia, and Europe
Abiotic factors: well-defined seasons, summers are hot, winters are cold

18. Woodlands/Shrublands
Average precipitation: cm/year
Temperature range: 10°C-40°C
Plants: evergreen shrubs, corn oak
Animals: foxes, jackrabbits, birds, bobcats, coyotes, lizards, snakes, butterflies
Location: surrounds the Mediterranean Sea, western coasts of North and South America, South Africa, and Australia
Abiotic factors: summers are very hot and dry; winters are cool and wet

19. Grassland Average precipitation: 50-89 cm/year
Temperature range: -40°C - 38°C
Plants: grasses and herbs
Animals: gazelles, bison, horses, lions, deer, mice, coyotes, foxes, wolves, birds, quail, snakes, grasshoppers, spiders
Location: North America (largest part), South America, Asia, Africa, and Australia
Abiotic factors: summers are hot, winters are cold, moderate rainfall, fires possible

20. Desert Average precipitation: 2-26 cm/year – driest biome
Temperature range: high 20°C – 49°C, low -18°C – 10°C
Plants: cacti, Joshua trees, succulents
Animals: lizards, bobcats, birds, tortoises, rats, antelope, desert toads
Location: every continent except Europe
Abiotic factors: varying temperatures, low rainfall

21. Tropical Savanna Average precipitation: 50-130 cm/year
Temperature range: 20°C – 30°C
Plants: grasses and scattered trees
Animals: lions, hyenas, cheetahs, elephants, giraffes, zebras, birds, insects
Location: Africa, South America, and Australia
Abiotic factors: summers are hot and rainy, winters are cool and dry

22. Tropical Rain Forest Average precipitatio: 200-1000 cm/year
Temperature range: 24°C – 27°C
Plant: broadleaf evergreens, bamboo, sugar cane
Animals: chimpanzees, Bengal tigers, elephants, orangutans, bats, toucans, sloth, cobra snakes
Location: Central and South America, southern Asia, western Africa, and northeastern Australia
Abiotic factors: humid all year, hot and wet

23. Other Terrestrial Areas
Mountains have abiotic conditions that change with increasing elevation, allowing many communities to exist.
Polar regions border the tundra at high latitudes and are cold all year.

24. Aquatic Ecosystems: Lesson Objectives
Identify the major abiotic factors that determine the aquatic ecosystems.
Recognize that freshwater ecosystems are characterized by depth and water flow.
Identify transitional aquatic ecosystems and their importance.
Distinguish the zones of marine ecosystems.

25. Freshwater Ecosystems
Major ecosystems include ponds, lakes, streams, rivers, and wetlands
Plants and animals are adapted to the low salt content and unable to survive in high salt content
2.5% of water on Earth is freshwater
68.9% is locked in glaciers, 30.8% is groundwater, and 0.3% is lakes, ponds, rivers, streams, and wetlands

26. Rivers and Streams Water flows in one direction
Characteristics change during the journey from the source to the mouth
Rapid waters have fewer species and less sediment and organic materials
Plants and animals must be adapted to withstand the constant water current

27. Lakes and Ponds An inland body of standing water Divided into 3 zones:
Littoral zone – area closest to the shore, shallow, lots of photosynthetic organisms
Limnetic zone – open water area that is well lit and is dominated by plankton
Profundal zone – minimal light penetration, much colder, lower in oxygen, limited number of species

28. Transitional Aquatic Ecosystems
Many aquatic environments are a combination of two or more different environments
Wetlands: marshes, swamps, and bogs; plant species grow in the humid, moist conditions; lots of animal diversity
Estuaries: among most diverse ecosystem; formed where freshwater and saltwater meet; many aquatic plants and detritivores

29. Marine Biomes
The oceans contain the largest amount of biomass, or living material, of any biome.
Most of the biomass is made of extremely small organisms.
Separated into shallow, sunlit zones and deeper, unlighted zones.
The portion of marine biome that is shallow enough for sunlight to penetrate is called the photic zone. Ex. coastlines

30. Marine Biomes
Deeper water that never receives sunlight makes up the aphotic zone.
The benthic zone is the area along the ocean floor that consists of sand, silt, and dead organisms.
The deepest region of the ocean is the abyssal zone.
Twice a day, the gravitational pull of the sun and moon causes the rise and fall of the oceans.
The intertidal zone is the area between low tide and high tide.

31. Marine Biomes
Plankton are small organisms that live in the waters of the photic zone.
Zooplankton are tiny animals that feed on plankton.
Coral reefs are one of the most beautiful and diverse biomes to study and are found only in warm water about 40 meters deep.