Ecology

1. Ecology Communities and Biomes

2. Limiting Factors • environmental factors that affect an organism’s ability to survive • Two types • Density-dependent • Density-independent

3. Limiting Factors • Density-dependent factors • has increasing effect as the population increases • Examples: Shelter & Space Food & Water supply Predators Disease Parasitism

4. Predator-Prey Relationships

5. Limiting Factors • Density-independent factors- affects all populations regardless of density • Most abiotic factors storm flood earthquake temperature fire

6. What would a football field look like in thirty years if it was not cared for or played on? ?

7. Succession • orderly, natural changes and species replacements that take place in the communities of an ecosystem Lake Succession

8. Begins with: Pioneer plants- first organisms to inhabit an area Ex. Moss and lichen Ends with: Climax community- tends to remain stable or long periods of time with little or no change Succession

9. Primary Succession • colonization of a new site from rock

10. Secondary Succession • sequences of changes that take place after a community is disrupted by natural or human actions. • Ex.- abandoned building, fire, hurricane

11. Trends in Succession • Small plants with short life cycles are replaced with large plants with long life cycles • diversity increases • less energy is wasted • food webs become more complex • populations stabilize

12. Biomes of the World • Biome- a large group of ecosystems that share the same type of climax community • Aquatic biomes- approximately 75% of the earth’s surface • Oceans, lakes, rivers • Terrestrial biomes- land

13. Terrestrial Biomes

14. Terrestrial Biomes Sample Climatograph • 3 factors that influence type of biome • Latitude • Altitude • precipitation } Influences temperature

15. Terrestrial Biomes • Tundra • Taiga • Temperate forest • Tropical Rainforest • Grasslands • Desert

16. Tundra • 12 cm precipitation per year usually snow • long winters and darkness • Permafrost -soil remains permanently frozen • Long winters and darkness, Short summers • Russia, Iceland, Greenland • Low temperatures • Plants have fast life cycles • Animals-Snowshoe hare, caribou, reindeer, voles, ducks, geese

17. Taiga • largest biome • wet climate, foggy acidic soil • Most of Canada, Alaska, Eurasia • 35 to 40 cm precipitation yearly • Plants- large coniferous forest (firs, pines) • Animals- Moose, elk, wolves, porcupines, caribou, black bear, crossbills

18. Temperate Forest • south of Taiga • has definite seasons • most of US, N & S America, Europe and Asia • ~ 100 cm precipitation yearly • mixture of trees (pines and hardwoods-deciduous trees) • plants shed leaves in winter, • Animals- Deer, opossum, black bear, fox, squirrel, many bird species and insects

19. Tropical Rainforest • equatorial • almost constant temperature of 25 oC • > 250 cm of rain fall or more yearly • very humid • greatest diversity • Central and South America   • Plants- large variety, tree branches form canopy, vines • Animals-Toucans, monkeys, gorilla, tree frogs, snakes, lizards, parrots

20. Grasslands • steppe, plains, or prairie • West of Mississippi • Uneven rainfall 25-75 cm • Plants- Scattered trees, grass varies in length • Animals-Bison, antelope, • gophers, jackrabbits, sheep

21. Desert • less than 25 cm of rainfall yearly • long droughts • Can have high or low temperature • W US, Africa, India, Asia, S America • sparse vegetation • Plant adaptations for survival • shallow root systems– absorb little rainfall quickly • stems can photosynthesize, • leaves modified to needles • waxy cuticle • Cacti •  Small animals- lizards, kangaroo rat, scorpions, snakes