1. Ecological Succession Ecosystems are constantly changing in response to natural and human disturbances.

2.  ecological succession: series of predictable changes that occur over time in an ecosystem

3. Primary Succession Succession that occurs on surfaces where no soil exists: Sides of volcanoes Rock after glaciers retreat Starts with the arrival of living things such as lichens that do not need soil to survive, called PIONEER SPECIES

4. Lichens: formed symbiotic relationship between fungus and algae and can grow on bare rock

5. Primary Succession  Soil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces  When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil  Simple plants like mosses and ferns can grow in the new soil

9. Glacial Retreat

11. Mount St. Helen’s Case study

12. 19781980

13.  1 year later

14. 5 years after 15 years after

15. 25 years after

16. Secondary Succession  succession that occurs following a disturbance that changes an existing community without removing the soil  wildfires, clearing of land for agriculture or development, wind storms, lakes that dry up, etc.  On-going process  Pre-existing seeds will germinate to establish new plants.

17. Yellowstone Fire 1988

18. Immediately after fire

19. 2 months after fire

20. 1 year later

21. 20 years later

22. Station Fire 2009: Chaparral Succession

24. Decomposition of a fallen log  Primary or Secondary Succession?

25. Old- field Succession  Occurs in farmland that has been abandoned  Grasses and weeds grow quickly, and procede many seeds that cover large areas

26. Maintenance of Prairie Ecosystems Before: high fuel load During controlled burn Just 2 months later

27. Climax Community  A stable group of plants and animals that is the end result of the succession process  Does not always mean big trees  Grasses in prairies  Cacti in deserts

28. 4-1 The Role of Climate

29. What Is Climate? Weather is the day-to-day condition of Earth's atmosphere at a particular time and place. Climate refers to the average year-after- year conditions of temperature and precipitation in a particular region.

30. Climate is caused by:  trapping of heat by the atmosphere  latitude  transport of heat by winds and ocean currents  amount of precipitation  shape and elevation of landmasses

31. The Greenhouse Effect Atmospheric gases that trap the heat energy of sunlight and maintain Earth's temperature range include:  carbon dioxide (CO 2 )  Methane (CH 4 )  water vapor (H 2 O)

32. The Greenhouse Effect The natural situation in which heat is retained in Earth’s atmosphere by this layer of gases is called the greenhouse effect. Sunlight Earth’s Surface Atmosphere Some heat escapes into space Greenhouse gases trap some heat

33. Greenhouse Effect in a Car

34. The Effect of Latitude on Climate  Solar radiation strikes different parts of Earth’s surface at an angle that varies throughout the year.  At the equator, energy from the sun strikes Earth almost directly.  At the North and South Poles, the sun’s rays strike Earth’s surface at a lower angle.

35.  Making Climate Graphs  Climate graphs show us the two factors in a climate:  Temperature and Precipitation

36.  Making Climate Graphs Let’s look at two climate graphs The line graph is temperature The bar graph is precipitation

37.  Making Climate Graphs Let’s look at two climate graphs The y-axis on the left is for temperature The y-axis on the right is for precipitation

38.  Making Climate Graphs What trends can we see on these graphs? 1.Cold winters, hot summers 1.Even precipitation (no rainy season) 1.Moose Factory, Ontario gets much colder in the winter than Chicago,IL