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Ecological Succession

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Presentation on theme: "Ecological Succession"— Presentation transcript:

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 in response to natural and human disturbances.

3 Primary Succession Succession that occurs on surfaces where no soil exists: Sides of volcanoes Rock after glaciers melts

4 Glacial Retreat


6 PIONEER SPECIES: The first species to populate an area after Primary Succession. Usually lichen and can grow on rock Lichens:formed symbiotic relationship between fungus and algae and can grow on bare rock

7 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 Mount St. Helen’s Case study


11 1 year later

12 5 years after 15 years after

13 25 years after

14 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. Pre-existing seeds will germinate to establish new plants.

15 Yellowstone Fire 1988

16 Immediately after fire

17 2 months after fire

18 1 year later

19 20 years later

20 Station Fire 2009: Chaparral Succession


22 Decomposition of a fallen log
Primary or Secondary Succession?

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

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

25 Succession in a Marine Ecosystem
Large whale dies and sinks to barren ocean floor. Attracts scavengers and decomposers. Within a year, most of the tissue has been eaten, the decomposition of the whale enriches the surrounding sediments. When only the skeleton remains, bacteria begin to decompose the bones.

26 The Role of Climate Photo Credit: ©Michael Fogden/DRK PHOTO

27 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.

28 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

29 The Greenhouse Effect Atmospheric gases that trap the heat energy of sunlight and maintain Earth's temperature range include: carbon dioxide (CO2) Methane (CH4) water vapor (H2O)

30 The Greenhouse Effect Some heat escapes into space Sunlight The natural situation in which heat is retained in Earth’s atmosphere by this layer of gases is called the greenhouse effect. Greenhouse gases trap some heat Carbon dioxide, water vapor, and several other gases in the atmosphere allow solar radiation to enter the biosphere but slow down the loss of heat to space. These greenhouse gases cause the greenhouse effect, which helps maintain Earth’s temperature range. Atmosphere Earth’s Surface

31 Greenhouse Effect in a Car

32 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.

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

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

35 Let’s look at two climate graphs
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

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

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