Unit 4 - Chapter 6, Part 1

1. Unit 4 - Chapter 6, Part 1 Kinds of Ecosystems and Communities David Rude

2. Kinds of Ecosystems and Communities

3. Outline • 6.1 Succession • 6.2 Biomes Are Determined by Climate • 6.3 Major Biomes of the World

4. Succession Communities proceed through is a series of regular, predictable changes in community structure over time. Activities of organisms change their surroundings & make the environment suitable for other kinds of organisms.

5. Succession Climax community • A relatively stable, long-lasting community that is the result of succession. • Not always predictable • Ecological Succession of the Climax Forest - video

6. Succession • Types of factors that determine the kind of climax community • Climate • Water • Substrate/soil • Colonizing organisms

8. Succession • Primary succession • Begins with • Total lack of organisms • Bare mineral surfaces or water

9. Succession • Primary succession (continued) • Examples • Volcanic lava flow • Glaciers retreating • Lower of sea level • Takes a long time • Few available nutrients for plants

10. Succession • Secondary succession • Begins with • Disturbance of an existing ecosystem. • Much more commonly observed • Proceeds more rapidly than primary succession.

11. Primary Succession • Terrestrial primary succession • Pioneer community • A collection of organisms able to colonize bare rock • Lichens • Break down rock and accumulate debris • Helps to form a thin soil layer • Soil begins to support small forms of life • May take 100 years to grow as large as dinner plate

12. Primary Succession Pioneer organisms

13. Primary Succession • Later Stages • Lichen community replaced by annual plants. • Annuals replaced by perennial community. • Perennial community replaced by shrubs. • Shrubs replaced by shade-intolerant trees. • Shade-intolerant trees replaced by shade-tolerant trees. • Stable, complex, climax community eventually reached.

14. Primary Succession Page 111 Primary succession on land

15. Primary Succession • Successional (seral) stage • Each step in the process of succession • Sere • The entire sequence of stages

16. Primary Succession • Characteristics of climax communities • Maintain species diversity for an extended period. • Contain multiple specialized ecological niches. • Maintain high levels of organism interactions. • Recycle nutrients • Maintain a relatively constant biomass.

17. Primary Succession • The general trend in succession • Increasing complexity • More efficient use of matter and energy

18. Primary Succession • Aquatic primary succession • Except for oceans, most are considered temporary • All receive inputs of • Soil particles • Organic matter from surrounding land • Results in gradual filling of shallow bodies of water

19. Primary Succession • Early stages • In deeper parts only floating plants and algae • As water depth becomes less • Submerged plants establish roots in sediment • Roots and stems below water accumulate more material • Help to trap sediments

20. Primary Succession • As water depth becomes less • Submerged plants establish roots in the sediments • Elodea and algal mats • Emergent plants become established • Have leaves that float on the surface of the water or project into the air. • Water lilies and cattails

21. Primary Succession • Later Stages – Transition to Terrestrial Community • Wet meadow forms • Grasses & sedges that can tolerate wet roots • Sometimes sphagnum moss forms a thick floating mat • Bog • Eventually becomes dryer • Transitions to climax community typical of the area

22. Primary Succession Page 112 Primary succession from a pond to a wet meadow.

23. Floating Bog

24. Bog

25. Rainforest Bog

26. Secondary Succession • Secondary succession • Occurs when an existing community is disturbed or destroyed • Much of the soil and some organisms remain • Soil and nutrients allow process to advance more rapidly than primary succession • Plants and organisms that survive disturbance can grow quickly and reestablish themselves

27. Secondary Succession • Nearby undamaged communities serve as sources of seeds and animals. • New climax community likely resembles the destroyed community.

28. Secondary Succession • Example of seral stages • Annual plants • Grasses and biennial herbs • Perennial herbs & shrubs • Pines • Oak & Hickory trees

29. Secondary Succession Secondary succession on land Page 113

30. Historical Perspective onSuccession and Climax • Original communities that European explorers found: • East – hardwood forests • North – evergreen forests • Central – grasslands • South - desert • Early ecologists saw these as the endpoint

31. Historical Perspective onSuccession and Climax • Settlers changed “original” ecosystems to agriculture • Poor farming practices destroyed soil • When farms were abandoned, began returning to its “original” condition. • New climax forest resembled original • Fewer species • Sometimes entirely different kinds of communities

32. Historical Perspective onSuccession and Climax • New species from other parts of the world changed the mix of organisms • Diseases removed species that were formerly dominant • Chestnut blight • Dutch Elm disease

33. Modern Concepts of Succession and Climax • Not a fixed, pre-determined community for each part of the world. • Main difference between climax community and successional community is its time scale. • Climate is only one of many factors that determine climax community

34. Modern Concepts of Succession and Climax • Human activities that alter climax communities • Agricultural practices • Logging • Suppression of fire • Changing the amount of water present • Draining an area • Irrigation and flooding

35. Biomes Are Determined By Climate • Biomes • Terrestrial climax communities with wide geographic distributions. • Different communities within a biome will show differences in exact species present • General structure and the kinds of niches and habitats present are similar

36. Biomes: Major Types of Terrestrial Climax Communities • Two primary non-biological factors that determine climax communities • Temperature • Patterns of precipitation • Total amount • Form – rain, snow, sleet • Distribution

37. Biomes: Major Types of Terrestrial Climax Communities • Major Biomes • Rainforest • Tropical • Temperate

38. Biomes: Major Types of Terrestrial Climax Communities • Major Biomes • Forest • Deciduous • Northern Coniferous • Dry

39. Biomes: Major Types of Terrestrial Climax Communities

40. Biomes: Major Types of Terrestrial Climax Communities • Major Biomes • Grassland • Savanna American Prairie

41. Pampas – South America

42. Savanna - Tanzania

43. Biomes: Major Types of Terrestrial Climax Communities • Major Biomes • Tundra Caribou Crossing the Tundra

44. Tundra

45. Biomes: Major Types of Terrestrial Climax Communities • Major Biomes • Desert • Hot • Cold

46. Northern India

47. Gobi Desert - Mongolia

49. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

50. The Effect of Elevation on Climate and Vegetation • Temperature • Warmest near equator, cooler toward the poles • Temperature decreases as altitude increases • Moving from sea level to mountain tops • Possible to pass through a series of biomes • Similar moving from the equator to the North Pole