ecological succession biology 11(d). learning objectives describe how events and processes that...
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Ecological SuccessionBiology 11(D)
Learning Objectives• Describe how events and processes that
occur during ecological succession can change populations and species diversity
Ecological Succession
Population – individuals of a given species in a particular area
Community – all the different populations in an area• Pioneer community – first inhabitants in new
community• Climax community – established community
Ecological succession – orderly change in makeup of a community over time• Pioneer Climax
Ecological Succession
Pioneer Community• Harsh
environment• Biomass
increasing• Energy
consumption inefficient
• Some nutrient loss• Low species
diversity• Fluctuations
common
Climax Community• Favorable
environment• Biomass stable• Energy
consumption efficient
• Nutrient cycling• High species
diversity• Fluctuations
uncommon
Pioneer vs. Climax Community
Ecological succession – land and water Two types:• Primary succession – newly formed area• Secondary succession – area that has been
disturbed
How do events and processes that occur during succession change populations and species diversity?
Ecological Succession
Primary succession in newly formed pond:1. No organisms2. Algae and bacteria 3. Heterotrophic protists and
small invertebrates4. Floating plants (pondweed)5. Larger plants (cattails)
grow around edges
Primary Succession in Pond
Primary succession in newly formed pond:6. Larger animals 7. Becomes marsh, fills in8. Shrubs and trees
Results: • Pioneer Climax• Aquatic Terrestrial• Increased species diversity• Complex food chains
Primary Succession in Pond
Primary succession on rocks:1. Cooled lava rocks form after volcanic
eruption2. Lichens and mosses
appear, dissolve rock, form soil
3. Dead lichens add organic matter
4. Small animals
Primary Succession on Rocks
Primary succession on rocks:6. More diverse plants 7. More diverse,
larger animals
Results:• Pioneer Climax• Barren rock Terrestrial ecosystem• More diverse species and populations
Primary Succession on Rocks
Secondary succession – sequence of changes after a climax community has been destroyed• Natural disasters– Forest fire– Flood
Secondary Succession
Secondary succession – sequence of changes after a climax community has been destroyed• Destruction by man– Clearing land for construction or harvest– Abandoned farmland
Secondary Succession
Secondary succession on abandoned farmland:1. Soil is sunlit and dry2. Weeds are pioneers species
Secondary Succession on Farmland
Secondary succession on abandoned farmland:3. Weeds die, adding nutrients to soil4. More plant species5. Soil shaded by grasses and shrubs6. Pine seedlings 7. Pine forest community (climax)
Results:Abandoned farmland Pine forestMore diverse species and populations
Secondary Succession on Farmland
Summary of Ecological Succession• Species, populations, and communities
change over time• Unfavorable environment Favorable
environment• Few food sources Many food sources• Few species Many species Diverse
populations• Pioneer community Climax community
Ecological Succession
Learning Objectives• Describe how events and processes that
occur during ecological succession can change populations and species diversity
Ecological Succession