1. Changes to the Environment Succession Primary Succession Secondary Succession Changes to Ecosystems Role Of Humans

2. Learning Objectives Compare and contrast the different types of ecological succession Distinguish between the different environmental factors that affect species Relate how limited resources affect population growth Changes to the Environment

3. Populations interact to form a constantly changing community Populations must adapt to changing conditions Ecological succession – the orderly change in the makeup of a community over time Succession

4. Pioneer community – the first inhabitants of a new community Succession Climax community – an established community that generally undergoes little change

5. Climax community gradually replaces pioneer community Succession Pioneer CommunityClimax Community Harsh environmentFavorable environment Increasing biomassStable biomass Inefficient energy consumptionEfficient energy consumption Nutrient lossNutrient cycling Low species diversityHigh species diversity Fluctuations commonFluctuations uncommon

6. Primary succession – occurs in newly formed areas where no organisms existed before – Occurs where there is no soil – Autotrophic prokaryotes are first to inhabit Primary Succession

7. Volcanic Eruption 1.Lichens and mosses colonize rocks 2.Lichens dissolve rock, forming soil 3.As lichens/mosses die, they add organic matter to the soil 4.Rich soil supports small animals, insects, and more plants 5.Barren rock becomes a terrestrial ecosystem Primary Succession

8. Secondary succession – occurs after a preexisting climax community has been partially or completely destroyed – Natural disasters – Land cleared for harvest or construction – Occurs where soil is already present Secondary Succession

9. Abandoned cleared field 1.Weeds are pioneer species 2.Dying weeds add nutrients to the soil 3.New plants thrive, creating shade 4.Pine forest becomes the climax community Secondary Succession

10. Primary SuccessionSecondary Succession No soilSoil present Pioneer species: autotrophic prokaryotes, lichens, mosses Pioneer species: herbaceous plants

11. Populations depend on each other Kelp forest ecosystem 1.Sea otters eat sea urchins; sea urchins eat sea kelp 2.If a disease kills the sea otters, the sea urchin population will increase 3.The sea urchins will destroy the kelp forest 4.With no food, sea urchin population declines Changes to Ecosystems Change that affects one population can destroy the entire ecosystem

12. Survival of a species – Dependent on maintaining population size – Must adapt to changes in limiting factors Food Water Space – Affects biodiversity Biodiversity – includes the variation in life within a given species, ecosystem, biome or on earth, along with the complex interactions occurring among species – Currently decreasing – Decline affects all life Changes to Ecosystems

13. Clearing land – Destroys ecosystems – Removes trees that absorb CO 2 Coal-burning machines – Releases CO 2 Increased CO 2 – Greenhouse effect – Global climate change – Loss of biodiversity Role of Humans

14. Biomagnification – an effect in which the concentration of pollutants in a food chain dramatically increases with each step up in trophic level Role of Humans

15. Dams – Displace communities – Increase water-borne diseases – Trigger earthquakes – Increase greenhouse gasses – Block fish migrations – Increase erosion – Cause loss of species Role of Humans

16. Burning of fossil fuels – Releases CO 2 and nitrogen – Greenhouse effect – Global warming – Acid rain Affects soil and water Kills plants Role of Humans

17. Excessive irrigation – Erosion depletes nitrogen from soil – Poor plant growth Fertilizers – Excess nitrogen – Affects soil and water – Algal blooms reduce O 2 – Kills aquatic life Role of Humans

18. Decrease biodiversity – Overhunting – Introduced animals Spread disease Decimate natural populations Role of Humans