ECOSYSTEMS, and ECOLOGY

1. ECOSYSTEMS, and ECOLOGY APES

2. WHAT IS AN ECOSYSTEM? An ecosystem is a community of organisms and its nonliving environment in which chemical elements cycle and energy flows. Ecosystems can be natural or artificial. Natural ecosystems carry out public service functions for us and are considered natural capital in an economic and social sense.

3. Food chains show how energy moves through the ecosystem • Trophic levels show feeding relationships in a community. They are commonly shown as a food chain or pyramid • Basic food chains show how organisms in an ecological community get the energy they need. • The food chain is made of PRODUCERS, various CONSUMERS AND DECOMPOSERS

4. ENERGY ENTERS ECOSYTEM • All energy in an ecosystem comes from the sun • First law of Thermodynamics: Energy cannot be created or destroyed (but it can be transformed into stored energy & heat)

5. ENERGY LEAVES ECOSYSTEM • Second law of thermodynamics:Energy is lost as it is transformed • In ecosystem, when energy is transformed, some energy is lost as HEAT

6. 1. Food Chain: Single path 3. Food Pyramid 2. Food Web: many paths ENERGY PATHS 3 ways to illustrate energy flow

7. FOOD CHAINS • A food chain shows the path of energy from one organism to the next • energy flows from producers to consumers • arrows point to who is eating (plant is eaten by herbivore) • Usually decomposers are left out, as they occur at many trophic levels

8. FOOD WEBS • A food web shows all feeding relationships in an ecosystem (made of many food chains)

9. FOOD WEBS remember: decomposers receive energy from all other organisms in an ecosystem CONSUMER(CARNIVORE) • Typically, food webs go like this: CONSUMER(OMNIVORE) CONSUMER(HERBIVORE) DECOMPOSER PRODUCER

10. FOOD CHAINS AND WEBS • Practice! Draw a food chain that includes the following organisms: • grasshopper • mouse • grass • owl CONSUMER(CARNIVORE) CONSUMER(CARNIVORE) CONSUMER(HERBIVORE) • Now label the organisms as producers, consumers (which type?), or decomposers PRODUCER

11. FOOD CHAINS/WEBS & ENERGY PYRAMIDS • Food chains/webs can be written as a pyramid: • Producers form the base of the pyramid • Consumers form the upper layers

12. PRIMARY PRODUCTIVITY • Producers convert solar energy into energy stored in carbon compounds during photosynthesis • This stored carbon is termed BIOMASS • Less than 1% of all available sunlight is used for photosynthesis

13. PRIMARY PRODUCTION • The rate at which plants capture and store chemical energy as biomass in a given amount of time is called their GROSS PRIMARY PRODUCTION (GPP) • Much of this biomass is used in cellular respiration by the plants. The difference in energy between what was produced and what was used is called NET PRIMARY PRODUCTION (NPP) and may be consumed by herbivores. Energy released during respiration is used for transporting food from the leaves to other parts of the plant, moving leaves and organelles, etc

14. When compared on a one-to-one per square meter basis, estuaries (coastal wetlands) have the highest net primary production. For this reason, there are many herbivores in estuaries. Open oceans and deserts have the least productivity

15. ENERGY PYRAMIDS Feeding relationships can be shown as an energy pyramid • Top Consumer • Energy stored by • Secondary Consumers • Energy stored by • Primary Consumers • ENERGY STORED • BY PRODUCERS • Each trophic level represents the energy contained in those organisms • There is less energy as you move up the pyramid (2nd law of thermodynamics) since most is lost as heat

16. TROPHIC LEVELS • Energy is lost with each trophic level • ~90% is released to the environment as heat • ~10% of the energy is used Only about 10% of the energy from one level is passed on to the next level

17. Does all the energy this caterpillar eats get passed to the bird who eats him? Plant material eaten by caterpillar 100 kilocalories (kcal) 35 kcal Cellular respiration 50 kcal Feces 15 kcal Growth Figure 19.25

18. Ecosystem video review • http://youtu.be/v6ubvEJ3KGM

19. Ecosystems develop during Ecological Succession • Succession is a change in the type of plants and animals in an area • Primary succession occurs on bare ground WHERE NO SOIL EXISTED BEFORE! • Primary succession creates soil

20. STAGE 1 of primary succession • The first plants to grow on the new ground are called PIONEERS • They can live without much soil • LICHENS and MOSSES ARE COMMON PIONEERS

21. Stage 2 of primary succession • Once the lichen has grown on the rocks and broken them down into smaller particles, dead lichen add humus and nutrients to the new soil, allowing different plants to colonize the area, eventually replacing the lichen. • GRASS IS OFTEN THE NEXT PLANT suited here • Grasses are often fast growing, requiring lots of sunlight and little rainfall

22. Stage 3 of primary succession • After only a few years, conditions are suitable for shrubs to grow and replace some of the grass. • SHRUBS ARE NEXT. Shrubs require deeper and richer soil layers to support root growth. • More animals can now live in the area. Biodiversity increases as shrubs provide food and shelter for many organisms

23. STAGE 4 of primary succession • The final stage of succession lasts the longest (hundreds of years) because the conditions will remain stable. Fast growing trees shade out lower plants • CLIMAX is the name of this stage • FORESTS are climax communities. They have a lot of biodiversity, since they are rich in soil and habitats for animals • The particular type of forest depends on the amount of rain and the temperature of the area.

24. To summarize… • Each stage ADDS more nutrients to the soil, builds up the soil, increases the amount of shade and allow more animals to find a place to live there (more habitats) • The first stages are fast. The climax stage lasts the longest and is the most stable. Climax stages are typical of the biome of the area

25. Major Biomes of the world • Climax communities with adequate precipitation become forests because they are not limited by water. • Tropical rainforests are warm year-round. They have highest productivity and therefore highest biodiversity though the soil is highly leached with that much rain. • Temperate deciduous forests have seasons, so the temperature varies between winter, spring, summer and fall.

26. Major biomes continued • GRASSLANDS are characterized by grasses and shrubs because the rainfall is not high enough to support large trees. They are very fertile since the grasses add humus to the soil and less leaching occurs. They make excellent agricultural lands

27. Hot and cold desert biomes • DESERTS are the driest biomes with so little rainfall that the biodiversity is low. • Hot deserts have high temperatures, with dry and sandy soils. • Cold deserts are very cold with permafrosted soil for most of the year

28. Ecosystems recover during SECONDARY SUCCESSION • Secondary succession is the series of changes that occur only after a disturbance (so plants and soil were there before) • Forest fires, floods, drought, logging, mining, farming are some examples of disturbances that can clear an area of plants • Secondary succession restores the community to its original condition. It begins with pioneers and ends the climax community too. The pioneers are often grasses whose seeds survived the disturbance • It is faster than primary succession

29. Comparing primary and secondary succession

30. Practice question Which of the following would be subject to primary succession? Explain your reasoning • Rock exposed by a retreating glacier • An abandoned farm • A forest that had been clear cut • Newly flooded agricultural land used to create a reservoir • A forest that has been burned

31. Answer to practice question • 1. Primary succession occurs in biotic communities in a previously uninhabited and barren habitat with little or no soil. • All other choices had previous vegetation and therefore, soil.

32. Ecosystem services of forests Forests clean water of sediments and nutrients; capture carbon from the air; slow down stormwater runoff; blocks wind preventing soil erosion; lowers evaporation of soil…

33. CASE STUDY: CATSKILL FORESTS OF NEW YORK • One way of estimating the value of an ecosystem service is to determine how much it would cost to replace it. Natural abiotic processes such as soil adsorption of pesticides and heavy metals; filtration of sediment and solid waste through roots and soil; recycling of nutrients by microbes cleaned the water to government standards. Building an operating a water treatment plant would have cost $6 billion! In New York City, water purification by watershed is $1billion. The forest provided the ecosystem service of cheap water treatment!

34. Other economic benefits of ecosystems • TOURISM DOLLARS are earned for tours featuring wildlife viewing, photography, kayaking, camping, fishing and hiking • JOBS that pay well such as commercial fishing depend on stable ecosystems to raise young to maturity; park rangers and managers to care for parks or nature preserves; hotel staff for lodgings

35. Valuation is not limited to economics The value of ecosystem services can include aesthetic, health, recreational, cultural and environmental benefits.

36. Threats to forest ecosystems Deforestation for agriculture Deforestation for urbanization Clearing land to make room for more housing and roads results in the same effect on carbon released to the air More houses also means more water and energy are needed so more stress on those resources • CASE STUDY: PALM OIL • Used to make soap, makeup and food • Record breaking deforestation to grow oil palm trees releases huge amounts of carbon from the soil, contributing to climate change • Threatens native species such as Apes, elephants, tigers in Indonesia and Africa

37. Deforestation practices • Clear cutting • Most damaging type of cutting down trees since ALL of the trees are removed regardless of size, age or commercial value. Leads to habitat fragmentation and soil erosion • Slash and burn • Type of clear cutting where the trees are burned on site. The ash enhances soil fertility • Selective logging is more sustainable since only some of the trees are cut down, leaving the others to continue growing

38. LEGISLATION TO PROTECT terrestrial ECOSYSTEMS 1. Wilderness Act of 1964: established the National Wilderness Preservation System which protects primitive areas in the US. • No drilling, mining, hunting or other activity can occur in these areas

39. US National Park Service 2. 1916, Congress passed the National Park Service Act – declared that the parks were to be maintained in a manner that leaves them unimpaired for future generations. • Recreational activities such as hiking, camping and fishing are allowed. No logging, mining or extractive industry is allowed in national parks. • Yellowstone is the first national park.

40. 3. Endangered Species Act • PROTECTS BIODIVERSITY in the USA • Forbids actions that destroy habitats or the endangered species themselves • Also bans TRADE in products made from endangered species

41. 4. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES treaty) • Protects endangered species by banning international transport or trade of these organisms or their body parts (for example elephant tusks)

42. Lower biodiversity indicates a disturbance in the area • One test of pollution or other changes in an ecosystem is to measure the biodiversity of the area. • While it can’t point to a specific threat, lower biodiversity indicates a need for further investigations and/or policy changes

43. CHEMICAL CYCLING IN ECOSYSTEMS • Ecosystems need a flow of energy AND chemical elements that can be recycled • What gets recycled in our ecosystem? • Energy?? NOOO • Water • Carbon • Phosphorus

44. Consumers • Generalized scheme for biogeochemical cycles that recycle matter. • Geologic processes are common to all cycles. However, most also involve the atmosphere (though not the Phosphorus cycle) Producers Decomposers Nutrients available to producers Abiotic reservoir Geologic processes Figure 19.28

45. Nitrogen (N2) in atmosphere • The nitrogen cycle Detritus Amino acids and proteins in plants and animals Detritivores Denitrifying bacteria Assimilation by plants Nitrogen-fixing bacteria in root nodules of legumes Decomposition Nitrates (NO3– ) Nitrogen fixation Nitrogen-fixing bacteria in soil Ammonium (NH4+ ) Nitrifying bacteria (b) The nitrogen cycle Figure 19.29b

46. Nitrogen Fixation by bacteria • Plants need nitrogen but cannot take it in from the air. The atoms in the nitrogen gas molecules are too tightly bonded. • Bacteria in the soil on the roots of leguminous plants take in nitrogen gas (N2) and make ammonia (NH4) and nitrates (NO3) which plants can then use to make proteins for cell parts

47. Which process fixes carbon in the food chain? CO2 in atmosphere Photosynthesis Burning Producers • The carbon cycle Wood and fossil fuels Cellular respiration Higher-level consumers Primary consumers Decomposition Detritivores Detritus (a) The carbon cycle Figure 19.29a

48. Carbon Cycle • Producers: Plants take in CO2 and make sugar by photosynthesis. • Consumers: Animals eat plants to get energy (respiration) from sugar and make proteins from the carbon. • Breath out CO2 as a waste product of respiration. • Animals die and decomposers break down the carbon and other elements back into the soil and air for plants to use again.

49. Uplifting of rock Phosphates in rock • The phosphorous cycle Phosphates in organic compounds Weathering of rock Consumers Producers Detritus Phosphates in soil (inorganic) Rock Precipitated (solid) phosphates Phosphates in solution Detritivores in soil What part of you has phosphate? DNA (c) The phosphorus cycle Figure 19.29c

50. The sulfur cycle (with human activities) Most of earth’s sulfur is stored underground in rocks and ocean sediments. Weathering releases sulfur. It combines with oxygen in the air to create sulfate which is absorbed by plants. Sulfur can be released as a gas (sulfur dioxide) by volcanoes. And can form sulfuric acid rain when combined with oxygen and water. Most of the sulfur that reaches the atmosphere is due to human activity, primarily the burning of coal, high sulfur diesel and the smelting of metals.