1. Science 1206/2200 Unit 1 - Chapter 2 Change and diversity in Ecosystems

2. What are some examples of pests? DEFINITION:Pg.52 Living organisms that fall into one of three categories: 1.Humans believe it to be UNDESIRABLE (ahem, gross). 2.It has a NEGATIVE impact on the human environment. 3.It is in COMPETITION with a HUMAN USE for a resource.

3. DEFINITION: Chemicals used to kill various pests. Pesticides Two main categories based on ORIGIN: FIRST GENERATION PESTICIDES SECOND GENERATION PESTICIDES

4. FIRST-GENERATION pesticides ORIGIN:NATURAL Examples: Arsenic, lead, mercury, nicotine SECOND-GENERATION pesticides ORIGIN: HUMAN-MADE/SYNTHETIC Examples:DDT, penicillin 4 SUBCATEGORIES: INSECTICIDE:kills INSECTS HERBICIDE:kills plants FUNGICIDE:kills mould/fungi BACTERICIDE:kills bacteria

5. Pesticides Over Time Pesticide types have changed over time. Older pesticides FAT-SOLUBLE When ingested by an organism, these pesticides attach to fat cells. This was highly effective as they PERMANENTLY remain in the organism.

6. Newer pesticides WATER-SOLUBLE When ingested, they are effective in the target pest, but do not accumulate in fat cells. This type dissolves in water and can be flushed out of an organism’s system.

7. Bioaccumulation Also known as BIOAMPLIFICATION or BIOMAGNIFICATION A phenomenon in food chains whereby FAT- SOLUBLE PESTICIDES build up in the fat cells of consumers at higher trophic levels.

8. Bioaccumulation and DDT DDT stands for: Dichlorodiphenyltrichloroethane second generation: human-made. Introduced as a FAT- SOLUBLE insecticide to control insects that: Feed on agricultural crops Damage forests (ex: spruce budworm) Carry diseases (ex: malaria)

9. It was VERY EFFECTIVE at killing pests But there was an unknown effect,it stayed in the bodies of other organisms...

11. FIRST NOTICED EFFECTS: Egg shell thinning in top carnivore birds, such as Bald Eagle Thin shells meant HIGH RATES of chick mortality It takes about 15years for DDT to break down in the environment.

12. What do we do? Ban DDT and other fat-soluble pesticides. It is now banned in CANADA (1977) and many parts of the world, BUT SOME COUNTRIES are still using it. Use water-soluble pesticides instead. Use sustainable alternatives to pesticides.

13. DDT Continues to be a Problem to Us Even Though We Have Banned It Third - world countries south of the U.S. border such as Mexico and Central America, continue to use DDT. Migratory birds go there in winter and bioamplify the DDT in their bodies The migratory birds Retur and are fed upon by predators in our country

14. IPM for short A sustainable approach to managing pests that involves: PREVENTION AVOIDANCE MONITORING SUPPRESSION

15. CHEMICAL CONTROL BIOLOGICAL CONTROL 2 MAIN TYPES OF PEST MANAGEMENT

16. Although chemicals are highly effective, there are several DISADVANTAGES to using them, including: Chemical Control BIOACCUMULATION Not TARGET-SPECIFIC Not 100 % EFFECTIVE (some pests will not be killed) Could lead to PESTICIDE RESISTANCE

17. Biological Controls Although they are more TARGET-SPECIFIC, there are several DISADVANTAGES including: Expensive Short-Term Effectiveness Organisms simply move to another area Methods include using: NATURAL PREDATORS DISEASE ORGANISMS COMPETITORS PHEROMONES

18. Pesticide Resistance Some pests are naturally immune to pesticides. Once non-immune pests are killed off, the immune PESTS are left to reproduce a new generation of PESTICIDE RESISTANT PESTS.

20. Forest Insect Pests in Newfoundland. 1. Eastern Hemlock Looper: Most damaging pest to our forestry. Causes complete defoliation (loss of leaves/needles) of balsam fir in one year.

21. 2. Spruce Budworm: Defoliator in the caterpillar stage. It can kill a tree over a number of years. It’s considered one of the most destructive forest pests in North America Forest Insect Pests in Newfoundland.

22. Biogeochemical Cycles and Human Impacts

23. Introduction Biogeochemical cycles The recycling of material s though living organisms and the physical environment. Biochemist Scientists who study how life works at a chemical level. The work of biochemists has lead to the understanding that living organisms are composed of some of the same elements that are found in air, water, and soil.

24. Biogeochemical Cycles Although there are 92 elements known to occur naturally on Earth, fewer than 20 elements are presently known to occur in the tissues of living things. For example, only elements make up 99.2% of human tissue.

25. Biogeochemical Cycles The four elements that make up the majority of living tissue are: ▫Oxygen ▫Carbon ▫Hydrogen ▫Nitrogen

26. The Cycling Process The 4 elements (O,C,N, and H) are cycled constantly between 2 parts of nature ▫Living Organisms ▫Physical Enviroment The cycling of these elements is dependent on two of processes in order to work: ▫Biological Processes ▫Geological Processes

27. Biological Processes The cycling of these elements require living organisms, which make up the biosphere of Earth. What are some examples of Biological Processes? ▫Respiration ▫Photosynthesis ▫Decomposition ▫Assimilation ▫Excretion

28. Geological Processes The cycling of these elements require the physical environment which includes ▫Air – Atmosphere ▫Land – Geosphere ▫Water – Hydrosphere Examples of geological processes ▫Fossilization ▫Erosion ▫Combustion/Burning ▫Weathering ▫Sedimentation

29. 3 Types of Cycles Carbon Cycle Nitrogen Cycle Oxygen Cycle

30. The Carbon Cycle Pg. 62-65 The cycling of carbon though the atmosphere, the physical environment, and ecosystems http://www.youtube.com/watch?v=dDBU0lg-HYE

31. Carbon and the Biosphere How important is Carbon for life? ▫Carbon is the element that is the backbone for all life on Earth. In other words, we are carbon- based life forms. How does carbon move though living organisms? ▫The two main processes that help cycle carbon though the biosphere are photosynthesis and cellular respiration

32. Carbon and Nonliving systems Where is carbon stored in the non-living environment? ▫Two types of carbon storage: 1.Organic reservoirs: stored as the result of decomposition of living organisms. The processes are specific and years to complete When detritus gets trapped under peat, it forms coal. When detritus gets trapped under oceans, it forms oil and natural gas

33. Carbon and Nonliving systems 2. Inorganic reservoirs 3 main areas Air -.03% of air is carbon Oceans – both dissolved (carbon gas) and in shells Land – in sedimentary rocks, which can be released during violent volcanic eruptions.

34. Carbon and Living Systems Reservoirs: Bodies of living things. Carbon returns in an inorganic form when living things die. Some ecosystems such as bogs store huge quantities of carbon in organic form. Decomposition is slow and can lock away. Sediments can form over this and creates coal.

35. The Nitrogen Cycle pg. 66-67 DEFINITION: The movement of nitrogen through the atmosphere, physical environment and ecosystems.

36. Nitrogen and the Biosphere WHAT IS NITROGEN USED FOR IN LIVING ORGANISMS? Nitrogen is used to make DNA and PROTEINS. DNA is the GENETIC MATERIAL found in every living cell. WHERE IS MOST NITROGEN FOUND ON EARTH? Most nitrogen on Earth is found in the air. The air is 79% NITROGEN. This atmospheric nitrogen is in the form N2, a gas. Although nitrogen is plentiful in the air, it is UNUSABLE to most living organisms (we cannot simply “breathe in” nitrogen).

37. Nitrogen and the Biosphere HOW DO LIVING ORGANISMS GET NITROGEN? Plants and animals cannot use N2 gas. We can use nitrogen in TWO FORMS: AMMONIA, NH3 NITRATES, NO3- WHAT ARE THE KEY NITROGEN CYCLE PROCESSES? NITROGEN FIXATION DENITRIFICATION

38. Nitrogen Cycles NITROGEN FIXATION Also known as NITRIFICATION Gaseous nitrogen, N2, is converted to usable forms in TWO WAYS: By LIGHTNING By NITROGEN-FIXINGBACTERIA These bacteria are found in the ROOT NODULES of LEGUMES such as ALFALFA and CLOVER.

39. Nitrogen Cycles DENITRIFICATION DENITRIFYING BACTERIA convert usable forms of nitrogen back into gaseous nitrogen, N2. These bacteria are found in the soil. These bacteria do not require oxygen. Denitrification ensures balance among soil nitrates, nitrites, and atmospheric nitrogen, and completes the nitrogen cycle. Lawns/Bogs Pg. 67

40. Oxygen Cycle Oxygen is used in the process of cellular respiration by both plants and animals. Carbon is released in the form of CO2 as a waste product of this reaction. Plants take in the inorganic gas CO2 and use it in the process of photosynthesis to make organic sugars such as glucose Oxygen is released as a waste product of the photosynthesis reaction. The reactions of cellular respiration and photosynthesis are reciprocals of each other

41. Oxygen Cycle

42. Human Impacts CARBON CYCLE GLOBAL WARMING and the GREENHOUSE EFFECT NITROGEN CYCLE AQUATIC EUTROPHICATION Deforestation - Increased CO2 levels add to global warming OXYGEN CYCLE

43. GLOBAL WARMING and the GREENHOUSE EFFECT Humans have DISRUPTED the CARBON CYCLE in TWO MAIN WAYS:  Burning FOSSIL FUELS: Increased CO 2  DEFORESTATION: Decreased O 2 production by plants Increased CO 2 The increase in CO 2 levels have led to an ENHANCED GREENHOUSE EFFECT.

44. WHAT ARE GREENHOUSE GASES? Gases that have the ability to HOLD HEAT IN the atmosphere. These gases are important to keep the Earth warm enough to sustain life.

45. 3 Main Greenhouse Gases 1) CARBON DIOXIDE CO 2 Sources: Cellular Respiration Combustion (burning) 2) METHANE CH 4 Sources: Fossil fuel production and transportation Decomposition Livestock

46. 3) NITROUS OXIDES Sources: Combustion Agricultural Fertilizers Industrial Emissions

47. Global Warming 101 Humans have DRAMATICALLY INCREASED the amount of greenhouse gases in the atmosphere, leading to the ENHANCED GREENHOUSE EFFECT, or GLOBAL WARMING.

48. Possible Effects Increased spread of disease Rising sea levels and loss of polar ice caps Figure below is 1979 versus 2005 Loss of freshwater sources More extreme weather Accelerated species extinction

49. Aquatic Eutropication Humans have impacted the nitrogen cycle by releasing 2 substances into AQUATIC ECOSYSTEMS: FERTILIZERS UNTREATED HUMAN SEWAGE Fertilizers, and untreated human sewage, contain NITRATES and PHOSPHATES. These chemicals LEACH into water ways through groundwater, road runoff, etc.

50. Lakes that have HIGH LEVELS of phosphates and nitrates can undergo EUTROPHICATION A transformation from an OLIGOTROPHIC LAKE to a EUTROPHIC LAKE.

51. Lakes that have HIGH LEVELS of phosphates and nitrates can undergo EUTROPHICATION A transformation from an OLIGOTROPHIC LAKE to a EUTROPHIC LAKE.

52. THINK ABOUT IT!!!!!!!!!!!!!