Tài liệu PDF Ecology of Protists

IUBS Unesco IVQB REPRODUCTIVE ECOLOGY OF TROPICAL FOREST PLANTS Research lnsights and Management Implications by K.S. Bawa, P.S. Ashton, R. B. Primack, J. Terborgh, Çalleh Mohd. Nor, F.S.P. Ng and M. Hadley REPRODUCTIVE ECOLOGY OF TROPICAL FOREST PLANTS Research lnsights and Management Implications by K.S. Bawa, P.S. Ashton, R.B. Prirnack,J. Terborgh, Salleh Mohd.Nor, F.S.P. Ng and M. Hadley Based on an lnternatlonal workshop organlzed by UnesceMAB and IUBS, In cooperatlon wlth the Universltl Kebangsaan Malaysla and the Malayslan MAB National Commlttee, and heid In Bang1 (Malaysla) from 8-12 June 1987 SPECIAL ISSUE - 21 BIOLOGY INTERNATIONAL THE INTERNATIONAL UNION OF BlOLOGlCAL SCIENCES NEWS MAGAZINE IUBS 1989 Preface The unabated devastation of tropical wildlands has become one of the most pressing issues of Our times. Not only are the rates of deforestation very high, but also approximately 40% of the existing forest areas have been degraded in recent times. It is estimated that tropical rain forests will largely disappear in about 30 years time, except for those that might be conserved as nature reser- ves. Obviously there is a need for greater investment in scientific research in ecology, conservation and management of tropical rain forests worldwide There are three crucial interrelated issues that a manager of indigenous forests must address: depletion of forest resources, regeneration and restoration of forest ecosystems, and conservation of genetic resources. The challenges ge- nerated by the reduction and degradation of forest cover can be adequately met only if serious attempts are made to manage and restore forest ecosystems. Restoration inevitably must involve improved reforestation of degraded lands through plantations of native species, and the extension of forest boundaries by artificial and natural regeneration. Finally, coupled with effective management including restoration, conservation of existing genetic resources is of high prio- rity. The resources to be conserved and the manner in which they ought to be conserved are serious issues requiring strong scientific input. Most research on the reproductive ecology of tropical forest plants from flowering to regeneration, however, has had strong theoretical underpinnings. The test of predictions emerging from hypotheses relating to coevolution and the structure, organization and dynamics of communities has been a major impetus for much of the work. Nevertheless, many types of basic research in reproductive ecology have strong practical applications in management and conservation of forest resources (Bawa and Krugman, 1990). In June 1987 a workshop on the reproductive ecology of tropical forest plants was held at Bangi, Malaysia, to review recent research in plant reproductive ecology and to examine the application of such research to the management and conservation of forest resources. Reproductive ecology was defined to include all stages of reproduction from the initiation of flowering to seedling establishment. The workshop was jointly sponsored by the Man and Biosphere Program of Unesco and the Decade of the Tropics Program of IUBS, in coope- ration with the Malaysian MAB National Committee and the Universiti Ke- bangsaan Malaysia. It was based on 20 invited papers and some 50 offered contributions, in the form of both oral and poster presentations. In this report, we provide a brief summary of the invited papers in the Ecology of Protists Ecology of Protists Bởi: OpenStaxCollege Protists function in various ecological niches Whereas some protist species are essential components of the food chain and generators of biomass, others function in the decomposition of organic materials Still other protists are dangerous human pathogens or causative agents of devastating plant diseases Primary Producers/Food Sources Protists are essential sources of nutrition for many other organisms In some cases, as in plankton, protists are consumed directly Alternatively, photosynthetic protists serve as producers of nutrition for other organisms For instance, photosynthetic dinoflagellates called zooxanthellae use sunlight to fix inorganic carbon In this symbiotic relationship, these protists provide nutrients for coral polyps ([link]) that house them, giving corals a boost of energy to secrete a calcium carbonate skeleton In turn, the corals provide the protist with a protected environment and the compounds needed for photosynthesis This type of symbiotic relationship is important in nutrient-poor environments Without dinoflagellate symbionts, corals lose algal pigments in a process called coral bleaching, and they eventually die This explains why reef-building corals not reside in waters deeper than 20 meters: insufficient light reaches those depths for dinoflagellates to photosynthesize Coral polyps obtain nutrition through a symbiotic relationship with dinoflagellates 1/7 Ecology of Protists The protists themselves and their products of photosynthesis are essential—directly or indirectly—to the survival of organisms ranging from bacteria to mammals ([link]) As primary producers, protists feed a large proportion of the world’s aquatic species (On land, terrestrial plants serve as primary producers.) In fact, approximately one-quarter of the world’s photosynthesis is conducted by protists, particularly dinoflagellates, diatoms, and multicellular algae Virtually all aquatic organisms depend directly or indirectly on protists for food (credit “mollusks”: modification of work by Craig Stihler, USFWS; credit “crab”: modification of work by David Berkowitz; credit “dolphin”: modification of work by Mike Baird; credit “fish”: modification of work by Tim Sheerman-Chase; credit “penguin”: modification of work by Aaron Logan) Protists not create food sources only for sea-dwelling organisms For instance, certain anaerobic parabasalid species exist in the digestive tracts of termites and woodeating cockroaches, where they contribute an essential step in the digestion of cellulose ingested by these insects as they bore through wood 2/7 Ecology of Protists Human Pathogens A pathogen is anything that causes disease Parasites live in or on an organism and harm the organism A significant number of protists are pathogenic parasites that must infect other organisms to survive and propagate Protist parasites include the causative agents of malaria, African sleeping sickness, and waterborne gastroenteritis in humans Other protist pathogens prey on plants, effecting massive destruction of food crops Plasmodium Species Members of the genus Plasmodium must colonize both a mosquito and a vertebrate to complete their life cycle In vertebrates, the parasite develops in liver cells and goes on to infect red blood cells, bursting from and destroying the blood cells with each asexual replication cycle ([link]) Of the four Plasmodium species known to infect humans, P falciparum accounts for 50 percent of all malaria cases and is the primary cause of disease-related fatalities in tropical regions of the world In 2010, it was estimated that malaria caused between one-half and one million deaths, mostly in African children During the course of malaria, P falciparum can infect and destroy more than one-half of a human’s circulating blood cells, leading to severe anemia In response to waste products released as the parasites burst from infected blood cells, the host immune system mounts a massive inflammatory response with episodes of delirium-inducing fever as parasites lyse red blood cells, spilling parasite waste into the bloodstream P falciparum is transmitted to humans by the African malaria mosquito, Anopheles gambiae Techniques to kill, sterilize, or avoid exposure to this highly aggressive mosquito species are crucial to malaria control Red blood cells are shown to be infected with P falciparum, the causative agent of malaria In this light microscopic image taken using a 100× oil immersion lens, the ring-shaped P falciparum stains purple (credit: modification of work by Michael Zahniser; scale-bar data from Matt Russell) Link to Learning 3/7 Ecology of Protists This movie depicts the pathogenesis of Plasmodium falciparum, the causative agent of malaria Trypanosomes Trypanosoma brucei, the parasite that is responsible for African sleeping sickness, confounds the human immune system by changing its thick layer of surface glycoproteins with each infectious cycle ... MIT Center for Real Estate Week 12: Real Estate and Regional Economic Growth • Exports, transfers, investments and the determinants of regional growth: demand. • Population growth and migration: supply • 3-Q model of regional response. Factor supply elasticity and the role of real estate. • Wages, productivity and real estate costs – across MSAs. MIT Center for Real Estate Income and Product Accounts in States Summary of Output and Income Accounts for Florida and Pennsylvania, 1991 Florida ($ billions) Pennsylvania ($ billions) Income Accounts* Income (Y) 262 242 Wages (w) 126 127 Other Income (y + G) 136 115 Consumption (C) 260 193 Private 214 161 Government 46 32 Federal Taxes (T) 38 41 Savings (S) -36 8 Output Accounts** Output (Q) 219 211 Wages (w) 126 127 Profits and Rents (π) 93 84 Consumption (C) 260 193 Investment (I) 44 27 Imports (M) 175 153 Exports (X) 92 144 INCOME (Y) - OUTPUT (Q) 43 31 MIT Center for Real Estate Regional Accounts: Flow of Funds • Regions do not have to have individually balanced accounts. Surpluses in goods can be balanced by deficits in capital or government flows: the following cross border flows however must sum to zero. Trade surplus: X-M [exports - imports] Gov. surplus (Federal): G-T [spending – taxes] Capital surplus: I – S [investment - savings] Profits surplus: y - π [received - earned] • Notice the in Florida, huge trade deficit is made up with huge negative savings. MIT Center for Real Estate Sources of Regional Demand . • Some variables are determined directly by the size of a state’s economy (Income or Output) : imports (M), Federal Taxes (T), consumption or savings (S) and profits earned in the state (π). • Other variables are determined by forces largely outside of the region and serve to bring money into the state, generating growth and ultimately determining state size (level of income or output): - Exports (X) - Investment (I) - Federal spending (G) - Unearned income: SS, retirement…(y) MIT Center for Real Estate Characterizing Export growth and Investment? ∑ e i n i = ∑ e i N+ ∑ e i (N i -N) + ∑ e i (n i -N i ) i i i i Share | Mix Competitive | Shift (i): industry n,e: regional growth in activity, level of activity N: national growth of activity • Share: a matter of timing • Mix: Historic industrial structure • Competitive: “our” companies versus “theirs” [innovation –vs- production costs: “product cycle] MIT Center for Real Estate Study of impact of each Demand factor on the Boston Area Economy over time (Coulson) Mix effect Share effect Competitive effect Impact on Region 0 1 2 3 4 years since start 8 9 10 11 MIT Center for Real Estate Regional Supply shifts are as important • Migration into a region that results from factors in the origin and not destination. [US history 1820-1920]. • Birth rates in the state – 20 years earlier! (Mass –vs- California Net Reproduction Rates). • Recent immigration from Mexico and Asia. MIT Center for Real Estate P Output Market Simultaneous Equilibrium in a region’s product, labor and structures markets. 1. Product Demand=production costs. 2. Costs = average of wages and rents. 3. Wages equilibrate labor supply with labor demand (proportional to output). 4. Rents do the same in structures market. Q D Q C=α K R + α L W W/P Labor Market L D =α L Q L S R Real Estate Market L K K D =α K Q W K S R MIT Center for Real Estate Changes in Regional output, prices, wages and rents in reaction to shift in product demand Qd to Qd’. 1). Prices (and costs) must rise. Ditto output. 2). Wages and employment rise. 3). Likewise for rents and stock of structures. 4). Reverse for downward demand shifts 5). Supply Elasticity and the Magnitude of price versus quantity changes? P Output Market Q Q D C=α Ecology of Fungi Ecology of Fungi Bởi: OpenStaxCollege Fungi play a crucial role in the MIT Center for Real Estate Week 12: Real Estate and Regional Economic Growth • Exports, transfers, investments and the determinants of regional growth: demand. • Population growth and migration: supply • 3-Q model of regional response. Factor supply elasticity and the role of real estate. • Wages, productivity and real estate costs – across MSAs. MIT Center for Real Estate Income and Product Accounts in States Summary of Output and Income Accounts for Florida and Pennsylvania, 1991 Florida ($ billions) Pennsylvania ($ billions) Income Accounts* Income (Y) 262 242 Wages (w) 126 127 Other Income (y + G) 136 115 Consumption (C) 260 193 Private 214 161 Government 46 32 Federal Taxes (T) 38 41 Savings (S) -36 8 Output Accounts** Output (Q) 219 211 Wages (w) 126 127 Profits and Rents (π) 93 84 Consumption (C) 260 193 Investment (I) 44 27 Imports (M) 175 153 Exports (X) 92 144 INCOME (Y) - OUTPUT (Q) 43 31 MIT Center for Real Estate Regional Accounts: Flow of Funds • Regions do not have to have individually balanced accounts. Surpluses in goods can be balanced by deficits in capital or government flows: the following cross border flows however must sum to zero. Trade surplus: X-M [exports - imports] Gov. surplus (Federal): G-T [spending – taxes] Capital surplus: I – S [investment - savings] Profits surplus: y - π [received - earned] • Notice the in Florida, huge trade deficit is made up with huge negative savings. MIT Center for Real Estate Sources of Regional Demand . • Some variables are determined directly by the size of a state’s economy (Income or Output) : imports (M), Federal Taxes (T), consumption or savings (S) and profits earned in the state (π). • Other variables are determined by forces largely outside of the region and serve to bring money into the state, generating growth and ultimately determining state size (level of income or output): - Exports (X) - Investment (I) - Federal spending (G) - Unearned income: SS, retirement…(y) MIT Center for Real Estate Characterizing Export growth and Investment? ∑ e i n i = ∑ e i N+ ∑ e i (N i -N) + ∑ e i (n i -N i ) i i i i Share | Mix Competitive | Shift (i): industry n,e: regional growth in activity, level of activity N: national growth of activity • Share: a matter of timing • Mix: Historic industrial structure • Competitive: “our” companies versus “theirs” [innovation –vs- production costs: “product cycle] MIT Center for Real Estate Study of impact of each Demand factor on the Boston Area Economy over time (Coulson) Mix effect Share effect Competitive effect Impact on Region 0 1 2 3 4 years since start 8 9 10 11 MIT Center for Real Estate Regional Supply shifts are as important • Migration into a region that results from factors in the origin and not destination. [US history 1820-1920]. • Birth rates in the state – 20 years earlier! (Mass –vs- California Net Reproduction Rates). • Recent immigration from Mexico and Asia. MIT Center for Real Estate P Output Market Simultaneous Equilibrium in a region’s product, labor and structures markets. 1. Product Demand=production costs. 2. Costs = average of wages and rents. 3. Wages equilibrate labor supply with labor demand (proportional to output). 4. Rents do the same in structures market. Q D Q C=α K R + α L W W/P Labor Market L D =α L Q L S R Real Estate Market L K K D =α K Q W K S R MIT Center for Real Estate Changes in Regional output, prices, wages and rents in reaction to shift in product demand Qd to Qd’. 1). Prices (and costs) must rise. Ditto output. 2). Wages and employment rise. 3). Likewise for rents and stock of structures. 4). Reverse for downward demand shifts 5). Supply Elasticity and the Magnitude of price versus quantity changes? P Output Market Q Q D C=α Types of Societies Types of Societies Bởi: OpenStaxCollege Maasai men are hunting with shepherd’s MIT Center for Real Estate Week 12: Real Estate and Regional Economic Growth • Exports, transfers, investments and the determinants of regional growth: demand. • Population growth and migration: supply • 3-Q model of regional response. Factor supply elasticity and the role of real estate. • Wages, productivity and real estate costs – across MSAs. MIT Center for Real Estate Income and Product Accounts in States Summary of Output and Income Accounts for Florida and Pennsylvania, 1991 Florida ($ billions) Pennsylvania ($ billions) Income Accounts* Income (Y) 262 242 Wages (w) 126 127 Other Income (y + G) 136 115 Consumption (C) 260 193 Private 214 161 Government 46 32 Federal Taxes (T) 38 41 Savings (S) -36 8 Output Accounts** Output (Q) 219 211 Wages (w) 126 127 Profits and Rents (π) 93 84 Consumption (C) 260 193 Investment (I) 44 27 Imports (M) 175 153 Exports (X) 92 144 INCOME (Y) - OUTPUT (Q) 43 31 MIT Center for Real Estate Regional Accounts: Flow of Funds • Regions do not have to have individually balanced accounts. Surpluses in goods can be balanced by deficits in capital or government flows: the following cross border flows however must sum to zero. Trade surplus: X-M [exports - imports] Gov. surplus (Federal): G-T [spending – taxes] Capital surplus: I – S [investment - savings] Profits surplus: y - π [received - earned] • Notice the in Florida, huge trade deficit is made up with huge negative savings. MIT Center for Real Estate Sources of Regional Demand . • Some variables are determined directly by the size of a state’s economy (Income or Output) : imports (M), Federal Taxes (T), consumption or savings (S) and profits earned in the state (π). • Other variables are determined by forces largely outside of the region and serve to bring money into the state, generating growth and ultimately determining state size (level of income or output): - Exports (X) - Investment (I) - Federal spending (G) - Unearned income: SS, retirement…(y) MIT Center for Real Estate Characterizing Export growth and Investment? ∑ e i n i = ∑ e i N+ ∑ e i (N i -N) + ∑ e i (n i -N i ) i i i i Share | Mix Competitive | Shift (i): industry n,e: regional growth in activity, level of activity N: national growth of activity • Share: a matter of timing • Mix: Historic industrial structure • Competitive: “our” companies versus “theirs” [innovation –vs- production costs: “product cycle] MIT Center for Real Estate Study of impact of each Demand factor on the Boston Area Economy over time (Coulson) Mix effect Share effect Competitive effect Impact on Region 0 1 2 3 4 years since start 8 9 10 11 MIT Center for Real Estate Regional Supply shifts are as important • Migration into a region that results from factors in the origin and not destination. [US history 1820-1920]. • Birth rates in the state – 20 years earlier! (Mass –vs- California Net Reproduction Rates). • Recent immigration from Mexico and Asia. MIT Center for Real Estate P Output Market Simultaneous Equilibrium in a region’s product, labor and structures markets. 1. Product Demand=production costs. 2. Costs = average of wages and rents. 3. Wages equilibrate labor supply with labor demand (proportional to output). 4. Rents do the same in structures market. Q D Q C=α K R + α L W W/P Labor Market L D =α L Q L S R Real Estate Market L K K D =α K Q W K S R MIT Center for Real Estate Changes in Regional output, prices, wages and rents in reaction to shift in product demand Qd to Qd’. 1). Prices (and costs) must rise. Ditto output. 2). Wages and employment rise. 3). Likewise for rents and stock of structures. 4). Reverse for downward demand shifts 5). Supply Elasticity and the Magnitude of price versus quantity changes? P Output Market Q Q D C=α Laws of Inheritance Laws of Inheritance Bởi: OpenStaxCollege Mendel generalized the results MIT Center for Real Estate Week 12: Real Estate and Regional Economic Growth • Exports, transfers, investments and the determinants of regional growth: demand. • Population growth and migration: supply • 3-Q model of regional response. Factor supply elasticity and the role of real estate. • Wages, productivity and real estate costs – across MSAs. MIT Center for Real Estate Income and Product Accounts in States Summary of Output and Income Accounts for Florida and Pennsylvania, 1991 Florida ($ billions) Pennsylvania ($ billions) Income Accounts* Income (Y) 262 242 Wages (w) 126 127 Other Income (y + G) 136 115 Consumption (C) 260 193 Private 214 161 Government 46 32 Federal Taxes (T) 38 41 Savings (S) -36 8 Output Accounts** Output (Q) 219 211 Wages (w) 126 127 Profits and Rents (π) 93 84 Consumption (C) 260 193 Investment (I) 44 27 Imports (M) 175 153 Exports (X) 92 144 INCOME (Y) - OUTPUT (Q) 43 31 MIT Center for Real Estate Regional Accounts: Flow of Funds • Regions do not have to have individually balanced accounts. Surpluses in goods can be balanced by deficits in capital or government flows: the following cross border flows however must sum to zero. Trade surplus: X-M [exports - imports] Gov. surplus (Federal): G-T [spending – taxes] Capital surplus: I – S [investment - savings] Profits surplus: y - π [received - earned] • Notice the in Florida, huge trade deficit is made up with huge negative savings. MIT Center for Real Estate Sources of Regional Demand . • Some variables are determined directly by the size of a state’s economy (Income or Output) : imports (M), Federal Taxes (T), consumption or savings (S) and profits earned in the state (π). • Other variables are determined by forces largely outside of the region and serve to bring money into the state, generating growth and ultimately determining state size (level of income or output): - Exports (X) - Investment (I) - Federal spending (G) - Unearned income: SS, retirement…(y) MIT Center for Real Estate Characterizing Export growth and Investment? ∑ e i n i = ∑ e i N+ ∑ e i (N i -N) + ∑ e i (n i -N i ) i i i i Share | Mix Competitive | Shift (i): industry n,e: regional growth in activity, level of activity N: national growth of activity • Share: a matter of timing • Mix: Historic industrial structure • Competitive: “our” companies versus “theirs” [innovation –vs- production costs: “product cycle] MIT Center for Real Estate Study of impact of each Demand factor on the Boston Area Economy over time (Coulson) Mix effect Share effect Competitive effect Impact on Region 0 1 2 3 4 years since start 8 9 10 11 MIT Center for Real Estate Regional Supply shifts are as important • Migration into a region that results from factors in the origin and not destination. [US history 1820-1920]. • Birth rates in the state – 20 years earlier! (Mass –vs- California Net Reproduction Rates). • Recent immigration from Mexico and Asia. MIT Center for Real Estate P Output Market Simultaneous Equilibrium in a region’s product, labor and structures markets. 1. Product Demand=production costs. 2. Costs = average of wages and rents. 3. Wages equilibrate labor supply with labor demand (proportional to output). 4. Rents do the same in structures market. Q D Q C=α K R + α L W W/P Labor Market L D =α L Q L S R Real Estate Market L K K D =α K Q W K S R MIT Center for Real Estate Changes in Regional output, prices, wages and rents in reaction to shift in product demand Qd to Qd’. 1). Prices (and costs) must rise. Ditto output. 2). Wages and employment rise. 3). Likewise for rents and stock of structures. 4). Reverse for downward demand shifts 5). Supply Elasticity and the Magnitude of price versus quantity changes? P Output Market Q Q D C=α Forms of Government Forms of Government Bởi: OpenStaxCollege Former Iraqi dictator .. .Ecology of Protists The protists themselves and their products of photosynthesis are essential—directly or indirectly—to the survival of organisms ranging from bacteria... data from Matt Russell) Link to Learning 3/7 Ecology of Protists This movie depicts the pathogenesis of Plasmodium falciparum, the causative agent of malaria Trypanosomes Trypanosoma brucei, the... 4/7 Ecology of Protists Trypanosomes are shown among red blood cells (credit: modification of work by Dr Myron G Shultz; scale-bar data from Matt Russell) Plant Parasites Protist parasites of