环境科学复习要点师兄版

1、CHAPTER ONE : Environmental InterrelationshipsEnvironment: the surrounding conditions that affect people and other organism. In a broaderdefinition, environment is everything that affects an organism during its lifetime.环境：与某一中心事物有关的周围事物，就是这个中心事物的环境。Environmental Science: is an interdisciplinary are

2、a of study that includes both applied and theoretical aspects of huma n impact on the world.The field of environmen talscie nee in volves an un dersta nding of scie ntific prin ciples, econo micin flue nces, and political acti on. En viro nment decisi ons ofent in volve compromise.(fig. 1.1)Internat

3、ional OrganizationIn order to solve the com mon en viro nmental issues, several intern ati onal orga ni zati ons were foun ded, and several intern ati onal conven ti ons were established.The intern ati onal joint commissi on (1909)boun dary waters treatyThe un ited n ati ons conference on en viro nm

4、ent and developme nt (1992, UNCED)susta in able developme nt and biodiversityAge nda 21The Kyoto conference on climate cha nge (1997)the Kyoto protocolThe Uni ted Nati ons Educatio nal, Scie ntific, and Cultural Orga ni zatio n (UNESCO)supported many environmen tal programs.An ecosystem is a regi on

5、 in which the orga ni sms and the physical environment form in teract ing un it.For solving regional environmental issues, it s very useful to adopt ecosystem approach.No region is free of environmental concerns.Regi onal vig nettes in AmericaThe Wideness Northcharacteristic: wilder ness-areas with

6、mi nimal huma n in flue nee.Much of this land is owned by gover nmen ts, not by in dividuals, so gover nment policies have alarge effect on what happe ns in these regi ons.The Agricultural Middlecharacteristic: inten sive agriculture.Origi nal, n atural ecosystems have bee n replaced by man aged agr

7、icultural en terprise.nonpoint pollution sources (pollution that does not have an easily identified point of origin).The Dry Westcharacteristic: in adequate rain fall, la nd is of low econo mic value, most of it is still the property of gover nment.Population density is low, much of the land has a w

8、ilderness character.The Forested Westcharacteristic: sufficie nt rain fall, coni ferous forests are the dominant vegetati on.Since most of these areas are not suitable for farmland, they have been maintained as forests with some grazing activity in the more open forests. timber cutting .En viro nmen

9、 tai in terests are concerned about the con seque nces loggi ng would have on orga ni sms that require mature, old-growth forests for their survival.The Great Lakes and Industrial Northeastcharacteristic: domin ated by large metropolita n complexes that gen erate social and resource n eeds that are

10、difficult to satisfy.A major concern about these polluta nts is that they bioaccumulate in the food cha in.Their major environmental priorities are cleaning up contaminated sites, providing more parks and recreati on facilities, reduc ing air and water polluti on, and improv ing tran sportati on.The

11、 Diverse Southcharacteristic: diverse.The South is a microcosm of all the regions previously discussed. The petrochemical industry dominates the economies of Texas and Louisiana, and forestry and agriculture are significant elements of the economy in other parts of the region. Major metropolitan are

12、as thrive, and much of the area is linked to the coast either directly or by the Mississippi River and its tributaries. The en viro nmen tal issues faced in the South are as diverse as those in all the other regi ons.Poverty has bee n a problem in many areas of the South. This creates a climate that

13、 en courages state and local gover nments to accept in dustrial developme nt at the expe nse of other values. Often, jobs are more important than the environmental consequences of the jobs; low-paying jobs are better tha n no jobs.En viro nmen tal problems are people problems.SummaryArtificial polit

14、ical boundaries create difficulties in managing environmental problems because most environmental units, ecosystems, do not coincide with political boundaries. Therefore, a regi onal approach to solvi ng environmen tal problems, one that in corporates n atural geographic units, is ideal. Each region

15、 of the world has certain environmental issues that are of primary concern because of the mix of populati on, resource use patter ns, and culture.En viro nmen tal problems become issues whe n some one finds a situati on offen sive. This in evitably leads to a confrontation between groups that have d

16、ifferent views on what constitutes an en viro nmen tal problem. Many social, econo mic, ethical, and scie ntific in puts shape a pers ons opinions. The process of environmen tal decisi on making must take all of these in puts into acco unt and arrive at an acceptable compromise. Environmental proble

17、ms are people problems. They occur because the uses of natural resources, which some people feel are justified, result in a diminished environment for others in the region. Environmental problems are defined by the person who perceives the problem. When perceptions differ, conflict occurs. Environme

18、ntal decisi ons in evitably in volve econo mic con siderati ons because some one is receivi ng value from the resources being used or some one perceives an econo mic loss because a use has bee n withdraw n.Compromise is the only way to resolve the Environmental conflictsCHAPTER THREE: Kinds of Ecosy

19、stems and Commu nitiesSuccessionThe com mun ities proceed through a series of recog ni zable, predictable cha nges in structure over time is called successi on.Primary succession is a successional progression that begins with a total lack of organisms and bare mi neral surfaces or water. Terrestrial

20、 Primary Successi onAquatic Primary Successi onSecondary SuccessionAn original community is destroyed and replaced by an new community, this progress is called secondary succession.Community: is an assemblage of all the in teract ing populatio ns of differe nt species of orga ni sms in an area.Clima

21、x community: The relatively stable, long-lasting community is called climax community Liche nA pion eer orga nismBiomes: Major Types of Terrestrial Climax CommunitiesThe effect of elevati on on climate and vegetati onDeserts: A lack of water is the primary factor that determines that an area will be

22、 desert. Deserts are areas that gen erally receive fewer than 25 centimeters of precipitati on per year.Grassland: Grasslands, also known as prairies or steppes, are widely distributed over temperate parts of the world. As with deserts, the major factor that con tributes to the establishme nt of a g

23、rassla nd is the amount of available moisture. Grassla nds gen erally receivebetween 25 and75 centimeters of precipitation per year. These areas are windy with hot summers and cold to mild wi nters.Savanna: Tropical parts of Africa, South America, and Australia have exte nsive grassla nds spotted wi

24、th occasional trees or patches of trees. This kind of a biome is often called a savanna. These areas of the world are typically tropical, with 50 to 150 centimeters of rain per yea r. The rain i s not distributed evenly through-out the year.Tropical Dry Rainforest : Many of the tropical dry forests

25、have a monsoon climate in which several mon ths of heavy rain fall are followed by exte nsive dry periods ranging from a few to as many as eight mon ths. (See figure 6.14) the rain fall may b e as low as 50 centimeters or as high as 200centimeters, but since the rain fall is highly seas on al, many

26、of the pla nts have special adaptations for enduring drought.Tropical Rainforest : Tropical rain forests are located n ear the equator in Cen tral and South America, Africa, Southeast Asia, and some islands in the Caribbean Sea and Pacific Ocean. (See figure 6.15.) The temperature is n ormally warm

27、and relatively con sta nt. There is no frost, and it rains nearly every day. Most areas receive in excess of 200 centimeters of rain per year. Some receive 500 centimeters or more. Because of the warm temperatures and abundant rain fall, most plants grow very rapidly; however, soils are often poor i

28、n nutrients because water tends to carry away any nu trie nts not immediately take n up by pla nts.Marine EcosystemsThose Aquatic Fcosystems that have a high salt content are called marine ecosystemsPelagic Marine Ecosystems In the open ocean, many kinds of organisms floats or swim actively. Crustac

29、ea ns, fish, and whales swim actively as they pursue food. Orga nisms that are not attached to the bottom are called pelagic organisms, and the ecosystem they are a part of is called a pelagic ecosystem.Benthic Marine Ecosystems: Orga ni sms that live on the ocea n bottom, whether attached or not, a

30、re known as benthic organisms, and the kind of ecosystem of which they are a part is called a ben thic ecosystem.Estuaries: An estuaries is a special category of marine ecosystem, that consist of shallow, partially en closed areas where freshwater en ters the ocea n. The salt in ess of the water in

31、the estuary changes with tides and the flow of water from rivers. The organisms that live here are specially adapted to this set of physical con diti ons, and the nu mber of species is less tha n in the ocea n or in freshwater.Freshwater EcosystemsThose that have little dissolved salt are called fre

32、sh water ecosystemsFreshwater ecosystems differ from marine ecosystems in several ways. The amount of salt prese nt is much less, the temperature of the water can cha nge greatly, the water is in the process of moving dow nhill, oxyge n can ofte n be in short supply, and the orga ni sms that i nhabi

33、t freshwater systems are differe nt.Lakes and Ponds: Large lakes have many of the same characteristics as the ocean. If the lake is deep, there is a euphotic zone at the top.Streams and Rivers: the water is shallow, light can penetrate easily to the bottom (except for large or extremely muddy rivers

34、). Even so, it is difficult for photosynthetic organisms to accumulate the nutrients necessary for growth, and most streams are not very productive.SummaryEcosystems change as one kind of organism replaces another in a process called succession. Ultimately, a relatively stable stage is reached, call

35、ed the climax com muni ty. Successi on may begin with bare rock or water, in which case it is called primary succession, or may occur when the orig inal ecosystem is destroyed, in which case it iscalled sec on dary successi on. The stagesthat lead to the climax are called successi onal stages.Major

36、regio nal terrestrial climax com mun ities are called biomes. The primary determ iners of the kinds of biomes that develop are the amount and yearly distributi on of rain fall and the yearly temperature cycle. Major biomes are desert, grassla nd, sava nna, tropical rain forest, temperate deciduous f

37、orest, taiga, and tun dra. Each has a particular set of orga ni sms that is adapted to the climatic con diti ons typical for the area. As one proceeds up a mountain side, it is possible to witness the same kind of change in biomes that occurs if one were to travel from the equator to the North Pole.

38、Aquatic ecosystems can be divided into marine (saltwater) and freshwater ecosystems. In the ocea n, some orga ni sms live in ope n water and are called pelagic orga ni sms. Light pen etrates only the upper few meters of water; therefore, this region is called the euphotic zone. Tiny photos yn thetic

39、 orga ni sms that float n ear the surface are called phytopla nkton. They are eate n by small ani mals known as zoopla nkton, which in tur n are eate n by fish and other larger orga ni sms.CHAPTER FOUR: Population Prin ciplesAn Essay on the Prin ciple of Population-Thomas Malthus（1798）Population: a

40、group of in dividuals of the same species in habit ing a particular area at a specific time.Population CharacteristicsNatality （出生率） ：refers to the number of individuals added to the population through reproducti on.Mortality （死亡率）:refers to the number of deaths in a population over a particular tim

41、e period. Age distribution （年龄分布） :the number of individuals in each age class as a ratio of one class to ano ther.Sex ratio （性另吐匕例）：refers to the relative numbers of males and females.Population Growth Curve 人口增长曲线Typical population growth tends to follow a particular pattern, consisting of a lag p

42、hase, an exponential growth phase, and a stable equilibrium phase.Four periods:a lag phase （滞后阶段） an exponential growth phase （增长阶段）a stable equilibrium phase （稳定平衡阶段） a death phase （死亡阶段）Growth as normally seen under artificial conditions, e.g: lab populationsLimits to population size are:1. Food 2

43、.Waste product elim in ati on 3. Disease con trol4.SpaceLogistic growthMost populations are limited in growth at some carrying capacity （K） （the maximum populationsize a habitat can accommodate）Environmental resistance to growth may be because of: Food and shelter llimitations ；Competiti on and pred

44、ati on by other orga ni sms ； Un favorable physical con diti onsCarrying Capacity （承载力）The carrying capacity of an area is the number of individuals of a species that can survive in that area over time.Limiting Factor : a particular condition or factor that limits the size of a population. eg: Oxyge

45、n supply, Food supply, Disease, Predators, Limited space.Reproductive StrategiesSpecies can be divided into two broad categories based on their reproductive strategies:K-strategists are usually large orga ni sms that have relatively long lives, produce few offspri ng, and provide care for their offs

46、pri ng.R-strategist is typically a small orga nism that has a short life, produces many offspri ng, and does not reach a carry ing capacity.Human Population Growth : The human population growth curve has a long lag phase followed by a sharply rising exp onen tial growth phase that is still rapidly i

47、n creas ing.Growth will slow dow n either due to decreased births or in creased deaths.SummaryPopulati onbirthrate （n atality） death rate （mortality）Populati on growth is determ ined by the comb ined effects of the birthrate and death rate.sex ratio Age distributi on typical populati on growth curve

48、carry ing capacityfour major categories K-strategistsr-strategists are gen erally small, short-liv ing orga ni sms that reproduce very quicklyThe human population is increasing at a rapid rate. The earths ultimate carrying capacity for huma ns is not known. The causes for huma n populati on growth a

49、re not just biological but also social, political, philosophical, and theological.第五单元Interactions: Environment and Organisms环境和生物间的相互作用Every form of life and all societies require a con sta nt in put of en ergyIf the flow of energy through organisms or societies ceases,they stop functioning and beg

50、in to dis in tegrate1 Ecological ConceptsEcology: is the study of the ways orga ni sms in teract with each other and with their non liv ing surro undin gs.Environment: Everything that affects an organism during its lifetime is collectively known as its en viro nment.it is useful to subdivide the con

51、cept of environment into abiotic (nonliving) and biotic (living) factors.Abiotic factors can be organized into several broad categories: energy, nonliving matter, and processes that in volve the in teractio n of non livi ng matter and en ergy.Biotic factorsnclude all forms of life with which it in t

52、eracts.Limiting Factors: a shortage or absence of a key factor restricts the success of the species; thus the factor is known as a limiti ng factor.Habitat: The habitat of an orga nism is the space that the orga nism in habits, the place where it lives (its address)Niche: is the functional role it h

53、as in its surro undings (its professi on).Limiting factor: A shortage or absence of a key factor restricts the success of the species; thus the factor is known as a limiti ng factor.2 The Role of Natural Selection and EvolutionPopulation: a group of in dividuals of the same species in habit ing a pa

54、rticular area at a specific time.Species : is a populati on of orga ni sms in which the in dividuals are pote ntially able to in terbreed and produce fertile offspri ng.Natural selecti on: is the process that determ ines which in dividuals withi n a species will reproduce and pass their genes to the

55、 n ext gen erati on.Evolution: the changes that can be seen in the genes and the characteristic displayed by successive gen erati ons of populati on of orga ni sms over time.Extinction: is the loss of an entire species.The Mechanism of Natural Selection1. Individuals within a species showed variatio

56、n; some of the variations were very useful and others were not.2. Organisms within a species typically produce many more offspring than can survive. This means that there is not eno ugh suitable habitat for all of the offspri ng to grow to maturity. 3. The excess number of individuals results in a s

57、truggle for survival. Individuals within the populati on must compete with each other for food, space, mates, or other requireme nts that are in limited supply.4. Because of variation among individuals, some have a greater chance of survivi ng and reproduci ng tha n others. 5. As time passes and eac

58、h gen erati on is subjected to the same process, the perce ntage of in dividuals show ing favorable variati ons will in crease and those having unfavorable variations will decrease. Thus, the species will become better and better adapted to its environment.4 community and ecosystem interactionsCommu

59、nity : is an assemblage of all the interacting populations of different species of organisms in an area.Major Roles of Organisms:Producers: are able to make n ew, complex, orga nic material from the atoms in their environment. Consumer s: all other orga ni sms rely on producers as a source of food, ei