动植物气候介绍蓝色蓝色模板课件.ppt

1、Interactions of LifeLife ScienceMelanie Buchanan-TillmanThe Living Earth The part of Earth that supports life is the biosphere.The biosphere includes the top portion of Earths crust,all the waters that cover Earths surface,and the atmosphere that surrounds Earth.Earths biosphere consists of many env

2、ironments.Ecosystems An ecosystem consists of all the organisms living in an area,as well as the nonliving parts of that environment.Ecology is the study of interactions that occur among organisms and their environments.Populations A population is made up of all organisms of the same species that li

3、ve in an area at the same time.Populations&Habitats A community is all the populations of all species living in an ecosystem.The place in which an organism lives is called its habitat.An organisms habitat provides the kinds of food and shelter,the temperature and the amount of moisture the organism

4、needs to survive.Questions 1.What three things make up the biosphere?2.What is an ecosystem?3.List three parts of the Earth included in the biosphere.4.Define the term ecology.5.Compare and contrast the terms habitat and biosphere.6.Identify the major difference between a community and a population,

5、and give one example of each.7.Think Critically:Does the amount of rain that falls in an area determine which kinds of organisms can live there?Why or why not?Populations:Competition Food&Space:Organisms living in the wild do not always have enough food or living space.Competition occurs when two or

6、 more organisms seek the same resource at the same time.Growth LimitsCompetition limits population size.Competition for food,living space,or other resources can limit population growth.In nature,the most intense competition is usually between the same species because they need the same kinds of food

7、 and shelter.Populations:Population Size Ecologists often need to measure the size of a population.The number of individuals of one species per a specific area is called population density.Trap-mark-release is one of the methods used to measure wild life populations.The Census is a method used in th

8、e US every 10 years to measure its population.Populations:Sample Counts,Limiting Factors and Carrying CapacitySample counts.Ecologists use sample counts to estimate the sizes of large populations.Limiting factors.In any ecosystem,the availability of food,water,living space,mates,nesting sites,and ot

9、her resources is often limited.A limiting factor is anything that restricts the number of individuals in a population.Limiting factors include living and non living features of the ecosystem.A limiting factor can affect more than one population in a community.Carrying capacity.Carrying capacity is t

10、he largest number of individuals of one species that an ecosystem can support over time.Biotic Potential.The highest rate of reproduction under ideal conditions is a populations biotic potential.Visualizing Population GrowthQuestions 1.Describe three ways in which ecologists can estimate the size of

11、 a population.2.Explain how birthrates and death rates influence the size of a population.3.Explain how carrying capacity influences the number of organisms in an ecosystem.4.Think Critically.Why are food and water the limiting factors that usually have the greatest effect on population size?Interac

12、tions Within Communities Organisms that use the outside energy source like the Sun to make energy-rich molecules are called producers.Some producers use chlorophyll for photosynthesis.Other producers do not contain chlorophyll and use chemosynthesis.Consumers Organisms that cannot make their own ene

13、rgy-rich molecules are called consumers.Herbivores are vegetarians.They include rabbits,deer,and other plant eaters.Consumers Carnivores are animals that eat other animals.Frogs and spiders are carnivores that eat insects.Consumers Omnivores,including pigs and humans,eat mostly plants and animals.Co

14、nsumersDecomposers,including fungi,bacteria,and earthworms,consume wastes and dead organisms.Decomposers help recycle once-living matter by breaking it down into simple,energy-rich substances.These substances might serve as food for decomposers,be absorbed by plant roots,or be consumed by other orga

15、nisms.Obtaining Energy Food chains.Ecology includes the study of how organisms depend on each other for food.A food chain is a simple model of the feeding relationships in an ecosystem.Grassgrasshoppertoadsnakehawk Start with a producer,end with a predator.Symbiotic Relationships Any close relations

16、hip between species is called symbiosis.Mutualism:A symbiotic relationship in which both species benefit is called mutualism.Commensalism:A symbiotic relationship in which one organism benefits and the other is not affected is called commensalism.Parasitism:A symbiotic relationship in which one orga

17、nism benefits but the other is harmed is called parasitism.Niches An organisms niche is its role in its environmenthow it obtains food and shelter,finds a mate,cares for its young,and avoids danger.Predator and Prey.An organisms niche includes how it avoids being eaten and how it finds or captures i

18、ts food.Predators are consumers that capture and eat other consumers.The prey is the organism that is captured by the predator.Cooperation.Individual organisms often cooperate in ways that improve survival.(Ants,bees,etc.)Questions 1.Explain why all consumers depend on producers for food.2.Describe

19、a mutualistic relationship between two imaginary organisms.Name the organisms and explain how each benefits.3.Compare and contrast the terms habitat and niche.4.Think Critically.A parasite can obtain food only from a host organism.Explain why most parasites weaken,but do not kill,their hosts.Perform

20、ance Task Design an experiment to classify the symbiotic relationship that exists between two hypothetical organisms.Animal A definitely benefits from its relationship with plant B,but is not clear whether Plant B benefits,is harmed,or is unaffected.The Census measures a human population.The census

21、has been taken every ten years since the early days of the United States of America.Although the Census Bureau carries out hundreds of surveys every year,its most well-known duty is still to conduct the decennial census.Census results have several high profile applications:they are used to reapporti

22、on seats in the House of Representatives,to realign congressional districts,and as a factor in the formulas that distribute hundreds of billions of dollars in federal funds each year.Because of the importance of this population count,procedural changes in the decennial census often reflect larger or

23、ganizational shifts at the Census Bureau.More about the Census1790Census Day was August 2,1790.Authorizing LegislationThe first census began more than a year after the inauguration of President Washington and shortly before the second session of the first Congress ended.Congress assigned responsibil

24、ity for the 1790 census to the marshals of the U.S.judicial districts under an act which,with minor modifications and extensions,governed census taking through 1840.The law required that every household be visited,that completed census schedules be posted in two of the most public places within each

25、 jurisdiction,there to remain for the inspection of all concerned.and that the aggregate amount of each description of persons for every district be transmitted to the president.EnumerationThe six inquiries in 1790 called for the name of the head of the family and the number of persons in each house

26、hold of the following descriptions:Free White males of 16 years and upward(to assess the countrys industrial and military potential)Free White males under 16 years Free White females All other free persons Slaves Under the general direction of Thomas Jefferson,the Secretary of State,marshals took the census in the original 13 States,plus the districts of Kentucky,Maine,and Vermont,and the Southwest Territory(Tennessee).Both George Washington and Thomas Jefferson expressed skepticism over the final count,expecting a number that exceeded the 3.9 million inhabitants counted in the census.