Ecosystems and Organisms

What Are The Three Most Important Aspects of Organisms in an Ecosystem? Populations Relationships Evolution Populations Relationships Evolution

Populations Definition: The simplest grouping of organisms in nature. Populations depend on: Resources Births Deaths Immigration Emigration Definition: The simplest grouping of organisms in nature. Populations depend on: Resources Births Deaths Immigration Emigration

Resources Limited resources such as food, water and living space will result in a population that levels off - carrying capacity. This graph shows the growth of a yeast population in culture. After a period of exponential growth, the size of the population begins to level off and soon reaches a stable value. This type of growth curve is called an S-shaped graph Limited resources such as food, water and living space will result in a population that levels off - carrying capacity. This graph shows the growth of a yeast population in culture. After a period of exponential growth, the size of the population begins to level off and soon reaches a stable value. This type of growth curve is called an S-shaped graph

If unlimited resources and growth this will result: Exponential graph or J curve Resources Cont…

Factors Affecting Birth Rates Age of reproduction Number of females Number of females at reproductive age Amount of offspring produced if high infant mortality rate Amount of time spent in raising and protecting young. Age of reproduction Number of females Number of females at reproductive age Amount of offspring produced if high infant mortality rate Amount of time spent in raising and protecting young.

Death There are three types of organisms: Type 1- high survival rate (low death rate) in the beginning of a life time then faster death rate at the end Type 2 - fairly even mortality rate. Type 3- High death rate in the beginning, then levels off at the end. There are three types of organisms: Type 1- high survival rate (low death rate) in the beginning of a life time then faster death rate at the end Type 2 - fairly even mortality rate. Type 3- High death rate in the beginning, then levels off at the end.

Immigration and Emigration The population will increase or decrease depending on the amount of organisms entering or leaving the area. rchives/Multimedia.aspx?Category =MT&Filter=27http:// rchives/Multimedia.aspx?Category =MT&Filter=27 The population will increase or decrease depending on the amount of organisms entering or leaving the area. rchives/Multimedia.aspx?Category =MT&Filter=27http:// rchives/Multimedia.aspx?Category =MT&Filter=27

Relationships Predator prey - As the predators go up or down so does the prey

Relationships cont.. Symbiosis- organisms living in direct contact with each other. Mutualism- both benefit Commensalisms - one benefits and the other is not harmed Parasitism - one benefits and the other is harmed Symbiosis- organisms living in direct contact with each other. Mutualism- both benefit Commensalisms - one benefits and the other is not harmed Parasitism - one benefits and the other is harmed

Competition Intraspecific competition- competition between organisms of the same species. Interspecific competition- competition between organisms of different species. obalchange1/current/lectures/competiti on/competition.htmlhttp:// obalchange1/current/lectures/competiti on/competition.html Invasive species and competition, may cause competition exclusion. Intraspecific competition- competition between organisms of the same species. Interspecific competition- competition between organisms of different species. obalchange1/current/lectures/competiti on/competition.htmlhttp:// obalchange1/current/lectures/competiti on/competition.html Invasive species and competition, may cause competition exclusion.

Evolution Evolution Adaptive behavior, physiology, and anatomy from genetic change can result in increased reproduction and ability to survive. Coevolution - when two or more species influence each others evolution. o101/IIIF1Casestudyofcoevo.shtmlhttp://evolution.berkeley.edu/evosite/ev o101/IIIF1Casestudyofcoevo.shtml cators/course/session4/elaborate_d.htm lhttp:// cators/course/session4/elaborate_d.htm l Adaptive behavior, physiology, and anatomy from genetic change can result in increased reproduction and ability to survive. Coevolution - when two or more species influence each others evolution. o101/IIIF1Casestudyofcoevo.shtmlhttp://evolution.berkeley.edu/evosite/ev o101/IIIF1Casestudyofcoevo.shtml cators/course/session4/elaborate_d.htm lhttp:// cators/course/session4/elaborate_d.htm l

Human Population The human population continues to grow exponentially, why? alance/numbers.htmlhttp:// alance/numbers.html tion.htmhttp:// tion.htm s/biology/units/humev/images.htmlhttp:// s/biology/units/humev/images.html The human population continues to grow exponentially, why? alance/numbers.htmlhttp:// alance/numbers.html tion.htmhttp:// tion.htm s/biology/units/humev/images.htmlhttp:// s/biology/units/humev/images.html