2.1.1 COMPONENTS OF AN ECOSYSTEM ANDLEVELS OF ORGANIZATION
A group of organismsthat share similarphysical characteristicand genetic traits thatinterbreed and producefertile offsprings. Sea lampreyThe basic unit of ecology ( Petromyzon marinus)or the basic unit of anecosystem.
POPULATION• A group of organisms of the same species living in the same place at the same time and which are capable of interbreeding.
COMMUNITY• A group of populations living and interacting with each other in a common habitat.• Habitat: The environment or place where normally or usually an individual lives.
ECOSYSTEM• A community of interdependent organisms (biotic factors) and the physical environment (abiotic factors) they inhabit.• The environment where biotic factors (living things) interact and abiotic factors ( non living things) are interconnected.
ECOLOGICAL NICHE• Role or funtion of the specie in its environment.• Where it lives ( habitat ), when and how it lives, and what it does (predator – prey relationship, mating, etc.)• For example: The sea lamprey eats fish blood (parasite) and is eaten (probably) by lake trout
KEY CONCEPTSSPECIES-organisms withsimilar characteristicsthat are able toreproduce fertileoffspring.POPULATION-organismsof the same specie thatlive together in a placeand interact with eachother.COMMUNITY-group ofpopulations living andinteracting with eachother.
KEY CONCEPTSNICHE – describes the role ofan organisms or population inits community or ecosystem.In other words, the functionof an organisms in its livingenvironment.HABITAT - is an ecological orenvironmental area that isinhabited by a particularspecies of animal, plant orother type of organism. It isthe natural environment inwhich an organism lives, orthe physical environment thatsurrounds (influences and isutilized by) a speciespopulation.
Key ConceptsEcosystem - Is acommunity ofinterdependent organismsand the physical (abiotic)environment which theyinhabit.Ecosystems may be ofvarying sizes from a dropof rainwater to a forest.Human ecosystems mayinclude a household or aschool or a nation.Ecosystems interact tomake a biosphere.
Key ConceptsBiosphere - is that part of theEarth inhabited by organisms.It is a thin layer that extendsfrom the upper part of theatmosphere down to thedeepest parts of the oceanswhich support life – 11 kmbelow sea level to 10 kmabove.From an ecological point ofview, the biosphere is the"global ecosystem",comprising the totality ofbiodiversity on earth andperforming all manner ofbiological functions, includingphotosynthesis, respiration,decomposition, nitrogenfixation and denitrification.
Abiotic Factors The non-living, physical and chemical components.COMPONENTSBiotic Factors Include:The living components of an • The atmosphere: humidity, temperature range, gases,ecosystem. clouds, air pressure, greenhouse gases, ozone layer, etcLiving organisms or their products that • Climate: light intensity or light exposure; temperaturedirectly or indirectly affect an range; precipitation; humidity; pressure, wind speedorganism in its environment. and direction, etc.Includes organisms such as plants, • Soil structure and chemistry: moisture, pH, nutrients,animals, protista like algae, euglena,amoebas, rotifers, diptera, etc, in components, temperature, etcgeneral phytoplankton and • Water chemistry: pH; salinity; dissolved nutrients;zooplankton. Also fungi like dissolved oxygen, turbidity, etcmushrooms, yeasts, and molds. • SeasonalityBacterias and archae too. But is alsoincludes predation, parasitism, • Level of pollutantscommensalism, mutualism, etc.Biotic factors interact as: producer,consumer, detritivore, scavenger,decomposer, parasite, host, predator,prey, competitor, herbivore, carnivore,omnivore, mutualist, and pathogen.
• Case study in commercialLIMITING FACTORS farming.Factors that prevent the growth In Scotland, until the 1970´s, large areas ofor limit the size of a population, a scottish blanket blog were viewed as a place forcommunity or organism growing commercial forestry operations. It was too wetlarger. for Sitka Spruce, the predominant cash wood crop to grow and too expensive toBiotic factors such as predation or drain. Then it was discovered that if a nurse cropcompetition or parasitism are of lodgepole pine was planted ahead of the Sitka,limiting factors. even though the lodgepole pine would die in the very wet conditions, they would dry the soilmAbiotic factors such as nutrients, enough to allow the Sitka to succeed. Thus, thesoil chemistry, water quality, drying of the area and closing in of the canopydissolved oxygen, temperature, trees with trees planted very close in rows wouldetc can restrict the growth of prevent growth of sphagnum moss.population. Lodgepole pine Sphagnum moss Sitka spruce