Unit 8: Ecology: Ecosystems and Communities An ecosystem consists of all the __plants_________ and ___animals______ that ____interact_______ with the ____nonliving______ things in an area. ____Biosphere________ = area on Earth where living things are found Biosphere is divided into __biomes______ that have ___different_______ types of plants, animals and ___climate______ conditions. Climate Matters! ___Weather_____ is the day-to-day conditions in a particular ___time____ and ___place___. ___Climate______ is the ___average_______ year-to-year conditions of both ___temperature_____ and ____precipitation______. Climate determines the types of ___plant______ species that live in an area – which then determines the types of __animals________ that will live there! Our atmosphere acts like an ___insulating______ blanket to keep the temperature relatively ___stable____ in the biosphere. __CO2____, __methane (CH4)______ and __H2O___vapor trap ___heat______ energy to help maintain the temperature. This ‘blanket’ keeps the Earth about __30ºC_____ warmer than it would be without the atmosphere. Greenhouse Effect The gases in the atmosphere act like __windows_____ in a greenhouse:

Biomes The ___temperature_________, amount of ___sunlight______ and ___precipitation________ determine the ___plants_____ and __animals______ that live in an area.

The more species that live in an area, the higher the ___biodiversity_________ (or ___variation_______!) The higher the biodiversity, the ___healthier_____ the ecosystem. Marine = ___high_______ biodiversity Tropical Rainforest = ___high______ biodiversity Savannah = ___medium_____ biodiversity Desert = ____low______ biodiversity Temperate Grassland = ___medium_____ biodiversity Temperate Deciduous Forest = __high_______ biodiversity Coniferous Forest (Taiga) = ___medium_____ biodiversity Tundra = ___low_______ biodiversity Biotic and Abiotic Factors Biotic = all the ___l iving_______ things in an ecosystem. (__plants________, ____animals______, ___fungi_________, __decomposers________) Abiotic = all the ___nonliving_____ things in an ecosystem. (____climate_______, ____precipitation____, ___temperature________, ____nutrients____) Habitats and Niches A habitat is the __area_____ where an organism ___l ives_______. A niche is the __role_______ an organism plays in the ecosystem – the ___physical________ and _____biological______ conditions in which an organism lives and how it __uses_____ those conditions. Producer = use the __sun’s_____ energy to do ___photosynthesis______ and __make____ their food. (Also called __autotrophs_________...) Consumer = can’t harness the sun’s energy directly, so they must ___consume_______ (__eat____) other organisms for food. (Also called _____heterotrophs________...) __Herbivores_________ eat only ____plant_______ material ___Carnivores________ eat only ____animal______ material ___Omnivores________ eat both ____plant______ and ____animal_____ material ___Detritovores_______ eat only ____dead______ matter ___Decomposers___________ are the ___bacteria______ and ______fungi____ that break down ___dead______ material and return ____nutrients______ to the ecosystem! An organism’s niche can include:

• Range of ____temperatures_______ needed for survival

• ___Food______ the organism ____eats_______

• ___Reproductive________ cycle

No two ___species____ can share the same ____niche____ in the same _habitat_______ at the same ____time_____. Ever. ___Similar______ yes – the __SAME______ NO!!!

Levels of Organization Smallest unit is the __individual_________. All the members of the same ___species______ in an area is called a ____population________. All the populations living in an area is called a ___community_______. All the biotic and abiotic factors in an area is the ___ecosystem__________. Community Interactions: 1. ___Competition______ occurs when organisms of the ___same______ or ___different____ species attempt to use the same __l imited______ resources. ( ___food____, _____water______, ___space_______, ______shelter______.) The more __similar_________ the organisms, the more _____competition______ between them – and there is ALWAYS a ___winner______ and a _____loser_____. 2. ___Predation___________ occurs when one organism ___catches________ and __eats__ another for food. The ___predator________ eats – the ____prey______ is eaten. **Generally the predator has __adaptations_________ to ___catch_______, while the prey species has ___adaptations______ to ___escape________ or ____hide______!*** 3. __Symbiosis__________ is a relationship between ___2__ species that live ____closely____ together. __Mutualism__________ = both species _____benefit______ from the arrangement. Examples: ___Lichens________, ___Ants_______ and their ___aphid_____ _____l ivestock________, __bees______ pollinating __flowers________.

___Commensalism_________ = one species is ___helped______ and the other is neither helped nor __harmed_______. Example: __barnacles_________ that ride on _____whales________ or ___clown_________ fish and ____anemones_______.

___Parasitism_________ = one species is ___helped_______ while the other is ____harmed_______. Examples: __fleas______, ____ticks_______ and ____l ice____.

Population Dynamics Population __Density_______ = the ___number_______ of individuals per unit ___area__. Example: ___people_______ per square ____mile______

Population __Growth____ = affected by ___birth_______ and ____death______ rates, individuals __entering_______ or ___leaving______ population. If births are ___greater_____ than deaths, population will ____grow_____. If births are ___equal_______ to deaths, population is ___stable________. If births are ___less_________ than deaths, population will ____decrease_______. Immigration = organisms ___entering_____ population Emigration = organisms ____leaving_____ population Methods of Growth Exponential Growth: only found in populations with __ideal______ conditions and ____unlimited________ resources. (**Not ___realistic_______.) When graphed, is called a ____”J”___ curve.

Logistic Growth: a ___realistic_______ model – as ___resources________ become less available, growth ___slows______ or __stops______ -- following a period of ___exponential_________ growth. When graphed, is called an ___”S”_ curve.

Population grows until it reaches a __maximum_______ number of individuals that can be ___supported________ by the available resources. The growth rate ___stops_____ and the population will maintain this ___number_______ -- called the _____carrying capacity________. Carrying capacity may be exceeded ____temporarily_______ -- but some will ___die___ from lack of ___resources______ -- so the total population will remain close to the ____carrying_______ ______capacity____.) A ___l imiting_______ factor causes population growth to ____decrease_______. Density-Dependent Factors: These become limiting only when population ___density_____ reaches a certain ____level______.

• __Competition________: for ____l imited______ resources

• ___Predation______: the ___predator_______/______prey____ relationship maintains ___balance______

• ___Parasitism_______ or ____disease_______: similar to __predation_____, but the ___parasite________ depends on the ___host______ for ____survival____.

Density-Independent Factors: affect ___ALL__ populations, regardless of population __size______.

• __Weather________, natural ____disasters_____, seasonal __cycles_____, human __activities______ (____damming_______ rivers, _____clear-cutting______ forests)

• Populations usually show a dramatic ___crash_______, but __MAY____ eventually ___recover_______.

Human Population Growth: Developed countries (like the U.S.) usually show __slow______ growth patterns. But ___developing_______ countries can have birth rates as high as ___3 people/second_______!) Humans have almost an __exponential______ growth curve, and we haven’t hit our ___carrying capacity___________ yet. It is estimated that by ___2050____, world population will reach _____9 billion________! Why so high? (*THINK*) Advances in ____medicine_______, ____agriculture_________ and ___sanitation______ have allowed more people to ____survive______ and live ___longer_____. Demographics Demographics is the scientific study of ___human___ populations. Scientists look at ___birth_______ and ______death____ rates, as well as the ___age___ structure of the population. This information helps scientists make ___predictions_____ about the growth of that population.

Humans CANNOT maintain this growth rate ____indefinitely_______ -- even humans have a _____carrying capacity________.

Growing ___quickly______! Birth rates much _greater_______ than death rates – child-bearing population very ___large______.

Growing ____slowly______ Birth rates ___sl ightly_____ greater than death rates.

___Litt le_____ to no ___growth______. Birth rates ____equal____ to death rates.