14.2 Community Interactions Section 14.2 KEY CONCEPT Organisms interact as individuals and as populations.

14.2 Community Interactions Two ways organisms interact: Competition and predation Competition: two organisms fight for a resource. Predation: one organism captures and eats another. The predator population depends on the prey population for survival

14.2 Community Interactions (1) Mutualism: both organisms benefit Symbiotic Relationships: LIVING TOGETHER Cactus provides fruit for bat to eat. Bat spreads cactus seeds.

14.2 Community Interactions (2) Commensalism: one organism benefits, the other is unharmed Human Our eyelashes are home to tiny mites that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle. Demodicids Eyelash mites find all they need to survive in the tiny follicles of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. + Organism benefits + Ø Ø Organism is not affected Commensalism

14.2 Community Interactions (3) Parasitism: one organism benefits, the other is harmed Organism benefits 0 _ Organism is harmed Hornworm caterpillar The host hornworm will eventually die as its organs are consumed by wasp larvae. Braconid wasp Braconid larvae feed on their host and release themselves shortly before reaching the pupae stage of development. _ Parasitism + 0

14.2 Community Interactions KEY CONCEPT Biomes are land-based, communities of organisms plus climate. Biomes are identified by their abiotic factors & ecological community.

14.2 Community Interactions Earth has six major biomes.

14.2 Community Interactions (1) Tropical rain forest biomes produce lush forests. –warm temperature –abundant precipitation all year Source: World Meteorological Organization

14.2 Community Interactions –Temperate grasslands are dry and warm during the summer; snow in winter. (2) Grassland biomes:primary plant life is grass. –Tropical grasslands are warm through the year, with dry and rainy seasons.

14.2 Community Interactions (3) Desert biomes are characterized by a very arid climate. –very little precipitation –four types: hot, semi- arid, coastal, and cold Tucson, Arizona Source: National Oceanic Atmospheric Administration

14.2 Community Interactions –Temperate rain forests have a long wet season and dry summers. (4) Temperate forest biomes have seasons. –Temperate deciduous forests have hot summers and cold winters.

14.2 Community Interactions (5) The taiga biome is located in cooler northern climates. –forests –long winters and short summers –little precipitation Source: Environment Canada Banff, Canada

14.2 Community Interactions (6) The tundra biome is found in the far northern latitudes with long winters. –winter lasts 10 months –limited precipitation –permafrost Barrow, Alaska Source: National Oceanic Atmospheric Administration

14.2 Community Interactions Polar ice caps and mountains are not considered biomes. Polar ice caps have no soil, therefore no plant community. The climate and organisms found on mountains change as the elevation changes.

14.2 Community Interactions Nevada has four Bioregions 1.Sierra Nevada 2.Mohave Basin & Range 3.Central Basin & Range (Great Basin) 4. Northern Basin & Range Bioregion: area that contains unique geologic, hydrologic and biological characteristics Compared to most states Nevada ranks near the top ten in biodiversity.

14.2 Community Interactions Sierra Nevada Mountain range bordering California Mostly granite (igneous rock cooled slowly) Alpine forest with several species of conifers, deer, fox, mountain lions, and jackrabbits.

14.2 Community Interactions Mojave Basin & Range Desert that touches CA, AZ, UT, southern NV “High Desert” (3,000-5,000 feet) 10” water Death Valley (lowest, hottest place) is here Joshua tree, sage, cactus, scorpions, rattlesnakes, lizards, hawks, deer, cougar

14.2 Community Interactions Central Basin & Range Central Nevada (68% of the state) This bioregion makes up majority of the state Valleys = basins, Mountains = ranges Pacific & N. American tectonic plates pulling apart here; some of thinnest crust on Earth The shifting tectonic plates create thin crust Wetter, cooler than Mojave Sagebrush, salt tolerant plants, pinyon, juniper, rabbits, hares, deer, mountain lions, etc.

14.2 Community Interactions Northern Basin & Range Northern NV into OR and UT Volcanic plateaus Grasslands, aspen forest Deer, cougar, coyote, eagle, lizards, etc.

14.2 Community Interactions Nevada Bioregions