Transcript Slide 1
Life: levels of organization – organism (individuals): any form of life – population: a group of interacting individuals of same species – community: populations of different species in given area – ecosystem: community + non–living environment (e.g. nutrients) – biome: an ecosystem that covers a large geographic area where plants of certain types live due to the specific climate in the area Temperate deciduous forest BIOME Biomes • Regions of the earth that are similar in organism type although the particular species differ • Driven largely by climate – temp., water, seasonality • Other factors – soil, topography Fig. 50.10 – Biomes of North America The Major Biomes • Tundra • Taiga – the boreal forest • Temperate forest, including deciduous and conifers • Savanna • Rain forest – temperate and tropical • Grasslands • Deserts 22.5 °C 5 °C 40 °C Bioclimatic tolerances The survival, growth, & reproduction of organisms is determined, in part, by maximum & minimum tolerance limits for physical conditions such as temperature (bioclimatic tolerances). Temperature • Temperature is partly determined by the amount of solar radiation hitting an area • Depends on latitude, angle of incidence Fig. 50.11 World biomes Fig. 50.24 Tropical Rain Forest • Most diverse biome • Characterized by tall trees, a dense canopy and vines • Exploited and endangered - half of this biome has been destroyed for cash crops despite poor soil • 90-100” rain/year Desert • Deserts cover 1/3 of the earth’s surface and are spreading because of overgrazing • Vegetation includes cacti and thorny bushes • <10” rain/year Grassland • Most has been converted to farmland due to rich soils • Good for crops and grazing animals • 10-30” rain/year Temperate Deciduous Forest • Most exploited biome • Only about .1% of original forest remain • This is our biome • 30-80” rain/year Coniferous Forest (Taiga) • Logging has stripped many parts of this biome • Vegetation primarily evergreen trees • 15-40”rain/year Taiga Forests & Boreal Climate Coniferous forests occur where winter temperatures are low and precipitation is abundant. Tundra • Vegetation limited, mostly lichens, moss and grasses • Not enough precipitation for trees • “permafrost” frozen soil • <10”rain/year Tundra Vegetation Extremely short growing seasons keep woody vegetation short and scattered, with ground cover is comprised mostly of mosses and lichens. October 2006 27 current climate modeled future climate possible vegetation shifts under global warming in North America Vertical Climate Change Ascending a mountain brings changes in temperature and precipitation, and so to will bring changes in vegetation types and micro-climates, as illustrated in this sketch that moves from grassland to tundra and icecap across a short distance of 180 km, and up a steep elevation of 4 km. Species dispersal Species may not inhabit an area because of biogeographical boundaries. Transplantation studies can give us information about potential ranges. Fig. 50.6 Arctic vegetation-climate feedbacks Describe this diagram in words 12/1/06 Chapin et al. 2005 34