BIO 1150 1st Edition Lecture 28The structure and distribution of terrestrial biomes are controlled by climate and disturbance- Biomes- major life zones characterized by vegetation type (terrestrial biomes) or physicalenvironment (aquatic biomes)- Climate (temperature, precipitation, wind, etc.) -important in determining why terrestrial biomes are found in certain areasEcology- organisms interacting with environmentTerrestrial Biomes- named for major physical or climatic factors and for vegetation- meld into each other (ecotones)- grass- forest has wide ecotones- aquatic- have narrow ecotoneVertical layering - important terrestrial biome feature - upper canopy (overstory)- low-tree layer- shrub (understory)- ground layer of herbaceous plants- forest floor- and root layerConvergent evolution- similar characteristics arising in distant biomes These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Disturbance and Terrestrial Biomes- Disturbance -changes a community (storm, fire, or human activity)Tropical Forest- Equatorial/subequatorial regions- tropical rain forests-rainfall is relatively constant- tropical dry forests -precipitation is highly seasonal- Temperature is high year-round (25–29C)- Layered vegetation; light competition is intense- High biodiversityDesert- occur in bands near 30 north and south of the equator, and in the interior of continents- Precipitation- low, less than 30 cm per year- Deserts may be hot or coldSavanna- Equatorial /subequatorial regions- Temperature averages (24–29C) and is seasonally variable;- precipitation is seasonal- Grasses and forbs make up most of the ground cover, and tend to be fire-adapted and tolerant of seasonal droughtChaparral- Occurs in mid-latitude coastal regions on several continents- Precipitation is seasonal; cool/rainy winters and springs, and hot dry (30C) summers- Dominated by shrubs, small trees, grasses, and herbs; many plants are adapted to fire and droughtTemperate Grassland- found on many continents- Winters are cold/dry (often below –10C); summers are hot /wet(often near 30C) - The dominant plants, grasses and forbs, are adapted to droughts and fire- Most grasslands have been converted to farmlandNorthern Coniferous Forest (Taiga)- spans northern North America and Eurasia - largest terrestrial biome on Earth- Winters are cold; summers may be hot (e.g., Siberia ranges from –50C to 20C); precipitation variesTemperate Broadleaf Forest- midlatitudes in the Northern Hemisphere, small areas in Chile, South Africa, Australia, and New Zealand- Significant amounts of precipitation fall during all seasons as rain or snow; winters average 0C; summers are hot and humid (near 35C)- Vertical layers are dominated by deciduous trees in the Northern Hemisphere and evergreen eucalyptus in AustraliaTundra- Arctic; alpine tundra exists on high mountaintops at all latitudes- Precipitation-low in arctic tundra, higher in alpine tundra- winters are cold (below –30C); summers are relatively cool (less than 10C)- Permafrost- permanently frozen layer of soil, prevents water infiltrationVegetation is herbaceous (mosses, grasses, forbs, dwarf shrubs and trees, and lichen) and supports birds, grazers, and their
View Full Document
Unlocking...