Biogeography - Geography - Lecture Slides, Slides of Geology

Download Biogeography - Geography - Lecture Slides and more Slides Geology in PDF only on Docsity! Biogeography and Soils The Basis of Life itself Introduction 1. This section covers the ecosystems which we find on Earth and the plants and soil which form the basis of each ecosystem. 2. We examine this living layer over a broad range of size scales to show the intricacy of the food webs which support us and other top predators. Biotic and Abiotic (or non-living) Components* 19-3© 2006 Pearson Education Canada Inc., Toronto, Ontario 19-3 Essentials for Plant GrowthSSWW • Sunlight—Essential for photosynthesis of green plants. Chlorophyll needs certain visible wavelengths. • Soil—The substrate for most plants (some can live in trees). Soil characteristics determine how the temperature and water change with time and depth. • Warmth—The temperature, particularly in the root zone of the soil and at the leaves and flowers. Critical Temperature is usually 5 C, where enzymes begin to function efficiently. Related best to the net radiation, Q*. • Water—The water must both be present and available in the soil. If it is bound too tightly to the soil it may be present, yet unavailable. Eurasian SSWW Suitability* 18-5© 2006 Pearson Education Canada Inc., Toronto, Ontario Figure 18.8 Growing Degree Days (GDDs)  Similar to Melting Degree Days, except use the Critical Temperature Tcritical * as threshold: Tmax + Tmin = Tavg 2 Tavg – Tcritical = daily contribution to the GDD’s. Sum all the GDD’s since last killing frost. *Varies with different plants (usually between 5 and 10 C) Docsity.com Soil Formation • Soil = organic matter (OM) + weathered bedrock • Soil biota and the detrital pathway • Soil horizons • Structure & texture • Cation exchange • Soil air and water soil corn cereal humans worms igneous sedimentary metamorphic planet interstellar dust solar system Soil: that part of the regolith that is heavily influenced by biological processes Detrital food pathway—natural, or artificial (in composters, either home or municipal) nematodes earthworms springtails termites fungi bacteria actinomycetes plant detritus humus SOIL BIOTA Patterns of organic matter accumulation O horizon Ah horizon nutrient cycle Boreal Temperate Tropical Prairie Desert Forest/grassland contrasts in Annual Organic Matter Accumulation shoots 20% roots 80% leaves, etc. 80% roots 20% forest prairie worms rodents, ants Soil Sampling and Mapping Units Figure 18.1 18-12© 2006 Pearson Education Canada Inc., Toronto, Ontario Docsity.com