The Earth’s ecosystems L3 English in Natural Science 自然科学の英語 2006 自然科学の英語-ENS-L3 Ecosystems • Definition: any system where there is interaction between organisms and their environment. • Two components – Biocenosis: all organisms – Biotope: physical medium (land, water, soil, air, etc) • Species linked by a food web – Exchange matter and energy • Size – Microecosystems: soil, bark of a tree – Mesoecosystems: forest, lake – Macroecosystems: valley, region, ocean 2006 自然科学の英語-ENS-L3 Niche • Species occupy a limited ‘niche’ – “multidimensional hypervolume in which the species can maintain a viable population” (Grinnell, 1914; Hutchinson, 1957) – Adaptation to environment • Climate (latitude, altitude) • Chemical factors (air, soil, water) • Biotic factors: other species • Factors determining the niche – Resources: food, light, nutrients – Other: space, time, body size • Generalist = wide, tolerant • Specialist = restricted, sensitive 2006 自然科学の英語-ENS-L3 Species co-existence • Competition food – Two species cannot share the same niche either winner or loser exclude each other A B • Symbiosis – Sharing the same niche agreement – Mutualism, commensalism (Rhizobium nodules and legume plants) 2006 自然科学の英語-ENS-L3 A B B time Food web Losses Input Solar energy Consumers Producers Matter Inorganic matter 2006 自然科学の英語-ENS-L3 Respiration Work Heat Decomposers Terrestrial pyramid Energy loss Increased entropy Reduced biomass Scavengers Predators Phytofagous Herbivorous Vegetation 2006 自然科学の英語-ENS-L3 Aquatic inverted pyramid Phytoplankton Zooplankton Predators Superpredators Scavengers Detritivorous Energy loss Increased entropy 2006 Reduced biomass 自然科学の英語-ENS-L3 Communities • Assemblages of species – Same taxon – Avoid competition • Different niches • Composition – Dominant species – Rare species – Keystone species ‘essential functional role’ – Immigrants • ‘adapt, coexist or leave’ – Dependent species • Symbiotic • Parasites 2006 Tall-grass prairie (Oklahoma,USA) Species % cover Sorghastrum natans 24 Panicum virginatum 12 Andropogon gerardi 9 Ailphium laciniatum 9 Desmanthus illioensis 6 Bouteloua curtipendula 6 Andropogon scoparius 6 Helianthus maximiliana 6 Schrankia nuttallii 6 20 additional species (average 0.8% each) 自然科学の英語-ENS-L3 16 Source: Rice, E.L. 1952. Ecology 33: 112-116 Kinds of vegetation SHAPE Trees Shrubs Herbaceous Mosses Lichens Aquatic plants 2006 自然科学の英語-ENS-L3 Forbs, herbs Grasses Ferns Epiphytes Emergent Floating Submerged Algae Ecosystem types of the World 2006 Terrestrial - Aquatic 自然科学の英語-ENS-L3 Terrestrial ecosystems Biomes: large terrestrial community units dominated by plants • Six major biomes in the World – Desert – Tundra – Grasslands – Shrubland – Savanna - woodland – Forests • Defined in relation to climatic patterns 2006 自然科学の英語-ENS-L3 Iceage Greenhouse 2006 自然科学の英語-ENS-L3 Deserts • • • • 2006 Rainfall: < 250 mm Temperature: -5 to >30 oC Vegetation type: grasses, forbs, shrubs Types: cold (mountain); hot Area: 30 m Km2 (20.5%) 自然科学の英語-ENS-L3 Tundra • • • • 2006 Rainfall: < 1000 mm Temperature: -15 to -5 oC Vegetation type: mosses, lichens, grasses, shrubs Types: arctic (N pole); alpine (mountains) Area: 25 m Km2 (17%) 自然科学の英語-ENS-L3 Grassland • • • • 2006 Rainfall: 250-600 mm Temperature: 2.5 to 15 oC Vegetation type: grasses + forbs = pasture Types: steppe (short); prairie; tropical (tall) Area: 12 m Km2 (8.2%) 自然科学の英語-ENS-L3 Shrubland • Rainfall: 250-600 mm Temperature: 2.5 to 30 oC • Vegetation type: shrubs, grasses, forbs • Types: Mediterranean; temperate; montane; tropical; scrubland (short) • Area: 4.3 m Km2 (3%) 2006 自然科学の英語-ENS-L3 Savanna • • • • 2006 Rainfall: 600-1500 mm Temperature: 5 to 30 oC Vegetation type: trees, shrubs, grasses, forbs Types: woodland (temperate); tropical Area: 25 m Km2 (17%) 自然科学の英語-ENS-L3 Forest • Rainfall: 600-4500 mm Temperature: > -5 oC • Vegetation: all types • Types: taiga; temperate; subtropical; tropical evergreen (perennial); deciduous; mangroves • Area: 31 m Km2 (21%) 2006 自然科学の英語-ENS-L3 Agro-ecosystems • Ecosystems that produce for human consumption • Area: 16 m km2 (11% of total land area) • Two types: cropland (40%); grazing land (rangeland, 60%) 2006 自然科学の英語-ENS-L3 Biome transition cold warm 2006 • Polar icecap • Tundra • Boreal forest (conifers, mixed) • Temperate forest (deciduous) • Mediterranean forest (evergreen) • Shrubland • Desert • Savanna/grassland • Tropical forest 自然科学の英語-ENS-L3 Mountains (European Alps) Continental (Australian bush) 2006 自然科学の英語-ENS-L3 Aquatic ecosystems Dominated by animals of all kinds • Freshwater (3 m Km2; 2%) – Lentic: lakes, ponds – Lotic: streams, rivers – Wetlands: marshes • Saltwater – – – – Estuaries Coastal Coral reefs Oceans • Shallow: continental shelf (benthic) • Deep: pelagic, abyssal 2006 自然科学の英語-ENS-L3 Oceanic ecosystems light darkness 2006 自然科学の英語-ENS-L3 Succession • Ecosystems are dynamic entities, not static • Change in time: from simple to complex grassland shrubland forest • Factors… climate, nutrients, growth, competition, dispersal 2006 自然科学の英語-ENS-L3 Succession patterns • Primary: start from scratch, ‘bare soil’ • Secondary: recovery after damage (I.e. natural disasters, human impact) TIME Trends • Increase total biomass/area • Increase biodiversity more niches available complex structure 2006 自然科学の英語-ENS-L3 Secondary succession • Natural disasters – – – – – Fire Drought Flood Volcanic eruption Diseases • Human impacts – – – – 2006 Deforestation Desertification Grazing Farming • • Resilience of organisms Adaptations – Fire: Banksia sp. cones – Drought: • • short life cycles (annual grasses, freshwater plankton) dormancy (fungi, seeds) – Flooding: mangroves • Renewal of ecosystems – Recovery – Re-colonization – Re-building biome 自然科学の英語-ENS-L3 Recovery • Natural disasters give advantage to best adapted species • Land management: fire favours grass livestock 2006 自然科学の英語-ENS-L3 Successional changes (15,000 yr) glaciers 2006 自然科学の英語-ENS-L3 ICE SHEET Tropical forests Last Ice Age Currently • sea level 100 m down • Less land area sea level UP • boreal forests >> tropical • boreal forests = tropical forest forest 2006 自然科学の英語-ENS-L3 References • Mitchell B. Rambler, Lynn Margulis, Rene Fester. 1989. Global ecology : towards a science of the biosphere / 園芸-緑地植物学 call 460 • Odum, E.P. 1993. Ecology and our endangered life-support systems / 園芸応用動物昆虫学 B-226 • Tokeshi, M. 1999. Species coexistence: ecological and evolutionary perspectives / B-207 2006 自然科学の英語-ENS-L3
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