LU5 ECOLOGICAL DIVERSITY

 A biome is a large, relatively distinct ecosystem that is characterized by similar climate, soil, plants and animals, regardless of where it occurs.

 A biome’s boundaries are determined by climate more than any other factor.  Biomes are distributed in accordance with two factors: (1) Temperature and (2) Precipitation

 Treeless regions found in the Arctic and on the tops of mountains, where the climate is cold and windy and rainfall is insufficient.  Average temperature is -12 to -6 o C  The summer growing season is just 50 to 60 days, when the sun shines 24 hours a day.

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 Mediterranean climates  Mild winter (10 o C); hot and dry summer (40 o C)  Chaparrals can be found from 30° to 50° N and 30° to 40° S latitudes.

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 Two different types of grasslands; (1) tall-grass, which are humid and very wet, and (2) short- grass, which are dry, with hotter summers and colder winters than the tall-grass.  Grassland biomes can be found in the middle latitudes, in the interiors of continents. In Argentina, South America, the grasslands are known as Pampas.

 There is a large area of grassland that stretch from the Ukraine of Russia all the way to Siberia. These are known as the Russian and Asian steppes.  In North America, the grasslands are known as prairie.

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 Coniferous forest which stretches across North America and Eurasia.  Winters are extremely cold but less harsh than tundra  Precipitation ~500 mm annually  Acidic, mineral poor soil

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 Dry areas found in both temperate and tropical regions.  Annual precipitation <250 mm  Plant cover is spotty, and much desert soil is exposed  Plants tend to have reduced/absent leaves

 Other desert plants shed their leaves for most of the year, growing only during the brief moist season From left: Baja, Mexico desert; desert in Uluru National Park, Australia; desert near the Kofa Mountains, Arizona. Source:

 Altitude of about 10,000 feet or more.  Cold, snowy, windy.  At high altitudes there is very little CO 2, which plants need to carry on photosynthesis.  Because of the cold and wind, most plants are small perennial groundcover plants which grow and reproduce slowly.

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 Warm and humid all year round  Annual precipitation mm  Highly weathered, mineral-poor soil  Minerals of tropical rain forests are tied up in the vegetation, rather than in soil

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 Element of climate in the temperate evergreen forest is precipitation: at least 2000 mm annually  The main stretch of this habitat is along the northwestern coast of North America from northern California though southern Alaska. There are also small areas in southern Chile, New Zealand, Australia and a few other places around the world

 Species: Big coniferous trees, deciduous trees, mosses and lichens, ferns  Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower.

Temperate evergreen forest in New Zealand Source:

 Hot summers and cold winters  Annual precipitation: mm  Covers most of the eastern part of the United States and a small strip of southern Ontario.  The dominant plant species of the biome are broad-leaved deciduous trees.

 8 major forest regions: (1) mixed mesophytic, (2) Appalachian oak, (3) hemlock-white pine- northern hardwoods, (4) oak-hickory, (5) maple- basswood, (6) beech-maple, (7) oak-pine, and (8) southern pine.

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 An ecosystem is much smaller than a biome.  An ecosystem can be as large as the Sahara Desert, or as small as a pond.  Ecosystem- individual communities and their abiotic environments.

 Ecosystems are dynamic interactions between plants, animals, and microorganisms and their environment working together as a functional unit  Ecosystems will fail if they do not remain in balance

 Food and territory are often balanced by natural phenomena such as fire, disease, and the number of predators  Ecological pyramids help us understand how ecosystems work: (1) Pyramid of numbers, (2) Pyramid of biomass, (3) Pyramid of energy

 Pyramid of numbers  Based on the number of organisms at each trophic level  Producers > primary consumers > secondary consumers Source: Tertiary consumers Secondary consumers Primary consumers Producers

 Pyramid of biomass  Based on biomass at each trophic level and typically resembles pyramid of numbers Source:

 Pyramid of energy  Producers > primary consumer > secondary consumer > tertiary consumer Source:

 The living things in an ecosystem. Eg. pond communities.  Major roles of organisms in communities  (1) Producers, (2) consumer, (3) decomposer  In a community, there are:  predation (Prey and predator),  symbiosis: mutualism, commensalism, parasitism

 The special place in a community in which a plant or animal lives is called its habitat  The ecosystem can be considered the neighborhood where an animal lives, and the habitat would be its address in that neighborhood  Within a community there are many habitats. Eg. forest.  The habitat of an animal supplies it with everything it needs to survive – food, water, and shelter  Some animals are able to live in more than one habitat. Others are not. Some are very limited in their habitats

 The ecological role and space that an organism fills in an ecosystem.  The ecological niche involves:  place where an organism lives  roles that an organism does in its habitat.  Eg. ecological niche of a sunflower growing in the backyard includes:  absorbing light, water and nutrients (for photosynthesis),  providing shelter and food for other organisms (e.g. bees, ants, etc.)  giving off oxygen into the atmosphere.

 Ecosystem management is the skillful, integrated use of ecological knowledge at various scales to produce desired resource values, products, services, and conditions in ways that also sustain the diversity and productivity of ecosystems

 Ecosystem management goals (Grumbine, 1994):  Maintain viable populations of all native species in situ  Represent, within protected areas, all native ecosystem types across their natural range of variation  Maintain evolutionary and ecological processes (i.e. hydrological processes, nutrient cycles, etc.)  Manage over periods of time long enough to maintain the evolutionary potential of species and ecosystems  Accommodate human use and occupancy within these constraints.

 Any species that is in danger of becoming extinct throughout all or a significant portion of its geographical range