BIOSPHERE AND BIOMES 14 AUGUST 2013

Transcription

1 BIOSPHERE AND BIOMES 14 AUGUST 2013 Lesson Description In this lesson we: Discuss the concept of the biosphere Look at the interconnectedness with components of the global ecosystem: lithosphere, atmosphere and hydrosphere Discuss the terrestrial and aquatic biomes of Southern Africa Key Concepts The Biosphere The part of the planet that supports life e.g. atmosphere(air), lithosphere (land) and hydrosphere(water The Lithosphere The lithosphere is the solid, rocky crust covering entire planet. This crust is inorganic and is composed of minerals. It covers the entire surface of the earth. This is where terrestrial organisms live The shape of the land surface is called its topography. A thin layer of soil supports life. Soil is formed from weathered rock The soil provides plants with nutrients and water to support all the organisms in a food chain The Atmosphere The atmosphere is the body of air which surrounds our planet. Most of our atmosphere is located close to the earth's surface where it is most dense. The air of our planet is 79% nitrogen and just under 21% oxygen; the small amount remaining is composed of carbon dioxide and other gasses. The atmosphere consists of five layers of gases that support life and protect us from harmful radiation from the sun

2 The Hydrosphere The hydrosphere is composed of all of the water on or near the earth. This includes the oceans, rivers, lakes, and even the moisture in the air. Ninety-seven percent of the earth's water is in the oceans. The remaining three percent is fresh water; three-quarters of the fresh water is solid and exists in ice sheets Aquatic organisms depend on the hydrosphere for life Interconnections of the Spheres The lithosphere, hydrosphere and atmosphere form the biosphere. The soil, water and air support life on earth. Life on earth is linked in each of the three spheres. All four spheres can be and often are present in a single location. For example, a piece of soil will of course have mineral material from the lithosphere. Additionally, there will be elements of the hydrosphere present as moisture within the soil, the biosphere as insects and plants, and even the atmosphere as pockets of air between soil pieces. There are two components to the biosphere o A biotic or living component animals, plants microorganisms etc. o An abiotic or non-living component water air temperature, soil etc. o The biotic and abiotic factors of the biosphere form the global ecosystem Living organisms are not evenly distributed throughout the biosphere. Scientists have divided the earth into regions according to their climate, soil, plants and animals that live their these regions are called biomes Biomes are sub-divided into ecosystems. Ecosystems are communities of organisms that interact in a particular environment. An organism lives in a certain place where it gets its food, space and where it reproduces this is called its habitat Scientists divide biomes into : o Terrestrial biomes that occur on land grasslands, savannah, fynbos o Aquatic biomes - marine, wetlands, coastal

3 South African Biomes Aquatic Marine and Coastal Biomes Include oceans, coral reefs and estuaries Biomes include salty water. Algae live in the water and produce oxygen and food South African marine biome contains 12% of the worlds fish species. Our coastline is 3000km long Water on the east coast is warm because of the warm Indian current and the water on the waest coast is cold because of the Benguela current. The west coast water are rich in nutrients which provides food for plankton and fish Organisms Plankton- phytoplankton (algae), zooplankton (microscopic crustaceans) fish and large fish sharks, dolphins, whales animals living on the bottom crabs, oysters, sponges, lobster etc. Organisms have to endure various abiotic factors: o Saltiness o Ocean currents and waves o Oxygen variation o Variations in sunlight o Depth and temperature of water o Concentration of nutrients Coral Reefs Shallow waters off the northern coast of Kwa-Zulu Natal Coral reefs are formed from calcium carbonate of tiny corral animals Large biodiversity Animals micro-organisms, invertebrates, fish, sea urchins, sea-stars, octopusi Open Sea Zone Open ocean Temperature is generally cold Plankton main food provider for fish, dolphins and whales

4 Wetlands Area of land which is covered predominately by shallow water. Include mountain springs, marshlands, flood plains, estuaries to swamp forests that are linked by river and streams. Rich in biodiversity: o Birds o Large amount of carbon o These wetlands share common and important functions in river catchments by providing a regular water supply, by filtering the water naturally o By reducing the effects of floods and droughts. Estuaries Are areas where freshwater of streams or rivers meet with the salt water of the sea Water conditions, temperature and salt content, change constantly with the tides Rich in nutrients Plants algae, seaweed, marsh grass and mangroves Animal prawns, sponges, mussels, barnacles, crabs Important Terms Biosphere Ecosystems Aquatic Lithosphere Biodiversity Terrestrial Atmosphere Biomes Estuary Hydrosphere Endemic

5 Questions Question 1 Study the map below where South Africa s terrestrial biomes are indicated with the letters A to G and answer the questions that follow a.) Define the term biome b.) Identify the biomes A-F c.) Which biome is a main tourist attraction during spring, when the whole area is covered with flowers? d.) Which biome includes one of the world s richest floral kingdoms? e.) Which biome attracts tourists to its many game farms? f.) Which biome is the largest? g.) Which biome will you find the following plant species? i. Vygies, quiver trees ii. Yellowwood and stinkwood iii. Mopani and baobab iv. Proteas, ericas and reeds Links Maps - edlist.sanbi.org/stats.php gs