Chapter 8 The Biosphere The biosphere The layer

Chapter 8 The Biosphere

The biosphere The layer around earth containing all living organisms

The biosphere consists of all living organisms and their habitats The atmosphere, hydrosphere and lithosphere all part of the biosphere since organisms can live in each of those spheres Examples: worms (lithosphere), fish (hydrosphere), skunks (atmosphere)

Chemical recycling For life to be possible, we need chemicals elements These chemicals are continually recycled and we call this process “biogeochemical cycles” These cycles move nutrients from the environments into living materiel and back again

Biogeochemical cycles What chemicals are recycled? Carbon, hydrogen, oxygen, nitrogen, phosphorus and sulphur Found in soil, rocks, atmospheric gases and in the tissues of plants and animals

Biogeochemical cycles Defined: the process where an element goes from one environment to another and returns again. We will study the carbon cycle and the nitrogen cycle You have already studied the water cycle (grade 7 & 8)

The carbon cycle http: //www. youtube. com/watch? v=vr. Dekm. Rb BVk&feature=player_embedded

The carbon cycle Carbon is the basic building block of many important complex molecules such as proteins, lipids and carbohydrates Carbon is also part of carbon dioxide and methane (gases found in the atmosphere) Carbon atoms are constantly being exchanged between living organisms, dead organisms, the atmosphere, oceans, rocks and soil

Carbon cycle p. 256 -257 Study this diagram! Understand each of the steps 1 -9 Photosynthesis, respiration, ingestion, decomposition, forest fires, shells & skeletons, carbonate rocks, volcanic eruptions, fossil fuels

Impact of human activity Humans have upset the natural balance of the earth’s carbon cycle by burning fossil fuels

The nitrogen cycle http: //www. youtube. com/watch? v=DP 24 Bce. O wt 8

The nitrogen cycle Nitrogen is used to make proteins, like DNA Most organisms cannot use the nitrogen gas found in the atmosphere (N 2) Specific bacteria is required to convert the nitrogen into ammonia, ammonium, nitrites and nitrates The conversion happens in the lithosphere and in the hydrosphere

Impacts on the nitrogen cycle Many factors can alter the nitrogen cycle Temperature, humidity, p. H and most importantly human activities Too much nitrogen from fertilizers can alter the soil balance Not enough nitrogen is also a problem, unless you are a carnivorous plant

Carnivorous plants http: //www. youtube. com/watch? v=kt. IGVt. Kdg wo Homework p. 280 #1 -6 Next topic: Biomes page 262 -279