CYCLES OF LIFE AND BIOMES Cycles within the Environment Decomposers are nature’s recyclers! Decomposers break down dead organisms; this process releases nutrients back into the soil for plants to use. The Nitrogen Cycle Nitrogen is a colorless, odorless gas which makes up about 8/10 of Earth’s atmosphere and is essential for ALL life. Living organisms need nitrogen in order for their cells to function properly. Like water, nitrogen is cycled through the environment. However, most organisms can’t take in nitrogen directly from the atmosphere. Nitrogen compounds are different kinds of chemicals that contain nitrogen and can be taken in by organisms. Nitrogen compounds are the way that most organisms receive the nitrogen they need to survive. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
Nitrogen compounds form in the atmosphere. The heat given off by lightning can cause gases to mix together in the atmosphere, forming nitrogen compounds. Nitrogen compounds reach the Earth’s surface by way of precipitation. Nitrogen compounds can also be made by some types of bacteria in soil. The Nitrogen Cycle Process Nitrogen is taken in by plants through their roots, animals eat plants, and the nitrogen is passed along the food chain to animals. Herbivores get nitrogen by eating plants. Carnivores get nitrogen by eating herbivores. Nitrogen is returned to the soil when an organism dies – decomposers break down the dead organisms and change the nitrogen compounds in the dead organism’s body into the kind plants can use. Then the nitrogen cycle begins again. The Carbon Dioxide Cycle Carbon dioxide is a heavy colorless gas that only makes up 1/100 of the Earth’s atmosphere . Carbon dioxide enters the atmosphere through cellular respiration (the process that involves animals taking in oxygen and breathing out carbon dioxide) and through combustion, which is the burning of materials (like forest fires). Fire takes in oxygen (which makes it burn) and releases carbon dioxide into the air. When dead animals decompose, carbon dioxide is released into the air The Oxygen Cycle Oxygen is a colorless, tasteless, odorless gas which forms about 20% of the Earth’s atmosphere. Oxygen enters the Earth’s atmosphere from plants, through the process of photosynthesis. Oxygen and carbon dioxide are also in water. Carbon dioxide and oxygen dissolve in water and are used by water organisms to live. These organisms in the water use oxygen and carbon dioxide during the processes of respiration and photosynthesis. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
Biomes of the World What is a biome? A biome is a large ecosystem with similar organisms and climate. Here are some examples of biomes. A rainforest is a warm ecosystem made up of many different varieties of plant and animal life which receives large amounts of rain. A deciduous forest is a forest with a cooler climate and not a lot of rain. Grasslands have tall grasses but no trees. This ecosystem receives very little rain…trees need a good deal of rain to grow, which is why they don’t grow here. Taiga is a cold and dry climate. Animals need to have thick fur or feathers to keep warm in this ecosystem. Did you know a desert is not necessarily HOT??? There are hot AND cold deserts and some desserts that are hot during day and cold at night. A desert is known as an area of land that receives less than 25 cm of precipitation each year. It is the lack of water that makes it a desert. The Tundra is a very cold ecosystem that receives little rain. Its soil is frozen most of the year. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.