1.2 Nutrient Cycles and Energy Flow p. 22-32

The Water Cycle &The Carbon Cycle & The Nitrogen Cycle Biogeochemical Cycles - The movement of matter through the biotic and abiotic environment. Examples: The Water Cycle &The Carbon Cycle & The Nitrogen Cycle Nutrients: substances made of elements that an organism use to build and repair the cells of its body

The Water Cycle Liquid water evaporates and rises into the atmosphere The water vapour condenses, forming liquid water or ice crystals (depending on the air temperature) and returns to the earth as rain, hail or snow Water falling on land may enter the soil and ground water or move across the surface entering lakes, rivers, and oceans.

The Water Cycle Water that is taken in by plant roots may be released from leaves through transpiration Animals take in water when they drinking or consume food. Water is returned to the environment from skin (perspiration), from lungs (exhaled) and in wastes Most of the water that is present in the water cycle is in the abiotic environment

The Water Cycle

Bill Nye Water Cycle Video.mp4

Magic School Bus Water Cycle Video.mp4

Why is nitrogen important to life? The Nitrogen Cycle Why is nitrogen important to life?  ALL organisms need nitrogen to make proteins Plants and animals could not live without nitrogen. It is an important part of many cells and processes such as amino acids, proteins, and even our DNA. It is also needed to make chlorophyll in plants, which plants use in photosynthesis to make their food and energy. 

Nitrogen makes up 78% of the atmosphere but cannot be used DIRECTLY by most organisms Get most from ammonia; converting nitrogen gas to ammonia is called nitrogen fixation Bacteria do this and without them nitrogen cycling would stop Lightning is the only other natural nitrogen fixing process (only 1% of world’s nitrogen fixing)

Processes in the Nitrogen Cycle Fixation: is the first step of making nitrogen usable by plants. Here bacteria change nitrogen into ammonium. Nitrification: ammonium gets changed into nitrates by bacteria. Nitrates are what the plants can then absorb. Assimilation: is how plants get nitrogen; they absorb nitrates from the soil into their roots. Then the nitrogen used Ammonification: decaying process; when a plant/animal dies, decomposers like fungi and bacteria turn the nitrogen back into ammonium so it can reenter the nitrogen cycle. Denitrification - Extra nitrogen in the soil put back out into the air by other bacteria

The Carbon Cycle All life based on carbon. Building block of all living things. Present as CO2 in the atmosphere and dissolved in the oceans.

The Carbon Cycle Relationship between photosynthesis and respiration. During photosynthesis, plants use CO2 to produce sugar During respiration, consumers eat the plants and release CO2 back into the atmosphere.

PHOTOSYNTHESIS (sugar) CO2 + H2O + light energy  C6H12O6 + O2 CELLULAR RESPIRATION C6H12O6 + O2  CO2 + H2O + energy

Plants use CO2 to make food, so carbon is now in the PRODUCERS. Here’s how it works…. Carbon (as CO2) is in the atmosphere or water. DECOMPOSERS break down dead plants & animals, returning CO2 to the atmosphere or water. Plants use CO2 to make food, so carbon is now in the PRODUCERS. Herbivores eat plants and carnivores eat herbivores, so now carbon is in the CONSUMERS. Plants & animals respirate, which returns CO2 to the atmosphere or water.

Figure 4, p. 50

Carbon Deposits Most of the earth’s carbon is not cycled – it is stored in carbon rich deposits. Earth’s Crust/Soil Layers of bones & shells from living things form rock. This carbon can be trapped for millions of years until geological conditions release it (erosion, volcano). Fossil fuels (coal, oil, and natural gas) are most valuable carbon deposits

Energy Flow in Ecosystems

THE SUN Source of all energy for ecosystems Plants use the sun’s energy for photosynthesis (to make food, which later serves as an energy source for other organisms).

The distribution of incoming solar radiation

Chemical Energy can be stored in cells and then released when needed. Chemical energy is used by all organisms to perform functions, including movement, growth, and reproduction.

Where does Chemical Energy used by organisms come from? Photosynthesis – the process in which the Sun’s energy is converted into chemical energy Photosynthesis Word Equation: carbon dioxide + water sugar + oxygen LIGHT ENERGY

Sugar (stored chemical energy) is stored in roots, stems, leaves and seeds of plants. Figure 3 Some sugars are used as building materials (not all sugar goes toward energy storage).

Producers vs. Consumers Producer – an organism that makes its own energy – rich food compounds using the Sun’s energy (via photosynthesis) Example: plants and algae (their green colour comes from a chemical called chlorophyll, which captures light energy)

Producers vs. Consumers Consumers obtain energy and building materials by eating other organisms. Example: Humans are consumers, obtaining energy by eating other organisms.

Photosynthesis produces stored energy in the form of sugar. To make stored energy available for use, the plant undergoes Cellular Respiration. Cellular Respiration: a chemical process by which sugar is converted into carbon dioxide, water and energy. Cellular Respiration Word Equation: sugar + oxygen carbon dioxide + water + energy

Photosynthesis and cellular respiration are complementary processes.

PHOTOSYNTHESIS CELLULAR RESPIRATION carbon dioxide + water sugar + oxygen sunlight CELLULAR RESPIRATION sugar + oxygen carbon dioxide + water + energy ***Complementary processes since the products of one reaction are needed as reactants for the other process. Provides us with evidence that we depend on other living organisms

Food Webs and Ecological Pyramids . Food Webs and Ecological Pyramids

Types of Consumers Detrivores: consumers that feed on organic matter (Organic matter: is the remains of a dead organism and animal wastes)

. Food Chains Every organism within an ecosystem provides energy for other organisms. Food Chains: a step-by-step sequence of who eats whom in an ecosystem, showing how energy is transferred from one organism to another. Example: The final carnivore in any food chain is called a top carnivore. All organisms continuously use and release energy to their environment. This means that energy is continuously lost from all levels of the food chain. Figure 3, p. 43 A simple food chain in a forest ecosystem (arrows show how energy is transferred)

. Trophic Levels Trophic Levels: a method of categorizing living things according to how they gain their energy. First trophic level contains producers and each higher level contains consumers. Less energy 3rd trophic level 2nd trophic level 1st trophic level More energy

THIRD TROPHIC LEVEL SECOND TROPHIC LEVEL FIRST TROPHIC LEVEL Secondary Consumers – rely on primary consumers for energy but they’re still dependent (indirectly) on producers. SECOND TROPHIC LEVEL Primary Consumers - organisms that feed on producers, rely on them directly for energy. FIRST TROPHIC LEVEL Producers- make their own food. Ex. Plants, algae, some bacteria

. Food Webs Food Web: A graphical representation showing the many feeding relationships among organisms in an ecosystem. Many food chains combined. Food webs are useful tools to figure out what may happen when a species is removed or added to an ecosystem

Stable Ecosystems Greatest biodiversity Complex food webs…if one organism is completely removed, it will have minimal effect on the overall web.

Ex: Rainforest

Unstable Ecosystems Ecosystems with less biodiversity have simpler food webs. If one organism is lost, there is a profound effect on all remaining organisms.

Ex. Arctic  few producers because of low temperatures and little energy from the sun. Less energy is available so few organisms can live here, making them more vulnerable.

Ecological Pyramids

Ecological Pyramids display relationships between trophic levels in ecosystems. Pyramid of Energy illustrate energy loss and transfer between trophic levels

Consumers eat the plants, gaining the stored energy. Most of the sun’s energy that plants absorb is used and the rest is stored. Consumers eat the plants, gaining the stored energy. This energy is used for life activities, so the consumers store even less energy. During any energy change, some energy is converted into an unusable form, heat that cannot be passed on (thus, some more energy is lost). As a result, the farther up the food chain you travel, the less energy available. Only about 10% of energy is transferred to the next trophic level. Pyramid of Energy drawn by measuring the amount of energy available at each trophic level

Only 10% of the total energy is passed to each level. Therefore, as you move up the food chain, there is less energy available. Animals located at the top of the food chain need a lot more food to meet their energy needs.

The number of trophic levels in a food chain is limited to five. Since overall loss of energy at each step is so large, there won’t be enough energy to support a higher-level consumer.

HOMEWORK Read and supplement notes 1.2 Complete ?’s p. 35 #2-6, 12, 13, 15