Science 9 Notes 1.2_ Energy Flow in Ecosystems PDF

Unit 1 Ecology Science 9 Mr. Yeo 2023-2024 Biology STATEMENT OF INQUIRY FOR UNIT 1 ▸ Human interactions with natural systems can have global consequences. KEY CONCEPT: Systems RELATED CONCEPTS: Interactions, Consequences GLOBAL CONTEXT: Globalization and Sustainability Unit Overview Introduction to...

Unit 1 Ecology Science 9 Mr. Yeo 2023-2024 Biology STATEMENT OF INQUIRY FOR UNIT 1 ▸ Human interactions with natural systems can have global consequences. KEY CONCEPT: Systems RELATED CONCEPTS: Interactions, Consequences GLOBAL CONTEXT: Globalization and Sustainability Unit Overview Introduction to Ecology Energy Flow in Ecosystems Biogeochemical Cycles Populations Communities and Relationships Weather and Climate Biomes of the World Biodiversity, Conservation and Invasive Species Human Impacts on the Environment Systems (IDU) Unit Outcomes By the end of the unit, students should be able to identify the different spheres of the earth and define an ecosystem identify abiotic and biotic factors within an ecosystem and describe interactions between them explain how things are organized within an ecosystem describe the roles of organisms within a food web describe the transfer of energy in a food chain and explain the effects of the elimination of any part of the chain describe and explain bioaccumulation and biomagnification develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem explain the difference between primary and secondary succession list and describe the effect of various abiotic and biotic factors that can limit the growth of a population describe the different patterns of interactions between organisms explain the difference between weather and climate describe the major terrestrial and aquatic biomes of the world describe three levels of biodiversity, explain ways in which biodiversity is important to ecosystems and humans, and describe some ways biodiversity can be preserved explain how invasive species harm ecosystems and threaten biodiversity discuss some ways in which humans have impacted the environment, and efforts being done to address these impacts describe a system, define open and closed systems, positive and negative feedback (IDU) Ecosystem Recycling The Sun powers life in an ecosystem Producers convert the energy from the Sun and transfer it to the consumers Energy is moved throughout the ecosystem through the feeding relationships (food webs) Decomposers obtain the last bits of available energy as they break down biotic components and release the nutrients and minerals back into the ecosystem 3 Earth’s Energy Budget All of life’s energy comes from the sun! Incoming solar energy 100% 30% reflected by clouds or Earth’s surface 19% absorbed by atmosphere and clouds 0.023% absorbed by plants 51% absorbed by land and oceans Photosynthesis The process where the Sun’s energy is converted into chemical energy (glucose/sugar) Occurs in plants (producers) Producer – an organism that makes its own energy-rich food compounds using the Sun’s energy On land, major producers are green plants, which contain chlorophyll inside their chloroplasts that capture light energy and create sugar carbon dioxide water ¾¾¾¾® sugar oxygen light energy 1 Process of Photosynthesis carbon dioxide water ¾¾¾¾® sugar oxygen light energy Primary Productivity Primary productivity: the rate (how fast) at which producers photosynthesize, i.e. make energy (from sunlight). Factors that affect primary productivity include Amount of water available to the plant Amount of sunlight available Carbon dioxide Trace elements (nitrogen, potassium) Cellular Respiration The opposite of photosynthesis Sugar is converted into carbon dioxide, water and energy The organism uses this energy to do everything Producers (plants) and consumers (animals that eat the producers) undergo cellular respiration sugar oxygen ¾ ¾® carbon dioxide water energy Photosynthesis and Cellular Respiration Photosynthesis carbon dioxide water ¾¾¾¾® sugar oxygen light energy Notice Anything? sugar oxygen ¾ ¾® carbon dioxide water energy Cellular Respiration Photosynthesis and Cellular Respiration Photosynthesis carbon dioxide water ¾¾¾¾® sugar oxygen light energy sugar oxygen ¾ ¾® carbon dioxide water energy Cellular Respiration What is created in one reaction is used up in the other reaction! Photosynthesis and Cellular Respiration Photosynthesis vs. Cellular Respiration To Photosynthesize or not to Photosynthesize Many organisms cannot photosynthesize they are called consumers – Consumers – an organism that obtains its energy from consuming other organisms To obtain usable energy from food, consumers undergo cellular respiration Photosynthesis and Life We completely rely on the Sun! No Sun = No Photosynthesis = No Food for plants = No Food for animals = No food for larger animals No Sun = No life on Earth = Living things can fall into two categories in how they obtain energy: Producers (AKA autotrophs) - produce energy by capturing sunlight or using chemicals (plants, algae, some bacteria). Consumers (AKA heterotrophs) - organisms that consume other organisms for food. Most autotrophs obtain energy from the sun through photosynthesis. The energy from sunlight is used to power chemical reactions to make sugar. Consumers can be further divided into specific categoriesHerbivore- organism that eats plants Carnivore- eats meat Omnivore- eats both plants + animals Herbivore Carnivore Omnivore Detritivores/Scavengers - organisms that obtain their energy from dead matter or waste ( Exvultures, crabs, earthworms) Decomposer (very special type of consumer) – cause decay and release nutrients back into the environment; crucial for the “circle of life” (Ex- bacteria, fungi) Food Chains A sequence of organisms each feeding on the next Shows how energy is transferred from one organism to another pine cone red squirrel weasel goshawk The arrow points to the consumer Food chains do not exist in nature. They simply show feeding relationships Food Chains – Try It Create a sample food chain using the following: grass, snakes, snails, birds. What happens when one link is broken in a food chain? Energy flows through an ecosystem in one direction, from the sun to autotrophs and then to various heterotrophs. Trophic levels- an assigned level in a food chain based on how an organism gets energy; first trophic level always assigned to a producer. Food chain- the path of energy through the trophic levels (energy flow depicted with arrows) Food Chains and Trophic Levels The trophic level of an organism in an ecosystem depends on its feeding position along a food chain First trophic level – producers Second trophic level – primary consumers ØWill eat producers only Third trophic level – secondary consumers ØCan eat primary consumers and producers Fourth trophic level – tertiary consumers ØCan eat secondary consumers, primary consumers, producers Typically, there are 4-5 available trophic levels Trophic Level Type of Organism Example FIRST Producer Sunflower seeds SECOND Primary Consumer Mouse THIRD Secondary Consumer Snake FOURTH Tertiary Consumer Hawk FIFTH Quaternary Consumer Fox Food chain= grass à mouse à snake à hawkà fox (arrows point in direction of energy flow). Food Webs Food Webs A much more accurate display of who eats who A representation of the feeding relationships within a community Highly complex – consumers feed on many species As in food chains, the arrow points from the thing being eaten to the thing eating it Food web- multiple connected food chains showing the complex interactions within an ecosystem. What does the owl feed on? What does the grasshopper feed on? There are 10 food chains in this one food web. How many can you find? Name one primary consumer, one secondary consumer, one tertiary consumer. Are the any quaternary consumers? (4th level consumer?) Check Your Understanding In this food web, the Sea Ducks are eaten by the Bald Eagle. - What three animals eat all the plants? Check Your Understanding In this food web, the Sea Ducks are eaten by the Bald Eagle. - What three animals eat all the plants? Food Webs Are very useful when figuring out what may happen when a species is removed from or added to an ecosystem If a species is removed, the number of animals that would normally eat it would decrease, why? The introduction of a new species can also dramatically alter the food web as new feeding patterns are established What Happens When Food Webs Get Out Of Balance? Check Your Understanding What would happen if the Small Planktivorous Fish was removed? What would happen if you removed the Phytoplankton? When an organism eats another, they are only consuming a small part of the energy that is stored. This is because so much energy is used for life processes such as movement and reproduction, and some energy is released as body heat. Seeds are using lots of energy for growthmuch of the energy it has stored has been spent. Whatever energy the mouse gets from the seeds, it will use up quickly for movement, growth, etc. The snake will gain energy from the mouse, but will again also use the energy it needs for life. Ten-percent-law: only 10% of energy is passed on from trophic level to trophic level. -Energy is typically measured in calories (cal) or Joules (J). (1 kilocalorie [kcal]= 1,000 calories) Seeds= 10,000 kcal. Mouse= 1,000 kcal Snake=100 kcal How much energy is passed on to each trophic level? TEN PERCENT Ecological Pyramids Ecological Pyramids display relationships between trophic levels in ecosystems There are three main types of ecological pyramids 1) Energy 2) Biomass 3) Numbers Energy Pyramid Energy from the Sun 0.01% Quaternary Consumers 0.1% Tertiary Consumers 1% Secondary Consumers 10% Primary Consumers 100% Primary Producers Decomposers feed at each level Energy loss and transfer between trophic levels The size of each layer represents the amount of energy available at that trophic level Only about 10% of the energy taken in by the individuals at one trophic level is passed on to individuals at the next level Where does the rest of the energy go? Heat At each trophic level, the bulk of the energy received from the previous level is used by the organism who obtained it for movement, growth, reproduction, etc. Less and less energy is available as we move up the pyramid This energy is eventually released as heat energy and lost to the ecosystem Heat Energy pyramid- A diagram that represents the amount of energy stored in the trophic levels. (Depicts the tenpercent law. Producers are on the bottom- most of the energy is found at the first trophic level. As the pyramid moves up through the trophic level, less energy is available. The more levels found between a producer and top-level consumer, the less energy remains. 1,000 kcal 10,000 kcal 100,000 kcal 1,000,000 kcal Biomass Pyramid Represents the mass (weight) of all the living organisms within that trophic level. 5th Trophic Level MASS MASS MASS MASS MASS 4th Trophic Level 3rd Trophic Level 2nd Trophic Level 1st Trophic Level Biomass- the dry weight of living tissue (organic matter) found within a trophic level. Typically measured in grams of organic matter per unit area. Most of an ecosystem’s dry organic matter is found in the first trophic level (producers). There must be LOTS of producers (algae, plants, etc) in order to support an ecosystem with higher-level carnivores. A biomass pyramid represents the amount of potential food available for each trophic level. Numbers Pyramid Represents the number of organisms that make up each trophic level Similar but not the same as a biomass pyramid In a forest ecosystem, the tiny plant-feeding insects in the second trophic level outnumber the trees in the first trophic level Large birds Small birds Insects Trees Decomposers