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There is a flow of materials and energy throughout every ecosystem

Ecology – Part 2 The Cycling of Matter and Energy in Ecosystems General Biology Name__________________. There is a flow of materials and energy throughout every ecosystem.

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There is a flow of materials and energy throughout every ecosystem

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  1. Ecology – Part 2The Cycling of Matter and Energyin EcosystemsGeneral BiologyName__________________

  2. There is a flow of materials and energy throughout every ecosystem

  3. There is a constant flow of materials and energy between the living (biotic) and nonliving (abiotic) parts of every ecosystem. • Materials (atoms, molecules) must be recycled but energy is NOT! • So, a constant supply of energy must enter every ecosystem. On earth, this is supplied by the SUN!

  4. Remember, organisms must be able to: • produce or obtain nutrients • convert the nutrients into usable forms of chemical energy (cellular respiration – producing ATP!!) • use these forms of energy to power their life processes.

  5. 2 Categories based on how living things produce/obtain nutrients…. Heterotrophs Autotrophs Capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds PRODUCER or Primary Producer Ex: All Plants, some microorganisms (bacteria) • Obtains food by consuming other living things • CONSUMER • Ex: Animals, fungi, some microorganisms (bacteria) Categories: Herbivores, Omnivores Decomposers

  6. Don’t forget – Different types of Autotrophy

  7. Types of Heterotrophy Carnivores kill and eat other animals. Ex: snakes, dogs Herbivores eat plant leaves, roots, seeds or fruits. Ex: birds, insects Scavengers consume the carcasses of dead animals. Ex: vulture Omnivores eat both plants and animals. Ex: humans, bears Detritivores chew or grind dead/waste matter into smaller pieces. Ex: snails, crabs Decomposers “feed” by chemically breaking down organic matter and recycle the materials for producers to use. Ex: bacteria and fungi

  8. Food Chains • Series of steps in an ecosystem in which organisms transfer energy and materials by eating and being eaten. • Arrow points to the “eater”. • Vary in Length but usually 4-5 steps max. • Example – how many steps (trophic levels) in the food chain below? • Must always start with a producer; then goes to one or more consumers. • Although not always shown, the final link is decomposers.

  9. Examples of Food Chains

  10. Food Webs • Diagram showing interconnected food chains • Shows networks of feeding interactions • Many animals eat more than 1 type of food • Each step in a food chain/web is called a trophic level • Changes at any level can cause drastic changes in other level(s).

  11. What would happen if….. -Algae was killed off? -Alligators were killed off?

  12. Decomposers & Detritivores in Food Webs • Convert dead/waste material into detritus • Eaten by detritivores • Ex: Grass Shrimp, Crayfish, Worms • Decomposers releases nutrient that can be used by primary producers • Nature’s Recyclers • Without them – nutrients would remain locked in dead organisms • Examples: Bacteria & Fungi

  13. Ecological Pyramids • These are used to show the relative amounts of energy, biomass, or numbers of organisms in each trophic level of a given food chain or web. • Three types: • Pyramid of Energy • Pyramid of Biomass • Pyramid of Numbers

  14. Energy Flow in the Community • Energy initially comes from SUN. • As energy passes through each member of chain, some energy is lost as HEAT. • WHY? Each organism performs cellular respiration and uses part of the energy for its own needs. Also some is lost to waste products. • Energy Pyramid – wider at bottom (more organisms can exist b/c more energy at this level. ENERGY PYRAMID

  15. Pyramids of ENERGY • Pyramids of Energy show the relative amount of energy available at each trophic level of a food chain/food web • What happens to the amount of energy available at each trophic level? • It DECREASES!! • Only 10% of available energy gets passed to the next level • Where does the other 90% go?? • Most released as heat, from C/R • Some lost in waste products

  16. Energy Pyramid

  17. Pyramids of BIOMASS • What’s Biomass??? • Total amount of living tissue within a given trophic level • Pyramid of biomass • The amount of biomass a given trophic level can support is determined by the amount of available energy. • Relative amount of living organic matter • Greatest biomass is at base – see image

  18. Pyramids of NUMBERS • Shows the relative number of individual organisms at each trophic level in an ecosystem. • In most ecosystems, the shape of the pyramid of numbers is similar to the shape of the pyramid of biomass for the same ecosystem, with the numbers of individuals on each level decreasing from the level before it. • This is the only pyramid that can be inverted!!

  19. Matter is recycled, energy is not…

  20. Nitrogen Cycle • Nitrates – chemical in soil that contain nitrogen. Needed by plants to make proteins. NITROGEN CYCLE (repeating steps) • Bacteria on roots change N in air into nitrates in soil. • Nitrogen in dead organisms changes to nitrates in soil. • Nitrates can be used by plants/animals to make proteins. • Bacteria change some nitrates in soil back into nitrogen in air.

  21. Soil • Soil comes from rocks that have broken down. • Place for plants to anchor roots • Home for worms, insects, rodents • Loosened, aerated by organisms • Many bacteria live there • Holds water, nutrients, gases http://www.statlab.iastate.edu/soils/photogal/ landuse.html 3

  22. Water Cycle All cells need water to live!! • Rain/snow – water falls to earth • Water runs into rivers, ponds, oceans • Water soaks into soil • Plants & animals use water; the rest flows into underground lakes/rivers • Plants/animals lose excess water (plants – transpiration; animals – evaporation) to the air • Evaporation from lakes, rivers, oceans • NOTE: repeating cycle; steps not necessarily in order!

  23. Oxygen-CO2 Cycle • OXYGEN • Given off by producers during photosynthesis • Used by all living things during respiration • CARBON DIOXIDE • Given off during respiration • Used by producers during photosynthesis • This cycle goes on in both land and water ecosystems.

  24. What did we learn so far? • The sun is the ultimate source of energy for most ecosystems. As a result, organisms exhibit different strategies to obtain this energy. • Energy relationships can be represented in a graphical depiction called a pyramid. • Elements cycle in various molecular forms through the bioshere. The carbon, oxygen, nitrogen and water cycles are examples essential to life. • Matter cycles through food chains but energy must be continually supplied. • There are varying levels of biodiversity found in the different biomes.

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