Living Things and Ecosystems

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    Students will learn about an ecosystem, the roles within an ecosystem (decomposers, consumers, producers), how matter and energy moves within an ecosystem, how ecosystems change, and what’s healthy or unhealthy within an ecosystem.

    Students have the Study Guide available in Google Science Classroom Assignments.  They should review the sections we've covered each night.  We will have short quizzes after each lesson.  If your student misses all or part of science class due to absence, band, IMPACT, etc. they can view Science, What Did I Miss? in our Google Science Classroom.  This will have everything they need to do to catch up.  Band and Impact students need to complete that work that same night.  If a student is absent due to illness, they have however many days they were absent to make up that work.

    Unit 1 Study Guide

    Lesson 7 - How Do Ecosystems Change?


    1. Ecosystems Can Change
    • all ecosystems change over time either slowly or quickly
    • changes affect what species can be found 
    • Examples
      • Drought (no water) or volcano eruption can cause plants to die which upsets food web
      • People can change ecosystems by cutting down trees or creating river dams
    • Changes disrupt the flow of matter and energy through the ecosystem.


    1. Disturbance Leads to Succession

    Disturbance:  event or change to an ecosystem that has lasting effects (can be caused by humans or be a natural process)

    Succession:  the changes in ecosystem after a disturbance

    If soil destroyed, succession takes a long time because new soil must be formed

    • Examples: volcanic eruption, glaciar scrape
    • Pioneer species: first species to grow after disturbance, example: lichen

    If soil in place, succession can happen faster

    • Examples: fire, floods, logging
    • Fire can release nutrients into soil 
    • Some growth can happen right away
    • Renewed ecosystems may or may not have the same kinds of species
    • Climax Species: long lived plants, hundreds of years after disturbance.  Some animals need to live in old forests to meet their needs -- certain owls.


    1. Changes with the Seasons
    • Most ecosystems change with the seasons 
    • different groups of organisms to live there at different times of the year 
    • Examples:
      • some animals migrate to warmer places. 
      • Others prepare for winter by going into dormancy, hibernating, or collecting food


    1. Climate Change and Ecosystems:
    • Scientists around the world agree that Earth's climate is rapidly warming over time
    • Affects ecosystems and the organisms that live in them
    • Example: food webs and life cycles have been altered
    • If the temperature or rainfall in an environment changes, some organisms will not be able to survive there.


    Lesson 6 - Healthy and Unhealthy Ecosystems

    Predator: An animal that captures and eats other animals:

    Prey: The animal that is captured and eaten.

    1. Healthy Ecosystems are:
    • where many different kinds of organisms can meet their needs
    • stable
    • have balanced numbers of predator and prey 
    1. A Healthy Forest Ecosystem on Isle Royale
    • island that scientists have studied for many years 
    • It’s a great ecological lab - animals can’t get on or off island
    • the wolves and moose there have an interesting predator and prey relationship
    • When healthy, the numbers of wolves (predator) and moose (prey) are balanced
    1. Unhealthy Ecosystems
    • if there are too many or too few of one type of organism
    • Unhealthy pond: 
      • too much algae 
      • When algae die, more bacteria (decomposers) use up the oxygen in the water
      • Fish die - they needed the oxygen
      • Pond ecosystem is not balanced

    If fish die, what will the turtle eat?  The turtles may not survive. If turtles die, what will happen to the heron (bird)?

    1. An Unhealthy Forest Ecosystem on Isle Royale
    • unusually warm weather = problem in the balance 
    • warm weather - more ticks are born
    • ticks kill the moose by disease
    • Fewer moose, wolves starve 
    • Not balanced


     Lesson 5 - How Matter and Energy Move in an Ecosystem

    Trophic pyramid illustrating the 10% energy transfer rule.

Light energy is captured by primary producers.

Amount of energy stored as biomass:

Primary producers—20,000 kcal per meter squared per year

Primary consumers—2,000 kcal per meter squared per year

Secondary consumers—200 kcal per meter squared per year

Tertiary consumers—20 kcal per meter squared per year

Quaternary consumers—2 kcal per meter squared per year

At each level, energy is lost directly as heat or in the form of waste and dead matter that go to the decomposers. Eventually, the decomposers metabolize the waste and dead matter, releasing their energy as heat also.Image credit: Khan Academy, modified from Ecological pyramid by CK-12 Foundation, CC BY-NC 3.0 


    energy pyramid: A model that shows the amount of energy that is passed on at each level of a food chain.

    food chain: model showing the path of energy through a series of organisms in an ecosystem.

    food web: A diagram that shows the many connected food chains and feeding relationships in an ecosystem.

    Big Ideas:

    Matter in an ecosystem is recycled

    • Plants use air, water, nutrients in soil and sunlight to make food and grow
    • Some animals eat the plants and use their matter to grow
    • Some other animals eat those animals and use that matter to grow
    • Decomposers use the dead animals and plants and their waste as matter to grow
    • Decomposers release the digested matter into air and soil

    Energy moves in one direction, and is constantly lost as heat

    • Energy enters the ecosystem as sunlight
    • Energy goes to the producers during photosynthesis - some used to grow, some stored, some given off as heat
    • The stored energy from the plant then goes to the consumer, where some used to grow, some given off as heat, and some stored
    • This stored energy then goes to the secondary consumer
    • At any stage, if the organism dies, decomposers will get the portion of energy that was stored

    Food Chains

    Example: The arrows show the direction energy moves through the food chain.      grass → mouse → snake → eagle

    Energy Pyramid:An energy pyramid shows
that the bottom level, the
producers, holds the most
stored energy. Each level above
producers holds less energy
because most of the energy is
lost as heat at each level.  Photo Credit:

    An energy pyramid shows that the bottom level, the producers, holds the most stored energy. Each level above producers holds less energy because most of the energy is lost as heat at each level.

    Food Web:A food web shows the feeding relationships between organisms in an ecosystem. The arrows show the direction of matter and energy as food.

    Most ecosystems have
many food chains. The many
overlapping food chains in this
meadow ecosystem form its
food web. Photo Credit:


    Humans in a food web:

    • Because no animals normally hunt humans, humans are at the top of all their food chains.
    • Humans are different from animals - they don’t live and get food from just one ecosystem.  The whole earth is a human’s ecosystem!


    Lesson 4 - The Role of Decomposers in an Ecosystem

    11/4 - 11/6


    decomposer: an organism in an ecosystem that gets energy and matter by breaking down dead organisms and their wastes.  Examples:  fungi, some bacteria. 

     Decomposer helpers:  earthworms, slugs, some kinds of flies and beetles.

    fungi: a group of living things that are decomposers and are neither plant nor animal.  Examples: mushrooms, yeast, mold 

    bacteria: a group of organisms that are too small to be seen without a microscope.  Some types are decomposers.   

    compost: a mixture of soil and decaying matter that provides the materials that plants need.  Usually contains kitchen and yard wastes that would have ended up in a landfill. 

    Big Ideas:

    • Decomposers get matter and energy from dead materials and waste and use it to live and grow.
    • Decomposers are fungi and bacteria 
    • Other organisms that help decomposers break down dead and waste are:  
      • earthworms living in soil  
      • kinds of flies and beetles that break down dead animals 
    • Fungi breaks down dead material and wastes and gets the energy and matter needed to survive and grow..
    • A fungus cannot take in all the matter it breaks down - some leftover matter enters the air and soil in the ecosystem.
    • Decomposers are nature’s recyclers.
    • Some decomposers(such as molds) can store food for a short time as sugar.
    • Bacteria cannot store excess food.  They must live in an environment where they are surrounded by food or it will die or become dormant (alive but not growing or developing)
    • Decomposers produce waste too - carbon dioxide, food waste, and when it dies.  Wastes go back into the ecosystem and provide nutrients to plants. CO2 that plants can use.  Methane that is poisonous. 
    •  Good waste for compost:  grass clippings, fruit and vegetable peels, leaves, eggshells, coffee grounds, shredded newspaper.  NOT MEAT SCRAPS!
    • Takes advantage of the natural process of decomposition to create rich soil for plants.
    • Compost piles - scraps decay and piles becomes smaller.  Stirred often, add earthworms to help break down and help stir.


    Lesson 1

    ecosystem: All the living and nonliving things that interact in an area.

    ecology: The study of how living and nonliving things interact with their environments.

    ecologist: Scientists that study ecosystems, They track animals to see where they go and what they do. They use computers to model ecosystems so they can learn more.

    organism: any living thing.

    Some nonliving things in an ecosystem are water, air, soil, sunlight  Organisms can depend on nonliving parts of their ecosystem for survival.

    Big ideas:

    • Organisms must meet their needs in an ecosystem, or they cannot survive there. 
    • Organisms that live in one ecosystem may not be able to survive in a different ecosystem.
    • Some ecosystems are large such as a rainforest, and others are small like a pond.
    • More plants and animals live in the rainforest ecosystem than any other ecosystem


    Lesson 2


    Producers: organisms in an ecosystem that make their own food

    Carbon Dioxide: a gas found in air

    Photosynthesis: the process of using the energy from the sun, carbon dioxide, and water to make food (sugar) and waste (oxygen)

    CO2 + water + light -------> sugar + oxygen

    Big Ideas:

    • All the food energy in any ecosystem originally comes from producers. 
    • Plants can produce more food through photosynthesis than they need at a time. They store this excess food in their roots, stems, and other plant structures to use later.
    • The three main things plants need to survive and grow are light, water, and carbon dioxide. Soil is not necessarily needed. 
    • Almost all living things need oxygen.  Plants release oxygen into the air and it is available for animals to breathe in.

    Lesson 3 - The Role of Consumers in an Ecosystem

    3.1 Consumers Eat Other Organisms

    consumer: an organism that gets energy by eating other organisms.  All animals are consumers.

    Big Ideas:

    • A consumer gets matter and energy by consuming (eating) food
    • The energy in all food once came from the sun and it was captured by producers during photosynthesis.  The energy stored in plants came from sunlight originally.
    • Most animals eat both plants and animals
    • Food provides the materials needed for:
      • Body repair
      • Growth 
      • Movement
      • Reproduction
      • Maintaining body functions
      • Staying warm

    3.2 Digestion Breaks Down Food to Release Energy

    digestion: the process that breaks down food

    circulation:  the process of moving blood in a large, complicated loop through the body.  Circulatory system includes the heart, blood vessels, and blood.

    Big Ideas 

    • Food gives animals the matter and energy they need to grow and survive.
    • Digestive system for most animals:  mouth, stomach, small intestine, large intestine.
    • Systems work together:  blood moves oxygen, energy, materials through body to be used.  It takes away waste - carbon dioxide and food waste.

    3.3 Consumers Store Excess Food

    Excess food:

    •  stored as sugar for short term needs
    •  stored as fat for long term needs.


    3.4 Consumers Produce Waste

    Food Waste: large intestine removes waste.  Solid wastes back into ecosystem.

    Using Oxygen creates waste:  Waste is carbon dioxide.  It goes back into the air when animal breathes out.

    Body: When animal dies, the body is broken down and passes into soil and air.  

    All waste becomes part of the nonliving things in the ecosystem -- air, soil, and water and are used again by other organisms.  Matter is recycled in an ecosystem.

    Animal waste (dung) is used as a fuel source in many places.  This waste is from the plant material eaten and not used by the animal 


    3.5 Humans are Consumers

    Needs: food, shelter, family, clean air, clean water.

    Food energy: to keep warm and power all activities your body does: move, breathe, repair, stay warm,

     All the food energy that humans use once came from the sun.  The energy in their food came from a plant at some point and the plant got its energy from the sun.