ECOLOGY UNIT

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ECOLOGY UNIT

• Chapters 20 21

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Chapter 20 Section 1

• Science Standard S7L4 Students will examine
  the dependence of organisms on one another and
  their environment.
• c. Recognize that changes in environmental
  conditions can affect the survival of both
  individuals and entire species.

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Key Vocabulary words page 674b

• Organism
• Habitat
• Biotic factor
• Abiotic factor
• Photosynthesis
• Species
• Population
• Community
• Ecosystem
• Ecology

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Living Things and the Environment

• Organism a living thing which obtains food,
  water, shelter, and other things it needs to
  live, grow, and reproduce from its environment.
• An environment that provides the things the
  organism needs to live, grow, and reproduce is
  called its habitat.
• Examples of habitats forest, tropical rain
  forest, ocean floor, and tree trunks.

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• An organism interacts with both the living and
  nonliving parts of its habitat.
• Biotic factors living parts of a habitat
  examples grass, plants, hawks, eagles.
• Abiotic factors the nonliving parts of an
  organisms habitat examples water, sunlight,
  oxygen, temperature, and soil.

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Abiotic Factors

• 1.Water all living things require water to
  carry out their life processes makes up a large
  part of the bodies of most organisms human
  bodies 65 water plants and algae need water
  with sunlight and carbon dioxide to make their
  own food by photosynthesis.
• 2.Sunlight needed for photosynthesis

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• 3.Oxygen most living things require oxygen to
  carry out life processes.
• 4.Temperature ones that are typical in an area
  determine the types of organisms that can live
  there.
• 5.Soil a mixture of rock fragments, nutrients,
  air, water, and the decaying remains of living
  things

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Levels of Organization

• 1.Species group of organisms that are
  physically similar and can mate with each other
  and produce offspring that can also mate and
  reproduce.
• 2.Population made up of all the members of one
  species in a particular area.
• 3.Community all the different populations that
  live close enough together in an area (a
  particular area contains more than one species of
  organisms) that interact by using the same
  resources (food, shelter).

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• 4.Ecosystem made up of the community of
  organisms that live in a particular area along
  with their nonliving surroundings Examples
  prairie, mountain streams, oceans, forests.
• Ecology is the study of how living things
  interact with each other and with their
  environment.
• Ecologists scientists who study ecology and how
  organisms react to changes in their environment.

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Chapter 21 Ecosystems and Biomes

• Science Standard S7L4 Students will examine
  the dependence of organisms on one another and
  their environment.
• a. Demonstrate in a food web that matter is
  transferred from one organism to another and can
  recycle between organisms and their environment.
• b. Explain in a food web that sunlight is the
  source of energy and that this energy move from
  organism to organism.

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Key Vocabulary page 710 B

• Producer Consumer Herbivore Carnivore
• Omnivore Scavenger Decomposer
• Food Chain Food Web Energy Pyramid
• Water Cycle Evaporation Condensation
• Precipitation Nitrogen Fixation
  Climate
• Biogeography Continental Drift Dispersal
• Exotic Species Biome Canopy Understory
• Desert Grassland Savanna Deciduous tree
• Coniferous Tree Tundra Permafrost
  Estuary Intertidal Zone Neritic Zone

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Energy Flow in Ecosystems

• Every organism has a role in the movement of
  energy through its ecosystem. This is necessary
  for the ecosystem to work.
• Organisms energy role - determined by how it
  obtains energy and how it interacts with other
  organisms.
• All organisms fill the energy role of producer,
  consumer, or decomposer.

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Producers

• Energy enters most ecosystems as sunlight.
• Capture the energy of sunlight and store it as
  food energy (plants, algae, and some bacteria)
• Use the suns energy for photosynthesis.
• Can make its own food green plant
• The source for all of the food in an ecosystem.

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Consumers

• Organisms that can not make their own food
  obtains energy by feeding on other organisms.
• Classified by what they eat
• herbivores eat only plants caterpillars
• and deer
• carnivores eat only animals lions and
• spiders
• omnivores eat both plants and animals
• crows, bears, humans
• scavenger feeds on the bodies of dead
• organisms vultures and
  catfish

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Decomposers

• Break down waste and dead organisms and return
  the raw materials to the ecosystem.
• natures recyclers
• Examples mushrooms and bacteria

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Food Chains

• Energy from the sun is transferred to each
  organism that eats a producer, and then to other
  organisms that feed on these consumers.
• The movement of energy through an ecosystem can
  be shown in diagrams called food chains or food
  webs.

• Food chains show only one path of energy flow,
  food webs show multiple paths.

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Food Webs

• Food webs consist of many overlapping food
  chains.

• An organism may play more than one role in an
  ecosystem.

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Energy Pyramids

• Diagram showing the amount of energy available at
  each level of a food web
• The most energy is available at the producer
  level.
• As you move up the pyramid, each level has less
  energy available than the level below.

• Only 10 of the energy at one level of a food web
  is transferred to the next higher level.
• The other 90 of the energy is used for the
  organisms life processes or is lost to the
  environment as heat.
• As a result, there are usually few organisms at
  the highest level in a food web.

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Cycles of Matter

• The supply of matter in an ecosystem is limited.
• Matter in an ecosystem includes water, carbon,
  oxygen, nitrogen, and many other substances.
• If matter can not be recycled, ecosystems will
  quickly run out of the raw materials necessary
  for life.

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Water Cycle

• Water is essential for life.
• To ensure a steady supply, Earths water must be
  recycled.
• The water cycle is a continuous process by which
  water moves from Earths surface to the
  atmosphere and back.
• Three processes evaporation, condensation, and
  precipitation make up the water cycle.

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• Evaporation process by which molecules of
  liquid water absorb energy and change to a gas.
• 1. Liquid water evaporates from oceans,
  lakes, and other surfaces and forms water vapor
  (gas) in the atmosphere.
• 2. The energy for evaporation comes from the
  heat of the sun.
• 3. Living things give off water plants
  release water vapor from their leaves humans
  release liquid water in wastes and water vapor
  when exhale.

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• Condensation process by which a gas changes to
  a liquid
• 1. As the water vapor rises higher in the
  atmosphere, it cools down.
• 2. The cooled vapor then turns back into tiny
  drops of liquid water.
• 3. The water droplets collect around
  particles of dust, eventually forming clouds.

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• Precipitation rain, snow, sleet, or hail.
• 1. As more water vapor condenses, the drops
  of water in the cloud grow larger.
• 2. Eventually the heavy drops fall back to
  Earth as precipitation.
• 3. Most precipitation falls back into oceans
  or lakes.
• 4. Some falls on land may soak into the soil
  and become ground water or it may run off the
  land, eventually flowing back into a river or
  ocean.

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Carbon and Oxygen Cycles

• Carbon is an essential building block in the
  bodies of living things.
• Most organisms use oxygen for their life
  processes.
• In ecosystems, the processes by which carbon and
  oxygen are recycled are linked.
• Producers, consumers, and decomposers play roles
  in recycling carbon and oxygen.

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The Carbon Cycle

• Producers take in carbon dioxide gas from the air
  during photosynthesis.
• These producers use carbon from the carbon
  dioxide to make food molecules.
• When consumers eat producers, they take in the
  carbon-containing food molecules.
• When consumer break down these food molecules to
  obtain energy, they release carbon dioxide and
  water as waste products.
• When producers and consumers die, decomposers
  break down their remains and return carbon
  compounds to the soil and carbon dioxide as a
  waste product.

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The Oxygen Cycle

• Oxygen cycles through ecosystems.
• Producers release oxygen as a result of
  photosynthesis.
• Most organisms take in oxygen from the air or
  water and use it to carry out their life
  processes.

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• Human activities affect the levels of carbon and
  oxygen in the atmosphere.
• When humans burn oil and other fuels, carbon
  dioxide is released onto the atmosphere.
• When humans clear forests for lumber, fuel, and
  farmland, carbon dioxide levels also rise.

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The Nitrogen Cycle

• Nitrogen is necessary building block in the
  matter that makes up living things.
• During the nitrogen cycle, nitrogen moves from
  the air to the soil, into living things, and back
  into the air.
• The air around us is 78 nitrogen gas, but living
  things can not use nitrogen gas (free nitrogen)
  because it is not combined with other kinds of
  atoms.

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• Most organisms can use nitrogen only once it has
  been fixed or combined with other elements to
  form nitrogen-containing compounds nitrogen
  fixation (performed by certain kinds of
  bacteria). This bacteria live in nodules (bumps)
  on the roots of legumes beans, peas, peanuts,
  alfalfa, clover which feed on the plants sugars.
  This supplies the plant with nitrogen in a
  usable form.

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• Once the nitrogen has been fixed, producers can
  use it to build proteins and other complex
  compounds.
• Decomposers break down these complex compounds in
  animal wastes and the bodies of dead organisms
  which returns this simple nitrogen compounds to
  the soil.
• Nitrogen can cycle from the soil to producers and
  then to consumers many times but bacteria break
  down the nitrogen compounds completely.
• These bacteria then release free nitrogen back
  into the air which the cycle continues from there.

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