I.Grade Level/Unit Number:Grade 6 Unit 5

II:Unit Title:Population Dynamics

III.Unit Length:7 weeks

  1. Major Goals and Learning Outcomes:
  • Why is the interaction of an organism essential for its survival?
  • What abiotic factors affect growth and survival of organisms?
  • How does habitat destruction affect biodiversity?
  • What is pollution?
  • How does human activity impact the environment?
  • What steps can humans take to reduce their impact on the environment?
  • Why has human population increased?
  • What effect does increased population have?
  • What is natural selection and how does it work?
  • What is adaptation?
  • What evidence is there for change over time?
  1. Objectives and RBT Tagged Verbs:

Number / Competency or Objective / RBT Tag
1.01 / Identify and create questions and hypotheses that can be answered through scientific investigations. / A1
1.02 / Develop appropriate experimental procedures for:
  • Given questions.
  • Student-generated questions.
/ B3
1.04 / Analyze variables in scientific investigations:
  • Identify dependent and independent.
  • Use of a control.
  • Manipulate.
  • Describe relationships between.
  • Define operationally.
/ B4
1.05 / Analyze evidence to:
  • Explain observations.
  • Make inferences and predictions.
  • Develop the relationship between evidence and explanation.
/ C3 (c4)
1.06 / Use mathematics to gather, organize, and present quantitative data resulting from scientific investigations:
  • Measurement.
  • Analysis of data.
  • Graphing.
  • Prediction models.
/ A2
1.07 / Prepare models and/or computer simulations to:
  • Test hypotheses.
  • Evaluate how data fit.
/ B2
1.08 / Use oral and written language to:
  • Communicate findings.
  • Defend conclusions of scientific investigations.
/ A1
1.09 / Use technologies and information systems to:
  • Research.
  • Gather and analyze data.
  • Visualize data.
  • Disseminate findings to others
/ A1
1.10 / Analyze and evaluate information from a scientifically literate viewpoint by reading, hearing, and/or viewing:
  • Scientific text.
  • Articles.
  • Events in the popular press.
/ B4
2.02 / Use information systems to:
  • Identify scientific needs, human needs, or problems that are subject to technological solution.
  • Locate resources to obtain and test ideas.
/ B3
2.03 / Evaluate technological designs for:
  • Application of scientific principles.
  • Risks and benefits.
  • Constraints of design.
  • Consistent testing protocols.
/ B4
2.04 / Apply tenets of technological design to make informed consumer decisions about:
  • Products.
  • Processes.
  • Systems.
/ B3
7.01 / Describe ways in which organisms interact with each other and with non-living parts of the environment:
  • Coexistence/Cooperation/Competition.
  • Symbiosis.
  • Mutual dependence.
/ B2
7.02 / Investigate factors that determine the growth and survival of organisms including:
  • Light.
  • Temperature range.
  • Mineral availability.
  • Soil/rock type.
  • Water.
  • Energy.
/ B6 (D6)
7.03 / Explain how changes in habitat may affect organisms. / B2
7.04 / Evaluate data related to human population growth, along with problems and solutions:
  • Waste disposal.
  • Food supplies.
  • Resource availability.
  • Transportation.
  • Socio-economic patterns.
/ B5
7.05 / Examine evidence that overpopulation by any species impacts the environment. / B4
7.06 / Investigate processes which, operating over long periods of time, have resulted in the diversity of plant and animal life present today:
  • Natural selection.
  • Adaptation.
/ B6(D6)

VI. LEP

VII. Materials Needed:

1

•Internet access

•Computer access

•Aquarium

•Terrarium

•OPTIONAL- pictures of balanced ecosystem

•Plastic bags

•12 nails per group

•Block of wood per group

•Flowered material

•Multi-colored beads

•The Lorax, by Dr. Seuss/ or video

•Poster paper/ poster board

•Markers/ crayons

•Construction paper

  • Black
  • White
  • Green
  • Newsprint

•Editorial Cartoon(6th grade support documents)

•Video/DVD- World Population: a Geographic Simulation of the history of humans Populations Growth. (Population Connection (202-332-2200 )

•Media resources for research

VIII. Big Idea

The earth is home to many different life forms, including plants, animals, humans, and other organisms. There is a high degree of interdependence among populations of organisms and the non-living components of their environments. These interactions may support a stable population, but often result in wide fluctuation of population numbers over time in natural environments. Many environmental factors such as varying amounts of heat, light, water, minerals, shelter, and food influence the growth and survival of individuals within a population.

Populations of various species co-exist within an ecosystem, often having to compete for limited resources of food, water, space and shelter. Some species, however, have symbiotic relationships in which interactions benefit long-term survival of one or both species. The interconnectedness of populations means that change in one population within a community of living things often results in a change in others. Over population by any species has an impact on the environment.

Any change in living or non-living parts of a habitat has the potential to impact population numbers. Organisms within a species must be able to find sufficient resources to survive. As environmental conditions change due to natural events or human activities, it may be more difficult for organisms to maintain health and the ability to reproduce and, over time, permits the survival of the species. A species that is not able to adapt to changing conditions will, over time, become extinct.

Organisms have survived and continue to live in a wide variety of conditions on the earth. Physical and behavioral adaptations have enabled organisms to meet basic needs, even in environments with extremes of heat, light, moisture, soil type, and energy.

Human population has grown at a constantly increasing rate over the last two centuries. This booming population growth has resulted in changes in landscapes, oceans, and atmosphere that interfere with life-sustaining natural systems. These systems when out of balance endanger the survival of many plant and animal populations.

Growth in human population, especially in some parts of the world, has been a challenge to science and technology as the search of ways to keep up with the demand for basic needs of food, clean air, and water and the safe disposal of waste products continues. Depletion of limited natural resources used in manufacturing and transportation as well as the pollution and land degradation that occurs due to the removal of these resources is accelerated as human population and individual consumption of resources increase.

Overpopulation by any species has an impact on the environment. Overpopulation results when the long-term ability to sustain quality of life is negatively impacted by the current population.

IX. Notes to Teacher:

This unit deals with the balance between living and non-living resources in natural systems and the imbalance that can result as population growth and demand for resources exceed limits that are sustainable over time. These lessons are designed to get students to consider individual actions and their impact on the environment. The goal is not to point blame for environmental problems but rather to create an awareness of issues as viewed from different perspectives and focus on the power of individuals to make a difference. Likewise this unit is one in which the teacher wants to be careful not to tell the students “what to think” but to provide opportunities for the students to consider various points of view. It is important to provide practice in the logical process of considering different sides of a controversial issue, separating fact from propaganda, and arriving at scientifically literate opinions on environmental issues that will impact the quality of environmental systems for years to come.

This unit provides an opportunity to connect science concepts to the everyday lives of students. Some issues like global warming are worldwide in scope, yet individual choices still make a difference. Others, like land use, are more local in nature. The power of this unit is best realized when it addresses not only the big global issues but also the issues being debated in the local community.

There is much attention in the media now to “thinking green.” This unitcould be a year-long one. Introduce the idea of stewardship of the environment in the fall. Keep up with news in the media and use Earth Day in late April as an opportunity to pull together a powerful culminating experience for students.

X. Global Content

NC SCS
Grade 6 / Activity / 21st Century Skills
1.01, 1.02, 1.04, 1.05, 1.07, 1.08, 7.01, 7.02, 7.03, / Balanced Systems and Their Disruption /
  • Working on a teams- teamwork
  • Explaining a concept to other-communication skills
  • Identifying cause and effect relationships - language skills /reading
  • Conveying thought or opinion effectively - communication skills
  • Develop visual aids for presentations- computer knowledge
  • Developing strategies to address problems- thinking/problem-solving skills
  • Organizing and relating ideas when writing- language skill/writing
  • Locating and choosing appropriate reference materials – language arts – reading

1.01, 1.05, 1.08, 1.10, 2.02, 7.03, 7.05 / Kaibab Story /
  • Organizing and relating ideas when writing- language skill/writing
  • Conveying thought or opinions effectively- communication skills
  • Searching for print information - information retrieval skills
  • Explaining a concept to others -communication skills
  • Identifying cause and effect relationships - language skills /reading

1.05, 1.08, 1.10
202, 7.03, 7.04
7.05 / Learning from the Lorax /
  • Organizing and relating ideas when writing- language skill/writing
  • Conveying thoughts or opinions effectively - communication skills
  • Explaining a concept to others -communication skills
  • Creating memos, letters, and other forms of correspondence- language skill/writing
  • Identifying cause and effect relationships- language skills /reading

1.05, 1.06, 1.07, 1.09, 1.10
7.03, 7.06 / Natural Selection You Can See /
  • Working on a team - teamwork
  • Explaining a concept to others -communication skills
  • Identifying cause and effect relationships- language skills /reading
  • Conveying thoughts or opinions effectively - communication skills
  • Explaining a concept to others -communication skills
  • Working independently- employability skills
  • Searching for print information- information retrieval skills

1.05, 1.06, 1.07, 1.08, 1.09, 1.10, 2.02, 2.04, 7.04, 7.05 / Six Billion People on Spaceship Earth... So What /
  • Working on a team - teamwork
  • Explaining a concept to others -communication skills
  • Identifying cause and effect relationships- language skills /reading
  • Conveying thoughts or opinions effectively- communication skills
  • Explaining a concept to others -communication skills
  • Working independently- employability skills
  • Searching for print information - information retrieval skills

Balanced Systems and Their Disruption

Objective

1.01, 1.02, 1.04, 1.05, 1.07, 1.08, 1.09, 2.02, 7.01, 7.02, 7.03

Background Information

Plant and animal communities exhibit an intricate web of interdependence with one another and with the non-living parts of an ecosystem. There is a delicate balance between living and non-living elements of each ecosystem. Relationships may be described as coexistence, cooperation, or competition. Symbiotic relationships are those in which two species of organisms live in close proximity and interact with one another in one of these ways:

Commensalism – one species derives food or shelter from the other without harming that organism or getting any benefit from that organism in return

Mutualism – two species are “mutually” dependent on one another (ex. - bee and flowering plant)

Parasitism – one species (parasite) gets food from another to the detriment of the other species (host) (ex. – a dog and a flea)

As the human population grows, more space and resources are used and more waste and pollution are returned to ecosystems. Resulting changes in and loss of wildlife habitat disturb the balance of nature and are a major cause of plant and animal species extinction.

Materials:

  • Aquarium
  • Terrarium
  • Pictures of a balanced ecosystem
  • Per group of 2 students if possible:
  • Plastic bags of 12 large nails and a small block of wood with another nail driven firmly into it
  • Computer and internet access

Engage:

Prepare a plastic bag for each group with 12 large nails and one larger nail driven into a small piece of wood. Ask each group to work on a flat surface and create a balanced system of the 12 nails that balances on the head of the nail in the wood. (As students work offer hints to guide thinking if needed.) Remind students that all parts of a system must work together and therefore nails cannot be placed one at a time on the head of the nail. Suggest that a system of the 12 nails be created first on the table and then lifted up and placed on the head of the nail in the block. Once groups have been successful in building a balanced system compare this balanced system to the earth’s natural systems. In both this system of nails and in natural systems of the earth various components or parts must interact and work together to achieve and maintain balance. Just as the nails form the balanced system on the head of the upright nail, systems in nature must demonstrate a similar balanced relationship between all of their components in order to thrive. This includes complex biological, chemical, and physical conditions and organisms, all interacting and dependent on each other for a balanced ecosystem.

Model stress on the system by trying to remove nails. Determine how many nails, and which nails, can be removed before the system collapses.

Image found at:

How does the system of nails balance?

Describe how all nails are “connected” and depend on other members of the system.

  • Why are some nails more important to the system than others?
  • How could additional nails be added to this system?
  • What are some natural ecosystems?
  • What parts of an ecosystem might the nails represent?
  • What relationships exist between these parts of an ecosystem?
  • How might natural ecosystems become “unbalanced”?

Explore:

As a class observe and record observations of a balanced system of living things in one or all of these ways:

Option 1: Students build a balanced system

Student-constructed terrariums of forest, desert, and swamp environments using information from this website would be ideal.

Option 2: Students observe a local habitat

This is especially good if a stream or forest is close by. Every school, however, has a habitat for living things just outside the classroom door that can be studied first hand. This is often the best place to start before one ventures to exotic habitats like rainforests, deserts, and tundra!

Option 3: Students observe a picture of a balanced system

Pictures of habitats, ecosystems, or biomes could be used if no other resource is available. Good sources include pictures from calendars, magazines, textbooks or trade books. Books like NC Wild Places provides pictures of NC habitats, and websites such as provide pictures of biomes (rainforest, tundra, taiga, desert, temperate, and grassland) and ecosystems (shoreline, temperate ocean, TropicalOcean, river and streams, ponds and lakes, and wetlands) of the world.

  • Make a list of living and non-living parts of the system being observed.
  • Brainstorm possible connections and interactions between the non-living and living things in a balanced and healthy system.
  • List the producers, consumers, and decomposers in this balanced system.
  • Draw a food chain in this system.
  • Brainstorm a list of things that might upset the balance of this system.

Explain:

Identify the following kinds of relationships: coexistence, cooperation, and competition in the system. Look for and describe any symbiotic relationships. Classify them as mutualistic, parasistic, or commensal. Draw and describe special adaptations of organisms for survival in this system. Give examples of the “connectedness and balance” of all living and non-living parts of this system.

Elaborate:

Have student groups research and prepare a presentation for classmates on the balance of physical conditions and interactions of living things in selected habitats, ecosystems, or biomes. The website at contains great information for this research. Teacher Domain website has good multimedia material as well as a lesson plan similar to this one. These are listed under Curriculum Resources at the end of this lesson.

Students work together to learn about the physical conditions, interesting plant and animal adaptations andinteractions, and any looming threats to the existence or natural balance of living and non-living components of this system.

The group designs visuals (concept map, illustrated poster, map, chart, etc.) on poster paper, white boards, or PowerPoint presentation to record the conditions of temperature, moisture, soil quality and type, light, and other conditions that define the habitat, ecosystem, or biome being studied. Labeled drawings can be used to show examples of different types of relationships between organisms in the biome such as coexistence, cooperation, and competition. Examples of typical food chains should be illustrated.

Each group member should select a different plant or animal from the biome or ecosystem to research using the web or library resources to answer these questions:

  • What makes this organism interesting and unique?
  • What adaptations does the organism have to survive in this environment?
  • How is the organism connected to others in this environment?
  • How does it get energy for life processes? If it is an animal, what does it eat? What eats it?
  • What advantages and disadvantages does the organism provide others?
  • How would scientists classify this relationship?
  • What might happen if the population of this organism increased or decreased dramatically?
  • What factors might produce such a change in population numbers of this organism?
  • What might happen if this organism were to become extinct?
  • Student research reports should include a drawing of the organism.

Evaluate:

Groups share visuals which describe the defining characteristics of each environment studied. Individuals share visuals highlighting interesting plants and animals in the environment.

Summarize sharing by having the class compare and contrast each of the environments studied:

  • How were they all alike?
  • How was each different from the others?
  • What are some examples of interesting plant and animal adaptations for low levels of heat, light, energy, moisture, or poor soil quality?
  • What are some interesting plant and animal adaptations for high levels of heat, light, energy, or moisture?
  • What are some common threats to populations of plant and animals in these environments?

Extension:

Webquest

This webquest was designed for third graders but could be adapted for sixth grade.

This webquest is designed for sixth graders. Students design a travel brochure with information on the plants and animals visitors might observe in the biome studies.