7.4.2.1 Natural Systems

Grade: 
7
Subject:
Science
Strand:
Life Science
Substrand:
Interdependence within the Earth System
Standard 7.4.2.1

Natural systems include a variety of organisms that interact with one another in several ways.

Benchmark: 7.4.2.1.1 Populations & Communities

Identify a variety of populations and communities in an ecosystem and describe the relationships among the populations and communities in a stable ecosystem.

Benchmark: 7.4.2.1.2 Roles of Organisms

Compare and contrast predator/prey, parasite/host and producer/consumer/decomposer relationships.

Benchmark: 7.4.2.1.3 Populations & Resources

Explain how the number of populations an ecosystem can support depends on the biotic resources available as well as abiotic factors such as amount of light and water, temperature range and soil composition.

Overview

Standard in Lay Terms 

Organisms in nature interact in various ways.

Big Ideas and Essential Understandings 

Big Idea:

Natural systems are a dynamic interaction between organisms and their ecosystems.  Minnesota is home to diverse and varied organisms. From populations of wolves and deer engaged in predator prey relationships, to snow depth and harsh temperatures: living and non-living components of an ecosystem influence the survival of species and their reproductive success. The emphasis of this standard is on the student understanding of stability and change in ecosystems.

Benchmark Cluster 

MN Standard Benchmarks

7.4.2.1.1

Identify a variety of populations and communities in an ecosystem and describe the relationships among the populations and communities in a stable ecosystem.

7.4.2.1.2

Compare and contrast predator/prey, parasite/host and producer/consumer/decomposer relationships.

7.4.2.1.3

Explain how the number of populations an ecosystem can support depends on the biotic resources available as well as abiotic factors such as amount of light and water, temperature range and soil composition.

THE ESSENTIALS:

                                   

©Gary Larson

Correlations 

Life Science

Content Standard C
As a result of their activities in grade 7, all students should develop understanding of

 

1.    Structure and function in living systems

2.    Reproduction and heredity

3.    Regulation and behavior

4.    Populations and ecosystems

5.    Diversity and adaptations of organisms

5A

Science in the middle grades should provide students with opportunities to enrich their growing knowledge of the diversity of life on the planet and to begin to connect that knowledge to what they are learning in geography. That is, whenever students study a particular region in the world, they should learn about the plants and animals found there and how they are like or unlike those found elsewhere. Tracing simple food webs in varied environments can contribute to a better understanding of the dependence of organisms (including humans) on their environment.

By the end of the 8th grade, students should know that

  • One of the most general distinctions among organisms is between plants, which use sunlight to make their own food, and animals, which consume energy-rich foods. Some kinds of organisms, many of them microscopic, cannot be neatly classified as either plants or animals. 5A/M1

5D

As students build up a collection of cases based on their own studies of organisms, readings, and film presentations, they should be guided from specific examples of the interdependency of organisms to a more systematic view of the kinds of interactions that take place among organisms. But a necessary part of understanding complex relationships is to know what a fair proportion of the possibilities are. The full-blown concept of ecosystem (and that term) can best be left until students have many of the pieces ready to put in place. Prior knowledge of the relationships between organisms and the environment should be integrated with students' growing knowledge of the earth sciences.

By the end of the 8th grade, students should know that

  • In all environments, organisms with similar needs may compete with one another for limited resources, including food, space, water, air, and shelter. 5D/M1a*
  • The world contains a wide diversity of physical conditions, which creates a wide variety of environments: freshwater, marine, forest, desert, grassland, mountain, and others. In any particular environment, the growth and survival of organisms depend on the physical conditions. 5D/M1b*
  • Interactions between organisms may be for nourishment, reproduction, or protection and may benefit one of the organisms or both of them. Some species have become so dependent on each other that neither could survive without the other. 5D/M2*
  • One organism may scavenge or decompose another. 5D/M2b
  • Given adequate resources and an absence of disease or predators, populations of organisms in ecosystems increase at rapid rates. Finite resources and other factors limit their growth. 5D/M3** (NSES)
  • All organisms, both land-based and aquatic, are interconnected by their need for food. This network of interconnections is referred to as a food web. The entire earth can be considered a single global food web, and food webs can also be described for a particular environment. At the base of any food web are organisms that make their own food, followed by the animals that eat them, then the animals that eat those animals, and so forth. 5D/M4** (BSL)

Framework for K-12 Science Education

Organisms and populations of organisms  are dependent on their environmental interactions both with other living things and with nonliving factors. Growth of organisms and population increases are limited by access to resources.  In any ecosystem, organisms  and populations with similar requirements for food, water,  oxygen, or other resources may compete with each other for limited resources,  access to which consequently constrains their growth  and reproduction. Similarly, predatory interactions may reduce the number of organisms or eliminate whole populations of organisms. Mutually beneficial interactions, in contrast, may become so interdependent that  each organism requires the other for survival. Although the species involved in these competitive, predatory, and mutually beneficial interactions vary across ecosystems, the patterns of interactions of organisms with their environments, both living and nonliving, are shared.  8LS2.A

Common Core Standards (i.e. connections with Math, Social Studies or Language Arts Standards):  connects with social studies through land use and land availability.

Misconceptions

Student Misconceptions 
  • 7.4.2.1.1 Lower elementary-school students can understand simple food links involving two organisms. Yet they often think of organisms as independent of each other but dependent on people to supply them with food and shelter. Upper elementary-school students may not believe food is a scarce resource in ecosystems, thinking that organisms can change their food at will according to the availability of particular sources. [1]
  • 7.4.2.1.1, 7.4.2.1.3 Students of all ages think that some populations of organisms are numerous in order to fulfill a demand for food by another population. [2]
  • Middle-school and high-school students may believe that organisms are able to effect changes in bodily structure to exploit particular habitats or that they respond to a changed environment by seeking a more favorable environment. [3]
  • It has been suggested that the language about adaptation used by teachers or textbooks to make biology more accessible to students may cause or reinforce these beliefs. [4]
  • 7.4.2.1.2 Some middle-school students think dead organisms simply rot away. They do not realize that the matter from the dead organism is converted into other materials in the environment. Some middle-school students see decay as a gradual, inevitable consequence of time without need of decomposing agents. [5]

[1] Leach, J., Driver, R., Scott, P., Wood-Robinson, C. (1992). Progression in understanding of ecological concepts by pupils aged 5 to 16.

[2] Leach, J., Driver, R., Scott, P., Wood-Robinson, C. (1992). Progression in understanding of ecological concepts by pupils aged 5 to 16.

[3] Jungwirth, E. (1975). Preconceived adaptation and inverted evolution (a case study of distorted concept formation in high school biology).Australian Science Teacher Journal, 21, 95-100.

Clough, E.E, Wood-Robinson, C. (1985). How secondary students interpret instances of biological adaptation.Journal of Biological Education, 19, 125-130.

[4] Jungwirth, E. (1975). Preconceived adaptation and inverted evolution (a case study of distorted concept formation in high school biology).Australian Science Teacher Journal, 21, 95-100.

[5] Smith, E., Anderson, C. (1986). Alternative conceptions of matter cycling in ecosystems. Paper presented at the annual meeting of the National Association for Research in Science Teaching.

Vignette

Mrs. G held up the two liter bottle and said, "Here is what we are going to use for some serious rotting, decomposition."

Jake stated, "But there is nothing in it!"

Melissa spoke up, "Yeah, how can we fit stuff inside the top? Will it be like the ship in the bottle mystery we talked about last week?"

"No, no, no.....we are going to have to do some engineering of the bottles to get them ready for the good stuff that you'll place inside." Mrs. G had gone to the local pop distributor and asked if they wanted to donate some bottles for her science class. The provided her with a hundred, new bottles and lids, as a donation. So, she drove up filled her hatchback with bottles and drove back to school. All it required was a letter of thanks with the school letterhead.

This lesson would be seen in a 7th grade classroom when the topic of energy flow through living systems is covered. Students can create compost columns using two liter bottles and a good supply of lawn, garden and food waste. The compost columns allow students to create a variety of experiments. Variables such as type of compost material, incubation temperature, moisture content, pH are among some the ideas that Mrs. G's students chose to explore. The independent variables are easy to obtain and measure as well as the energy expended as the columns do their work. Temperature of the columns is a direct measure of the energy contained in the organic material as well as the energy consumed by the organisms that were decided upon by students to do the decomposing.

Student constructed the columns according to Mrs. G's instruction. The building required the use of some sharp instruments and heating up some dissecting probes and nails, so she asked for some parent volunteers for the day. When it was all said and done the students constructed decomposition columns out of the bottles that would be easy to maintain, observe and measure.

One of the students decided they would bring in grass clipping from the lawn mower. Gina wondered how the amount of water in the grass might impact how fast it would rot. So she and her group used three columns to study various amounts of moisture and rate of decomposition.

"Mrs. G, I think that the column that is the wettest will decompose the fastest." Gina said.

"How will you know when it has decomposed?" asked Mrs. G.

"Usually, we take the lawn clippings and put them in our compost pile out back. My dad sprays it down with water and pretty soon it turns to dirt that he puts on the garden. It starts out green grass clippings and then it looks like dirt. So I think it will look like dirt when it is all decomposed." Gina answered.

The investigation began for Mrs. G's class. There were many columns that needed attention daily, depending on the independent variable. The students made observations daily for the course of the experiment, that included qualitative descriptions and quantitative measures. Data tables filled, graphs were created, hypotheses proved and disproved. Conclusions were drawn.

The students were able to watch the energy leave the organic materials as they decomposed. Mrs. G asked some biology students from the high school to come over with probeware and measure things like temperature and carbon dioxide content of the bottles. The 7th graders were impressed with the technology of plug and play with the probes. The carbon dioxide probes were also impressive as students would breathe on them and watch the values go up and down.

Mrs. G brought in sugar cubes to burn and then burned some of the materials students had used in the columns as well. That lead to an interesting discussion of energetics and enzymes. The students all agreed it is better to release energy slowly over time that burst into flame after they eat their coco-blops cereal.

When the lab was all finished the composted material was used by Mrs. G for the plants in the greenhouse as a source of soil and nutrients. Students planted bean seeds in the compost and compared their composted soils to see who could get the tallest plants.

Mrs. G was able to make connections as the energy and nutrients flowed through these simple systems. Students watched as organic material was recycled, energy released and nutrients picked up by other living things.

Resources

Instructional Notes 

Instructional suggestions/options:

Project Wild K-12 activity guide This is a great resource for many levels of science. In order to get the maximum benefit from Project Wild, Wet, Learning Tree, look for the continuing series of workshops frequently happening around the state.

Selected activities:

Instructional Resources 

Additional resources or links

7.4.2.1.2 Competition on Sable Island In this lesson, students will discuss the concept of competition in nature and will learn about competition between the gray seals and harbor seals of Sable Island. They will conclude by illustrating maps of the island to show the seals' feeding behaviors and the shark's predatory activities, and they'll write paragraphs describing their maps.

The BBC series Planet Earth has a amazing photograhy, but also lots of relationship between organisms. The segment about "Caves" shows a 100 meter high pile of bat guano and all the organisms that depend on that occurring. Predator prey relationships can be seen in the bats leaving the cage in the pitch of night and a snake, relying on infrared light (heat) from the bats to try and strike one for a meal.

Crocodiles are famously sun-loving reptiles, so why would they live in complete darkness in cool, dank caves? And where else would they do it but in Madagascar, home to some of the most unusual creatures ever to evolve on Earth? On "Secrets of the Crocodile Caves," NOVA ventures into a wilderness unlike any other.

New Vocabulary 

Vocabulary/Glossary

  • abiotic non living components of an ecosystem (weather, wind, water...)
  • biotic living components of an ecosystem
  • environment  all the living and nonliving things with which an organism interacts
  • ecology  study of relationships and interactions of abiotic and biotic components
  • ecosystem  group of organisms in an area that interact with  one another together with their non living environment.
  • community  living part of any ecosystem
  • population  group of the same type of organisms living together in the same area
  • habitat  place in which an organism lives
  • producer  organism that can make its own food
  • consumer  organism that feeds directly or indirectly on producers
  • decomposer  organism that feeds on dead organic matter and breaks it down into simpler substances
  • food chain  food and energy links between the different plants and animals in an ecosystem
  • food web  all the food chains in an ecosystem that are connected
  • niche  role of an organism in its community or environment
  • competition  struggle among living things to get the proper amount of food, water, and energy
  • predator  animal that kills and eats other animals.
  • prey  organism that is killed and eaten by another animal
Technology Connections 

Internet connections if possible to access lessons dealing with predator /prey relationship. Competition on Sable Island  In this lesson, students will discuss the concept of competition in nature and will learn about competition between the gray seals and harbor seals of Sable Island. They will conclude by illustrating maps of the island to show the seals' feeding behaviors and the shark's predatory activities, and they'll write paragraphs describing their maps.

Cameras/flip videos/microscopes for doing science and recording pictures, data.

web based journey north  A global study of wildlife migration and seasonal change.

Hardware cameras that connect to microscope to see microscopic organisms and display them on the white board

Assessment

Students:

Abiotic and Biotic Factors - You are a scientist who is studying the ecosystem of an amusement park. List all the abiotic and biotic factors in this ecosystem. Identify at least five relationships. Identify how a change in one abiotic factor would impact other factors in the amusement park ecosystem.

The diagram below shows the feeding relationships between populations of organisms in an area. The arrows point from the organisms being eaten to the organisms that eat them.

Using only the the relationships between the organisms shown in the diagram, if most of the worms are killed, which of the following statements describes what will happen to the number of robins and why?

1.    The number of robins will increase because there are fewer worms to eat them.

2.    The number of robins will decrease because there are not enough worms for them to eat.

3.    The number of robins will stay the same because the worms are killed, not the robins.

4.    The number of robins will stay the same because a change in the population of worms will not affect any other population of organisms.

The diagram below shows the feeding relationships between populations of organisms in an area. The arrows point from the organisms being eaten to the organisms that eat them.

Using only the relationships between the organisms shown in the diagram, which of the populations of organisms would be affected if the seaweed were removed?

1.    Only the populations of large fish, seals, and killer whales would be affected.

2.    The populations of all of the organisms except the killer whales would be affected.

3.    Only the populations of shrimp, large fish, and small fish would be affected.

4.    The populations of all of the organisms would be affected.

Sparrows and bluebirds are living in the same park. They both use the same kind of nesting sites. Which of the following statements is TRUE?

1.    The sparrows compete with other sparrows, the bluebirds compete with other bluebirds, but the sparrows and bluebirds do not compete with each other for the nesting sites.

2.    The sparrows do not compete with other sparrows, the bluebirds do not compete with other bluebirds, and the sparrows and bluebirds do not compete with each other for the nesting sites.

3.    The sparrows compete with other sparrows, the bluebirds compete with other bluebirds, and the sparrows and bluebirds compete with each other for the nesting sites.

4.    The sparrows do not compete with other sparrows, the bluebirds do not compete with other bluebirds, but the sparrows and bluebirds compete with each other for the nesting sites.                   

Teachers:

  • Questions could be used as self-reflection or in professional development sessions.
  • What are the avantages and disadvantages of technology vs hands-on data collection by students?
  • How is the anthropomorphic depiction (giving animals human characteristics) of animals in children's videos influencing our students? 

Administrators:                      

  • Students acting out roles as predators/prey, lots of activity in the classroom or outside. 
  • Students might be given the chance to have input in local land use issues and administration may be asked to aid in transportation to and from.

Differentiation

Struggling Learners 

Struggling and At-Risk:

Snow, D. (2003). Noteworthy perspectives: Classroom strategies for helping at-risk students (rev. ed.). Aurora, CO: Mid-continent Research for Education and Learning.

In 2002, McREL conducted a synthesis of recent research on instructional strategies to assist students who are low achieving or at risk of failure. From this synthesis of research, McREL identified six general classroom strategies that research indicates are particularly effective in helping struggling students achieve success.

Hands on labs like the one in the vignette helps special ed students comprehend concepts better than straight book work.

Posters will also allow these students to create a food chain if they have trouble with the food web. 

Hands on activities as in the vignette will help at risk students.

English Language Learners 

Herr, N. (2007). The sourcebook for teaching science. This page contains                strategies to help teachers better attend to the needs of their ELL learners. These strategies are grouped according to the following learning tasks:                           listening, visualization, interpersonal communication, laboratory,                              demonstrations, reading and writing, instruction and vocabulary

Posters will also allow ELL students to use pictures to help with the vocabulary necessary.

Extending the Learning 

G/T

Teachers First is an educational support website that may help with G/T students

Cogito is another website that is available for G/T Students.

Gifted students may have more in-depth food webs.

Multi-Cultural 

Science education should include the use of culturally relevant content.  Atwater (1995a-c) and Banks(1987,1988) have proposed several ways to integrate culturally relevant content into the curriculum.  The value of using such approaches is that they can improve the conversation about beliefs in science and hone beliefs about science for all students.

Posters will also allow multi-cultural students to use pictures to help with the vocabulary necessary.

Multicultural science education.  Official NSTA Position Statement.

Freelang.net hosts a English to Ojibwe and Ojibwe to English dictionary that may be used to look up meanings to vocabulary words.

Activities like those in the vignette would help students

Special Education 

Posters of  food webs will allow special education students to find pictures from magazines or the internet to help them create food webs.

Technologies for Special Needs Students: In their newsletter, "Tech Trek", from the National Science Teachers Association, there are suggestions for using                  technology including voice recognition software

Hands on labs like the one in the vignette helps special ed students comprehend concepts better than straight book work.

Parents/Admin

Parents 

Help study with vocabulary terms.  Hear about the composting taking place in the classroom.

Comments

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