Habitat and Life Cycles Teacher Guide

Unit

Habitat and Life Cycles

Subject

Life Science

Grade Level

ES 3-4

Activity Names

Predator and Prey

Virtual Greenhouse

Being Prepared

The students will be using computers to run these simulations. Determine whether you want the students to work one on one or in pairs. If there are enough computers it may be worthwhile to have each student run the simulations and answer the questions on their own, then pair up with another student and discuss their ideas, along with the evidence on which they are basing their thinking. After discussion, any discrepancies in their thinking could be resolved by running the simulations again.

Getting Started

If you will be using a computer lab, make the necessary arrangements in advance and allow plenty of time for exploration of the simulations.

The controls for the simulations are not always intuitive to new users. However, they always have very descriptive assistance provided in the text preceding the simulations. Encourage frustrated students to review the written instructions before attempting to further interaction with the model.

Note: In the Predator and Prey activity the controls for the rabbit and plant simulation use the arrow keys on the keyboard and the hawk and rabbits simulation uses the the mouse rather than the arrow keys.

In the Virtual Greenhouse activity the mouse controls simulations.

Suggested Timeline

There are two simulations in this unit. Determine whether you want to start with the Predator and Prey or Virtual Greenhouse. The simulations will require 2-3 class periods of 60 - 90 minutes each in order to give students adequate time to explore the simulations, collect the data, and discuss their claims and evidence. Opportunities to re-run the simulations after their discussions will assist students in solidifying their understanding of the concepts in this unit.

Thinking about the Discovery Questions

This unit introduces students to the concepts related to habitats and life cycles in the natural world. Students begin to develop understandings about how organisms are adapted to a particular habitat and how these adaptations allow them to be successful. In addition they start to how changes in a particular habitat may impact the organisms in that habitat.

The first activity, Predator and Prey, in this unit looks at the question "What adaptations help predators and prey survive?". Animals have body parts that capture and convey different kinds of information needed for growth and survival; for example, eyes for light, ears for sounds, and skin for temperature or touch. Animals respond to these inputs with behaviors that help them survive (e.g., find food, run from a predator). Plants also respond to some external inputs (e.g., turn leaves toward the sun).

The second activity, Virtual Greenhouse, in this units looks at the question "How are plants adapted to live in different environments?" Plants and animals depend on their surroundings to get what they need, including food, water, shelter, and a favorable temperature. Animals depend on plants or other animals for food. They use their senses to find food and water, and they use their body parts to gather, catch, eat, and chew the food. Plants depend on air, water, minerals (in the soil), and light to grow. Animals can move around, but plants cannot, and they often depend on animals for pollination or to move their seeds around. Different plants survive better in different settings because they have varied needs for water, minerals, and sunlight.

Misonceptions

Many students see adaptation as a deliberate action by an organism or a population to improve its chance of survival. In the theory of natural selection, populations change or "adapt" over generations by chance. This often happens because a few individuals form new combinations of existing genes or undergo genetic mutation. If this genetic change helps the organism survive in the environment, then individuals who inherit the trait will gain an advantage and "out-reproduce" other members of the population. Carefully designed instruction can help students gain a more accurate understanding of adaptation as a process that occurs over generations in a population. The way we use the word "adapt" in everyday language is probably one of the barriers to understanding. It can help to elicit prior understanding and guide students through a discussion by giving examples of "adaptation". Try using the picture below and ask children to explain how the different beaks might have evolved over time to help an entire population adapt. 

Credit: Howtosmile.org Digital Library

Learning Objectives

NGSS

• Performance Expectations
  • 3-LS4-2. Use evidence to construct an explanation for how the variations in characteristics among individuals of the same species may provide advantages in surviving, finding mates, and reproducing.
  • 3-LS4-3. Construct an argument with evidence that in a particular habitat some organisms can survive well, some survive less well, and some cannot survive at all.
• Disciplinary Core Ideas
  • Adaptation
    • For any particular environment, some kinds of organisms survive well, some survive less well, and some cannot survive at all.
  • Ecosystem Dynamics, Functioning, and Resilience
    • When the environment changes in ways that affect a place's physical characteristics, temperature, or availability of resources, some organisms survive and reproduce, others move to new locations, yet others move into the transformed environment, and some die.
  • Inheritance of Traits
    • Many characteristics of organisms are inherited from their parents.
    • Other characteristics result from individuals' interactions with the environment, which can range from diet to learning. Many characteristics involve both inheritance and environment.
  • Interdependent Relationships in Ecosystems
    • Plants depend on water and light to grow.
  • Structure and Function
    • Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior, and reproduction.
  • Variation of Traits
    • The environment also affects the traits that an organism develops.
• Practices
  • Analyzing and Interpreting Data
    • Represent data in tables and various graphical displays (bar graphs and pictographs) to reveal patterns that indicate relationships.
  • Constructing Explanations and Designing Solutions
    • Identify the evidence that supports particular points in an explanation.
  • Developing and Using Models
    • Develop models to describe phenomena.
  • Engaging in Argument from Evidence
    • Construct an argument with evidence, data, and/or a model.
• Crosscutting Concepts
  • Cause and Effect
    • Cause and effect relationships are routinely identified and used to explain change.
  • Structure and Function
    • The shape and stability of structures of natural and designed objects are related to their function(s).

NSES

• Standards
  • 4ASI1.1. Ask a question about objects, organisms, and events in the environment. This aspect of the standard emphasizes students asking questions that they can answer with scientific knowledge, combined with their own observations. Students should answer their questions by seeking information from reliable sources of scientific information and from their own observations and investigations.
  • 4CLS1.1. Organisms have basic needs. For example, animals need air, water, nutrients, and light. Organisms can survive only in environments in which their needs can be met. The world has many different environments, and distinct environments support the life of different types of organisms.
  • 4CLS1.2. Each plant or animal has different structures that serve different functions in growth, survival, and reproduction. For example, humans have distinct body structures for walking, holding, seeing, and talking.
• NSES Life Science - Organisms and Their Environment
  • All animals depend on plants. Some animals eat plants for food. Other animals eat animals that eat the plants. Plants and animals have characteristics that help them survive in a particular environment.
  • An organism's patterns of behavior are related to the nature of that organism's environment, including the kinds and numbers of other organisms present, the availability of food and resources, and the physical characteristics of the environment.
• NSES Life Science - Characteristics of Organisms
  • Organisms have basic needs. For example, animals need air, water, nutrients, and light. Organisms can survive only in environments in which their needs can be met.

Discussion: Setting the Stage

Predator and Prey

• If you visit a field where rabbits live, and spend 2-3 hours observing, what do you think you would see? What might you notice if you were to visit the field once a month over the course of several years?

  Possible answer. You might see a few rabbits and see where what plants they are choosing to eat. If you return over several months and years, you may notice an increase or decrease in rabbits and their preferred foods.

Virtual Greenhouse

• Imagine you are the owner of a greenhouse. Knowing that some plants have different requirements for survival, what can you do to help ensure the plants will thrive under your care?

  Possible answer. There are several things that might be done, for example plants that need more light might be put higher in the greenhouse while those that need lower amounts of light closer to the floor. Watering schedules would vary depending on the plants and their needs.

Discussion: Formative Questions

• What do animals need to survive?

  All animals depend on plants. Some animals eat plants for food. Other animals eat animals that eat the plants. All animals need water to survive.

• What do plants need to survive?

  Plants depend on air, water, nutrients, and light to grow.

• How are plants adapted to live in different environments?

  Different plants prefer different types and amounts of light, water, and nutrients to survive. 

• Can these three different types of plants live in the same environment? Why or why not?

  This question can be tricky. The three plants have very different structures and will not all thrive with the same amounts of sunlight exposure and water. For example, the pink flowers with large, bushy leaf systems can survive in low light; the purple flowers with moderate amounts of leaves need partial sunlight; the blue flowers with spiny leave can survive in full sunlight. But -- they could all possibly survive in the same forest if the environment provided varying gradients of sunlight and varying amounts of moisture retention/soil drainage. 

• How do the structures of organisms enable life's functions?

  Animals have body parts that capture and convey different kinds of information needed for growth and survival; for example, eyes for light, ears for sounds, and skin for temperature or touch. Animals respond to these inputs with behaviors that help them survive (e.g., find food, run from a predator). Plants also respond to some external inputs (e.g., turn leaves toward the sun).

• How do organisms obtain and use the matter and energy they need to live and grow?

  Organisms have unique characteristics that allow them to obtain matter and energy and process it for survival, growth, and reproduction.

Discussion: Wrapping Up

• What happens to ecosystems when the environment changes? Use the evidence from the data you collected from the simulation to support your claim.

  Changes in the environment may require animals and plants to migrate in order to survive. Some animals and plants may have genetic characteristics that allow them the to adapt to those changes over time, and through multiple generations. Some environmental changes can be catastrophic to habitats and can cause extinction of plants, animals, or both. 

• How and why do organisms interact with their environment and what are the effects of these interactions?

  Plants and animals interact with the environment for the purpose of survival, growth, and to reproduce. If there are more plants and animals than the environment can support, or if the conditions within that environment change, the animals may need to find a new environment in which they can find the fundamentals necessary for survival. If it is not possible to migrate, animal populations that have the genetic material that allows them to adapt to the changed conditions may survive. Plant populations that have the genetic material that allows them to adapt to the conditions may survive. Plants without the genetic characteristics that allow them to adapt will die. Plant seeds that have been carried to an environment with the right conditions may survive and grow in the new environment.

Additional Background

From the Framework for Science K-12, Grade Band Endpoints for Life Science:

By the end of grade 2: All organisms have external parts. Different animals use their body parts in different ways to see, hear, grasp objects, protect themselves, move from place to place, and seek, find, and take in food, water and air. Plants also have different parts (roots, stems, leaves, flowers, fruits) that help them survive, grow, and produce more plants.

By the end of grade 5: Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior, and reproduction. (Boundary: Stress at this grade level is on understanding the macro-scale systems and their function, not microscopic processes.)

By the end of grade 8. All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular). Unicellular organisms (microorganisms), like multicellular organisms, need food, water, a way to dispose of waste, and an environment in which they can live. Within cells, special structures are responsible for particular functions, and the cell membrane forms the boundary that controls what enters and leaves the cell. In multicellular organisms, the body is a system of multiple interacting subsystems. These subsystems are groups of cells that work together to form tissues or organs that are specialized for particular body functions. (Boundary: At this grade level, only a few major cell structures should be introduced.)

By the end of grade 12. Systems of specialized cells within organisms help them perform the essential functions of life, which involve chemical reactions that take place between different types of molecules, such as water, proteins, carbohydrates, lipids, and nucleic acids. All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells. Multicellular organisms have a hierarchical structural organization, in which any one system is made up of numerous parts and is itself a component of the next level. Feedback mechanisms maintain a living system's internal conditions within certain limits and mediate behaviors, allowing it to remain alive and functional even as external conditions change within some range. Outside that range (e.g., at a too high or too low external temperature, with too little food or water available), the organism cannot survive. Feedback mechanisms can encourage (through positive feedback) or discourage (negative feedback) what is going on inside the living system.

Analysis

Predator and Prey

1. Look at the graph below. Between 0 and 10 seconds, what happened to the plant population?

   The population of rabbits went slightly up, then down a little, stayed almost the same for awhile, then went back up.

2. Look at the graph above. Between 10 and 30 seconds, what happened to the plant population?

   The plant population in the graph had a downward trend from the 10 second point to the 30 second point. Q. What would happen to the rabbit population in the snowy field if there were no hawks? A: The rabbit population would likely increase to the point that all the food in the field would be eaten, and would result in all the rabbits dying. Q. If there were no hawks, and the environment changed from snowy to brown, what might happen to the rabbit population? A. Without hawks, the color of the rabbit is not relevant. The rabbits would likely reproduce until they eat all the food. At that point the population will decline and eventually most of the rabbits will die.

3. What would happen to the rabbit population in the snowy field if there were no hawks?

   The rabbit population would likely increase to the point that all the food in the field would be eaten, and would result in all the rabbits dying.

4. If there were no hawks, and the environment changed from snowy to brown, what might happen to the rabbit population?

   Without hawks, the color of the rabbit is not relevant. The rabbits would likely reproduce until they eat all the food. At that point the population will decline and eventually most of the rabbits will die.

Virtual Greenhouse

1. In which flower box does this plant grow best?

   This plant grows best in Box E.

2. Why does each type of plant do better at a different light level?

   Different plants survive better in different settings because they have varied needs for water, minerals, and sunlight.

3. Can these three different types of plants live in the same environment? Why or why not?

   These three plants will generally live in different environments due to their varied needs for water, minerals, and sunlight. It is possible that these plants could live in the same area. For example, in a forest, the plants might find varying amounts of light, and moisture, and even different minerals, depending where in that forest they are located.

Further Investigation

Predator Prey

In the Further Investigation section of this simulation, students have the opportunity to customize their model, by deciding which elements of the ecosystem they would like to incorporate. The model begins with a snowy ecosystem, and both white and brown rabbits. Over time the snow melts, which impacts the hawks ability to find the rabbits depending on their color, and the color of the field at that time. The graphs show the results through the season on the populations of both the white and brown rabbits.

Discuss these relationships with your students based on a local ecosystem to help students transfer their understanding to a new and different environment.

Virtual Greenhouse

The Further Investigation model in Virtual Greenhouse allows students to plant mystery seeds in planters with varying amounts of water, and run the model. Some of the plants thrive and flower, others shrivel. Students can then move the shriveled plants to the environment in which they believe the plants will thrive, and see what results.

Consider field trips to a real greenhouse to observe how the various needs of different plants are being met in the greenhouse environment, and to hear from the horticulturist the variation in needs of the plants and the work necessary to ensure the different needs are being met. A field trip to a natural setting would allow students to observe where different kinds of plants are growing, and the various conditions in the environment of each plant. (Canopy, understory, shade, full sun, moist/dry soil, etc..) Student teams could be assigned to an area, and asked to analyze the conditions for the plants there,