N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
Cycles and Adaptations
A system can include processes, structures, and cycles as well as objects. Systems
often contain other systems that may interact. There is interdependency of the
components within a system. Systems should be emphasized as students
investigate the roles of various organisms within an ecosystem.
Constancy and change are essential features of the natural world. As students
observe the world around them, they look for evidence of what changes and what
does not change. Because change is a continuing thread in science, it should not be
taught in isolation but incorporated in all units of science study. Change influences
systems (including cycles). A very small change in a system can produce major
differences in what the system will be like in the future. For example, if one
organism in an ecosystem dies out, the ecosystem could change dramatically over
time.
One way scientists conclude that an ecosystem has changed is by studying treegrowth rings. In general, each ring on a tree represents one year of growth. The
widths differ due to changes in the climate and water availability. In the picture
below, the thick, inner rings show conditions were favorable for tree’s growth,
whereas the thin, outer rings indicate less favorable conditions. One year’s growth
is represented by a light band and a dark band. The light band, earlywood,
represents growth in the spring or wet season. The dark band, latewood,
represents growth in the summer or dry season (see illustration on the following
page). Favorable conditions are dependant on many factors: tree type,
temperature, wind, amount of precipitation, soil composition, sunlight, and insects.
These factors may differ from year to year. Using this information, scientists can
conclude what the climate was like in the past.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
2
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
In this unit, students analyze and compare how adaptive characteristics
increase the ability of a species to survive and reproduce. In an environment
the living and nonliving things that affect each other, or interact, form an
ecosystem. An ecosystem contains many habitats, or places, where many organisms
live and where their basic needs are met. In previous grades, students have
studied the composition of various habitats and the interdependency of living
organisms with each other and with nonliving parts of ecosystems. In 5th grade,
students will understand that different species may live in the same habitat, but
each one has a specific niche (role). For example, deer, rabbits, and squirrels may
live in the same leafy forest, but because deer browse higher up on trees, rabbits
graze on grasses, and squirrels eat acorns, each animal occupies a different niche.
Adaptations are inherited traits and learned behaviors that help a species meet its
needs and survive. If a species is to survive, individuals must reproduce and pass
on their traits to future generations. Adaptations may create a change in a system,
because they may cause one particular species to be favored over another,
resulting in a shift in the balance within an ecosystem. Students should have
learning experiences with a variety of ecosystems, such as desert, forest,
grassland, wetland, and ocean. A review of the interactions in food webs and food
chains will reinforce student understanding of the importance of adaptations.
The arrows in a food web or food chain should always show the flow of energy
through a system. They should point from the organism being consumed to the
organism doing the consuming.
Example of a simple food chain with arrows showing energy flow:
Example of a food web with arrows showing energy flow:
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
Sun
By describing the unique adaptive characteristics of various species, students will
understand how a diversity of organisms can co-exist within an ecosystem. By
identifying the commonalities of organisms adapted to a particular ecosystem,
students will predict whether an organism can survive and reproduce. For
example, desert organisms have adaptations to conserve water; therefore, a rain
forest plant, lacking this adaptation, will not be able to survive in a desert.
All living things reproduce to make more of their own kind. The stages in the life of
a living organism as it grows, develops, and matures to reproduce to the next
generation are known as its life cycle. Students will describe and compare life
cycles of plants and animals. The following charts provide a basis for comparisons
of plants and animals. Students should note differences and similarities between
and within the life cycles of plants and animals.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
Animals
Hatch from
eggs
Birds
Insects
Live birth
Most mammals
Some fish
Plants
Non-seed Plants
(Spores)
Mosses
Ferns
Seed Plants
(Seeds)
Flowering Plants
Conifers
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
The focus for students is to compare, not memorize, plant and animal life cycles.
For example, students could compare the life cycles of the sparrow and rabbit as
in the diagram below.
Sparrows
Hatch from egg
Nest in a tree
Feed their young
Rabbits
Nests
Parents care for
young
Young look like
parents
Grow and
change
Live birth
Nest in a burrow
Nurse their young
Organisms have two main types of traits: those that are inherited and those that
are learned. Inherited traits are passed from parents to offspring in plants and
animals. In previous grades students learned that offspring generally look like
their parents. In fifth grade this concept should be expanded to include more
specific examples and to further differentiate between inherited and learned
characteristics. When studying learned characteristics, the focus in 5th grade
shifts to those behaviors that result from environmental influence. Some examples
are outlined in the chart.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Inherited
Revised May 2007
Learned-Environmental influence
The color of your hair
Penguins huddling to keep warm
A snake’s skin
A leaf’s shape
A raspberry bush produces raspberries
A giraffe’s long neck
Clarifying Statements
A cow runs at the sound of a rattle
snake
Fish come to the top of the bowl when
you feed them
When the fire alarm sounds, we exit the
building
Rabbit avoiding sharp cactus spines
Cycles
Most of the materials that organisms need are present in an ecosystem and are
cycled through nature and used and reused by living organisms. Students must
understand the significance of the carbon, nitrogen, and water cycles in relation to
animals, plants, and ecosystems. These cycles are introduced in The Natural World
while mastery of the carbon, nitrogen and water cycles are accomplished during
this unit of study.
The carbon cycle is the continual movement of carbon dioxide and oxygen between
living things in ecosystems. Living organisms get the oxygen they need in order to
live by breathing air. They utilize the oxygen in the air during respiration and
release carbon dioxide back into the air as a waste product of this process. Plants
need carbon dioxide to make food during photosynthesis-the process by which
plants capture light energy from the sun and use it to manufacture food (sugars)
from carbon dioxide and water. Oxygen is released back to environment as a waste
product of this process. Decomposition is also a process that contributes to this
cycle. Fungi and bacteria obtain energy by breaking down waste or remains of other
living things. Carbon dioxide is released into the environment through this process.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
Decomposers
release carbon
dioxide.
Teacher background, please note: Plants also carry on respiration and use oxygen
in a similar way to animals. This process is different from photosynthesis. A
common misconception that many students and adults hold is that plants do not
need oxygen. Plants use oxygen to carry on respiration within their cells to release
the energy they have made.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
The nitrogen cycle is the constant movement of nitrogen between living things and
the environment. Nitrogen is one substance needed to make up structures in living
organisms. It is the most abundant gas in the atmosphere, but most organisms
cannot use this form of nitrogen. Decomposers return nitrogen compounds from
dead organisms into the soil. The processes in the nitrogen cycle change the
nitrogen into usable forms for living organisms. After nitrogen gas is changed to a
form plants can use, plants pass the nitrogen to animals through the food chain.
Plants and animals return nitrogen to the environment in their wastes. Bacteria
break down this form of nitrogen and release nitrogen gas back into the
atmosphere.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
The water cycle is the constant movement of water between the surface of the
Earth and the atmosphere through the processes of evaporation and transpiration,
condensation, and precipitation. In previous grades students learned the process
of evaporation, condensation, and precipitation. In fifth grade students should
understand that transpiration is a loss of water through a plant’s leaves.
Transpiration
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t – 5 t h G rad e S ci en c e
Cycles and Adaptations
Unit 5
Clarifying Statements
Revised May 2007
Cycles and Adaptations (cont’d)
Note: Many campuses use the Constancy and Change Vistas, which contain lessons
on either lifecycles or adaptations. The Vistas suggest the following organisms
(focus is indicated in parenthesis):
Kindergarten – Ladybugs (life cycle)
3rd Grade – Frogs (adaptations)
1st Grade – Mealworms (life cycle)
4th Grade – Bats (adaptations)
2nd Grade – Butterflies (life cycle)
5th Grade – Brown Pelican (adaptations)
Dissections are not recommended for elementary students.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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