| (a) Introduction.
(1) Grade 7 science is interdisciplinary in nature;
however, much of the content focus is on organisms and the environment.
National standards in science are organized as multi-grade blocks
such as Grades 5-8 rather than individual grade levels. In order to
follow the grade level format used in Texas, the various national
standards are found among Grades 6, 7, and 8. Recurring themes are
pervasive in sciences, mathematics, and technology. These ideas transcend
disciplinary boundaries and include change and constancy, patterns,
cycles, systems, models, and scale. The strands for Grade 7 include
the following.
(A) Scientific investigation and reasoning.
(i) To develop a rich knowledge of science and the
natural world, students must become familiar with different modes
of scientific inquiry, rules of evidence, ways of formulating questions,
ways of proposing explanations, and the diverse ways scientists study
the natural world and propose explanations based on evidence derived
from their work.
(ii) Scientific investigations are conducted for different
reasons. All investigations require a research question, careful observations,
data gathering, and analysis of the data to identify the patterns
that will explain the findings. Descriptive investigations are used
to explore new phenomena such as conducting surveys of organisms or
measuring the abiotic components in a given habitat. Descriptive statistics
include frequency, range, mean, median, and mode. A hypothesis is
not required in a descriptive investigation. On the other hand, when
conditions can be controlled in order to focus on a single variable,
experimental research design is used to determine causation. Students
should experience both types of investigations and understand that
different scientific research questions require different research
designs.
(iii) Scientific investigations are used to learn about
the natural world. Students should understand that certain types of
questions can be answered by investigations, and the methods, models,
and conclusions built from these investigations change as new observations
are made. Models of objects and events are tools for understanding
the natural world and can show how systems work. Models have limitations
and based on new discoveries are constantly being modified to more
closely reflect the natural world.
(B) Matter and energy. Matter and energy are conserved
throughout living systems. Radiant energy from the Sun drives much
of the flow of energy throughout living systems due to the process
of photosynthesis in organisms described as producers. Most consumers
then depend on producers to meet their energy needs. Subsequent grade
levels will learn about the differences at the molecular and atomic
level.
(C) Force, motion, and energy. Force, motion, and energy
are observed in living systems and the environment in several ways.
Interactions between muscular and skeletal systems allow the body
to apply forces and transform energy both internally and externally.
Force and motion can also describe the direction and growth of seedlings,
turgor pressure, and geotropism. Catastrophic events of weather systems
such as hurricanes, floods, and tornadoes can shape and restructure
the environment through the force and motion evident in them. Weathering,
erosion, and deposition occur in environments due to the forces of
gravity, wind, ice, and water.
(D) Earth and space. Earth and space phenomena can
be observed in a variety of settings. Both natural events and human
activities can impact Earth systems. There are characteristics of
Earth and relationships to objects in our solar system that allow
life to exist.
(E) Organisms and environments.
(i) Students will understand the relationship between
living organisms and their environment. Different environments support
different living organisms that are adapted to that region of Earth.
Organisms are living systems that maintain a steady state with that
environment and whose balance may be disrupted by internal and external
stimuli. External stimuli include human activity or the environment.
Successful organisms can reestablish a balance through different processes
such as a feedback mechanism. Ecological succession can be seen on
a broad or small scale.
(ii) Students learn that all organisms obtain energy,
get rid of wastes, grow, and reproduce. During both sexual and asexual
reproduction, traits are passed onto the next generation. These traits
are contained in genetic material that is found on genes within a
chromosome from the parent. Changes in traits sometimes occur in a
population over many generations. One of the ways a change can occur
is through the process of natural selection. Students extend their
understanding of structures in living systems from a previous focus
on external structures to an understanding of internal structures
and functions within living things.
(iii) All living organisms are made up of smaller units
called cells. All cells use energy, get rid of wastes, and contain
genetic material. Students will compare plant and animal cells and
understand the internal structures within them that allow them to
obtain energy, get rid of wastes, grow, and reproduce in different
ways. Cells can organize into tissues, tissues into organs, and organs
into organ systems. Students will learn the major functions of human
body systems such as the ability of the integumentary system to protect
against infection, injury, and ultraviolet (UV) radiation; regulate
body temperature; and remove waste.
(2) Science, as defined by the National Academy of
Sciences, is the "use of evidence to construct testable explanations
and predictions of natural phenomena, as well as the knowledge generated
through this process." This vast body of changing and increasing knowledge
is described by physical, mathematical, and conceptual models. Students
should know that some questions are outside the realm of science because
they deal with phenomena that are not scientifically testable.
(3) Scientific hypotheses are tentative and testable
statements that must be capable of being supported or not supported
by observational evidence. Hypotheses of durable explanatory power
that have been tested over a wide variety of conditions become theories.
Scientific theories are based on natural and physical phenomena and
are capable of being tested by multiple independent researchers. Students
should know that scientific theories, unlike hypotheses, are well
established and highly reliable, but they may still be subject to
change as new information and technologies are developed. Students
should be able to distinguish between scientific decision-making methods
and ethical/social decisions that involve the application of scientific
information.
(4) Statements containing the word "including" reference
content that must be mastered, while those containing the phrase "such
as" are intended as possible illustrative examples.
(b) Knowledge and skills.
(1) Scientific investigation and reasoning. The student,
for at least 40% of the instructional time, conducts laboratory and
field investigations following safety procedures and environmentally
appropriate and ethical practices. The student is expected to:
(A) demonstrate safe practices during laboratory and
field investigations as outlined in Texas Education Agency-approved
safety standards; and
(B) practice appropriate use and conservation of resources,
including disposal, reuse, or recycling of materials.
(2) Scientific investigation and reasoning. The student
uses scientific practices during laboratory and field investigations.
The student is expected to:
(A) plan and implement comparative and descriptive
investigations by making observations, asking well defined questions,
and using appropriate equipment and technology;
(B) design and implement experimental investigations
by making observations, asking well defined questions, formulating
testable hypotheses, and using appropriate equipment and technology;
(C) collect and record data using the International
System of Units (SI) and qualitative means such as labeled drawings,
writing, and graphic organizers;
(D) construct tables and graphs, using repeated trials
and means, to organize data and identify patterns; and
(E) analyze data to formulate reasonable explanations,
communicate valid conclusions supported by the data, and predict trends.
(3) Scientific investigation and reasoning. The student
uses critical thinking, scientific reasoning, and problem solving
to make informed decisions and knows the contributions of relevant
scientists. The student is expected to:
(A) analyze, evaluate, and critique scientific explanations
by using empirical evidence, logical reasoning, and experimental and
observational testing, so as to encourage critical thinking by the
student;
(B) use models to represent aspects of the natural
world such as human body systems and plant and animal cells;
(C) identify advantages and limitations of models such
as size, scale, properties, and materials; and
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