Science

Draft - Updated 6/13/01

7th grade

1. The student understands and uses scientific concepts and principles.

Life Sciences

Biological Evolution

1.1 Describe how biological evolution accounts for species diversity, adaptation, natural selection, extinction, and change in organisms over time.

Elaborations :

• Millions of animals, plants, and microorganisms are alive today. Although species of organisms may look different, analysis of internal structures, similarities in chemical processes, and evidence of common ancestry point to unity among organisms.
• Biological evolution suggests that the diversity of species developed over many generations. Mutations in the genes of individual organisms give rise to modifications in the characteristics of organisms. Species acquire unique characteristics through biological adaptation, involving the selection of naturally occurring variations in populations.
• Biological adaptations include changes in structures, behaviors, or physiology that enhance an organism's survival and reproductive success in a particular environment. Changes in environmental conditions can affect the survival of individual organisms or entire species.
• Small differences between parents and offspring can accumulate (through differential breeding) in successive generations. In this way, descendants can be very different from their ancestors.
• Extinction of species is common. It occurs when the environment changes and the adaptive characteristics of a species are insufficient for survival. Fossils indicate that many organisms that lived on earth in the past no longer exist.
• Thousands of sedimentary rock layers provide evidence for the long history of the earth, and the fossils they contain demonstrate the long history of changing life forms. More recently deposited rock layers are more likely to contain fossils resembling existing species.

Structure and organizations of living systems

1.2 Understand that all living things reproduce and pass on genetic information, and that an organism's characteristics are determined by both genetic and environmental influences.

Elaborations :

• Reproduction is a characteristic of all living systems. Since no individual organism lives forever, reproduction is essential to the continuation of every species
• In many species, including humans, females produce eggs and males produce sperm. Plants also reproduce sexually. The egg and sperm are produced in the flowers of the flowering plants. An egg and sperm unite to begin development of a new individual
• Every organism requires a set of instructions for specifying its traits. Heredity is the passage of these instructions from one generation to another. The new individual receives genetic information from its mother (via the egg) and its father (via the sperm). Sexually produced offspring are never identical to either of their parents
• Hereditary information is contained in genes, located in the chromosomes of each cell. Each gene carries a single unit of information. One or more genes can determine an inherited trait of an individual, and a single gene can influence more than one trait. A human cell contains many thousands of different genes.
• The characteristics of an organism can be described in terms of a combination of traits. Some traits are inherited and others are acquired through interactions with the environment.

Life Processes and the Flow of Matter and Energy

1.3 Understand that individual organisms use matter and energy for life process, and the mechanisms accomplishing these processes are complex, integrated, and regulated.

Elaborations:

• Energy can be changed from one form to another in organisms. Food contains molecules that serve as both an energy source and building material. Plants use the energy from light to build sugars from carbon dioxide and water. This food can be used immediately or stored for later use in the plant.
• Organisms that eat plants break down the plant material to produce the molecules and energy they need to survive. Then, they are consumed by other organisms.
• Animals get energy from oxidizing their food, and heat energy may be a by-product in such reactions.
• In ecosystems, the major source of energy is sunlight. Producers convert energy entering the ecosystems as sunlight into chemical energy through photosynthesis. That energy then passes from organism to organism in food webs.
• Over a long time, matter is transferred from one organism to another repeatedly, and between organisms and their physical environment. As in all material systems, the total amount of matter remains constant in the system, even though its form and location may change.

Interdependence of Life

1.4 Explain how organisms interact with their environment and with other organisms to acquire energy, cycle matter, influence behavior, and establish competitive or mutually beneficial relationships.

Elaborations:

• A population consists of all individuals within a species that live together at a given place and time. An ecosystem encompasses all populations living together and their physical surroundings.
• The number of organisms an ecosystem can support depends on available resources and environmental factors, such as amount of light and water, range of temperatures and soil composition.
• Populations increase at rapid rates when adequate resources to maintain life are available and no disease or predators are present. Many factors limit population growth in specific ecosystem niches, such as predation, climate, or inadequate food or water sources.
• In all environments (examples: freshwater, forest, or desert) growth and survival of organisms depend on physical conditions. Organisms with similar needs compete with one another for resources, including food, space, water, air, and shelter.
• Relationships among organisms may be competitive or mutually beneficial, such as producer/consumer, predator/prey, or parasite/host relationships. One organism may scavenge or decompose another. Some species have become so adapted to each other that neither could survive without the other.

Environmental and resource issues

1. 5 Explain how human societies use of natural resources affects quality of life and the health of ecosystems.

Elaborations:

• Environmental degradation and resource depletion vary from region to region and from country to country. Various factors affect the amount consumption, scarcity, or loss, such as overpopulation, environmental laws, technological resources, or affluence of a country's residents.
• Human activities can induce environmental hazards through acquisition, urban growth, land use decisions, and waste disposal. Such activities may accelerate changes in resource availability, ecosystem viability, and an environment's carrying capacity for life.

Earth Science

Processes and interactions in the earth system

1.1 Describe the processes of constructive and destructive forces and how they continually change land forms on earth.

Elaborations:

• Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). The earth's surface is shaped in part by the motion of liquid water, glaciers, and wind over very long times, which act to level mountain ranges.
• The interior of the earth is very hot. Heat flow and movement of material within the earth cause earthquakes and volcanic eruptions and create mountains and ocean basins. Gas and dust from large volcanoes can change the atmosphere.
• Some changes in the solid earth can be described as the "rock cycle." Old rocks at the earth's surface weather, forming sediments that are buried, then compacted, heated, and often recrystallized into new rock. Eventually, those new rocks may be brought to the surface by the forces that drive plate motions, and the rock cycle continues.
• Sedimentary rocks are formed by the weathering and erosion of igneous, metamorphic, or sedimentary rocks (the sediments are compressed); metamorphic rocks are formed by solid-state alteration (heat, pressure, deformation, and recrystallization) of sedimentary, igneous, or other metamorphic rocks; igneous rocks are formed (crystallize from magma) by the melting of sedimentary, metamorphic, or other igneous rocks.
• Human activities, such as reducing the amount of forest cover, increasing the amount and variety of chemicals released into the atmosphere, nuclear weapons tests, and intensive farming, have changed the earth's land, oceans, and atmosphere. Some of these changes have decreased the capacity of the environment to support some life forms.

History and evolution of the earth

1.2 Describe the components and relationships of the earth system, including the solid earth - geosphere (crust, hot convecting mantle and dense metallic core); the hydrosphere (surface water - oceans, rivers and lakes, and streams); the atmosphere (a mixture of gases); and the biosphere (living organisms).

Elaboration:

• Three-fourths of the earth's surface is covered by a relatively thin layer of water (some of it frozen), and the entire planet is surrounded by a relatively thin blanket of air.

1.3 Know the importance of fossils in documenting life and environmental changes over time.

Elaborations:

• Fossils document the existence of plant and animal life on earth over long periods of time.
• Environmental changes, species extinction or evolution, and climatic variances can be tracked with fossil records. Fossils taken from various layers of sedimentary rock can provide a physical timeline of life on earth.
• The importance of fossils cannot be minimized. They provide physical evidence of life as it existed before recorded history, for example, the diversification of earth environments or changes in species diversification.

Components and patterns of the earth system.

1.4 Explain how natural forces determine patterns and arrangements of continents, landforms, and oceans and how the theory of plate tectonics accounts for movement over time.

Elaborations:

• Earth systems have internal and external sources of energy, both of which create heat.
• The sun is the major source of energy received by the earth's surface.
• Two primary sources of internal energy are the decay of radioactive isotopes and the effects of gravitational energy from the earth's original formation (heating resulting from internal compression and accretion of earth material)
• The outermost solid layer of the earth--including both the continents and the ocean basins--consists of separate plates that ride on a denser, hot, gradually deformable layer of the earth.
• The slow movement of material within the earth results from heat flowing out from the deep interior and differential gravitational forces on regions of different density.

Hydrosphere/atmosphere.

1.5 Classify rocks and soils into groups based on their chemical and physical properties; describe the processes by which rocks and soils are formed.

Elaborations:

• The earth is mostly rock and rock is composed of minerals which are made of atoms. Rocks are classified based on the ways that they are formed: igneous rocks from the cooling of molten material; sedimentary rock from weathered rock and sediments gradually buried and cemented together by dissolved minerals (chemical change); and metamorphic rock from buried rock that is reformed by high pressure and temperature (possibly through partial melting and recrystallizing).
• Some minerals are very rare and some exist in great quantities, but - for practical purposes - the ability to recover them is just as important as their abundance. As minerals are depleted, obtaining them becomes more difficult. Recycling and the development of substitutes can reduce the rate of depletion but may also be costly. · Sediments, including sand and smaller particles (sometimes containing the remains of organisms), are gradually buried and are cemented together by dissolved minerals to form solid rock again.
• Rock bears evidence of the pressures and temperatures that created it. Soil consists of weathered rocks, decomposed organic materials from dead plants, animals, and bacteria, water, and air. Soils are often found in layers, with each having a different chemical composition and texture.
• Although weathered rock is the basic component of soil, the composition and texture of soil and its fertility and resistance to erosion are greatly influenced by plant roots and debris, bacteria, fungi, worms, insects, rodents, and other organisms.

2. The student conducts scientific investigations.

Develop abilities necessary to do scientific inquiry

Questioning
2.1 Generate questions that can be answered through scientific investigations

Designing and conducting investigations
2.2 Design, conduct, and evaluate scientific investigations, using appropriate equipment, mathematics, and safety procedures

Explanation
2.3 Use evidence from scientific investigations to think critically and logically to develop descriptions, explanations, and predictions

Modeling
2.4 Correlate models of the behavior of objects, events, or processes to the behavior of the actual things; test models by predicting and observing actual behaviors or processes

Communication
2.5 Communicate scientific procedures, investigations, and explanations orally, in writing, with computer-based technology, and in the language of mathematics

Apply science knowledge and skills to solve problems or meet challenges

Identify problems
2.6 Identify and examine common, everyday challenges or problems in which science/technology can be or has been used to design solutions

Designing and testing solutions
2.7 Identify, design, and test alternative solutions to a challenge or problem

Evaluating potential solutions
2.8 Compare and contrast multiple solutions to a problem or challenge

3. The student understands the nature and contexts of science and technology.

Understand the nature of scientific inquiry

Intellectual honesty
3.1 Understand the operational and ethical traditions of science and technology such as skepticism, cooperation, intellectual honesty, and proprietary discovery

Limitations of science and technology
3.2 Understand that scientific investigation is limited to the natural world

Dealing with inconsistencies
3.3 Provide more than one explanation for events or phenomena; defend or refute the explanations using evidence

Evaluating methods of investigation
3.4 Describe how methods of investigation relate to the validity of scientific, experiments, observations, theoretical models, and explanation

Evolution of scientific ideas
3.5 Explain how scientific theory, hypothesis generation, experimentation, and observation are interrelated and may lead to changing ideas

Know that science and technology are human endeavors, interrelated to each other, to society, and to the workplace

All peoples contribute to science and technology
3.6 Know that science and technology have been developed, used, and affected by many diverse individuals, cultures, and societies throughout human history

Relationship of science and technology
3.7 Compare and contrast scientific inquiry and technological design in terms of activities, results, and influence on individuals and society; know that science enables technology and vice versa

Careers and occupations using science, mathematics, and technology
3.7 Investigate the use of science, mathematics, and technology within occupational/career areas of interest