NSTA RSS Feeds 

Search Results

Heredity and Variation: Genes in Action Science Object
Science Object
Heredity and Variation: Genes in Action
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the second of three Science Objects in the Heredity and Variation SciPack. It explores sexual reproduction and the process of meiosis.

We now know that structures and functions at the molecular and cellular levels provide the mechanism for reproduction and the continuity...  [view full summary]
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the second of three Science Objects in the Heredity and Variation SciPack. It explores sexual reproduction and the process of meiosis.

We now know that structures and functions at the molecular and cellular levels provide the mechanism for reproduction and the continuity of species. Instructions for development are passed from parents to offspring in thousands of discrete genes, each of which is a segment of a molecule of DNA. An organism’s particular genetic information, coded in its DNA (genotype), contains genes that provide the information necessary to assemble proteins. Offspring of asexual organisms inherit all of the parent's genes. In organisms that reproduce sexually, specialized female and male sex cells (gametes) are formed during a process of cell division called meiosis. Each of these sex cells contains a random half of the parent's genetic information.

When a particular male gamete fuses with a particular female gamete during fertilization, they form a cell with one complete set of paired chromosomes, a combination of one half-set from each parent. This random combining of gametes and their chromosomes during fertilization results in millions of different possible combinations of genes, which causes the offspring genotypes to vary from their parents’. Some of the new gene combinations make little difference in the ability of the offspring to reproduce or survive, some can produce organisms with capabilities that enhance their ability to survive and reproduce, and some can be deleterious, resulting in an inability to survive and/or reproduce. Learning Outcomes:
  • Distinguish among the following structures by describing their relationship to one another: DNA, chromosomes, genes, and alleles.
  • Describe the role genes play in the production of proteins and defining the phenotype of an organism.
  • Compare and contrast the DNA in cells produced during asexual reproduction versus the DNA in gametes produced during meiosis.
  • Indentify and describe those steps within the process of meiosis that explain the random distribution of genotypes among offspring resulting from sexual reproduction.
  • Explain how the recombination of the allele pairs for individual genes during sexual reproduction results in phenotypic variation among offspring.

[hide full abstract]
Member Price: Free      Nonmember Price: Free
Heredity and Variation: Inheritance Science Object
Science Object
Heredity and Variation: Inheritance
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of three Science Objects in the Heredity and Variation SciPack. It explores the historical perspective and experiments of Mendel. Sexual reproduction results in the continuity of species accompanied with a great deal of variation in physical traits. One familiar...  [view full summary]

Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of three Science Objects in the Heredity and Variation SciPack. It explores the historical perspective and experiments of Mendel.

Sexual reproduction results in the continuity of species accompanied with a great deal of variation in physical traits. One familiar observation is that offspring are very much like their parents but still show some variation— differing somewhat from their parents and from one another. People have long been curious about heredity, using even the most primitive understanding of inheritance to cultivate desirable traits in domesticated species. In the 1800s, Gregor Mendel took his observations of heredity and variation to new heights through carefully designed and executed breeding experiments that generated repeatable inheritance patterns. Mendel developed a model for explaining the patterns he observed, describing discrete units or “particles,” which both segregate and assort independently of one another during inheritance. This model offered a foundational explanation for how variation is generated through sexual reproduction. Although Mendel’s model over-simplified how traits are inherited and expressed, it set the stage for the discoveries of chromosomes and genes from which contemporary genetics grew.

Learning Outcomes:
  • Explain how domestication of plants and animals produced an early understanding of inheritance.
  • Use Mendel’s model to explain patterns of inheritance represented in graphic form (for example, data tables, histograms, etc.).
  • Identify the conditions required for an inheritance pattern to be explained correctly by Mendel’s model.
  • Use data representing patterns of inheritance to support the idea that some observable traits are defined by discrete units of inheritance that segregate and assort independently of one another during inheritance.

[hide full abstract]
Member Price: Free      Nonmember Price: Free
Gravity and Orbits: Orbits Science Object
Science Object
Gravity and Orbits: Orbits
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object, co-developed between NASA and NSTA, is the third of three Science Objects in the Gravity and Orbits SciPack. It provides an understanding of how gravitational forces influence the motion of an object in orbit. When a force acts toward a single center, an object’s forward motion and...  [view full summary]
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object, co-developed between NASA and NSTA, is the third of three Science Objects in the Gravity and Orbits SciPack. It provides an understanding of how gravitational forces influence the motion of an object in orbit. When a force acts toward a single center, an object’s forward motion and its motion toward that center can combine to create a curved path around the center. Gravity governs the motion of all objects in the solar system. The Sun’s gravitational pull holds the Earth and other planets in their orbits, just as the planets’ gravitational pull keeps their moons in orbit around them.
[hide full abstract]
Member Price: Free      Nonmember Price: Free
Interdependence of Life: Population Balance in Biomes Science Object
Science Object
Interdependence of Life: Population Balance in Biomes
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of four Science Objects in the Interdependence of Life SciPack. It explores population balance in biomes.

Interdependent and fluctuating interactions among living organisms and populations and the abiotic components of their environment cause cyclical...  [view full summary]
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of four Science Objects in the Interdependence of Life SciPack. It explores population balance in biomes.

Interdependent and fluctuating interactions among living organisms and populations and the abiotic components of their environment cause cyclical changes in the overall ecosystem resource equilibrium.

Interactions among living organisms within a population and among organisms of different populations take place on an ever-changing environmental stage. The nonliving environment—including land and water, solar radiation, rainfall, mineral concentrations, temperature and topography—shapes Earth’s ecosystems. Because each species can tolerate a limited range of physical conditions, the diversity of physical conditions creates a wide variety of ecosystems. In all these environments organisms use vital, yet limited, resources; each seeking its share in specific ways that are limited by biotic and abiotic factors.

Learning Outcomes:
  • Explain why there are such diverse ecosystems on Earth.
  • Given a description of changes in abiotic factors defining an ecosystem (i.e. temperature, precipitation, soil composition, atmospheric composition, amount of available solar energy) and the tolerance of a few species to these factors, identify graphs that accurately predict their effects on size and growth rate of these species.
  • Identify and explain graphs that accurately represent examples of dynamic equilibrium.
  • Explain how the population sizes of predators and their prey maintain a balance over many generations.

[hide full abstract]
Member Price: Free      Nonmember Price: Free
Interdependence of Life: Organisms and Their Environments Science Object
Science Object
Interdependence of Life: Organisms and Their Environments
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of four Science Objects in the Interdependence of Life in Ecosystems SciPack. It explores organisms and their environments.

All organisms, including human beings, live within and depend on the resources in their environment. These resources include both...  [view full summary]
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of four Science Objects in the Interdependence of Life in Ecosystems SciPack. It explores organisms and their environments.

All organisms, including human beings, live within and depend on the resources in their environment. These resources include both living (biotic) factors such as food and nonliving (abiotic) factors such as air and water. The size and rate of growth of the population of any species, including humans, are affected by these environmental factors. In turn, these environmental factors are affected by the size and rate of growth of a population. Populations are limited in growth to the carrying capacity of the ecosystem, which is the amount of life any environmental system can support with its available space, energy, water, and food.

Learning Outcomes:
  • Identify and describe biotic and abiotic factors that influence the size and growth rate of a specific population in a particular environment.
  • Describe possible immediate and long-term effects on an individual population that exceeds the carrying capacity of its environment.
  • Given a line graph displaying an individual population size and its rate of growth, infer the carrying capacity of the environment for that population.

[hide full abstract]
Member Price: Free      Nonmember Price: Free
Heredity and Variation: Mutation Provides Variation Science Object
Science Object
Heredity and Variation: Mutation Provides Variation
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of three Science Objects in the Heredity and Variation SciPack. It explores the role of mutations in genetic variation. The random combination of genes during sexual reproduction is not the only source of variation in organisms. Although some genes may be passed...  [view full summary]

Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of three Science Objects in the Heredity and Variation SciPack. It explores the role of mutations in genetic variation.

The random combination of genes during sexual reproduction is not the only source of variation in organisms. Although some genes may be passed for many thousands of generations with no consequential changes in its function, occasionally a mutation occurs in which a gene may be altered. Gene mutations can occur spontaneously through random errors in copying, or induced by chemicals or radiation that affect the DNA’s chemical bonds. Only if a mutated gene is in a gamete is it possible for copies of it to be passed down to offspring, becoming part of all their cells, altering the nature of some proteins produced by the DNA. The function of a mutated gene may not be altered or it may have its function in protein synthesis altered, which subsequently affects the physical traits expressed in the organism. Mutations provide additional sources of variation that can be helpful, harmful or of no impact on the survival an individual.

Learning Outcomes:
  • Compare and contrast genetic mutations with genetic variations resulting from the process of meiosis.
  • Identify and describe the general processes involved in the creation of genetic mutations.
  • Describe possible consequences of genetic mutations.
  • Describe conditions necessary for genetic mutations to be inherited by an organism’s offspring.

[hide full abstract]
Member Price: Free      Nonmember Price: Free
Flow of Matter and Energy in Ecosystems: Carbon, Carbon Everywhere Science Object
Science Object
Flow of Matter and Energy in Ecosystems: Carbon, Carbon Everywhere
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the second of three Science Objects in the Flow of Matter and Energy in Ecosystems SciPack. It explores how the cycling of carbon and other nutrients from non-living to living components and back is one of the most important of ecosystem functions and is representative of the cycling...  [view full summary]
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the second of three Science Objects in the Flow of Matter and Energy in Ecosystems SciPack. It explores how the cycling of carbon and other nutrients from non-living to living components and back is one of the most important of ecosystem functions and is representative of the cycling of other elements.

All matter that comprises organic molecules, including hydrogen, oxygen, nitrogen, phosphorous and others are transferred cyclically among living organisms and their non-living environment. The cycling of elements from non-living to living components and back is one of the most important ecosystem characteristics. For example, carbon, an essential element in organic molecules, is conserved as it is transferred from inorganic carbon in an ecosystem to organic molecules in living organisms of the ecosystem and back as inorganic carbon to the environment. The carbon cycle, in the following description, serves as an example of one of the essential biogeochemical cycles.

Learning Outcomes:
  • Trace the path of a carbon atom from the atmosphere through a biomass pyramid and ultimately back to the atmosphere
  • Describe how photosynthesis and consumer respiration affect the flow of carbon through an ecosystem
  • Predict the biological effects of increasing levels of atmospheric carbon due to the massive combustion of fossil fuels
  • Identify the process that emits carbon to the atmosphere from producers, consumers and decomposers

[hide full abstract]
Member Price: Free      Nonmember Price: Free
Flow of Matter and Energy in Ecosystems: Does Matter Matter? Science Object
Science Object
Flow of Matter and Energy in Ecosystems: Does Matter Matter?
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of three Science Objects in the Flow of Matter and Energy in Ecosystems SciPack. It explores the structure of the biomass in an ecosystem and overall cycling of matter. However complex the workings of living organisms, they share with all other systems the same physical...  [view full summary]
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of three Science Objects in the Flow of Matter and Energy in Ecosystems SciPack. It explores the structure of the biomass in an ecosystem and overall cycling of matter. However complex the workings of living organisms, they share with all other systems the same physical principles that describe the conservation and transformation of matter.

Ecosystems are a community of interdependent organisms and the chemical and physical factors making up the environment with which they interact. For every ecosystem on Earth there is a particular biomass (matter) distribution among organisms in its populations. While the specific biomass distribution in any given ecosystem is unique because of resource availability, there is a common overall biomass distribution pattern in all ecosystems. Greater biomass exists in populations that obtain matter from the physical environment than in populations that obtain matter from other living organisms. As matter flows through different levels of organization in living systems—cells, organs, organisms, communities—and between living systems and the physical environment, chemical elements are recombined in different ways. Matter is conserved through each change.

Learning Outcomes:
  • Define an ecosystem and understand how it comprises an interdependent community of organisms along with their interactions with the chemical and physical components of the environment
  • Categorize organisms in a community based on their sources of matter/biomass and nutrients as one of the following: producers, herbivores (primary consumers), carnivores (secondary consumers; tertiary or top-consumers),
  • omnivores, and decomposers
  • Predict the relative biomass for different levels in a biomass pyramid for a typical ecosystem
  • Explain how matter is conserved in the interactions between consumers and producers, but that in a biomass pyramid there is less biomass at the consumer level compared to the producer level

[hide full abstract]
Member Price: Free      Nonmember Price: Free
Force and Motion: Newton's Third Law Science Object
Science Object
Force and Motion: Newton's Third Law
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the last of four Science Objects in the Force and Motion SciPack. It provides a conceptual and real-world understanding of Newton’s Third Law of Motion, addressing common misconceptions associated with this law. Whenever one object exerts a force on another, an equal amount of force...  [view full summary]
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the last of four Science Objects in the Force and Motion SciPack. It provides a conceptual and real-world understanding of Newton’s Third Law of Motion, addressing common misconceptions associated with this law. Whenever one object exerts a force on another, an equal amount of force is exerted back on it. These equal and opposite forces are exerted simultaneously on the objects involved.
[hide full abstract]
Member Price: Free      Nonmember Price: Free
Gravity and Orbits: Gravitational Force Science Object
Science Object
Gravity and Orbits: Gravitational Force
Grade Level: Elementary School, High School, Middle School
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object, co-developed between NASA and NSTA, is the second of three Science Objects in the Gravity and Orbits SciPack. It investigates the variables that influence gravitational forces acting on objects. Mass is a measure of the amount of matter that makes up an object (regardless of where...  [view full summary]
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object, co-developed between NASA and NSTA, is the second of three Science Objects in the Gravity and Orbits SciPack. It investigates the variables that influence gravitational forces acting on objects. Mass is a measure of the amount of matter that makes up an object (regardless of where that object is located) and weight is a measure of the gravitational force acting on an object. The strength of the gravitational force between masses is proportional to the product of the masses and inversely proportional to the square of the distance between them. Gravity will cause all objects at the same distance from Earth’s surface to fall toward Earth with the same acceleration regardless of their mass.
[hide full abstract]
Member Price: Free      Nonmember Price: Free
Results: 1 - 10 of 5573 1 2 3 4 5 6 7 8 9 ... 558 Next