Life,
Earth, and Physical Science
Introduction
The theme of this course will focus on helping
you use scientific inquiry to
discover patterns, trends, structures, and relationships that may be inferred from
simple principles. These principles are related to the properties or
interactions within and between systems.
The systems can be described and understood by
analysis of the interaction of components. Energy, forces, and motion
combine to change Earth's physical features. The changes in the physical Earth
and the species that lived on Earth are found in the rock record. For species to continue, reproduction must be successful.
Three branches of science will be discussed in
this course: Life Science, Earth and
Space Science, and Physical Science.
|
Branch of Science |
Topic |
Focus |
|
Life Science |
Species
& Reproduction |
This
topic focuses on the continuation of the species. |
|
Earth & Space Science |
Physical
Earth |
This
topic focuses on the physical features of Earth and how they formed. This
includes the interior of Earth, the rock record, plate tectonics, and landforms. |
|
Physical Science |
Forces
& Motion |
This
topic focuses on forces and motion within, on, and around the Earth and the
universe. |
Let's Practice
Below is a list of the content statements and
elaborations that you will be studying in this course.
Life Science
Content Statement # 1
Diversity of species, a result of variation of
traits, occurs through the process of evolution and extinction over many
generations. The fossil records provide evidence that changes have occurred in
number and types of species.
Content Elaboration
Fossils provide important evidence of how life
and environmental conditions have changed.
Changes in environmental conditions can affect
how beneficial a trait will be for the survival and reproductive success of an
organism or an entire species.
Throughout Earth’s history, extinction of a
species has occurred when the environment changes and the individual organisms
of that species do not have the traits necessary to survive and reproduce in
the changed environment. Most species (approximately 99 percent) that have
lived on Earth are now extinct.
Every organism alive
today comes from a long line of ancestors who reproduced successfully every
generation.
Content
Elaboration
Reproduction is the
transfer of genetic information from one generation to the next. It can occur
with mixing of genes from two individuals (sexual reproduction). It can occur
with the transfer of genes from one individual to the next generation (asexual
reproduction). The ability to reproduce defines living things.
Animals and plants can
reproduce or create new life.
Content Statement #3
The characteristics of an organism are a result
of inherited traits received from parent(s).
Content Elaboration
Expression
of all traits is determined by genes and environmental factors to varying
degrees. Many genes influence more than one trait, and many traits are
influenced by more than one gene.
During
reproduction, genetic information (DNA) is transmitted between parent and
offspring. In asexual reproduction, the lone parent contributes DNA to the
offspring. In sexual reproduction, both parents contribute DNA to the
offspring.
Earth Science
Content Statement #1
The composition and properties of Earth’s
interior are identified by the behavior of seismic waves.
Content Elaboration
The refraction and reflection of seismic waves
as they move through one type of material to another is used to differentiate
the layers of Earth’s interior. Earth has a core, a mantle, and a crust.
Impacts during planetary formation generated heat.
These impacts converted gravitational potential energy to heat. Earth’s core is also able to generate its own thermal energy because of decaying atoms. This continuously releases thermal energy. Thermal energy generated from Earth’s core drives convection currents in the asthenosphere.
Content Statement #2
Earth’s lithosphere consists of major and minor
tectonic plates that move relative to each other.
Content Elaboration
Historical data and observations such as fossil
distribution, paleomagnetism, continental drift and seafloor spreading
contributed to the theory of plate tectonics. The rigid tectonic plates move
with the molten rock and magma beneath them in the upper mantle.
Convection currents in the asthenosphere cause
movements of the lithospheric plates. The energy that forms convection currents
comes from deep within the Earth.
There are three main types of plate boundaries:
divergent, convergent and transform. Each type of boundary results in specific
motion and causes events (such as earthquakes or volcanic activity) or features
(such as mountains or trenches) that are indicative of the type of boundary.
The diagram above shows
several kinds of interactions at plate boundaries, including convergent
boundaries where oceanic crust meets oceanic crust, at left, and where oceanic
crust meets continental crust, at right. Divergent and transform boundaries
associated with seafloor spreading are shown in the center.
Content Statement #3
A combination of constructive and destructive
geologic processes formed Earth’s surface.
Content Elaboration
Earth’s surface is formed from a variety of
different geologic processes, including but not limited to plate tectonics.
Water, wind, glaciers, and
gravity all can change the land through the processes of erosion.
Content Statement #4
Evidence of the dynamic changes of Earth’s
surface through time is found in the geologic record.
Content Elaboration
Earth is approximately 4.6 billion years old. Earth
history is based on observations of the geologic record and the understanding
that processes observed at present day are similar to those that occurred in
the past (uniformitarianism). There are different methods to determine relative
and absolute age of some rock layers in the geologic record. Within a sequence
of undisturbed sedimentary rocks, the oldest rocks are at the bottom
(superposition). The geologic record can help identify past environmental and
climate conditions .
Physical Science
Content
Statement #1
Objects can experience a force due to an
external field such as magnetic, electrostatic, or gravitational fields.
Content Elaboration
Magnetic, electrical, and gravitational forces can
act at a distance.
Each side in a tug-of-war
game uses force to try to pull down the other side.
Ryan Child/U.S. Navy
Content Statement #2
Forces can act to change the motion of objects.
Content Elaboration
The motion of an object is always measured with
respect to a reference point.
Forces can be added. The net force on an object
is the sum of all the forces acting on the object.
If there is a nonzero net force acting on an
object, its speed and direction will change.
Kinetic friction and drag are forces that act
in a direction opposite the relative motion of objects.
The swings on this
amusement park ride are in motion.
©
Photohunter/Shutterstock.com
Let's Practice