CHAPTER 5: THE LIVING ENVIRONMENT
A. DIVERSITY OF LIFE
K-2
Some animals and plants are alike in the way they
look and in the things...
Plants and animals have features that help them live
in different...
Stories sometimes give plants and animals attributes
they really...
3-5
A great variety of kinds of living things can be
sorted into groups...
Features used for grouping depend on the purpose
of the grouping.
6-8
One of the most general distinctions among organisms
is between plants...
Animals and plants have a great variety of body plans
and internal...
Similarities among organisms are found in internal
anatomical features...
For sexually reproducing organisms, a species comprises
all organisms...
All organisms, including the human species, are part
of and depend on two...
9-12
The variation of organisms within a species increases
the likelihood...
The degree of kinship between organisms or species
can be estimated...
B. HEREDITY
K-2
There is variation among individuals of one kind
within a population.
Offspring are very much, but not exactly, like their
parents...
3-5
Some likenesses between children and parents, such
as eye color...
For offspring to resemble their parents, there must
be a reliable way...
6-8
In some kinds of organisms, all the genes come from
a single parent...
In sexual reproduction, a single specialized cell
from a female merges...
New varieties of cultivated plants and domestic animals...
9-12
Some new gene combinations make little difference,
some can produce...
The sorting and recombination of genes in sexual
reproduction results...
The information passed from parents to offspring
is coded...
Genes are segments of DNA molecules. Inserting, deleting,
or substituting...
Gene mutations can be caused by such things as radiation
and chemicals...
The many body cells in an individual can be very
different from one another...
C. CELLS
K-2
Magnifiers help people see things they could not
see without them.
Most living things need water, food, and air.
3-5
Some living things consist of a single cell. Like
familiar organisms...
Microscopes make it possible to see that living things
are made...
6-8
All living things are composed of cells, from just
one to many millions...
Cells continually divide to make more cells for growth
and repair...
Within cells, many of the basic functions of organisms--such
as extracting...
About two thirds of the weight of cells is accounted
for by water...
9-12
Every cell is covered by a membrane that controls
what can enter...
Within the cell are specialized parts for the transport
of materials...
The work of the cell is carried out by the many different
types...
The genetic information in DNA molecules provides
instructions...
Complex interactions among the different kinds of
molecules in the cell...
Gene mutation in a cell can result in uncontrolled
cell division...
Most cells function best within a narrow range of
temperature and acidity...
A living cell is composed of a small number of chemical
elements...
D. INTERDEPENDENCE OF LIFE
K-2
Animals eat plants or other animals for food and
may also use plants...
Living things are found almost everywhere in the
world. There are...
3-5
For any particular environment, some kinds of plants
and animals...
Insects and various other organisms depend on dead
plant and animal...
Organisms interact with one another in various ways
besides...
Changes in an organism's habitat are sometimes beneficial...
Most microorganisms do not cause disease, and many
are beneficial.
6-8
In all environments--freshwater, marine, forest,
desert, grassland...
Two types of organisms may interact with one another
in several ways...
9-12
Ecosystems can be reasonably stable over hundreds
or thousands...
Like many complex systems, ecosystems tend to have
cyclic fluctuations...
Human beings are part of the earth's ecosystems.
Human activities...
E. FLOW OF MATTER AND ENERGY
K-2
Plants and animals both need to take in water, and
animals need...
Many materials can be recycled and used again, sometimes
in...
3-5
Almost all kinds of animals' food can be traced back
to plants.
Some source of "energy" is needed for all organisms
to stay alive and grow.
Over the whole earth, organisms are growing, dying,
and decaying...
6-8
Food provides the molecules that serve as fuel and
building material...
Over a long time, matter is transferred from one
organism to another...
Energy can change from one form to another in living
things. Animals get...
9-12
At times, environmental conditions are such that
plants and marine...
The amount of life any environment can support is
limited by...
The chemical elements that make up the molecules
of living things...
F. EVOLUTION OF LIFE
K-2
Different plants and animals have external features
that help them thrive...
Some kinds of organisms that once lived on earth
have completely disappeared...
3-5
Individuals of the same kind differ in their characteristics,
and sometimes...
Fossils can be compared to one another and to living
organisms...
6-8
Small differences between parents and offspring can
accumulate...
Individual organisms with certain traits are more
likely than others...
Many thousands of layers of sedimentary rock provide
evidence...
9-12
The basic idea of biological evolution is that the
earth's present-day...
Molecular evidence substantiates the anatomical evidence...
Natural selection provides the following mechanism
for evolution...
Heritable characteristics can be observed at molecular
and whole-organism...
New heritable characteristics can result from new
combinations...
Natural selection leads to organisms that are well
suited for survival...
The theory of natural selection provides a scientific
explanation...
Life on earth is thought to have begun as simple,
one-celled organisms...
Evolution builds on what already exists, so the more
variety there is...
