Download Organisms have energy roles that they serve in their environments

PASS Review for 7th Grade Science
CHEMISTRY
Matter is composed of extremely small particles called atoms and that atoms are the smallest part of pure substances that cannot be broken down into simpler
substances. Matter can be classified on the basis of its composition as follows:
Elements
Elements are pure substances that cannot be changed into simpler substances. Elements are composed of one type of atom.
Compounds
Compounds are pure substances that are composed of two or more types of elements. Compounds can only be changed into simpler
substances called elements by chemical changes (7-5.10), which are not as easy as separating mixtures into their components.
Mixtures
Mixtures are composed of different substances that are mixed together. They can be separated easily into their component substances by
these processes:
Filtration
Filtration is used to separating solid particles from a liquid by pouring the mixture through a filter paper in a funnel. The filter
paper traps the solid particles and only allows the particles of the liquid to pass through. This method is used, for example, in
water treatment plants as part of the process for separating dirt and other solid particles from water to produce clean drinking
water.
Sifting
Sifting is used to separate smaller solid particles from larger solid particles. The mixture of different sized solid particles is put
into a container that has a screen material at the bottom with holes of a certain size. When the mixture is shaken, the smaller
particles go through the screen leaving the larger particles in the container. Cooks, for example, sift flour to get a small particle
size for baking leaving larger particles of flour in the sifter above the screen. Sand and gravel companies, for example, separate
rocks into different sized particles for road building and other construction projects using this method.
Magnetic attraction
Magnetic attraction is used to separating magnetic material from a mixture of other substances. When a magnet is stirred
through the mixture, it pulls out the magnetic material from the mixture. A “cow magnet”, for example, is given to a cow to
swallow. It stays in the first stomach of the cow keeping magnetic materials like wire and other harmful materials that cows
swallow from going into the rest of their digestive system.
Evaporation
Evaporation is used to separate a solid that has dissolved in a liquid solution. The solution is heated until all the liquid turns to a
gas (evaporates) leaving the solid behind. Salt in salt water or ocean water, for example, is separated by heating the solution
until all the water evaporates leaving the solid salt in the container.
Chromatography
Chromatography is used to separate and analyze the solutes (5-4.5)in a solution. A small amount (2-3 drops) of the solution is
put on a piece of filter paper, which is put in a solvent (5-4.5). The substances in the solution, called solutes (5-4.5), that dissolve
most easily travel the furthest; and substances that do not dissolve easily do not travel very far. The bands of color that are
formed, for example, allow scientists to identify the substances in the solution by comparing them to the location of known
substances forming bands of color on different filter papers.
Floatation
Floatation is used to separate solids, which float from remaining liquids in a mixture. The solids are stirred and when they float
to the top, they are skimmed off the surface of the liquid and put into a different container. This method is used, for example, in
some water purification plants.
Metals and nonmetals are two major groups of elements that have different physical properties as follows:
Metals
Physical properties of metals include the following:
Luster
Having a shiny surface or reflecting light brightly
Conductors
Heat and electricity move through them easily.
Malleable
Ability to be hammered into different shapes
Ductile
Ability to be drawn into a wire
High density
Heavy for their size
Nonmetals Physical properties of nonmetals include the following:
Dull
Not shiny
Nonconductors
Heat and electricity do not move through them easily
Brittle
Break or shatter easily
The elements on the periodic table are identified with numbers increasing from left to right across each row of the table. Along with this number (atomic number)
there is also a symbol that identifies each element on the table. There are two large sections of elements on the periodic table. On the periodic table there is a
zigzag line on the right side of the table. Metals are to the left of this line. Nonmetals are to the right.
Families
Also called groups, are columns of elements on the periodic table that have many similar properties; they are usually numbered 1-18. A
family of elements has some chemical characteristics that are similar.
Metals
Groups of elements generally located on the left side of the periodic table. Examples on metals are: Sodium (Na), Calcium (Ca), Iron (Fe),
and Aluminum (Al).
Nonmetal Families are generally located on the right side of the periodic table. Examples of nonmetals are: Chlorine (Cl), Oxygen (O), Sulfur (S), and Iodine (I).
Chemical symbols show the atoms of the elements composing a substance. Atoms of common elements have different symbols as follows:
Symbol
Element
Na
Cl
H
0
C
N
Sodium
Chlorine
Hydrogen
Oxygen
Carbon
Nitrogen
Chemical formulas are constructed from the symbols of the elements composing the substances. Elements are made up of one type of atom and their formulas
have one symbol. Compounds are composed of more than one element and their formulas have more than one type of symbol showing the different atoms that
compose the compound. In a chemical formula, the numbers as subscripts show the ratio of the number of atoms of the different elements in the compound.
Acids and bases are solutions usually with water as the solvent:
Acids
Acids can be identified by their sour taste (lemons and oranges contain acids)—but students should not use a taste test on laboratory chemicals; by
their reaction with some metals (for example, zinc), and by their reaction with bases to form a neutral pH solution.
Bases
Bases can be identified by their bitter taste (soapsuds have a bitter taste)—but students should not use a taste test on laboratory chemicals; by their
slippery feels when rubbed between thumb and fingers---but some strong bases burn the skin so this test should not be used; and by their reaction with
acids to form a neutral pH solution.
pH
pH is a measure of the concentration of solutions of acids and bases and is measured on a scale of 1-14. A basic solution has a pH greater than 7 and
an acidic solution has a pH less than 7. If a solution is neither an acid nor a base, it has a pH of 7 and is called neutral. Pure water has a pH of 7. The
stronger the acid, the lower the pH (less than 7) while the stronger the base, the higher the pH (greater than 7).
Indicators Indicators are substances that can be used to determine the whether a solution is an acid or base. The following indicators can be used to determine
relative pH
Litmus paper
Blue litmus paper turns red in an acid, and stays blue in a base. Red litmus paper turns blue in a base, and stays red in an acid.
Both red and blue litmus paper turn purple in a solution that is neutral (neither an acid nor a base).
pH paper
pH paper can turn a series of colors in solutions of pH. The color of the paper is compared to the chart of the vial to determine
the pH.
Phenolphthalein
Phenolphthalein turns magenta in a strong base and stays clear in an acid
When substances are mixed and at least one new substance is formed, a chemical reaction has occurred.
Chemical equations Are used to represent chemical reactions that have occurred. They contain the chemical formulas (7-5.5) for the substances that are mixed
and the new substance(s) that are formed. An arrow separates them.
Reactants
The substances that are mixed in a chemical reaction are called the reactants and appear on the left side of the arrow in a chemical
equation.
Products
The new substances that are formed in a chemical reaction are called the products and appear on the right side of the arrow in a chemical
equation.
For example, the following chemical equation shows the formation of water (H20) from oxygen (02) and hydrogen (H2). The reactants are oxygen (02) and hydrogen
(H2), located on the left side of the arrow. The product, water (H20), is on the right side of the arrow.
2H2 + 02 →
2H20
Reactants →
Products
The amount of matter does not change during a chemical reaction; only the atoms are rearranged to form new substances. The law of conservation of matter is
based on countless experiments in which the mass of the reactants has been found to equal the mass of the products. The law of conservation of matter states
that matter can neither be created nor destroyed, but can be changed in form. In other words, the total mass of the material(s) before the reaction is the same as
the total mass of material(s) after the reaction.
A balanced chemical equation has the same number of each kind of atom on both sides of the arrow. When students multiply the number in front of the chemical
formula in the equation by each number written below the symbol of the atoms in the formula, the number of each kind of atom on the left side of the arrow must
equal the number of each kind of atom on the right side of the arrow for the equation to be balanced
In the chemical equation for the reaction of water (liquid) changing to hydrogen and oxygen (gas)
2H20  2H2 + 02

There are 2 x 2 Hydrogen (H) = 4 Hydrogen (H) atoms on the left of the arrow and 2 x 2 Hydrogen (H) = 4 Hydrogen (H) atoms on the right of the arrow;

There are 2 x 1 Oxygen (O)= 2 Oxygen (O) atoms on the left of the arrow and 1 x 2 Oxygen (O) atoms on the right of the arrow; (if no number appears in front
of the formula or below the atom, it is an understood “1”).

Therefore, there are the same numbers of atoms of hydrogen (4) and oxygen (2) on both sides of the equation and the equation is said to be balanced.
Since there are the same number of each kind of atom on both sides of the arrow and atoms represent kinds of matter, the amount of matter is the same on both
sides of the equation, which supports the law of conservation of matter.
physical properties of matter can be observed and measured without changing the kind of matter being studied. Chemical properties are not usually visible. They
can be recognized only when substances react chemically with one another, that is, when they undergo a change in composition. The following physical properties
can be used to help identify a substance:
Melting Point
Melting point is the temperature at which a solid can change to a liquid. The temperature at which a pure substance melts is unchanging.
Therefore, the melting point of a pure substance can be used as a physical property for identifying it. Ice melts to form water at 00C or 32oF.
Boiling Point
Boiling point is the temperature at which a liquid changes state into a gas. The liquid starts to form bubbles throughout, which grow larger,
rise to the surface, and burst. This temperature is unchanging for a given substance, at sea level, and can be used to identify that
substance. The boiling point for pure water is 100oC or 212oF.
Density
Density, defined qualitatively, is the measure of the relative “heaviness” of objects with a constant volume, is the mass of a given volume of
a substance. The density of a given substance is unchanging and can be used as a physical property to identify it. The density of water is a
universal standard: 1 milliliter of water (at 4oC) equals 1 cubic centimeter of water equals 1 gram of water. The density of water is 1 g/mL or
1 g/cm3 or 1g/cc. Lead for example is a very heavy, dense metal. The density of lead is much greater than the density of the very light
metal, aluminum.
Color
Color of a given substance is distinctive and can be used to help identify a substance.
Chemical properties can also be used to help identify a substance. Chemical properties are not usually visible. Chemical properties can be recognized only when
substances react chemically with one another, that is, when they undergo a change in composition.
 Chemical reactivity is the tendency of a substance to undergo a chemical reaction usually with other specific substances.
 When a substance reacts with oxygen quickly and releases heat and light energy, the process is called burning.
 When a substance, for example iron, reacts with oxygen and water slowly, the process is called rusting.
Physical changes do not change the identity of a substance. When a substance changes state, the substance does not change identity. A change in state,
therefore, is a physical change. When substances change in size or shape, they do not change identity; therefore, these changes are also physical changes.
When the following changes occur, however, the substance usually changes identity; therefore, the changes are chemical changes:
Color change
When a substance changes color, the chemical composition of the substance has usually changed; therefore, this is a chemical change.
Temperature change When substances change temperature after being mixed with other substances, the chemical composition of the substances has usually
changed; therefore, this is a chemical change.
Precipitate formation When two or more liquids are mixed and a solid (precipitate) forms, the chemical composition of the substances has usually changed;
therefore, this is a chemical change.
Gas formation
When substances are mixed or heated and a gas is given off, the chemical composition of the substances has usually changed; therefore,
this is a chemical change.
CELLS
A cell is the smallest unit of life that conducts all life functions. Each cell has major structures within it that perform these life functions. Structures that are common
to plant and animal cells are the cell membrane, nucleus, mitochondria and vacuoles. Structures that are specific to plants are the cell wall and chloroplasts.
Students should know that
 the cell is the smallest unit of life
 cells vary in size, but contain many of the same major parts
 the cell membrane is the outside covering of a cell. It controls what comes in and out of a cell
 the cytoplasm is the gel-like fluid inside of a cell. The other organelles are embedded in the cytoplasm
 the nucleus contains DNA and is the control center of the cell
 the vacuole(s) act as storage centers
 the chloroplasts are the food-making structures of a plant cell
 the mitochondria use oxygen to release energy from food. It is sometimes called the “powerhouse” of the cell
 the cell wall provides extra support and shape for plant cells. It is made mostly of cellulose
Major structural differences between a plant and an animal cell include.

Plant cells have a cell wall, but animal cells do not. Cell walls provide support and give shape to plants.

Plant cells have chloroplasts, but animal cells do not. Chloroplasts enable plants to perform photosynthesis to make food.

Plants cells usually have one or more large vacuole(s), while animal cells have smaller vacuoles, if any are present. Large vacuoles help provide shape
and allow the plant to store water and food for future use.
Bacteria and Protists
Students should know that there are three basic bacterial shapes.
Round
Round bacteria are referred to as cocci 
Rod shaped
Rod shaped bacteria are known as bacilli
Spiral
Spiral shaped bacteria are corkscrew shaped are known as spirilla
Protists are organisms that are classified into the kingdom Protista. Although there is a lot of variety within the protists, they do share some common
characteristics. All protists have

a nucleus with a nuclear membrane

are usually one-celled.

live in moist environments
Protists are grouped by the way they move and obtain food:

Protists with Pseudopods (for example the amoeba) These protists move by extending their bodies forward and then pulling the rest of their bodies
forward as well The finger-like structures that they project forward are called pseudopods (false foot). The pseudopods are also used to trap food.

Protists with Cilia (for example the paramecium) these protists move by beating tiny hair-like structures called cilia.. The cilia act as tiny oars that allow
the protist to move through its watery environment. The cilia also beat and help to capture food

Protists with Flagella (for example the Euglena) These protists move pulling themselves with long whip like structure called flagella. These protists can
have one or more flagella that help them move. The euglena is unique in that it has characteristics of both a plant and an animal, it contains
chloroplasts that photosynthesize and also can consume other organisms as well.
Cellular processes for survival
Photosynthesis-The life cycle begins with photosynthesis within a plant cell. The plant, uses the energy from sunlight, carbon dioxide, and water, to take food.
The plant cell then releases oxygen as waste. Once the “food” is formed it is either used by the plant or consumed by an animal. This food is broken down in the
plant or animal’s cell through a process called respiration.
Respiration
-Breaks “food” into carbon dioxide, water, and energy. Carbon dioxide and water are the waste products of respiration. The cell uses the
energy to build, repair, and reproduce cells.
Elimination -Rids the cells of waste products that would be toxic to the cell. Molecules move from a crowded area to a less crowded area (diffusion), as waste
molecules accumulate in a cell, the waste will move out of the cell and be eliminated.
Mitosis
Cell reproduction is called mitosis. Mitosis enables a cell to make an exact copy of it. Mitosis is a process of cell division, which results in the
production of two daughter cells from a single parent cell. The daughter cells are identical to one another and to the original parent cell. Mitosis is needed for
growth, replacement, and asexual reproduction.
Genetics

Genes are usually known as the physical unit of heredity. Genes are formed from DNA, located on the chromosomes and are responsible for the
inherited characteristics that distinguish one individual from another. Each human individual has an estimated 30,000 separate genes.

Chromosomes are the self-replicating genetic structures of cells.

Inherited traits are those that are passed from parent to offspring. Examples of inherited traits are eye color, eye shape, hair type, or face shape.

Some of the traits passed from parent to offspring are dominant. A dominant trait is one that will always be expressed. Alleles for dominant traits are
represented by a capital letter.

Some of the traits are recessive. A recessive trait is one that will only be expressed if two recessive traits have been passed. In the presence of a
dominant trait, the recessive trait will not appear. Alleles for recessive traits are represented by a lowercase letter.

The phenotype of an organism encompasses its physical and behavioral characteristics. For example, eye color, height, or skin color, all constitute the
phenotype of an individual. In other words, the phenotype refers to the physical characteristics of an individual.

The genotype consists of the genetic makeup of an organism. It represents the collection of all the genes found on the chromosomes in the nucleus of
each cell. These genes are used as a "blueprint" or set of instructions for building and maintaining a living creature.
Mechanisms of Inheritance
Biological information can be passed on from one generation to the next. Each gene is copied and then the copy is transferred
to the new cell or organism as it reproduces and duplicates itself:

Reproduction is a basic and fundamental process common to all forms of life on earth.

In this process organisms and cells produce new copies of themselves by following the instructions and blueprints they all carry in the genetic code.

During reproduction these instructions and blueprints, in the form of biological information, are copied and then passed on from one generation to the
next. This is inheritance. The offspring receives one gene from each parent.

Cellular life depends on the ability of cells to grow, copy their biological information, and then divide into two new cells, ensuring that each new cell
receives a complete copy of all the information it needs. This is cell division.
A monohybrid inheritance is the inheritance of a single characteristic.

The cross that involves one pair of contrasting traits

For example, crossing a tall (Tt) plant a short (tt) plant is a monohybrid cross

Every new cell has received one gene from each parent

For example a cell with Tt genotype has received a gene for tall height dominance (T) from one parent and a recessive gene for short height from the
other parent (t).
Each parent has two genes and the probability that the offspring receive one or the other gene is determined by a Punnett square.
Some characteristics that organisms have are inherited from their parents and some can be influenced by environmental factors.
An inherited trait is a particular genetically determined characteristic or quality that distinguishes an organism from other organisms.



Inherited traits are passed on from generation to generation when chromosomes carrying genes are passed from parent to offspring in sex cells.
Some inherited traits are dominant, some are recessive, and some are neither.
Examples of inherited traits in humans include color blindness, baldness, blood type, and skin color, the ability to taste certain substances, or free or
attached ear lobes.
Any characteristic or behavior that cannot be attributed to a genetic value or genes of the individual is said to be a result of environmental factors. Examples of
environmental factors that can affect traits of organisms include temperature, diet, medical care, or living conditions. Environment determines the phenotypic
pattern of expression.
HUMAN BODY
The human body is divided into specific levels of organization and that these levels are what make the human body a complex organism. The levels of
organization, from the simplest structure to the most complex are:
Cells
The basic units of structure and function within the human body. Though all cells perform the processes that keep humans alive, they also have
specialized functions as well. Examples are nerve cells, blood cells, and bone cells.
Tissues
Organs
A group of specialized cells that work together to perform the same function. There are four basic types of tissue in the human body:
 Nerve tissue—carries impulses back and forth to the brain from the body
 Muscle tissue—contracts and shortens, making body parts move
 Epithelial tissue—covers the surfaces of the body, inside and outside
 Connective tissue—connects all parts of the body and provides support
Blood, an example of a tissue, is composed of several types of cells, including red blood cells, white blood cells, platelets, and plasma that
function to transport materials from one part of the body to another.
Are comprised of two or more different types of tissues that function together to perform a specific function. The task is generally more complex
than that of the tissue. For example, the heart is made of muscle and connective tissues which function to pump blood throughout the body.
Systems
A group of two or more organs that work together to perform a specific function for the human body. All of the different organ systems work
together and depend on one another. There are eleven different organ systems in the human body: circulatory, digestive, endocrine, excretory
(urinary), immune, integumentary (skin), muscular, nervous, reproductive, respiratory, and skeletal.
Major Organs
Function (s)
System
Circulatory
Respiratory
Heart
Blood vessels (arteries, capillaries and
veins)
Nose
Trachea
Bronchi
Digestive
Diaphragm
Mouth
Esophagus
Stomach
Small intestines
Large intestines
Rectum and anus
Major Organs
Causes blood to flow through the body by it pumping action
Tubes that carry blood throughout the entire body
Collects air from the environment and moistens and heats the air before
it enters the trachea
The windpipe; moves air from the nose to the lungs
Tubes that move air from the trachea to the lungs; one bronchus leads
to each lung; part of each bronchus is outside the lung and part is
inside.
The dome-shaped muscle that aides in the breathing process
Begins to break down food into smaller pieces through mechanical
digestion; saliva in the mouth starts the process of chemical digestion
The transport tube that carries chewed food to the stomach
Continues the process of mechanical digestion; secretes enzymes that
perform some chemical digestion of food
The organ where most of the chemical digestion of food takes place;
nutrients from food are also absorbed through the small intestines
The organ where water is absorbed from the food and taken into the
bloodstream; prepares the remaining food material for elimination from
the body
The rectum is a short tube that stores solid waste until it is eliminated
from the body through the anus.
Function (s)
System
Digestive continued
Liver
Pancreas
Gallbladder
Excretory (Urinary)
Kidneys
Ureters
Bladder
Nervous
Urethra
Brain
Spinal cord
Peripheral nerves
Muscular
Skeletal muscles
Smooth muscles
Skeletal
Cardiac muscles
Bones
An ancillary organ of the digestive system that produces bile which is
used by the body to break up fat particles.
An ancillary organ to the digestive system that functions to produce
enzymes that help break down starches, proteins, and fats in the small
intestine.
An ancillary organ to the digestive system that functions to store bile
produced by the liver.
The two kidneys function to get rid of urea , excess water, and some
other waste materials which are eliminated in urine
Tubes which connect each kidney to the bladder
A saclike muscular organ which stores urine until it is released from the
body
Tube through which urine passes before it is removed from the body.
An organ of the central nervous system which has three distinct parts
that all serve to control and coordinate the body’s activities. The
cerebrum controls thoughts, voluntary actions, and the sensations
related to the five senses. The cerebellum helps with balance and
coordination. The brain stem is located at the base of the brain and
controls vital and involuntary processes, for example, breathing, the
beating of the heart, and digestion.
A bundle of nerves that begins at the brain stem and continues down
the center of the back. It connects with nerves outside the central
nervous system and controls reflexes and directs sensations to the
brain.
A network of nerves that branch out from the spinal cord and connect to
the rest of the body. The peripheral nervous system is divided into
groups called the motor and sensory nervous systems.
Voluntary muscles that are attached to bones and provide the force
needed to move your bones
Involuntary muscles that control many types of movement in the body
(i.e, digestion)
Involuntary muscle that forms the heart
Provide shape and support for the body and protection for many organs
and structures; some bones produce blood cells; some store minerals
The different organs systems in the human body function together and depend on one another for the human body to function successfully, even though each
system performs its own unique function. Of the eleven systems in the body, students should know how the following systems work together:
Nervous System
The main role of the nervous system is to relay electrical signals through the body. The nervous system directs behavior and movement
and, along with the endocrine system, controls physiological processes, for example digestion, circulation, or movement.
The body cells need oxygen to function. Taking in oxygen and transporting it to cells are the jobs of the respiratory and circulator systems.
Circulatory System
The main role of the circulatory system is to transport nutrients, gases (for example oxygen and carbon dioxide), hormones, and wastes
through the body.
Respiratory System The main role of the respiratory system is to provide gas exchange between the blood and the environment. Primarily, oxygen is absorbed
from the atmosphere into the body and carbon dioxide is expelled from the body.
The circulatory and digestive systems work together to ensure that nutrients made available by digestion get to the cells of the body.
The digestive and excretory systems work together to take in materials your body needs and gets rid of wastes.
Digestive System
The main roles of the digestive system are to breakdown and absorb nutrients that are necessary for growth and maintenance.
Excretory System
The main role of the excretory system is to filter out cellular wastes, toxins and excess water or nutrients from the circulatory system.
The muscular and skeletal systems work together to help the body move.
Muscular System
The main role of the muscular system is to provide movement. Muscles work in pairs to move limbs and provide the organism with mobility.
Muscles also control the movement of materials through some organs, for example the stomach and intestine, and the heart and circulatory
system.
Skeletal System
The main role of the skeletal system is to provide support for the body, to protect delicate internal organs and to provide attachment sites for
the organs.
Disease
A disease is a condition that does not allow the body to function normally. Diseases can affect either an individual organ or an entire body system. Diseases are
divided into two groups—infectious and noninfectious.
Tiny organisms called pathogens cause infectious diseases. These pathogens can be bacteria, viruses, fungi, or protists. These pathogens can come from another
person, a contaminated object, an animal bite, or the environment. The immune system is responsible for distinguishing between the different kinds of pathogens
and reacting to each according to its type. Once a pathogen enters has entered the body, it works by damaging individual cells within the organs or in some cases
attacks an entire body system.
Some examples that students should know are:
Colds
A common cold is an illness caused by a virus infection located in the respiratory system. Cold viruses can only reproduce when they are
inside living cells. When located on an environmental surface (for example a doorknob or drinking glass), cold viruses cannot reproduce.
However, they are still infectious and can be transported from the environmental surface to the nose or mouth.
Flu (Influenza)
Influenza, commonly known as "the flu," is a highly contagious viral infection of the respiratory system. Influenza typically causes fever,
muscle aches, and a more severe cough than the common cold and usually last longer.
Strep throat
(bacterial) Strep throat is a contagious disease caused by infection with bacteria. Strep throat symptoms include fever, pain, redness, and
swelling of the throat and tonsils. Strep throat may produce mild or severe symptoms.
Athlete’s foot
Athlete’s foot is a common fungal infection of the skin of the feet. The fungus is contracted from public environments and then grows in the
warm and moist environment usually between the toes, and can be difficult to get rid of.
AIDS
Acquired immunodeficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV). This virus attacks the cells in the
immune system making the organism unable to fight off other pathogens that may attack the body.
Noninfectious diseases are diseases that are not caused by pathogens in the body and are not spread from organism to organism. These diseases are either
caused by cardiovascular disease, allergies, diabetes, and cancer are examples of noninfectious diseases.
Some noninfectious diseases that students should know are:
Diabetes
Diabetes is a disease that results in the glucose, or sugar, level of the blood being higher than the normal range. It is caused by a person’s
inability to either produce or use properly a natural chemical produced in the body called insulin. The higher level of blood sugar results
many disorders of the body, for example it increases problems with circulation of blood, and it can lead to kidney disease and heart disease,
or cause vision problems.
Asthma
(Involves the respiratory system) Asthma is a disease that affects the lungs and the airways that deliver air to the lungs. It causes periodic
attacks of wheezing and difficult breathing. An asthma attack occurs when the airways become inflamed in response to a trigger, such as
dust, mold, pets, exercise, or cold weather. However, some attacks start for no apparent reason
Parkinson’s disease Parkinson's disease occurs when certain nerve cells in the brain die or become damaged. Parkinson's disease does not affect everyone the
same way. In some people the disease develops quickly, in others it does not. Although some people become severely disabled, others
experience only minor motor disruptions. Tremor is the major symptom for some people, while for others tremor is only a minor complaint
and different symptoms are more troublesome. At present, there is no cure for Parkinson's disease.
Skin Cancer
Skin cancer is a disease in which cancer cells are found in the outer layers of your skin. Your skin protects your body against heat, light,
infection, and injury. It also stores water, fat, and vitamin D. Sunburn and UV light can damage your skin, and this damage can lead to skin
cancer. However, there are other determining factors, including heredity and the environment.
ECOLOGY
The ecosystems are divided into specific levels of organization and that these levels are what make the ecosystem complex. The levels of organization, from the
simplest to the most complex are:
Species
Species are the different kinds of organisms found on Earth. A more exact definition of species is a group of similar organisms
that can reproduce with each other.
Populations
A population comprises all the individuals of a given species in a specific area or region at a certain time. The location where a population
obtains food, water, shelter and other things needed in order to survive is called its habitat. The particular role that the population serves in
its environment is called its niche.
Communities
Ecosystems
Community refers to all the different populations in a specific area or region at a certain time. Its structure involves many types of
interactions among species. Some of these involve the gathering and use of food, space, or other environmental resources. Others involve
nutrient cycling through all members of the community.
Ecosystems are dynamic units composed of the community and the abiotic environment, including water, sunlight, oxygen, temperature and
soil.
Biomes
Biomes are the largest recognizable assemblage of animals and plants on Earth and are determined mainly by climate.
Organisms have energy roles that they serve in their environments. Each role is determined by how the organism obtains its energy and how they interact with
other organisms in the environment. These roles can be as a producer, consumer or decomposer. The flow of energy can be represented using the following
diagrams:
Food chain
Uses pictures or words and arrows to show the movement of energy through the trophic levels of organisms. The trophic level of an
organism indicates the position that the organism occupies in the food chain—what it eats and what eats it. The levels are numbered
according to how far the particular organism is along the chain from the primary producer at Level 1, to herbivores (Level 2), to predators
(Level 3), to carnivores or top carnivores (Levels 4 or 5).
Food web
Describes the organisms found in interconnecting food chains using pictures or words and arrows. Food webs describe the complex
patterns of energy flow in an ecosystem by modeling who consumes whom or what.
Energy pyramid
Shows the amount of energy that moves from one trophic level to another in a food chain. The most energy is available at the producer level
of the pyramid. Energy availability decreases as it moves up the energy pyramid.
There are various factors that can change the environment. Students should be able to construct cause and effect models for each factor and how it affects the
environment.
Changes in the environment can occur due to natural hazards.
Landslides
Landslides are rock, earth, or debris flows on slopes due to gravity. They can occur on any terrain given the right conditions of soil,
moisture, and the angle of slope. Landslides can be caused by rains, floods, earthquakes, and other natural causes, as well as, humanmade causes such as excessive development or clear-cutting for lumber. Examples of ways that landslides can effect the environment are
blocking roads, damaging or destroying homes, destroying habitats, or disrupting power lines.
Wildfires
Fire is a natural event in most forest ecosystems. Fires can be beneficial to the ecosystem and are an essential component in the life cycle
of some trees. Generally, fires are neither good nor bad. They occur naturally through lightning strikes or when humans start them
accidentally or intentionally. Examples of the effects of wildfires on the environment are increased air pollution, habitat destruction, or
destroying homes or property.
Floods
A flood is an unusually high water stage in which water overflows its natural or artificial banks onto normally dry land. There are two basic
types of floods. In a regular river flood, water slowly climbs over the edges of a river. The more dangerous type, a flash flood, occurs when a
wall of water quickly sweeps over an area. A number of factors can contribute to the cause of a flood, including:
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heavy, intense rainfall
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over-saturated soil, when the ground can't hold anymore water.
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high river, stream or reservoir levels caused by unusually large amounts of rain
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urbanization, or lots of buildings and parking lots
Examples of the effects of floods on the environment include damaging property, endangering humans and animals, or causing soil erosion
and deposition of sediment.
Changes in the environment can occur due to changes in populations. Changes in populations can occur when new members enter a population or when members
leave a population. These changes can have an effect on the amount of resources available in the environment. This can lead to competition for food, water,
space, or shelter.
Births and Deaths
New births are the main way that organisms are added to a population. The number of births in a population during a certain amount of time
is called the birth rate. Deaths are the main way that organisms leave a population. The number of deaths in a population during a certain
amount of time is called the death rate.
Immigration & Emigration The size of the population can change when members move into or out of the population. Immigration is when organisms ove in from
another environment. When part of the population leaves the environment, this is known as emigration.
Changes in the environment can occur due to limiting factors.
Climate
Climate refers to the temperature and amount of rainfall in a particular environment. Changes in temperature and the amount of rainfall
from the norm can change an environment which will have an effect on the populations in the area.
Availability of food
Organisms require a certain amount of food to survive. When the amount of food available in a given area is less than what the various
populations need, food becomes a limiting factor.
Availability of water,
space, and shelter
Plants and animals need space for various reasons. Plants need space in order to, grow, and obtain the necessary nutrients from the soil.
Animals need space in order to find food and shelter. When the amount of space in an environment cannot support the populations present,
space becomes a limiting factor.
Carrying capacity
The maximum number of organisms an environment can support
SOIL
Soil quality is based on properties that can be observed such as soil profile, composition, texture, or particle size, as well as measured, such as permeability and
pH.
Observable properties:
Soil profile:
Soils form in layers, or horizons, and all the layers make up the soil profile. A mature soil profile consists of three layers – topsoil, subsoil,
and parent material above bedrock. Topsoil that is nutrient rich, containing a mixture of humus, clay, and minerals is most suitable for plant
growth. Most animals live in the topsoil horizon.
Composition:
Soil is a mixture of rock particles, minerals, decayed organic material, air, and water. The decayed organic matter in soil is humus. The
sand, silt, and clay portion of soil comes from weathered bedrock material. The combination of these materials in soil affects the type of
plants that can grow in it or animals that can live in it.
Texture:
Soil texture depends on the size of individual soil particles and is determined by the relative proportions of particle sizes that make up the
soil. Texture names may include loam, sandy clay loam, silt loam, or clay depending upon the percent of sand, silt, and clay in the soil
sample.
Particle size:
Soil particles are classified by size ranging from coarse sand to very fine sand to silt, and finally to the smallest particle, clay. Soil particles
that are larger than 2mm are called gravel.
Measurable properties:
Permeability:
Soil particles have open spaces between them that let water flow through. How freely that water flows is the permeability of the soil. The
closer the particles pack together because of particle size, the less permeable the soil is. Measuring permeability involves calculating the
rate of drainage.
pH:
Soils can be basic or acidic and usually measure 4-10 on the pH scale. Indicators can be used to measure the pH of soils. Most plants
grow best in soils with a pH of between 5 and 7. Lime is a kind of fertilizer and can be added to make the soil more basic.
Soil is one of the most valuable abiotic factors in an ecosystem because everything that lives on land depends directly or indirectly on soil. Soil formation takes a
long time, so the quality of soil that is in an ecosystem helps to maintain that ecosystem. Should soil quality change in any of its properties, the ecosystem and life
in it could also change. An example of this change is evident because Earth is losing about 7% of its topsoil each decade, and the result is an increase in global
deserts. Ecosystems change as soil quality changes.
WATER
When water falls to Earth, some water soaks into the ground becoming part of groundwater and gravity causes some of it to flow downhill instead of soaking into
the ground; this is called runoff.
Groundwater:
is water that soaks into the ground. Soil and rock that allow the water to pass through is called permeable. The water enters into the zone
of aeration, which is unsaturated. Groundwater will keep moving deeper into Earth until it reaches a layer of rock that is not permeable.
The area where the water has filled all the space in the soil is called the zone of saturation; the top of this zone is the water table.
Groundwater can also flow slowly through the underground rock sometimes dissolving it away forming tunnels, caves, and caverns.
Surface-water:
is runoff that has not soaked into the ground. As runoff travels downhill, it forms the water in streams and rivers. An area that is drained by
a river and all the streams that empty into it, the tributaries, is called a drainage basin or watershed. A divide is the high ground between
two drainage basins. By studying a map that contains rivers and marking all the tributaries of that river, the watershed area can be
identified.
The availability of water as groundwater or surface-water is important to the ecosystems in that area.
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Flowing water can erode the land in one location and deposit the sediments in another.
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The floodplain of a river may deposit sediment after heavy rains enriching the area with new soil needed for growing vegetation. This new soil is nutrient rich.
Crops or natural vegetation grow well in it.
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The drainage basin provides the needed water for animal life also.
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Deltas may form where the river ends its journey into a still body of water like a lake or the ocean. A unique ecosystem forms in delta regions, like the Santee
delta in South Carolina or the Mississippi delta in Louisiana.
Water is important to human activities:
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Human beings are dependent upon water for survival, not only for drinking but for agriculture and industry as well.
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Dams have been place along some rivers in order to produce hydroelectric power and to offer recreation in the lakes that form behind the dams.
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Lakes, rivers, and the ocean contain sources of food and minerals.
Earth is 71% water with about 3% usable fresh water. Students need to know where this water is, how it moves, and why it is so important as an abiotic factor
within an ecosystem.
Natural resources are materials from Earth that are used by living things. Some resources can be replaced and reused by nature; these are renewable resources.
Natural resources that cannot be replaced by nature are nonrenewable.
Renewable:
Air, water, soil, and living things are renewable resources. The water cycle allows Earth’s water to be used over and over. New soil is
formed to replace soil that has been carried away by wind and water (although new soil forms very slowly). Trees and other new plants
grow to replace those that have been cut down or died. Animals are born to replace animals that have died. Renewable resources are
replaced through natural processes at a rate that is equal to or greater than the rate at which they are being used.
Nonrenewable:
Fossil fuels (coal, oil, natural gas), diamonds and some other minerals are nonrenewable. They exist in a fixed amount and can only be
replaced by processes that take millions of years. Nonrenewable resources are exhaustible because they are being extracted and used at
a much faster rate than the rate at which they were formed.
Natural resource can be depleted, used to the point that they are no longer available. Conservation measures are necessary.
Depletion
of nonrenewable resources is understandable because they are known to be in a non-replenishing supply. If renewable resources are used
at an increasing rate so that they cannot be naturally replaced fast enough, they too can be depleted. Depletion of a natural resource, such
as trees, can contribute to global warming.
Conservation
The wise use of a natural resource. As the number of people on Earth gets larger, the need for natural resources increases. The terms
reduce, reuse, recycle and protect are important ways that people can be involved in conservation of natural resources.