Download Biology Keystone Cliffnotes Chapter Review

Ms. Leung’s Honors Biology
Keystone Exam Review
Name:____________________
Topics Covered Include:
Intro to Biology, Chemistry, Biochemistry, The Cell,
Cell Transport, Photosynthesis, Cell Respiration,
Cell Division, DNA, Proteins, Genetic Technology,
Evolution, Classification & Ecology
*Chapter numbers correspond to Prentice Hall Dragonfly textbook!
Chapter 1
Introduction to Biology/Review of Science
Chapter 1 reviews science. Science is about exploring the world around us through an
application of the scientific method. The scientific method involves the following steps:
observe, hypothesize, experiment, gather data, analyze results, present findings, and
repeat experiments. The metric system is always used in science and the most powerful
piece of equipment in biology is the microscope. A controlled experiment is when only one
variable is altered. Controlled experiments are best in science because you can determine
the results of manipulating only 1 variable. In a lab the independent variable is the
variable you have control over (the variable you choose) and the dependent variable is
what you are measuring. For example, in an experiment that tests how colors of light
effect plant growth the colors chosen for the experiment would be the independent
variable while the height of the plants would be the dependent variable. In science,
theories are developed based on experiments and data. A theory is a well-tested
explanation that is a particular hypothesis that has never been proven incorrect.
Biology is the study of life. Living things share similar characteristics such as : being
made of cells, reproducing, containing genetic material, growing and developing,
obtaining and using materials and energy, responding to the environment, maintaining a
stable internal environment, and changing over time. Living things can be studied in
different levels depending on their complexity. The pathway of organization for an
organism includes: atoms, molecules, cells, tissues, organs, organ systems, and
organisms. We can extend the levels of organization to include how the organism fits into
the world. From an organism, there are populations (groups of organisms living together),
communities (populations living in defined areas), ecosystems (all living and nonliving
components of a community), and the biosphere which includes all parts of Earth and every
ecosystem.
Chapter 2
Chemistry & Biochemistry
Living things are made of chemical elements. The basic unit of matter is the atom. Atoms
are composed of protons (Atomic Number, positive charge), neutrons (Add together with
protons for Atomic Mass, no charge) which are found in the nucleus, and electrons
(Equivalent to Atomic Number if atom is neutral, negative charge) which circle the
nucleus in electron orbitals. An element is made of only 1 type of atom, and compounds
are composed of 2 or more elements that are chemically combined.
Elements are important in forming chemical bonds. A covalent bond occurs when atoms
equally share electrons, which means that electrons circle both atoms at an equal rate. An
ionic bond occurs when there is a difference in charge between the atoms and one atom
steals an electron from its’ partner. Carbon bonding to hydrogen is an example of a
covalent bond. Salt being formed from sodium and chlorine is an example of an ionic bond.
Ions are found in the body and are important to living things. Ions can be positively
charged (occurs when an atom donates its’ electron, example is when sodium gives chlorine
its electron and sodium becomes Na+) or negatively charged (occurs when an atom takes in
another electron, example is when chlorine takes sodium’s electron and chlorine becomes
Cl-.
Water is a very unique molecule and living things are made mostly of water. Water has a
special type of bond called a polar covalent bond. A partial charge exists between
hydrogen and oxygen creating this special bond. Polar means that water has a slight
charge. When 2 water molecules bond together, they form a hydrogen bond. Hydrogen
bonds are weaker than covalent and ionic bonds and give water its’ unique properties such
as its high boiling point and its’ ability to form a “dome” on top of a penny. Cohesion is
when molecules of the same substance are attracted together like two water molecules
that cling together. Adhesion is an attraction between molecules that are made of
different substances such as when water sticks to the side of a thin glass tube.
The pH scale is also important to living things. If the pH changes too much, the organism
can be out of homeostasis (internal balance) which could be fatal. The pH scale ranges
from 1-14 (1-6 Acid, 7 Neutral, 8-14 Base) and is most dangerous at a level of 1 or 14.
Buffers are materials (weak acids or bases) such as antacids that neutralize stomach acid
to make the internal environment of the stomach more comfortable for the person.
Chapter 2 (continued)
Chemistry & Biochemistry
Organic chemistry is known as carbon chemistry. Carbon is found in all living things and
can bond 4 times because it has 4 valence (outer) electrons. It can form single, double, or
triple bonds and can form straight or branched chains and rings.
Monomers are small subunits that form polymers or macromolecules. Polymerization
describes how monomers combine to form a polymer. Water can be released or formed
depending on if a polymer is being formed from the combination of smaller subunits or
broken apart into smaller subunits. A condensation/dehydration reaction is when a
polymer is formed and water is released. A hydrolysis reaction is when water is used to
break apart a polymer into its original monomers.
There were 4 major macromolecules in living things (monomers are in parenthesis):
Proteins (amino acids), Nucleic Acids (nucleotides), Carbohydrates (glucose (example of a
monosaccharide)), lipids (fatty acids (for most)). Carbohydrates are sugars and are made
of carbon, hydrogen, and oxygen in a 1:2:1 ratio. Carbohydrates are a good source of
energy and examples can be found in pasta and bread. There are monosaccharide’s (1
sugar), disaccharides (2 sugars), and polysaccharides (many sugars). Lipids are also
energy molecules. They are in oils, fats, and waxes. Lipids are also part of the cell
membrane (phospholipid bilayer). They are a diverse group. Saturated fats are fatty
acids that have all single bonds between the carbon and hydrogen’s. Unsaturated fats
have at least 1 double bond. Nucleic acids are important for hereditary information.
Examples are DNA and RNA. Proteins are another diverse group. Examples of proteins
include enzymes (catalysts) and meat. Proteins can help with fighting infections, speeding
up chemical reactions, and transporting materials. Proteins have a unique shape which
corresponds to its function. Temperature and pH can impact the structure of a protein and
if it is denatured that means that the protein has changed its’ shape based on the
environment and can no longer function. The example we talked about in class was making
scrambled eggs. The egg white which is mainly all protein changes shape as the egg is
heated in your frying pan. There is a change of shape in the protein which is why the
scrambled eggs look different then the eggs that were released when the shells were
immediately cracked.
Chemical molecules are involved in reactions. In a chemical reaction, reactants yield
(arrow) products. The products are different molecules then the reactants. Energy can
be lost or gained in the process. Activation energy is the amount of energy necessary for
the reaction to begin. Not all reactions involve releasing energy (downhill graph), some
absorb energy (uphill graph). All reactions occur to help an organism maintain homeostasis.
Chapter 7
The Cell
The cell is the basic unit of life because all living things are made of at least 1 cell. Cells
are differentiated, which means specialized in how they look based on what they do. The
discovery of the cell was made possible through the invention of the microscope because it
was the first time in history that the invisible world was made visible. There are 3 parts
of the cell theory which is a major concept in biology: all living things are made of cells,
the cell is the basic unit of structure and function, and new cells are produced from
pre-existing cells.
There are 2 main types of cells. Prokaryotes are bacteria and are simple cells without a
nuclei and membrane bound organelles. Eukaryotes are plant and animal cells and contain
nuclei and membrane bound organelles. Regardless of the type of cell, all cells have
genetic information, cytoplasm, ribosome’s (only organelle that’s an exception), and a
membrane to hold the cell intact. Plant and animal cells differ because plant cells have a
cell wall, chloroplasts, and a large central vacuole while animal cells have centrioles.
The table below lists the major organelles and their functions:
Organelle
Nucleus
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Golgi
Ribosome
Lysosome
peroxisome
Vacuole
Nucleolus
Mitochondria
Chloroplasts
Cytoskeleton
Cell membrane
Cell wall
Function
Contains genetic information
Contains ribosomes to make proteins
Makes lipids & is involved in detoxification
Adds finishing touches to make proteins fully functional
Makes proteins
Contains enzymes to breakdown lipids, carbs, proteins,
involved in digestion
Contains enzymes involved in chemical reactions
Stores water, enzymes, salts, etc
Makes ribosomes
Powerhouse of cell, makes ATP
Make food for plants
Cell skeleton, made of protein fibers of microfilaments
(thinner) & microtubules (thicker)
Provides protection & pathway for materials to travel in &
out of cell
Thick sugar/protein boundary layer in plant cells
The cell membrane is a double layer membrane that has multiple names: fluid mosaic
model, plasma membrane, and phospholipid bilayer. It is made of phospholipids (contains
2 regions: hydrophilic “heads” =like water & hydrophobic “tails” =doesn’t like water),
proteins (allow for transport of materials in & out of cell), and sugar molecules. When we
learned about the cell we also talked about methods of cell transport.
Chapter 7 (continued)
Transport Across the Cell Membrane
There are a variety of methods for the movement of materials in & out of the cell.
Transport Method
Function
Diffusion
No energy required, movement of molecules from a high to
low concentration
Osmosis
No energy required, diffusion of water across a membrane
Facilitated Diffusion
No energy required, diffusion with the help of proteins
Active Transport
Requires energy, diffusion of molecules against their
concentration gradient
Related to the cell membrane we discussed water movement in more detail. The cell is
always trying to maintain homeostasis which requires an equal balance of the movement of
water and molecules in and out of the cell.
Solution
Isotonic
Description
Equal concentration of molecules in and out of the cell, cell is
normal size
Hypertonic
Water leaves the cell because there are more molecules outside
of the cell, cell shrinks in size
Hypotonic
Water rushes into the cell because there are more molecules
inside of the cell, cell gets larger in size
Plasmolysis
This occurs when a plant cell becomes so dehydrated that the
cell membrane pulls away from the cell wall because water has
left the cell due to more molecules outside of the cell drawing
water towards them
Materials move in and out of the cell in 2 major processes. Exocytosis refers to how
materials exit the cell. Endocytosis refers to how materials enter the cell. Pinocytosis is
“cell drinking” and phagocytosis is “cell eating.”
Chapter 8
Photosynthesis
Photosynthesis refers to the chemical process in which plants make their own food. It is
powered by energy from the sun. It requires carbon dioxide, water, and the sun’s energy
and the products are glucose (C6H12O6) and oxygen. Glucose is a sugar that can be broken
down into energy for the plant. The ultimate source of energy for living things is a
molecule called ATP (adenosine triphosphate). It is the energy currency the cell can use
because there is a tremendous amount of energy between the 3 phosphate bonds in the
molecule. Just like how on your birthday you may receive a check from a relative but you
have to go to the bank to cash the check before you can make a purchase, the “check” in
photosynthesis is glucose and the “cash” is ATP. You will learn about how living things can
obtain ATP in the next chapter!
Autotrophs are producers and can make their own food. They begin all food chains.
Heterotrophs are consumers and rely on other living things for food. Remember, a
biomass pyramid is a triangular shape that shows us how 90% of energy is lost between
each level in the form of heat or unconsumed material. At the top of the pyramid there
are the fewest number of organisms because it takes so many organisms beneath them to
provide enough energy to support the top of the food chain/pyramid.
There are 2 main processes in photosynthesis. In the Light Reactions, pigments such as
chlorophyll in the chloroplast thylakoid membranes absorb sunlight to provide enough
energy to excite electrons. Water is an important reactant that provides electrons for
the electron transport chain and hydrogen ions which build up and then travel through
the ATP synthase protein in the thylakoid membrane to make ATP. Oxygen is released as
a byproduct when water is broken down and ATP and NADPH (carbon molecule carrying
energy) are produced and enter the Calvin Cycle in the stroma (liquid region) of the
chloroplast. In the Calvin Cycle light is no longer directly required. Carbon dioxide is
rearranged into different carbon molecules and glucose is formed. NADPH is converted
into NADP+ and ATP is converted into ADP + P and these molecules go back to the Light
Reactions so that the cycle can restart.
The rate of photosynthesis can be altered if the amount and availability of the reactants
is altered. Also, if the plant is exposed to different colors of light the amount of food it
produces can increase or decrease depending on the color of light. For example, remember,
plants are green because they reflect green light and not absorb it!
Chapter 9
Cellular Respiration
Cellular respiration is how living things obtain ATP energy from glucose. The process
requires glucose and oxygen and releases carbon dioxide, water, and ATP energy. The
mitochondria is known as the cell powerhouse because it is the site of cell respiration.
There are 3 processes involved in cellular respiration. Stage 1 is glycolysis. Glycolysis is
the splitting of glucose (into two 3-carbon molecules called pyruvic acid) and occurs in the
cytoplasm of the cell. Only a small amount of energy is released. If oxygen is available
the other 2 stages of cell respiration can occur.
Stage 2 is called the Krebs Cycle or Citric Acid Cycle. This stage occurs in the
mitochondria matrix (liquid inside organelle). Pyruvic acid is rearranged into different
carbon intermediate molecules to produce carbon dioxide and the energy carriers NADH,
ATP, and FADH2.
Stage 3 is called the Electron Transport Chain and occurs in the membrane of the
mitochondria. The energy molecules produced in the Krebs Cycle unload their electrons.
From the motion of electrons traveling across the molecules in the electron transport
chain there is a buildup of hydrogen ions which ultimately results in electrons bonding with
these ions to form water. The electrons are drawn down the chain due to the presence of
oxygen at the end of the chain. From the movement of the hydrogen ions there is a
buildup of these ions which eventually travel through the ATP synthase protein to
produce ATP which is the energy molecule a cell can use. Once the energy molecules unload
electrons they return to Stage 2 to become recharged. Stage 3 produces the most ATP
energy molecules and in the whole process of cellular respiration there are 36 ATP
molecules produced.
Organisms such as bacteria can be very unique and do not need as much energy as other
living things and can skip stage 2 and 3. We call them anaerobes if they do not need
oxygen. Fermentation occurs when oxygen is not required for cellular respiration.
Typically only 2 ATP molecules can be formed at once. The two types of fermentation are
alcoholic fermentation and lactic acid fermentation. Both are basically glycolysis with
one extra step. In alcoholic fermentation alcohol is a product and in lactic acid
fermentation lactic acid is a product. Alcoholic fermentation occurs in the rising of
bread. Lactic acid fermentation can occur in humans if you use up energy faster than the
mitochondria can undergo cell respiration. Your muscles cramp up because they are not
getting enough oxygen and your body is only undergoing lactic acid fermentation.
Chapter 10
Cell Growth & Division
The cell cycle involves all aspects related to cell growth including interphase and mitosis.
The cell spends most of its time in interphase. Interphase is a growth phase for cells in
which the cell prepares to divide by making more cytoplasm, organelles, and proteins.
DNA is also replicated which means the number of chromosomes are replicated since they
contain DNA. Interphase has 3 phases: G1, S, and G2. The “G” phases are growth phases
and the “S” phase is when DNA replicates. Having 3 segments in interphase provides
check points to make sure the cell is growing normally. If there is a problem at one of the
phases the cell will enter the G0 phase and will be recycled. This is important because if a
cell divides uncontrollably we call that cancer. In cell division identical copies of cells are
made and increase in an exponential rate. If a mistake is made with one cell then all of the
cells produced from this one cell will also contain the mistake.
Mitosis is cell division. The goal is to create 2 identical cells, meaning they have an equal
number of chromosomes, organelles, and amount of cytoplasm. Eukaryotic cells undergo
mitosis. The phases of mitosis are PMAT or prophase, metaphase, anaphase, and
telophase. Prophase is the longest phase of mitosis and chromosomes are visible,
centrioles separate, the nuclear membrane breaks down, and the spindle fibers form. In
metaphase chromosomes line up in the middle of the cell and their centromere (think of a
chromosome like an X, the middle of X is the centromere & each line of X is a chromatid)
is connected to the spindle fibers. In anaphase the centrioles at opposite ends of the
cell pull the spindle fibers to separate the chromosomes to opposite sides of the cell. In
telophase the nuclear membrane reforms, spindle fibers disappear, and cytokinesis
(cytoplasm division) occurs. In animal cells the cleavage furrow forms which separates
the two cells and in plant cells a cell plate forms as a divider between the 2 cells.
Remember, if we are talking about human cells we start mitosis with 92 chromosomes in 1
cell and end with 2 cells that each have 46 chromosomes! Remember, bacteria do not have
a nucleus and undergo a much simpler process of cell division called binary fission in which
the DNA strand replicates the cell divides in half!
In meiosis gametes or sex cells are formed. A cell starts with 92 chromosomes but ends
with gametes that contain 23 chromosomes each. Egg and sperm are gametes. A female
egg and male sperm will combine to form a zygote which is the start of a human embryo
with 23 chromosomes from each parent. In meiosis the cells that are produced by males
and females are not identical. Meiosis is divided into Meiosis 1 with PMAT1 and Meiosis 2
with PMAT2, and there is no interphase between the 2 stages. In prophase 1 of meiosis
an event called crossing over occurs in which homologous chromosomes (same size, shape,
genetic info) can exchange pieces of DNA. This in addition to the fact that a human
zygote contains 23 chromosomes from each parent is why we have genetic diversity among
parents and offspring.
Chapter 11
Genetics Introduction
Gregor Mendel is the Father of Genetics. He was a monk who studied pea plants and
noticed that traits were inherited from the parent plants to the offspring. He had 2 laws
that dealt with inherited traits, the law of segregation and the law of independent
assortment. He discovered dominant and recessive traits because he noticed that
sometimes the offspring did not show a trait the parents expressed but then it appeared
again in the next generation.
Genetics is the study of heredity. Traits are specific characteristics. The word gene
refers to the DNA that codes for a trait and alleles are alternate versions of a trait (Ex.
purple or white plant color) Dominant alleles (capital letters) are always expressed and
recessive alleles (lowercase letters) are only expressed if an organism has 2 copies of the
recessive allele. Probability is the likelihood of a specific event occurring and helps us to
predict the traits that offspring may have based on the parents.
A Punnett Square is a box that shows possible inherited genotypes of offspring.
Homozygous means that both alleles are dominant or both are recessive. A heterozygous
genotype is when an organism has 2 different alleles. The phenotype is the physical
appearance of the organism. Monohybrid crosses are the 4 box Punnett Squares that
compare 1 trait. Dihybrid crosses are the 16 box Punnett Squares that compare 2 traits.
There are a few special examples that do not follow the complete dominance and recessive
rules. For example, in incomplete dominance a red and white flower are crossed to form a
pink flower which means both red and white are dominant and blended together to form
the offspring. Codominance is when you see an organism that shows both colors like a
black and white spotted organism.
Multiple alleles means that there are more than 2 options for the organism. For example,
if you look at blood types a person could be type A, B, AB, or O. Polygenic traits are
traits that are controlled by many genes such as eye color or height. Think back to our
lab in class and all of the different pigments and heights that you analyzed! As always,
when we discuss genes the environment can and does play a role in how an organism
develops too!
Chapter 12
DNA & RNA
The central dogma in biology is DNA to RNA (transcription in the nucleus) and then RNA
to proteins (translation at the ribosome).
DNA stands for deoxyribonucleic acid and is made of deoxyribose sugar. DNA never
leaves the nucleus. It is the hereditary molecule that carries an organism’s genetic code.
It is a double stranded twisted, helical ladder that resembles a spiral staircase. The sides
of the molecule are made of a sugar (connects to nitrogen bases) and phosphate backbone.
The nitrogen bases are bonded together in pairs and make up the inside of the molecule.
The pyrimidines are cytosine, uracil (in RNA only), and thymine. The purines are adenine
and guanine. Adenine always bonds with thymine and guanine always bonds with cytosine.
DNA replicates before cell division. The molecule is split in half and DNA polymerase is
the enzyme that adds new bases to each exposed strand so that the end products are 2
identical DNA molecules.
RNA stands for ribonucleic acid. It is a single stranded molecule made of ribose sugar.
The bases of RNA are adenine and uracil which bond together, and guanine and cytosine
which also bond together. There are 3 kinds of RNA: mRNA (messenger RNA-carries DNA
message from nucleus to ribosome), tRNA (brings the amino acid to the ribosome after
reading mRNA), and rRNA (makes up the ribosome). RNA polymerase is the enzyme that
makes mRNA.
Protein synthesis is also called translation. mRNA sits on the ribosome and is read 3
bases at a time which is called a codon. Codons code for amino acids. The arrangement of
amino acids determines the proteins structure which results in its function. If a mistake
is present at all in the DNA (a mutation) that codes for amino acids which we call a gene
(segment of DNA coding for an amino acid), then the protein will be produced incorrectly
which can result in serious consequences for the organism. There are many different
types of mutations, all of which involve changes in the DNA that forms proteins. Proteins
become fully functional after the Golgi adds finishing touches to them which involves
unique folds in their structure. Proteins can stay in the cell or exit the cell depending on
their function. The part of DNA that does not code for DNA are called introns, while the
part of DNA that codes for proteins are called exons because they are expressed in the
protein.
Gene expression is studied in examples such as the lac operon in bacteria which is a way
for scientists to understand a simpler model than a human related to how genes are turned
on and off (meaning proteins are made or not made) depending on their environment.
Differentiation refers to the specialization of cells into specific types such as nerve
cells, etc. This is related to gene expression. In humans the hox genes control this
process.
Chapters 13&14
___
Genetic Technology
There are many different types of genetic technology. A few are listed below
Technology
Hybrid
Artificial
selection/selective
breeding
(PCR) polymerase
chain reaction
Cloning
Gene therapy
Genetic engineering
Gel electrophoresis
Transformation
Transgenic organism
Recombinant DNA
Description
Cross between 2 different organisms to create an organism with
ideal traits (Ex. liger)
Humans interfere by choosing parents
Like a photocopy machine for DNA samples
Create a genetically identical offspring (Ex. dolly-sheep)
Often involves using plasmids (bacteria) or modified viruses,
genes are altered to help people and inserted into plasmids or
viruses to carry “helpful corrected genes” into persons DNA to
fix malfunctioning gene
Humans manipulate DNA purposely
Separate DNA based on size using electric charge, way to
identify someone, involves restriction enzymes which cut DNA at
specific locations
When recombinant DNA is inserted into a chromosome of a cell
When an organism contains genes from another species
When DNA of one organism is attached to another organism
There are many inherited genetic conditions. Some are autosomal (on regular
chromosomes) while some are sex-linked (on X-chromosome, passed on from the mother
to the son, or could be passed on to a daughter if both parents carry the allele). Genetic
conditions can be dominant or recessive. Examples included Down Syndrome (3 copies of
chromosome 21 due to nondisjunction), Sickle Cell Anemia (cells are misshapen and cannot
carry enough oxygen) and Hemophilia (blood is unable to clot). Karyotypes are pictures of
chromosomes in order from tallest to shortest and arranged in homologous pairs.
Karyotypes can show large chromosome abnormalities.
Polyploidy- contains extra sets of chromosomes. Ex. strawberries, fatal in animal cells,
positive in plant cells
Pedigree- “glorified family tree” has special symbols, shows how 1 trait is passed through
a family
Chapter 15 & 18
Evolution & Classification
The theory of evolution corresponds to Charles Darwin’s theory of natural selection
which states that the strongest and most fit organisms survive. Darwin traveled around
the world in 1831 gathering evidence for evolution (how things change over time) by
studying fossils (compare bones to understand how form reflects function), embryology
(compare development of embryos), the geographic distribution of species (compare
locations of organisms that seem related), and homologous structures (structures derived
from the same type of tissue). In addition to these sources of evidence we now also have
DNA evidence which is our most powerful comparison for relationships of organisms.
Darwin described in his book Origin of Species how organisms adapt to their
environment. Over millions of years sometimes these adaptations can lead to new species
of organisms, like in the case of the Galapagos finches (the birds that had beaks adapted
for specific food sources). The other famous organism studied by Darwin were the
Galapagos tortoises. Tortoises were adapted on the desert like islands with curved
shaped shells so that they could reach their necks to gather food. Darwin was influenced
by many scientists. Charles Lyell wrote Principles of Geology, a book that looked at how
changes in the earth influenced the current time period. Darwin took this book on the
HMS Beagle ship. Jean-Baptiste Lamarck had the incorrect idea about how acquired
traits could be inherited but he was influential because part of his idea was correct and
Darwin built his own ideas off of the work of Lamarck. Alfred Wallace was a major
influence who started to come up with the same idea as Darwin but did not have enough
data. . The work of Wallace is what led Darwin to publish his book which was finished and
laying on his bookshelf for years while Darwin feared the reaction of the public to his new
and revolutionary idea of survival of the fittest.
Evolution led to the establishment of classification which relates to taxonomy or the
branch of science in which organisms are named and put into a group based on similar
characteristics. Scientific names were developed by Carolus Linnaeus and are written in
italics in Latin with the genus name first and capitalized, followed by the species name
(Ex. human = Homo sapiens). This is known as a binomial nomenclature system since the
name has 2 words. This name is the same anywhere in the world. The classification
brackets in order are kingdom, phylum, class, order, family, genus, and species.
Organisms in the same kingdom share general similarities while organisms in the same
species are very much alike. There are typically 5 kingdoms though there can be six:
animal, plant, fungi (mushroom- cannot make their own food), protists (most are onecelled organisms found in water- amoeba), and bacteria (sometimes divided as eubacteria
and archaebacteria). To show relationships among organisms cladograms (looks like a tree,
where branches meet there is a relationship between organisms) and dichotomous keys
(chart with a series of yes/no questions used to identify an organism) are used.
Chapters 3-6
Ecology
Ecology is about how organisms interact with each other and with their environment. The
levels of organization for the planet are biosphere (earth), biome (ecosystems with same
climate), ecosystem (all organisms in an area and the non-living environment), community
(populations living together), population (same species), and individual. Ecology involves also
looks at how energy travels through an ecosystem (refer back to photosynthesis). Biotic
factors are living things while abiotic factors refer to nonliving things.
There are a few major cycles studied in ecology: water cycle, carbon cycle, and nitrogen
cycle. These cycles show us how materials flow through an ecosystem and are renewed by
processes. Sometimes you will read about limiting nutrients which are nutrients that cycle
through an ecosystem very slowly but are extremely important.
Weather refers to the daily conditions while climate looks at an average condition of the
atmosphere. There are 3 major climate zones: polar zones, temperate zones, and tropical
zones. The atmosphere is involved in the major cycles of ecology. If conditions are not
ideal problems such as the greenhouse effect can arise which is when carbon dioxide,
methane, water vapor, and other gases trap heat energy often due to human overuse and
cause the temperature of the planet to increase which can greatly impact certain habitats.
There are a variety of ways in which organisms interact with each other: predation,
competition, symbiosis (2 species live close together), mutualism (both species benefit),
commensalism (one species benefits & the other is unaffected), and parasitism (one
species benefits & the other is harmed).
Ecosystems are constantly changing due to earth’s natural processes and ecological
succession refers to changes in a community over years. Pioneer species are organisms
that are first to populate a particular area (ex. lichen after volcano eruption). Biomes are
large areas with distinct characteristics related to climate and present organisms. The
major biomes are the tropical rain forest, tropical dry forest, tropical savanna,
temperate grassland, desert, temperate woodland and shrubland, temperate forest
(YOUR BIOME), northwestern coniferous forest, boreal/taiga forest and tundra.
There are also aquatic ecosystems such as freshwater ecosystems (flowing-water (river),
wetlands (water covers soil), standing-water (pond)). Estuaries are where wetlands
formed from rivers connecting into the sea and have a mix of salt and fresh water and
are associated with salt marshes and mangrove swamps. Marine ecosystems can be
further divided: intertidal zone, coastal ocean, coral reefs, open ocean and the benthic
zone. Ecosystems can change depending on human influence and use of renewable and
nonrenewable resources. Sustainable development focuses on how humans can interact
and use the earth’s resources in a positive way.