1. Alabama High School Graduation Exam Biology Focus
Standards:
1.) Select appropriate laboratory glassware, balances, time measuring equipment, and optical instruments to
conduct an experiment.
2.) Describe cell processes necessary for achieving homeostasis, including active and passive transport, osmosis,
diffusion, exocytosis, and endocytosis. 3.) Identify reactants and products associated with photosynthesis and cellular respiration and the purposes of these two
processes. 4.) Describe similarities and differences of cell organelles, using diagrams and tables.
5.) Identify cells, tissues, organs, organ systems, organisms, populations, communities, and ecosystems as levels of
organization in the biosphere.
6.) Describe the roles of mitotic and meiotic divisions during reproduction, growth, and repair of cells.
7.) Apply Mendel's law to determine phenotypic and genotypic probabilities of offspring.
8.) Identify the structure and function of DNA, RNA, and protein.
9.) Differentiate between the previous five-kingdom and current six-kingdom classification systems.
10.) Distinguish between monocots and dicots, angiosperms and gymnosperms, and vascular and nonvascular plants.
11.) Classify animals according to type of skeletal structure, method of fertilization and reproduction, body symmetry,
body coverings, and locomotion.
12.) Describe protective adaptations of animals, including mimicry, camouflage, beak type, migration, and hibernation.
13.) Trace the flow of energy as it decreases through the trophic levels from producers to the quaternary level in food
chains, food webs, and energy pyramids.
14.) Trace biogeochemical cycles through the environment, including water, carbon, oxygen, and nitrogen.
15.) Identify biomes based on environmental factors and native organisms.
16.) Identify density-dependent and density-independent limiting factors that affect populations in an ecosystem.

2. 1.) Select appropriate laboratory glassware, balances, time measuring
equipment, and optical instruments to conduct an experiment.
• Identifying safe laboratory procedures when handling chemicals and using Bunsen burners and
laboratory glassware
• Using appropriate SI units for measuring length, volume, and mass
• Describing the steps of the scientific method
• Comparing controls, dependent variables, and independent variables
Laboratory Equipment, Safety, and Procedures
Graduated cylinder -glassware to accurately measure liquid volume in mL
Meniscus-the curve at the surface of a liquid
Pipette, burette, and syringe-used to dispense measured amounts of liquids
Dropper-dispense small amounts of liquids (in drops at a time)
Test tube- used for holding mixing, and storing small amounts of liquids
Beaker and Erlenmeyer flask-used for holding and storing large amounts of liquids
Petri dish-used to grow and observe bacteria cultures

3. Practice 1
Match each piece of glassware to its BEST use. Each description for use may be
Used more than once.
_____ 1. test tube A. growing and observing bacteria
_____ 2. beaker B. accurately dispensing small, measured
amounts of liquids
_____ 3. graduated cylinder C. dispensing small amounts of liquids in drops
_____ 4. Erlenmeyer flask D. storing or mixing liquids
_____ 5. syringe E. accurately measuring a volume of liquid
_____ 6. pipette
_____ 7. burette
_____ 8. petri dish
_____ 9. dropper
Practice 2
1. In a biology experiment, Alphonzo needs to measure exactly 10 mL of water.
Which of the following pieces of equipment would be MOST appropriate for him
to use? A. beaker B. graduated cylinder C. Erlenmeyer flask D. test tube

4. Mass- the measure of how much matter is in an object
Gram- SI unit for mass
Scale balance- used to measure mass
Triple Beam balance- type of scale balance used more commonly in high schools
Weight- the measurement of force exerted by gravity on an object
Newtons- SI unit for force (and weight)
Spring scale- equipment used to find force or weight
Ruler or meter stick- used to measure length in millimeters, centimeters, or meters
Meter- SI unit for length
Practice 3
1. Which of the following is NOT true about weight?
A. Weight is a force. B. Weight depends on gravity
C. Weight can be measured on a spring scale D. Weight is measured in grams.
2. The biology student also tracks the length of each mouse in his experiment. What
piece of equipment should he use to determine length?
A. triple beam balance B. scale balance C. spring scale D. ruler or meter stick

5. Thermometer- equipment used to measure temperature
Bunsen burner- uses a gas flame to heat
Hot plate- uses electricity to heat
Test tube clamp- designed to hold test tubes, especially when hot
Tongs- used to move hot glassware like beakers and flasks
Heat resistant gloves- used to handle hot glassware
Practice 4
1. When heating materials in a test tube, you should hold the test tube with
A. beaker tongs B. a test tube clamp C. resistant gloves D. wrench
2. Which of these is NOT correct instruction about heating substances in a test tube?
A. Do Not cap the tube when heating
B. Keep the test tube moving in and out of the flame
C. Be sure the test tube is completely filled
D. Point the open end of the test tube away from others

6. Eyewash station- used to rinse the eyes when they have contacted a chemical
Safety shower- used to rinse skin or clothing of a hazardous chemical
Biohazards container- used to collect biohazards such as blood, cell cultures, or
living tissues
Broken glass container- used to collect broken glass
Fire Extinguisher- used to put out fires
Safety goggles- used to protect the eyes
Lab apron- used to protect the clothing
Gloves- used to protect the hands
Biohazard- anything that can transport a disease or illness; examples: blood, cell
cultures, animal tissue
Practice 5
1. When any accident occurs during a lab activity, you should
A. always report it to the teacher
B. notify the office
C. include it in your lab report
D. tell the students in the next class.

7. Scientific Investigations—The Scientific Process (Scientific Method)
Problem-an observation that needs an explanation or a question that needs an
answer
Hypothesis- a possible explanation or answer to a scientific problem that can be
tested; educated guess
Experiment- a step-by-step procedure used to test a hypothesis
Conclusion- the interpreted results of an experiment based on the data; may prove or
disprove the hypothesis
Theory- an idea that is accepted as true because it is supported by repeated evidence

8. Practice 1
___ 1. What is the first step in the A. conclusion
scientific process? B. forming a hypothesis
___ 2. After stating a problem, what is C. theory
the next step? D. conducting the experiment
___ 3. Deciding what kind of data to E. designing the experiment
gather takes place during which step? F. stating the problem
___ 4. Which step comes after conducting the
experiment?
___ 5. When are variables and controls
determined?
___ 6. Which step gives a possible explanation
to a problem that can then be tested?
___ 7. If an idea can be proven over and over again,
it can proceed to which step?
___ 8. Data is gathered in which step?
___ 9. During which step is the hypothesis proved or disproved?

9. Practice 2
1. A scientist might begin a new project by
A. testing a hypothesis C. creating a new experiment
B. making careful observations D. analyzing data
2. In science, a hypothesis is useful only if
A. it is always correct C. it can be tested
B. it can be proven incorrect D. the explanation is already known
3. You observe mold growing on the wall near a leaking hot water heater. You
believe that water must be important for mold growth. You decide to perform an
experiment to test the idea. Your idea that water is important for mold growth is
an example of
A. an experiment C. an observation
B. a conclusion D. a hypothesis

10. Experiment- a set of steps used to test a hypothesis
Data- observations, measurements, and other information gathered in an experiment
Control group- the group that is used for comparison; it does not receive the tested
Element (no variables)
Experiment group- a group that receives one element being tested (variable)
Placebo- a substance given to a control group that has no effect on the experiment
but is used to eliminate bias
Constants- factors that remain the same for all groups during an experiment
Variable- a factor that is changed during an experiment in order to tests its effect
Independent variable- the variable used to produce an effect (you change)
Dependent variable- the measurable change that occurs because of the independent
variable

11. A pharmaceutical company gets FDA approval to test a memory
Practice 3
1. What is the set of steps used to collect information to test a hypothesis called?
A. a principle B. a theory C. a control D. an experiment
2. Brandon tests the effects of sunlight on bean seed germination. The amount of
sunlight is the
A. control B. dependent variable C. independent variable D. placebo
Read about the experiment below and then answer the questions that follow.
A pharmaceutical company gets FDA approval to test a memory
enhancing medication on humans. The pharmaceutical company
chooses 100 participants and splits them into two groups of 50 each.
Once a day and over a period of 6 months, each participant is given a
pill. In one of the groups, the pill contains the medication. In the other
group, the pill contains no active ingredient. Once a week, the
participants are given a test that measures their memory. The score for
the test is recorded for each participant each week.

12. Problem 4 1. The test scores recorded in this experiment over the 6 months’ time are called the A. conclusion B. independent variable C. hypothesis D. data 2. The pill containing no active ingredient is called a A. placebo B. variable C. hypothesis D. constant 3. Which group of participants represents the control group? A. the group that is given the memory test each week B. the group that is given the memory enhancing medication C. the group that is given the pill with no active ingredients D. the group that is not given the memory test each week 4. Which of the following is the dependent variable in this experiment? A. 6 months’ time B. the memory enhancing medication C. the change in memory D. the memory test

13. A strawberry farmer conducted an experiment to test the optimum
Data table- a way to format and organize data into rows and columns
Raw data- information (data) gathered during an experiment before it has been
analyzed
Practice 4 Read the information and study the table.
A strawberry farmer conducted an experiment to test the optimum
pH level of soil to give the greatest production of strawberries. He
believed that the optimum pH would be around 5.5. For each pH
level, he recorded average pounds of strawberries produced per plant
and total pounds of strawberries produced per acre. His results are
shown in the table below.

14. The Effects of Soil pH on Strawberry Production
1. At a pH level of 6.0, how many
pounds of strawberries per plant
are recorded?
A C. 7342
B D. 7750
2. At what pH level did plants average
0.57 pounds of strawberries per
plant?
A C. 7.0
B D. 8.5
3. Which of the following accurately
describes what happens to
strawberry production as pH levels
change?
A. As pH increases, strawberry
production increases.
B. As pH decreases, strawberry
C. As pH increases, strawberry
production increases until it
reaches an optimum level, and
then the production decreases.
D. As pH increases, strawberry
production remains constant
pH Level
Pounds per Plant
Pounds per Acre
4.5
0.44
5982
5.0
0.47
6390
5.5
0.51
6934
6.0
0.54
7342
6.5
0.57
7750
7.0
0.55
7478
7.5
0.52
7070
8.0
0.46
6254
8.5
0.40
5439

15. Line graph- a visual representation of data
showing how something has changed
over a period of time
Bar graph- a visual representation of
data used to show different quantities
between different groups especially
when data is not continuous
Pie graph- a visual representation of
data used to show parts (or percentages)
of a whole

16. 2.) Describe cell processes necessary for achieving homeostasis, including active and passive transport, osmosis, diffusion, exocytosis, and endocytosis.
Introduction to Cellular Transport
Homeostasis- the process of keeping the internal conditions in an organism stable
Cellular transport- the movement of materials into and out of cells
Cell membrane- the membrane that surrounds the contents of a cell and allows
only certain things in and out of the cell
Selectively permeable- a property of cell membranes that allows only certain
things to cross but not others
Phospholipids bilayer- the two layers of phospholipids molecules arranged tail to
tail that help to make up cell membranes
Active transport- processes that require some of the cell’s energy; move a
substance from an area of lower to higher concentration
Passive transport- processes that does not require energy from the cell

17. Diffusion- the movement of molecules from an area of higher concentration to an
area of lower concentration
Facilitated diffusion- the diffusion of molecules across a membrane through special
proteins in the membrane
Osmosis- the movement of water across a membrane
Solute- dissolved particles
Hypertonic-higher solute concentration outside the cell; cause cell to shrink
Hypotonic- higher solute concentration inside the cell; cause cell to swell
Isotonic- equal solute concentration inside and outside the cell

18. Practice
1. If a membrane allows movement of only certain materials, it is called
A. somewhat permeable C. somewhat impermeable
B. selectively permeable D. selectively impermeable
2. The cell membrane is made primarily of
A. carbohydrates C. proteins
B. nucleic acids D. phospholipids
3. When active transport is used, the cell
A. does not use any of its own energy C. uses energy from other cells
B. uses some of its own energy D. uses the energy stored mainly in the nucleus
4. During passive transport, a cell
A. does not use any of its own energy B. uses energy from other cells
B. uses some of its own energy D. uses the energy stored mainly in the nucleus

19. 5. Osmosis always involves the movement of
A. oxygen molecules C. water molecules
B. carbon dioxide molecules D. sugar molecules
Endocytosis- process used by a cell to take in large particle
Exocytosis- process used by a cell to release materials out of the cell

20. Standard #3 Identify reactants and
Products associated with photosynthesis
and cellular respiration and the purposes
of these two processes.
Cellular respiration- process that
converts glucose and oxygen into carbon
dioxide and water and releases energy as
ATP
Photosynthesis- process that uses light
energy to convert carbon dioxide and
Water into glucose and oxygen
Cellular Respiration
Photosynthesis
Take place where
All cells
Cells with chlorophyll
Occurs
All of the time
In the presence of light
What goes in? (the reactants)
Glucose and oxygen
Carbon dioxide and water
What comes out? (the products)
Energy Source
Chemical bonds in glucose
light
Results
Energy is stored as ATP
Energy is stored as glucose

21. Practice
1. Which of the following is a TRUE statement about cellular respiration?
A. Cellular respiration converts the energy directly from the sun into energy stored in chemical bonds.
B. Cellular respiration cannot occur without sunlight
C. Cellular respiration occurs in plant cells and in animal cells.
D. Cellular respiration converts carbon dioxide and water into carbohydrates and glucose.
2. Which is the following is TRUE statement about photosynthesis?
A. Photosynthesis occurs only in cells that contain chlorophyll.
B. Photosynthesis converts the chemical energy stored in carbohydrate bonds to light energy.
C. Photosynthesis converts carbohydrates and oxygen into carbon dioxide and water.
D. Photosynthesis occurs when light energy is not available.

22. Standard #4 Describe similarities and differences of cell organelles, using diagram
and tables.
Prokaryotic cells- simple cells that do not have a nucleus; found in bacteria
Eukaryotic cells- cells that have a true nucleus; found in plants, animals, fungi,
protists.

23. Schematic of typical animal cell, showing subcellular components
Schematic of typical animal cell, showing subcellular components. Organelles: (1)
nucleolus (2) nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER)
(6) Golgi apparatus (7) Cytoskeleton (8) smooth ER (9) mitochondria (10) vacuole
(11) cytoplasm (12) lysosome (13) centrioles

24. Functions of Cell Organelles
Cell Membrane- controls what goes into and out of the cell
Mitochondrion- powerhouse of the cell; produce energy for the cell
Nucleus- controls cellular processes; DNA found here
Vacuole- used for storage; water, salts, wastes, etc
Chloroplasts- found only in plant cells; contain chlorophyll and produce starch
Cytoskeleton- helps the cell keep its shape
Cytoplasm- found between the cell membrane and nucleus; house all organelles
Endoplasmic Reticulum- transport system of the cell
Ribosomes- build protein
Golgi Apparatus- package and distribute proteins and lipids; looks like a stack of pancakes
Cell Wall- found only in plant cells; provides extra protection for the cell
Practice
1. Plant and animal cells BOTH contain which of the following?
A. a large vacuole B. a nucleus C. a cell wall D. chloroplasts
2. A biology student looks at an unidentified cell under the microscope. The student identifies a nucleus,
several oblong organelles, a cell membrane, and a cell wall. Which of the following type of cell could
this be?
A. a red blood cell B. an oak leaf cell C. a skin cell D. a liver cell

25. Plant Cells Animal Cells
Have a Cell Membrane, Nucleus, Mitochondria, Ribosomes, Golgi Apparatus, and Endoplasmic Reticulum?
Yes
Have a Cell Wall? No
Have Lysosomes?
No (rarely)
Have Vacuoles?
None or Small
Have Chloroplasts?

26. Standard #9 Differentiate between the previous five-kingdom and current six-
kingdom classification systems.
Classification of Organisms
Level of Organization (smallest & most specific)
Largest & Least specific ---> Kingdom-----King
Phylum----Phillip
Class-----Came
Order---Over
Family-For
Genus-Good
Species-Soup

27. 1. What is the lowest taxonomic level at
Practice
1. What is the lowest taxonomic level at
which the white pine tree and the douglas
fir tree share common characteristics?
A. kingdom B. order C. family D. genus
2. The smallest biological division that can
interbreed and produce fertile offspring is
A. kingdom B. phylum C. genus D. species
White Pine
Douglas Fir
Kingdom
Plantae
Division
Coniferophyta
Class
Pinopsida
Order
Pinales
Family
Pinaceae
Genus
Pinus
Pseudotsuga
Species
strobus
menziesii

28. Five Kingdom System- classification system that includes Animalia, Plantae, Fungi, Protista, and Monera
Six Kingdom System- classification system that includes Animalia, Plantae, Fungi, Protista, Eubacteria, and Archaebacteria

29. Standard #5 Identify cells, tissues, organs, organ systems, populations,
communities, and ecosystems as levels of organization in the biosphere.
Cell differentiation- process that creates different types of specialized cells
Cells- the basic unit of structure of all living organisms
Tissue- group of similar cells working together to perform a certain function
Organ- group of similar tissues working together
Organ system- group of organs working together

30. Levels of Ecological Organization:
organisms populations communities ecosystems biosphere

31. Standard #6 Describe the roles of mitotic and meiotic divisions during
reproduction, growth, and repair of cells.
Cell cycle- the process that somatic cells go through in order to grow and to
reproduce
-Interphase- longest part of the cell cycle; consist of 3 main parts
--G1 Phase- cell grows and develops and new proteins are made
--S phase- DNA replication takes place
--G2 Phase- cell prepares for mitosis by making RNA and proteins

32. Mitosis- division of the nucleus; results in two cells identical to the parent cell;
Diploid number (2n)of chromosomes
-Phases:
Prophase- first stage and longest phase; chromatin condenses
Metaphase- chromatids line up along the midline of the nucleus
Anaphase- centromeres divide and sister chromatids separate
Telophase- new nuclear membranes are formed around each set of chromosomes

33. Meiosis- the process that forms the sex cells called gametes (ova and sperm cells;
haploid number (n) of chromosomes
-Phases I & Phase II (cells divide and then divide again to produce 4 cells with half
the genetic material as the parent cell)

34. Practice
1. Offspring that are genetically identical to the parent organism are produced by
A. mitosis B. pollination C. fertilization D. binary propagation
2. Sexual reproduction always produces
A. haploid gametes B. diploid gametes C. identical gametes D. bipolar gametes
Match each of the following terms with its definition
___ 1. sex cells A. cells that contain a diploid number
___ 2. mitosis B. cells that contain a haploid number
___ 3. somatic cell C. the process that produces diploid cells
___ 4. meiosis D. the process that produces haploid cells
5. How many times does chromosome separation occur in meiosis?
A B C D. 4
6. Interphase is the longest phase of the cell cycle. It consist of 3 main parts. Name
and describe each.

35. I know that was a lot of information!
What you need:
-Must have at least 2 questions per standard
-One foldable per standard
-Standard #3 Photosynthesis & Respiration
-Standard #4 Cell organelles & Function
-Standard #9 Differentiate between 5 Kingdom & 6 Kingdom Systems
-Standard #5 Cellular Organization
-Standard #6 Mitosis and Meiosis
-Copy and Paste a picture of Plant & Animal cell on panel under standard #4
-Remember to always be creative. Folder Foldable MUST be completed by
Friday! This is your Final Examination make it count.
-You may work on your Folder Foldable at home once I have given instruction for
Standards. So what you don’t finish in class could be finished at home. Just
remember, Folders are due Friday

36. Standard #7 Apply Mendel's law to determine phenotypic and genotypic probabilities of offspring.
Phenotype is the physical characteristics of an organism--what it looks like; Example: brown hair
Genotype is the combination of alleles (genes); Example: Bb
Punnette Square- a diagram that shows all possible gene combinations for a cross
Monohybrid- crossing one trait from two parent organisms
Dihybrid- studying two traits crossed from parent organisms
Genotype
Definition
Phenotype BB
Homozygous dominant (or pure dominant)
Brown hair Bb
Heterozygous ( or hybrid) bb
Homozygous recessive (or pure recessive)
White hair

37. Standard #8 Identify the structure and function of DNA, RNA, and protein.
Double Stranded
Single Stranded
Sugar is Deoxyribose
Sugar is Ribose
Bases: Adenine (A) binds Thymine (T)
Cytosine (C) binds Guanine (G)
Bases: Adenine (A) binds Uracil (U)

38. Standard #10 Distinguish between monocots and dicots, angiosperms and gymnosperms, and vascular and nonvascular plants.
Cotyledon is a seed leaf that provides food for the embryo in the seed of a plant as it begins to grow
monocot--1 seed leaf, leaf has parallel veins, vascular bundles scattered, roots branched
dicot --2 seed leaf, leaf has veins are branched, vascular bundles in a circle, large central roots (TAPROOT)
Angiosperms are a taxonomic class of plants in which the mature seed is surrounded by the ovule (think of an apple).
Gymnosperms are a taxonomic class that includes plants whose seeds are not enclosed in an ovule (like a pine cone). Gymnosperm means as "naked seed".
Vascular tissue made of 2 types of veins:
-xylem- takes water and minerals UPWARD
-phloem- takes sugar DOWNWARD to roots
 Roots hold plant in ground, absorb water and minerals, and store food

39. Flower Structure and Function
Male Parts
Stamen This is the pollen producing part of the plant. The number of stamen is usually the same as the number of petals.
Anther This is the part of the stamen that produces and contains pollen.
Filament This is the fine hair-like stalk that the anther sits on top of.
Female Parts
Pistil Each pistil is constructed of one to many rolled leaflike structures.
Stigma It is the sticky bulb that you see in the center of the flowers, it is the part of the pistil of a flower which receives the pollen grains and on which they germinate.
Style This is the long stalk that the stigma sits on top of.
Ovary Usually at the bottom of the flower, that has the seeds inside and turns into the fruit that we eat. The ovary contains ovules.
Ovule The part of the ovary that becomes the seeds.
Other Important Parts of a Flower
Petal The colorful, often bright part of the flower. They attract pollinators and are usually the reason why we buy and enjoy flowers.
Sepal The parts that look like little green leaves that cover the outside of a flower bud to protect the flower before it opens.
Flower Types
Imperfect Flower A flower that has either all male parts or all female parts, but not both in the same flower. Examples: cucumbers, pumpkin, and melons.
Perfect Flower A flower that has both the male parts and female parts in the same flower. Examples: roses, lilies, and dandelion.

40. Standard #11 Classify animals according to type of skeletal structure, method of fertilization and reproduction, body symmetry, body coverings, and locomotion.
skeletal structure—vertebrates and invertebrates; invertebrates (no backbone) or vertebrates (backbone)
fertilization—external and internal;
reproduction—sexual and asexual
body symmetry—bilateral, axial, and asymmetry
body coverings—feathers, scales, and fur
locomotion—flagella, cilia, and pseudopodia

41. Protective Adaptations of Animals
Standard #12 Describe protective adaptations of animals, including mimicry, camouflage, beak type, migration, and hibernation.
Protective Adaptations of Animals
Anything that helps an organism survive in its environment is an adaptation.  It also refers to the ability of living things to adjust to different conditions within their environments.
mimicry
Allows one animal to look, sound, or act like another animal to fool predators into thinking it is poisonous or dangerous.  
camouflage
Protective coloration and protective resemblance allow an animal to blend into its environment.  Another word for this might be camouflage.  Their camouflage makes it hard for enemies to single out individuals. 
beak type
migration
Is the behavioral adaptation that involves an animal or group of animals moving from one region to another and then back again. Animals migrate for different reasons.  The reasons are as follows: better climate, better food, safe place to live, safe place to raise young, and go back to the place they were born.
hibernation
Is a deep sleep in which an animal's body temperature drops to about the temperature of the environment.  Body activities, such as heartbeat and breathing are slowed causing the animal to need very little food. Animals that hibernate are: bats, woodchucks, snakes, and bears. During the hibernation the animals live off of the fat that is stored in their body. 

42. Standard #13 Trace the flow of energy as it decreases through the trophic levels from producers to the quaternary level in food chains, food webs, and energy pyramids.
All food chains, food webs, and pyramids
Start with GREEN plants
Primary consumer-eats plants
Secondary consumer-eats animal that eats plant
Tertiary consumer-eats secondary consumer
Matter in the environment is recycled through:
Producers (autotrophs) can make their own food
Consumers (heterotrophs) eat producers either directly
or indirectly and other consumers
-herbivores-eat only plants
-carnivores-eat only meat
-omnivores- eat both plant and animals
Decomposers (saprophyte) eat dead or
decaying organisms
Parasite lives in or on another living organism and can
only reproduce in the host

43. Standard #14 Trace biogeochemical cycles through the environment, including water, carbon, oxygen, and nitrogen.

44. Standard #15 Identify biomes based on environmental factors and native organisms.
A biome is a climatically and geographically defined area of ecologically similar communities of plants, animals, and soil organisms, often referred to as ecosystems
Biomes:
The desert biome
Deserts cover about one fifth of the Earth's surface and occur where rainfall is less than 50 cm/year. Soils often have abundant nutrients because they need only water to become very productive and have little or no organic matter.
Tropical forest Tropical forests are characterized by the greatest diversity of species. They occur near the equator, within the area bounded by latitudes 23.5 degrees N and 23.5 degrees S. One of the major characteristics of tropical forests is their distinct seasonality: winter is absent, and only two seasons are present (rainy and dry). The length of daylight is 12 hours and varies little.
Temperate forest Temperate forests occur in eastern North America, northeastern Asia, and western and central Europe. Well-defined seasons with a distinct winter characterize this forest biome. Moderate climate and a growing season of days during 4-6 frost-free months distinguish temperate forests.
The grassland biome
Grasslands are characterized as lands dominated by grasses rather than large shrubs or trees. In the Miocene and Pliocene Epochs, which spanned a period of about 25 million years, mountains rose in western North America and created a continental climate favorable to grasslands.
The tundra biome
Tundra is the coldest of all the biomes. Tundra comes from the Finnish word tunturi, meaning treeless plain. It is noted for its frost-molded landscapes, extremely low temperatures, little precipitation, poor nutrients, and short growing seasons.
The freshwater biome
Freshwater is defined as having a low salt concentration — usually less than 1%. Plants and animals in freshwater regions are adjusted to the low salt content and would not be able to survive in areas of high salt concentration (i.e., ocean). There are different types of freshwater regions: Ponds and lakes, Streams and rivers, and Wetlands
The marine biome
Marine regions cover about three-fourths of the Earth's surface and include oceans, coral reefs, and estuaries. Marine algae supply much of the world's oxygen supply and take in a huge amount of atmospheric carbon dioxide. The evaporation of the seawater provides rainwater for the land. Oceans, Coral reefs, and Estuaries

45. - density-independent-natural disasters, climate
Standard #16 Identify density-dependent and density-independent limiting factors that affect populations in an ecosystem.
Examples:
- density-dependent-disease, predator-prey relationships, availability of food
and water;
- density-independent-natural disasters, climate
• Discriminating among symbiotic relationships, including mutualism,
commensalism, and parasitism
Symbiotic relationship- 2 organisms living together for the benefit of both
3 types of symbiotic relationships:
Commensalism-organism benefits from the host it is living off of, but the host is NOT harmed
Mutualism-2 organisms that live together and depend on each other for survival
Parasitism-relationship where one organism is helped, but the other organism is HARMED
Predator animals that eat other animals
Prey the animal that gets eaten