Wednesday, May 21, 2014 Science Final – Study Guide Answers
40 Multiple Choice covering ideas learned over the year
You will need a #2 pencil for the exam. Look at how much you have learned this year! Wow!!!
Unit 1: Nature of Science / Experimental Design
1. Science – Collects and organizes facts and knowledge about nature or the natural world.
Tests ( experiments ) are conducted to discover these facts and knowledge and then give explanations and make predictions about nature.
2. Science is CONPTT…Consistent, Observable, Natural, Predictable, Testable, Tentative
3. Pseudoscience – A claim or belief that is said to be based on science, but it is not.
The claim or belief may meet some but does not meet all of the CONPTT criteria.
Examples : Angels ; Ground Hog predicting when spring will arrive ; Astrology ( fortune telling ) ; Ghosts ; Alien beings visiting the earth ; God ; the devil ; Easter Bunny.
Experiments are NOT designed and NOT conducted to prove something or create something.
Experiments are carried out to support a hypothesis or answer a scientific question.
4. Parts of experiments: Hypothesis, Observation, Constant, Conclusion, Variables
5. Independent variable is the factor that is changed by you in order to do the experiment.
(To properly do the experiment, you only change one factor to see what will result )
Dependent variable is the factor that happens because of the change that was made. ( It is what you are looking for as a result in your experiment. )
6. Models help us understand things that are too big or too small for us to study. They are helpful because they represent something that we can understand. They are flawed because they aren’t 100% accurate. For instance, the models of cells have color to help you see the difference between organelles. Real cells, you remember, don’t. You actually have to stain them to be able to distinguish the different parts of the cell.
7. Charts, graphs, data tables all help us to organize, easily read and understand data.
8. Bias ( personal beliefs ) is when you think you know the answer; it sways how you look at the data. If I thought that 7th graders at Ladue were brilliant, then that might bias me when I read the essays that they write. Bias should never be allowed to interfere with an experiment
or affect the results or conclusions of an experiment. Bias colors how we look at something.
9. A microscope is one tool used in science. When using a microscope, you are looking through 2 lens. To calculate the total magnification: you multiply the power of the eyepiece lens and the power of the objective lens that you are using ( high or low power ).
Example experiment:
Question : Which paper towel holds more water ? Bounty or Sparkle or Green Forest brand
Hypothesis : IF the 3 brands of paper towels are soaked in some water, THEN, Bounty will hold more water BECAUSE Bounty is quilted paper and the others are not.
10. Independent Variable : The 3 different brands of paper towel in the experiment.
11. Dependent Variable : How much water you measure that each towel picks up from out of the container that they are placed in. How much water the towels absorb.
12. Constants : ( things you keep the same for all tests ) :
1. All towels tested are paper towels.
2. All towels are the same size ( 8 inch by 10 inch by 1/16 inch thick )
3. All towels will try to pick up the same kind of liquid – water.
4. Each towel is put into it’s own individual container, each container has 20 ml of water.
5. All towels sit and soak up water for the same amount of time – 2 minutes.
Data ( results ) : Bounty picked up 10 ml of water ; Sparkle picked up 12 ml of water ;
Green Forest picked up 7 ml of water.
13. Conclusion : Bounty did not hold the most water. Maybe quilted paper towel doesn’t help
to pick up more water. We did NOT support our hypothesis.
Unit 2: Cells / Cell Processes / Reproduction
Characteristics of Living Things
14. How do you know if something is a “living thing” ? Well, living things :
1. Reproduce themselves 2. Respond to a stimulus
3. Develop skills and abilities 4. Made of cells
5. Have homeostasis (can regulate internal body processes with relation to
changes in the external environment / weather )
6. Have metabolism ( set of chemical reactions within a living thing that help
maintain life. Getting and using energy is required )
15.Cell Theory:
1. All living things are made up of cells.
2. Cells come from cells by cell division ( cell reproduction ).
3. All cells have basically the same parts and chemicals.
16. Two basic kinds of cells : Plant and Animal ( NOT counting the bacteria cell )
17. Basic cell parts :
Animal cell : Nucleus , Cytoplasm , Mitochondria , Cell Membrane , Ribosome , Chromosome
18. Plant cell : Nucleus , Cytoplasm , Mitochondria , Cell Membrane , Ribosome , Chromosome , Cell Wall , + Chloroplast
Cell Processes:
19. All living things need energy and use energy to stay alive.
Energy is needed by living things and cells to : Grow ; Reproduce ; Digest food ;
Remove wastes ; Keep a constant body temperature ( in warm-blooded creatures ).
20. Most living things on Earth get their energy directly or indirectly from the sun.
21. Plants use the suns energy to make food ( sugar / glucose )
Animals either eat plants , another animal or both to get energy.
22. Transfer of Energy: Energy is transferred from one living thing to another living thing.
23. Photosynthesis : Plants make their own food in the chloroplasts.
24. Carbon Dioxide + Energy (sun) + Chlorophyll + Water ----à Food (glucose/sugar) + Oxygen
25. Cellular Respiration : The way plant and animal cells get their energy from food.
26. Glucose ( food or sugar ) + Oxygen ----à Carbon Dioxide + Water + Energy
27. Cellular Respiration occurs in the cell. The specific part of the cell where food is
burned ( broken down ) to make energy is the Mitochondria.
Note that the chemical process of photosynthesis is the same as cellular respiration
except it is reversed ( look at the 2 equations above ).
28. Diffusion : Movement of a substance from an area of high concentration
to an area of low concentration.
29. Osmosis : Movement of water from an area of high concentration to an area of low concentration. Osmosis usually happens into and out from a cell.
In that case, the water travels through the cell membrane’s pore.
30. We say that the cell membrane is selectively permeable when it lets one kind of chemical in or out through the cell membrane, but not another.
Reproduction
31. DNA is the genetic material that holds all the information for producing a new living thing.
DNA is found in all cells.DNA is found in the chromosomes which are located in the nucleus of most cells. Chromosomes are made up of genes which are the physical characteristics that distinguishes a living thing.
32. A normal human has 46 chromosomes in every body cell ( bone, skin, muscle, etc. ).
Two kinds of Reproduction :
33. Asexual - One parent. Very little or no variation occurs between the parent and offspring.
Examples : Binary Fission ( splitting of one cell into two identical cells ) ;
Budding ; Runners ; Rhizomes ; Spores ; Regeneration ; Parthenogenesis.
Where happens ?? …in : 1. Body cells ( bone, muscle, skin , etc. )
2. Single-cell creatures ( bacteria , amoeba , paramecium )
3. Some simple forms of animals
4. Plants that do not produce a flower
34. The advantages of asexual reproduction are that it is quick, and you don’t have to spend any energy hunting down a partner. No need to learn courtship dances or spend energy making a home for your mate.
35. Sexual – Two parents. Great deal of variation occurs between the parent and offspring.
Example : Fertilization ( combining of sex cells…..sperm and egg )
Where happens ?? …in : 1. Flowering plants
2. Most higher level forms of animals.
Advantages of sexual reproduction: It increases the variation and helps avoid actions of parasites.
36. Fertilization occurs when the DNA of the egg cell & the DNA of the sperm cell combine to form a new life. Sex cells join together ( fertilization ) to form a zygote ( fertilized egg )
37. Gametes are the sex cells ( sperm and egg ).
38. In flowering plants, the male sexual parts are called the stamen ;
the female sexual parts are called the pistil.
Both sexes are found on the same plant ( a plant is both male & female ).
The reproductive parts in a plant are found in the flower.
The sex cells have ½ the chromosome number for the kind of living thing.
39. Humans have 46 chromosomes in their body cells.
Humans have 23 chromosomes in their sex cells.
Sperm cell ( 23 chromosomes ) + Egg cell ( 23 chromosomes ) =
Human zygote ( 46 chromosomes ).
Unit 3: Evolution / Natural Selection
40. Charles Darwin is the author of the book “Origin of the Species” in the mid-1800’s. This book was very important for it gave the first scientific explanation for how different kinds of creatures came to be on this earth. It also explained how some species may not have adapted and became extinct. ( People at that time could not explain how fossil bones of huge size could have existed when those creatures were not to be found on earth….they had no clue that dinosaurs had once existed and the bones were from dinosaurs. )
41. Much of this book was based on ideas from the breeding of farm animals ; the fossil record found in the earth ; and, comparative studies of living species of animals ( finches, tortoises, iguanas, etc. ) from the Galapagos Islands ( located off the coast of Peru in S. America ).
42. It is thought by scientists that the universe and Earth was created 4.5 billion years ago.
43. It is thought by scientists that life began in the oceans of the Earth 3.5 billions years ago.
All forms of life must adapt to their environment or they will go extinct.
44. Charles Darwin was the first to suggest that a “MORE FIT” species ( that is to say, a species better adapted to it’s environment ) will survive and reproduce its own kind. A species that is “less fit” will not compete as well for food/water, living space or mates. A “less fit” species will reproduce fewer numbers or fewer numbers will survive. In this case, it is nature that chooses who lives and who dies based on which is best adapted ( stronger, smaller, faster, best to hide, sharpest claws, smartest, who has a more variety of diet, etc. ) and also, which is more lucky.
45. Natural Selection means “survival of the fittest, who is best adapted to the environment ”.
To adapt, all forms of life must change over time. This change may be in the way they act, the way they look, how they use their body, how they live with the changing conditions of the
environment. They may have to migrate, hibernate, change feeding habits, change mating habits, learn to cooperate with other creatures.
Evolution by Natural Selection means that “mother nature” choose which creatures live and which become extinct based on “survival of the fittest”. The creature that is best adapted to the environment is the one most fit and the one that survives.
The theory of Evolution by Natural Selection has 4 main parts :
1. Overproduction - ( certain species produce many eggs or babies ). There is a purpose….
2. Competition - All creatures compete with their own species or different species for
living space ; food / water ; mates ; etc. In some cases, the surplus ( “extra “ members of a species ) will become food to help the survival of another species.
3. Variation – All creatures are a little different from others of the same species. Some of these differences may be genetic and can be passed on to the young. These variations (differences) may also help an individual to adapt better to the environment and live to reproduce.
4. Selection – Mother nature selects which individual lives and which dies based on who is
best fit / best adapted.
The changing ( in any way or form ) of any species over time is called evolution.
46. Evolution means “change over a long period of time”.
NOTE : The evolutionary change will be very small for an individual. However, with many, many, many little changes adding up over the time period of hundreds of generations, the change will occur and be seen. Fossil evidence is very helpful to understand evolution. By comparing individual bones or the size of the entire skeleton we discover the changes that have occurred in a species from one time to another time that the species has lived.
47. Evidence for evolution might be seen in “ homologous structures ”. The tail of a bird, whale,
and cow are used for different purposes….but they are all tails…located in the same location on the 3 animals. Each tail has adapted for use by it’s own creature for a different environment and for a different purposes. These tails are homologous structures and might indicate that all 3 creatures have a common ancestor.
48. Fossils tell us about animals & plants that once lived here. They tell us about the environment and what was going on many years ago. They tell us that former animals had similarities to animals today. That species have changed over time. That organisms have evolved.