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Tuesday, September 4, 2012

Introduction Themes in the Study of Life-different areas of biology

  • You can read this all in CAMPBELL biology
  • Introduction Themes in the Study of Life
  • different areas of biology
  • brain, organ system, nerve cell, nervous tissue
  • Systems biology
  • Protists and bacteria
  • matching DNA nucleotide sequences Themes in the Study of Life.html

 Theme: New properties emerge at each level in the biological hierarchy The hierarchy of life unfolds as follows:
biosphere ecosystem community
population organism organ system
organ tissue cell organelle molecule atom.
With each step upward from atoms, new properties emerge as a result of interactions among components at the lower levels. In an approach called reductionism, complex systems are broken down to simpler components that are more manageable to study. In systems biology, scientists attempt to model the dynamic behavior of whole biological systems based on a study of the interactions among the system’s parts.

Theme: Structure and function are correlated at all levels of biological organization The form of a biological structure suits its function and vice versa.
• Theme: The cell is an organism’s basic unit of structure and function The cell is the lowest level of organization that can perform all activities required for life. Cells are either prokaryotic or eukaryotic. Eukaryotic cells contain membrane-enclosed organelles,including a DNA-containing nucleus.
Prokaryotic cells lack such organelles.
• Theme: The continuity of life is based on heritable information in the form of DNA Genetic information is encoded in the nucleotide sequences of DNA. It is DNA that transmits heritable information from parents to offspring. DNA sequences program a cell’s protein production by being transcribed into RNA and
then translated into specific proteins, a process called gene expression. Gene expression also results in RNAs that are not translated into protein but serve other important functions. Genomics
is the large-scale analysis of the DNA sequences within a species as well as the comparison of sequences between species.

• Theme: Feedback mechanisms regulate biological systems In negative feedback, accumulation
of an end product slows the process that makes that product. In positive feedback, the end product stimulates the production of more product. Feedback is a type of regulation common to life at all levels, from molecules to ecosystems.
• Evolution, the Overarching Theme of Biology Evolution accounts for the unity and diversity of life and also for the match of organisms to their environments.

1. All the organisms on your campus make up

a. an ecosystem. d. an experimental group.

b. a community. e. a taxonomic domain.

c. a population.

2. Which of the following is a correct sequence of levels in life’s

hierarchy, proceeding downward from an individual animal?

a. brain, organ system, nerve cell, nervous tissue

b. organ system, nervous tissue, brain

c. organism, organ system, tissue, cell, organ

d. nervous system, brain, nervous tissue, nerve cell

e. organ system, tissue, molecule, cell

3. Which of the following is not an observation or inference on

which Darwin’s theory of natural selection is based?

a. Poorly adapted individuals never produce offspring.

b. There is heritable variation among individuals.

c. Because of overproduction of offspring, there is competition

for limited resources.

d. Individuals whose inherited characteristics best fit them to

the environment will generally produce more offspring.

e. A population can become adapted to its environment over


4. Systems biology is mainly an attempt to

a. analyze genomes from different species.

b. simplify complex problems by reducing the system into

smaller, less complex units.

c. understand the behavior of entire biological systems.

d. build high-throughput machines for the rapid acquisition

of biological data.

e. speed up the technological application of scientific


5. Protists and bacteria are grouped into different domains because

a. protists eat bacteria.

b. bacteria are not made of cells.

c. protists have a membrane-bounded nucleus, which bacterial

cells lack.

d. bacteria decompose protists.

e. protists are photosynthetic.

6. Which of the following best demonstrates the unity among

all organisms?

a. matching DNA nucleotide sequences

b. descent with modification

c. the structure and function of DNA

d. natural selection

e. emergent properties

7. A controlled experiment is one that

a. proceeds slowly enough that a scientist can make careful

records of the results.

b. tests experimental and control groups in parallel.

c. is repeated many times to make sure the results are accurate.

d. keeps all variables constant.

e. is supervised by an experienced scientist.

8. Which of the following statements best distinguishes

hypotheses from theories in science?

a. Theories are hypotheses that have been proved.

b. Hypotheses are guesses; theories are correct answers.

c. Hypotheses usually are relatively narrow in scope; theories

have broad explanatory power.

d. Hypotheses and theories are essentially the same thing.

e. Theories are proved true; hypotheses are often falsified.

9. Which of the following is an example of qualitative data?

a. The temperature decreased from 20°C to 15°C.

b. The plant’s height is 25 centimeters (cm).

c. The fish swam in a zigzag motion.

d. The six pairs of robins hatched an average of three chicks.

e. The contents of the stomach are mixed every 20 seconds.

10. Which of the following best describes the logic of scientific


a. If I generate a testable hypothesis, tests and observations

will support it.

b. If my prediction is correct, it will lead to a testable


c. If my observations are accurate, they will support my


d. If my hypothesis is correct, I can expect certain test results.

e. If my experiments are set up right, they will lead to a

testable hypothesis.


A typical prokaryotic cell has about 3,000 genes in its DNA,

while a human cell has about 20,500 genes. About 1,000 of

these genes are present in both types of cells. Based on your

understanding of evolution, explain how such different organisms

could have this same subset of genes. What sorts of

functions might these shared genes have?


Based on the results of the snake mimicry case study, suggest

another hypothesis researchers might use to extend the



Evolution In a short essay (100–150 words), discuss

Darwin’s view of how natural selection resulted in both

unity and diversity of life on Earth. Include in your discussion

some of his evidence. (See p. xv for a suggested grading

rubric. The rubric and tips for writing good essays can

also be found in the Study Area of MasteringBiology.)

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