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Chapter 1

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Chapter 1 – Introduction


I.                     Life is organized into many structural levels.

a.     Atoms are the basis because they form the molecules of sugars, proteins, lipids, and water.

b.     These molecules make up organelles and they make up cells.

c.      Those cells are grouped into tissues.

d.     The tissues are grouped into organs and the organs into systems.

e.     The structural levels go past individuals and into the populations.

                                                              i.      Populations are a localized group of organisms belonging to the same species.

                                                            ii.      Several populations of species living in the same area create a community.

                                                          iii.      An ecosystem is formed when several communities work together along with the abiotic environment to form an energy processing system.

                                                           iv.      Biomes are formed from large-scale communities that have predominant vegetation types and distinctive combinations of plants and animals.

                                                             v.      The biosphere is the sum of all the plant’s ecosystems.

f.        Vitalism is the doctrine that life is a supernatural phenomenon beyond the bounds of chemical and physical laws.

g.     Reductionism is reducing complex systems to simpler components that are more manageable to study.

II.                   Cells

a.     The lowest structural level capable of performing all the activities of life.

b.     All organisms are composed of cells.

c.      Cells are the basic unit of structure and function.

d.     1665 – Robert Hooke, an English scientist first described and named cells.

                                                              i.      Thought that his discovery was unique to cork and did not realize the greatness of his discovery.

e.     Anton van Leewoenhoek, a Dutch scientist discovered single-cell organisms.

                                                              i.      He viewed the microorganisms in pond water, blood, and sperm cells from animals.

f.        1839 – Matthias Schleiden and Theodor Schwann, both German, developed the cell theory.

                                                              i.      Cells are the basis of all structure and function.

                                                            ii.      All cells come from other cells.

                                                          iii.      The ability of cells to divide to form new cells is the basis for all reproduction and for growth and repair in multicellular organisms.

g.     The microscope has reveled the complex structure of the cell.

                                                              i.      All cells are enclosed by a membrane that regulates the passage of materials between the cell and its surroundings.

h.      Two major kinds of cells exist.

                                                              i.      Prokaryotic cells are the simplest organisms because they do not contain a nucleus or membrane bound organelles.  This includes bacteria.  DNA is not separated.

                                                            ii.      Eukaryotic cells are more complex because they contain internal membranes called organelles.  The DNA is also organized with proteins into structures called chromosomes.  They also contain cytoplasm.

III.                  Instructions

a.     Biological instructions are encoded in DNA.

b.     DNA is the substance of genes that are units that transmit information from parents to offspring.

c.      DNA is made of building blocks called nucleotides.

                                                              i.      Specific sequences of nucleotides encode specific information of a gene.

                                                            ii.      The entire library of instructions is kept in the nucleus of each cell as microscopic genes.

d.     All forms of life employ the same genetic code.

e.     Inheritance depends on a mechanism for copying DNA.  As a cell divides, it makes copies of its DNA to go into both cells.

IV.               Structure and function

a.     There is a relationship between an organism’s structure and how it works.  Form fits function.

                                                              i.      Biological structure gives clues about what it does and how it works.

                                                            ii.      Knowing a structure’s function gives insights about its construction.

V.                 Organisms in Open Systems

a.     Organisms live in an open system, which means that it continually reacts with the environment by exchanging materials and energy.

b.     These interactions form an ecosystem.  The dynamics of an ecosystem include two major processes.           

                                                              i.      Cycling of nutrients

                                                            ii.      The flow of energy

VI.               Regulatory mechanisms ensure a dynamic balance in living systems.

a.     Regulation of biological process is critical for maintaining the ordered state of life.  Many biological processes are self-regulation; that is, the product of a process regulates that process.

                                                              i.      Positive feedback speeds a process up

                                                            ii.      Negative feedback slows a process down.

                                                          iii.      This can be achieved using chemical mediators like hormones.

VII.              Diversity

a.     Biologists have identified 1.5 million species.

b.     Thousands are added each year.

c.      Taxonomy is the branch that is concerned with naming and classifying species.

d.     It consists of different levels with each level becoming more specific.  (King Phillip Came Over From Great Spain)  The broadest classification is kingdoms of which there are currently six.

                                                              i.      Archaebacteria

1.      Single celled

2.      Prokaryotic

3.      Live in extreme conditions (heat, salt, and methane)

4.      Halophiles, thermophiles, and menthenogens

                                                            ii.      Eubacteria

1.      Single-celled

2.      Prokaryotic

3.      Organisms often causing illness.

4.      Seen daily

5.      Three basic shapes

6.      Streptococcus, E. coli

                                                          iii.      Protista

1.      Single-celled

2.      Eukaryotic

3.      Usually found in aquatic environments

4.      Can cause disease

5.      Euglena, paramecium

                                                           iv.      Fungi

1.      Multicellular

2.      Eukaryotic

3.      Saprophytic

4.      Mushrooms, mold

                                                             v.      Plantae

1.      Multicellular

2.      Eukaryotic

3.      Autotrophic

4.      Oak

                                                           vi.      Animalia           

1.      Multicellular

2.      Eukaryotic

3.      Autotrophic

4.      Cats, dogs, and humans

e.     Unity exists in the diversity of life forms at the lower levels of organization, which is seen in a universal genetic code, similar metabolic pathways, and similarities of cell structure.

VIII.            Evolution is the Core theme of biology

a.     Life evolves

b.     Species change over time and their history can be described as a branching tree of life.

c.      Species that are very similar share a common ancestor at a recent branch point on the phylogenetic tree.

d.     Less closely related organisms share a more ancient common ancestor.

e.     All life is connected and can be traced back to primeval prokaryotes that existed more than three billion years ago.

IX.               Science is a Process

a.     Testable hypotheses are the hallmarks of the scientific process

                                                              i.      Science is a way of knowing and good scientists are people who ask questions and believe they are answerable, are curious, observant and passionate in their quest, are creative, imaginative, and intuitive, and are generally skeptics.

b.     The scientific method is a process, which outlines a series of steps used to answer questions.

                                                              i.      It is not a rigid procedure

                                                            ii.      It is based on the conviction that natural phenomena have natural causes.

                                                          iii.      Requires evidence to logically solve problems.

c.      The key is forming a hypothesis which is an educated answer to a question

                                                              i.      Inductive reasoning is making an inference from a set of specific observations to reach a general conclusion.

                                                            ii.      Deductive reasoning is making an inference from general premises to specific consequence, which logically follows if the premises are true.

                                                          iii.      Usually use takes the form of if…then

                                                           iv.      Usually possible causes.

                                                             v.      They reflect past experience with similar questions.

                                                           vi.      Multiple hypotheses should be proposed whenever possible.

                                                         vii.      They must be testable.

                                                       viii.      They can be eliminated, but not confirmed with absolute certainty

d.     Another feature is the controlled experiment, which includes both a control and experimental group.

                                                              i.      The controlled group is the groups in which all variables are held constant.

                                                            ii.      Variables are conditions of an experiment that is subject to change and that may influence and experiment’s outcome.

                                                          iii.      The experimental group in a controlled experiment, the group in which one factor or treatment is varied.

e.     Science is an ongoing process that is built on prior scientific knowledge

f.        Scientific theories are comprehensive conceptual frameworks which are well supported by evidence are widely accepted by the scientific community.

X.                 Science and technology are functions of society

a.     Science and technology are interdependent.

                  b.  Technology extends our ability to observe and measure, which                       enable scientists to work on new questions that were previously                            unapproachable.