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Introductory Comments (chapter 1). Why study Biology?. Overall the reason is to begin to develop biological literacy so that you can: gain an understanding of life. But what is life?. Life is more easily understood by looking at the characteristics of living organisms, which are as follows:.

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why study biology
Why study Biology?

Overall the reason is to begin to develop biological literacy so that you can:

gain an understanding of life.

but what is life
But what is life?

Life is more easily understood by looking at the characteristics of living organisms, which are as follows:

the ability to get convert and use energy e g photosynthesis aerobic respiration
The ability to get, convert, and use energy E.g.: photosynthesis & aerobic respiration
why study biology1
Why study Biology?

In order to understand how scientists conduct research


The cats, mice, grass, insects etc. that all live in a given area


The living organisms of the community + the abiotic factors that affect them


where they document some phenomenon (e.g., Jane Goodall’s work with chimpanzees)

controlled experiments
Controlled experiments

which often involve hypothesis testing.


propose hypotheses make sure that they are falsifiable and testable
Propose hypotheses. Make sure that they are falsifiable and testable.

Alternative – statement that there is a difference between the experimental and control groups

Null – statement that there is no difference between the experimental and control groups

King snakes in West Virginia are immune to venom of sympatric rattlesnakes but not to venom of allopatric rattlesnake venom.

King snakes in West Virginia are immune to venom from sympatric and allopatric rattlesnakes.

design predictions if then statements and an experiment
Design predictions (if-then statements) and an experiment

If king snakes from West Virginia are immune to venom of both sympatric and allopatric rattlesnakes, then a bite from any rattlesnake will not harm or kill the king snake.

Experiment design-

Collect 40 king snakes

Collect 20 sympatric and 20 allopatric rattlesnakes

Randomize sample

Put king snakes with rattlesnakes and observe the king snakes response to bites by rattlesnakes

conduct the experiment
Conduct the experiment

with appropriate control group (the group that is held constant for comparison), dependent (measured variables) and independent variables (manipulated variables). Bias should be prevented by considering the placebo effect, utilizing a blind or a double blind design (so the subjects and the researchers do not know if they are in the experimental group or the control group), and randomizing the subjects.

analyze data
Analyze Data

Apply the appropriate statistical tests (determined a priori or before the data were collected)

make inferences
Make inferences

based on the results and reject or fail to reject the null hypothesis. Never prove

objectively report
Objectively report

the results and inferences (write a paper and/or give a presentation)

why study biology2
Why study Biology?

to understand how biology applies to you and then integrate what you have learned into your decision making


Medical applications, human genome project, the search for a vaccine for AIDS, and genetic engineering.

Understanding our impact on current and future biodiversity and ultimately on our own species. Human induced extinctions and decreases in genetic variability are occurring.

Understanding our impact on the environment (and again on biodiversity) and ultimately the survival of our own species.



and Domains

definitions i
Definitions I

Biodiversity - number of species of living organisms in a given area

definitions ii
Definitions II

A species is composed of organisms that appear to be similar (in looks) and that are capable of interbreeding with other like individuals. This is the Biological Species Concept proposed by Ernst Mayr.

definitions iii
Definitions III

Autotrophs are organisms that are capable of building their own large organic molecules by using CO2 and energy from their environment.

Photosynthetic autotrophs use sunlight energy

Chemosynthetic autotrophs use energy from chemical reactions involving I norganic molecules.

definitions iv
Definitions IV

Heterotrophs are organisms that are not capable of synthesizing their own food and thus obtain their nourishment from autotrophs, other heterotrophs or from organic wastes (e.g., decomposers).

definitions v
Definitions V

A theory is generated by a related set of insights supported by evidence. It explains some aspect of nature and is a valued entity (e.g., evolution).

Evolution is just a theory.


Viruses. Not considered to be living (they cannot reproduce on their own) by many biologists, they are worth mentioning. A virus is a noncellular infectious agent possessing a nuclei acid core that cannot reproduce itself. Viruses may be composed of DNA or RNA within the protein coat (but

domains archaea and bacteria
Domains Archaea and Bacteria

bacteria all are prokaryotic (meaning that they do not possess membrane-bound organelles), autotrophs (photosynthetic and chemosynthetic) and heterotrophs. Archaea is the domain containing the greatest metabolic diversity. Bacteria were the first living organisms, they prepared the environment for other organisms, all other living organisms originated (evolved) from bacteria, and they are ubiquitous (they live throughout the entire biosphere). Prokaryotes are unicellular.


-mostly single-celled eukaryotes but there are some colonial forms as well as some that are truly multicellular (the algae). Some are heterotrophs & some are photosynthetic autotrophs.

kingdom fungi myceteae
Kingdom Fungi (Myceteae)

predominantly multicellular eukaryotes. They have external digestion and all are heterotrophs.

kingdom plantae
Kingdom Plantae

plants. All are eukaryotic and they are photosynthetic autotrophs. They are multicellular, the cells have cell walls, and they are sessile (they do not move)

kingdom animaliae
Kingdom Animaliae

animals ranging from sponges to humans. They are multicellular eukaryotes and all are heterotrophic. They all move at some time in their life cycles. There are no cell walls and the vast majority of the animals are invertebrates.










Genus + species (maybe subspecies) makes up the Scientific name

how to write a scientific name
How to write a scientific name



Felis catus

After first use (but not at the beginning of a sentence)

F. catus or F. catus


A cell is the smallest living unit

The Cell Theory states that all organisms are composed of one or more cells, which are the basic units of organization and which, arise from preexisting cells.



of Cells

cell membranes in both prokaryotes and eukaryotes
Cell membranes (in both prokaryotes and eukaryotes)


  • Components - lipids (primarily phospholipids), cholesterol, and proteins
  • Organized as a bilayer which is fluid (the fluid mosaic model describes the structure of these membranes). The polar (containing oxygen for hydrogen bonding) heads are hydrophilic and the nonpolar tails are hydrophobic.
cell membranes
Cell membranes

Function - basically these membranes serve as barriers which allow some substances to move in and out and prevent other substances from such movements. The proteins that are part of the cell membrane have various functions depending on their structures (e.g., reception, recognition, transport; read sections 3.6 and 3.7 in the text).

cell membranes1
Cell membranes



diffusion simple
Diffusion (Simple)

the movement of substances from an area of higher concentration to an area of lower concentration (or down a concentration) gradient across a selectively permeable membrane (pore size and polarity are important in this type of movement).


is the movement of water across a selectively permeable membrane in response to the relative concentrations of solutes on the inside and outside of the membrane. The external environment of cells may be isotonic (same solute concentration), hypertonic (higher solute concentration), or hypotonic (lower solute concentration)

facilitated diffusion
Facilitated Diffusion

the movement of molecules with a concentration gradient but using a membrane protein which functions as a channel or as a carrier (facilitated diffusion). This type of transport does not require energy (nor do the others described above).

active transport
Active transport

involves the movement of substances against a concentration gradient and it requires an energy expenditure

nucleus usually the largest organelle in the cell and only in eukaryotes
Nucleus(usually the largest organelle in the cell and only in eukaryotes)


lipid bilayer membrane (like the cell membrane) surrounding the interior of the nucleus and containing nuclear pores

nucleolus (plural nucleoli)- a small dense area

chromosomes - the DNA and associated proteins


nucleus part ii
Nucleus Part II

Membrane - functions as a barrier (see discussion of plasma membrane)

Nucleolus - the formation of ribosomes

chromosomes - contain genes whose expression leads to the formation of proteins which in turn control all aspects of an individual either directly or indirectly (e.g., through the ability to learn).

nucleoplasm - the cytoplasm or fluid medium of the nucleus

Remember that prokaryotes do not have their chromosomes packaged within nuclei, but instead the DNA of prokaryotes is found in a nuclear area.


found in both prokaryotes and eukaryotes but with structural differences.

Structure - small consisting of a large and a small subunit (chemically made up of rRNA and proteins)

Function - the sites of protein synthesis

endoplasmic reticulum er found only in eukaryotes
Endoplasmic Reticulum (ER) (found only in eukaryotes)

Structure - basically a system of membranous tunnels and sacs

Smooth ER is devoid of ribosomes

Rough ER is associated with ribosomes (they are attached to the surface)


Smooth ER - lipid synthesis

Rough ER - protein synthesis

golgi apparatus or complex
Golgi Apparatus or complex

(found only in eukaryotes)

Structure - flattened connected sacs that look like a stack of pancakes.

Function - the processing of lipids and proteins


and other vesicles (found only in eukaryotes)

Structure of lysosomes - membrane bound sacs containing hydrolytic enzymes associated with the Golgi (actually formed from the Golgi)

Function - digestion of substances


Structure – cigar-shaped, double membrane-bound organelle

Function – Energy transfer by ATP synthesis


Structure Green spindle-shaped double membrane bound organelles

Function Photosynthesis

Origin - probably arose from photosynthetic endosymbiotic bacteria

Cell wall (found in most bacteria and in plants, protists, and fungi; but with differing chemical compositions)

Structure - thick layer surrounding the cell membrane

Function - protection and support


Structure - a fluid filled sac that may take up 50-90% of the cell (e.g., central vacuole of plants)

Function - storage


Structure - a net-like continuation of various protein filaments

Function in Support

other components
Other components

Cytoplasm is the liquid matrix within the cell

Some cells also possess locomotor and/or non-locomotor appendages (e.g., flagella, cilia, and pili)

there are four basic types of animal tissues
There are four basic types of animal tissues

epithelial - coverings and linings

connective - support and storage

nervous - the conduction of electrical impulses, and the coordination of the body’s activities and responses to stimuli

muscle - contraction (heartbeat, voluntary and involuntary movements)

there are three basic types of plant tissues
There are three basic types of plant tissues

epidermis – coverings

vascular tissue – transport

ground tissue - support