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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Overall the reason is to begin to develop biological literacy so that you can:
gain an understanding of life.
Life is more easily understood by looking at the characteristics of living organisms, which are as follows:
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
Regardless of the area of interest, scientists make their discoveries by:
where they document some phenomenon (e.g., Jane Goodall’s work with chimpanzees)
which often involve hypothesis testing.
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.
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.
Collect 40 king snakes
Collect 20 sympatric and 20 allopatric rattlesnakes
Put king snakes with rattlesnakes and observe the king snakes response to bites by rattlesnakes
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.
Apply the appropriate statistical tests (determined a priori or before the data were collected)
based on the results and reject or fail to reject the null hypothesis. Never prove
the results and inferences (write a paper and/or give a presentation)
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.
Biodiversity - number of species of living organisms in a given area
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.
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.
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).
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
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.
predominantly multicellular eukaryotes. They have external digestion and all are heterotrophs.
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)
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
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.
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).
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)
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).
involves the movement of substances against a concentration gradient and it requires an energy expenditure
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
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
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
(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
Origin - probably arose from photosynthetic endosymbiotic bacteria
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
Cytoplasm is the liquid matrix within the cell
Some cells also possess locomotor and/or non-locomotor appendages (e.g., flagella, cilia, and pili)
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)
epidermis – coverings
vascular tissue – transport
ground tissue - support