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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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Introductory Comments (chapter 1)

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Introductory comments chapter 1

Introductory Comments (chapter 1)


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 possession and inheritance of dna from parent to offspring

The possession and inheritance of DNA from parent to offspring.


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


Homeostasis the maintenance of a fairly constant environment

Homeostasis - the maintenance of a fairly constant environment.


Reproduction or the production of offspring

Reproduction or the production of offspring


Adaptation to the environment

Adaptation to the environment


The ability of populations of living organisms to evolve

The ability of populations of living organisms to evolve


Response to stimuli

Response to stimuli


A higher level of organization than non living objects and composed of one or more cells

A higher level of organization than non-living objects and composed of one or more cells.


Why study biology1

Why study Biology?

In order to understand how scientists conduct research


Levels of organization

Levels of organization


Molecules

Molecules


Subcellular structures

Subcellular structures


Introductory comments chapter 1

Cell


Tissue

Tissue


Organ

Organ


Organ system

Organ System


Organism

Organism


Population

Population


Community

Community

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


Ecosystem

Ecosystem

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


Biosphere

Biosphere


Introductory comments chapter 1

Regardless of the area of interest, scientists make their discoveries by:


Observations

Observations

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


Controlled experiments

Controlled experiments

which often involve hypothesis testing.

Steps:


Make observation s

Make observation(s)


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


Introductory comments chapter 1

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.


Introductory comments chapter 1

Biodiversity

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 Inorganic 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.


Introductory comments chapter 1

Biodiversity


Introductory comments chapter 1

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.


Protists

Protists

-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.


Classification

Classification

Domain

Kingdom

Phylum

Class

Order

Family

Genus

species

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


How to write a scientific name

How to write a scientific name

Feliscatus

Or

Felis catus

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

F. catus or F. catus


Introductory comments chapter 1

Cells: Structures and Functions (chapter 3)


Cells

Cells

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.


There are two basic types of cells prokaryotic and eukaryotic cells

There are two basic types of cells: Prokaryotic and Eukaryotic Cells


Introductory comments chapter 1

Components

of Cells


Cell membranes in both prokaryotes and eukaryotes

Cell membranes (in both prokaryotes and eukaryotes)

Structure

  • 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

MORE ABOUT

TRANSPORT


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).


Osmosis

Osmosis

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)

Structure

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

nucleoplasm


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.


Ribosomes

Ribosomes

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)

Function

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


Lysosomes

Lysosomes

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


Mitochondria

Mitochondria

Structure – cigar-shaped, double membrane-bound organelle

Function – Energy transfer by ATP synthesis


Chloroplasts

Chloroplasts

Structure Green spindle-shaped double membrane bound organelles

Function Photosynthesis

Origin - probably arose from photosynthetic endosymbiotic bacteria


Introductory comments chapter 1

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


Vacuoles

Vacuoles

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

Function - storage


Cytoskeleton

Cytoskeleton

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


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