NOTES FOR BIOLOGY 1001

SECTION 005

Spring 2005

DR. STEVEN POMARICO, INSTRUCTOR

PART 1A

CHAPTER 1

CONCEPTS AND METHODS IN BIOLOGY

What is Biology?

--- The science of living organisms and life processes.

We all recognize what life is, but it’s difficult to define.

Some of the characteristics of life:

1) Life has DNA

Everything that lives has DNA.

Deoxyribonucleic acid, or DNA, is a special molecule that sets the living world apart from the nonliving by carrying the hereditary instructions for assembly of new organisms.

The passing of DNA from one generation to another is the basis of inheritance.

Inheritance-Acquisition of traits by transmission of DNA from parent to offspring.

This process of transmitting the DNA to new generations is built into the functions of reproduction.

Reproduction-Mechanism by which an organism produces offspring.

Governed by instructions in DNA

DNA also provides the instructional methods that guide the growth and development of multicellular organism.

2) Life has the ability to acquire material and energy

>The material and energy are often transformed<

Energy-Capacity to do work

Producers - Autotrophs - take in raw materials and make their own food.

Consumers - Heterotrophs -Depend on energy stored in tissues of producers.

Decomposers - Heterotrophs - Depend on energy from breakdown of remains and wastes of producers and consumers

Metabolism changes the raw material and energy into the forms which are needed for maintenance, growth, reproduction, etc.

3) Life response to stimuli - a change outside (or inside) leads to another change

Organisms have receptors to detect external and internal stimuli.

Some reactions are slow and some reactions can’t be seen

Many of the responses to stimuli maintain homeostasis.

-Homeostasis - the ability to maintain the structure and

regulate the internal environment.

>>>>>Life is arranged in a complex but organized structure.

The complexity of life is built in levels. (See fig 1.5)

Each level has ingredients or components which interact to make something greater than the sum of the parts.

The cell is the smallest level which can survive and reproduce. Because of this it’s the lowest level that is actually living.

>>>>> Hierarchy of biological organization (the definitions for these are handled separately, here you should concentrate on the organization)

-Subatomic particles

-Atoms

-Molecules

-Organelles (not present in prokaryotes)

-Cells

-Tissues (present only in multicellular eukaryotes)

-Organs (present only in multicellular eukaryotes)

-Organ systems (present only in multicellular eukaryotes)

-Multicelled organisms

-Populations

-Community

-Ecosystem

-Biosphere

>>>>>All life forms have these characteristics in common, yet there is an amazing diversity in the forms of life on the planet.

-Millions of living species

-Millions more now extinct

-Classification schemes attempt to organize diversity

All living organisms are organized into groups.

There are many ways that things may be grouped

Plants verses animals

One of the early classification placed the animals in one group and the plants in another.

The bacteria, fungi and many protists were considered plants while some of the protists were grouped with the animals.

Most biologist now favor a three group system. These groups are termed domains

There are two prokaryotic domains; Bacteria and Archaea and a eukaryotic domain; Eukarya.

PROKARYOTES	EUKARYOTES
No nucleus or nuclear envelope	Nucleus with a nuclear envelope
Genetic material in a “nucleoid region”	Genetic material within the nucleus
No organelles or internal membranes	Contains cytosol with membrane-bound organelles

Within the domains are at least 6 groups known as kingdoms (See fig. 1.7).

Each of the major organizational groups called kingdoms have different attributes which define them. (See table 1-1)

The six kingdoms:

Archaebacteria

Eubacteria

Protistans

Fungi

Plants

Animals

>>>>>Remember our definition of biology?

--- The science of living organisms and life processes.

What is science?

A subject to study in school?

Science is an activity!

Science is a process of discovery

The principles behind this discovery process are:

1) all events have a natural cause - natural causality

2) natural causes obey natural laws

3) natural laws don’t change with time or distance

The process of scientific discovery usually proceeds by the scientific method

Make observations - Rocks sink in water

Metal bars sink in water

Raybans sink in water when accidentally dropped in

Form a hypothesis - things that have weight sink in water

Make a prediction - if I drop a variety of things in the water they will sink.

Conduct experiments to test the prediction

- Drop the following in the water:

a 25-pound log

10 pounds of ice

Your roommate

Make conclusions - do the results of the experiments support your hypothesis

If not then you have to change your hypothesis

If they do then you’re one step closer to a theory

A theory is an explanation of natural events which is based on a LARGE number of observations and/or experiments.