Chapter 1

• 40 million Species of organisms. 

• About 2 million have been identified and named, only a few thousand have been studied.

• All living things are called Organisms.

• The first life form arose more than 3.5 BILLION years ago.  (Single Celled organism.)

• Over time Organisms Change (Evolution)

• Organisms also inhabit extreme locations on Earth:     -Antarctic Ice     -Hot vents on the ocean floor     -Inside of other organisms

• Each organism is adapted to the specific features of its environment.

• BIOLOGY - the Science of Life - is The Study of ALL Living Things.

SIX UNIFYING THEMES OF BIOLOGY

A. Cell Structure and Function

B. Stability and Homeostasis

C. Reproduction and Inheritance

D. Evolution (Change)

E. Interdependence of Organisms

F. Matter, Energy, and Organization

CELL STRUCTURE AND FUNCTION

• THE CELL IS THE BASIC UNIT OF LIFE. 

• UNICELLULAR ORGANISMS - ONE CELL

• MULTICELLULAR - MORE Than One Cell

• Cells are Highly Organized. 

• Specialized Structures called ORGANELLES.

• Cells go through DIFFERENTIATION.

STABILITY AND HOMEOSTASIS

• Living Things Maintain Very Stable Internal Conditions such as Temperature, Water Content, and even Food Intake.

• Maintaining this Stable Level of INTERNAL CONDITIONS is called HOMEOSTASIS and is found in all Living Things, including single cells.

• Examples??

REPRODUCTION AND INHERITANCE

• REPRODUCTION process in which Organisms produce new organisms like themselves by transmitting hereditary information to their offspring.

• The Hereditary Information is in a form of a large molecule called DEOXYRIBONUCLEIC ACID OR DNA.

• A short segment of DNA that contains the instructions for the development of a SINGLE TRAIT is called a GENE.

• The DNA of every body cell is IDENTICAL.  Each cells uses CERTAIN GENES from the complete set.

• Used by Unicellular Organisms

• Hereditary Information from different organisms IS NOT COMBINED.  One Cell gives rise to TWO NEW CELLS.  Each of the TWO Cells contains an IDENTICAL COPY (Clones) DNA from the Original Cell.

ASEXUAL REPRODUCTION

SEXUAL REPRODUCTION• used by Multicellular organisms• Hereditary Information from TWO

Organisms of the SAME SPECIES Combine. 

• Female EGG• Male SPERM. • The Joining of Egg and Sperm produces a

FERTILIZED EGG CALLED A ZYGOTE, • It contains Hereditary Information from

both the Parents. 

EVOLUTION

• Populations of organisms EVOLVE, or CHANGE over Generations (TIME).

• NATURAL SELECTION - driving force in Evolution - Organisms that have certain Favorable Traits are Better able to Successfully Reproduce - SURVIVAL OF THE FITTEST.

• The survival of organisms with Favorable Traits causes a gradual Change in populations of organisms over many generations.

• Modern Day Horse - 57 Million Years.

INTERDEPENDENCE OF ORGANISMS

• ECOLOGY is the study of Interactions of Organisms with one another and with their Environment.

• THE PASSING OF ENERGY FROM ONE ORGANISM TO ANOTHER.

• Grass (Producer) to (Consumer) Herbivore (plant eater) to (Consumer) Leopard. 

• Nonliving factors (Abiotic) are also necessary for survival of organisms…     A. Air     B. Water     C. Energy (THE SUN)     D. Minerals

• BIOSPHERE - The part of the Earth that supports life.

• Includes all the LAND, WATER, and AIR, where organisms live.

• Organisms respond to their environment by either:     A.  Adapting     B.   Fleeing     C.   Or Dying

• Most organisms can survive a temporary change.

• Permanent change can lead to extinction.

• Main cause - Human Interference?

• ALMOST ALL THE ENERGY FOR LIFE ON EARTH COMES FROM THE SUN.

• PHOTOSYNTHESIS - plants and Unicellular Organisms capture the energy from the Sun and change it into a form of energy that can be used by living things.

• Converts Water and Carbon Dioxide into Sugars and Starches

MATTER, ENERGY, AND ORGANIZATION

• Organisms that make their own food, like plants, are called AUTOTROPHS (Producers). 

• Organisms that must take in FOOD to meet their Energy needs are called HETEROTROPHS (Consumers). 

• Includes all Animals and Fungi as well as many Unicellular Organisms and a few Plant Species.

CHARACTERISTICS OF LIFE

1. CELLS -  All organisms are COMPOSED of CELLS.  Unicellular or Multicellular

2. ORGANIZATION -  Living things are HIGHLY ORGANIZED at both the Molecular and Cellular Level.

3. ENERGY USE - All organisms USE ENERGY for GROWTH AND REPAIR in a process called METABOLISM.

• Which is the sum of all the Chemical Processes that occur in the organism.

4. HOMEOSTASIS - All Living Things maintain stable internal Conditions - HOMEOSTASIS.  All organisms RESPOND to the

ENVIRONMENT. 

5. GROWTH - All organisms GROW and DEVELOP.

• Single celled organisms grow and develop into mature cells.

• Multicellular organisms - Growth is an Increase in Size. Development is a change in Shape or Form.

6. REPRODUCTION - REPRODUCTION IS NECESSARY FOR THE SURVIVAL OF A SPECIES. 

7. ADAPTATION - SPECIES of organisms ADAPT to their ENVIRONMENTS through EVOLUTION. 

Molecular Level• The simplest part of a living system are the

atoms and molecules from which the organisms are made.

• An example is DNA. DNA is a very complex molecule made of thousands of atoms.

Cellular Level• In a cell many different molecules

interact with one another. The cell is the smallest unit of life capable of carrying out all the functions of living things.

Tissue Level• Tissues are a group of cells that

perform a specific function in an organisms

– Ex. Muscles

Organ Level

• An organ is made of several different types of tissues that function together for a specific purpose.

– Ex. Heart, liver

Organ System Level

• An organ system is made of several organs working together to perform a function.

– Ex. Circulatory, digestive, reproductive

Population Level

• A group of organisms of the same species that lives together in a particular location.

Community Level

• A community includes all the populations of different kinds of organisms living in the same place.