Principles of Biology By: Alan, Ryan, Julien

Four Principles of Biology Biology is based off of these four theorems or principles which help guide the rest of biology Gene theory:The idea that characteristics of living organisms are controlled by genes Cell Theory: The base that everything living is made of cells Homeostasis: The maintaining of a stable internal environment Evolution: The change in the characteristics of living things over time

Gene Theory The Gene Theory is a theory that states that characteristics of living organisms are controlled by genes These Genes are passed from parent to child Gene= a Segment of DNA It has instructions to encode a protein Genes are located on larger Structures called Chromosomes Chromosomes are found inside every cell Chromosomes contain DNA Molecules Molecules of DNA are encoded with instructions that tell cells what to do

Pictures of a Chromosome, and DNA Structure

Cell Theory The cell theory says that all living things are made up of cells A cell is the structural unit of a living organism Cells can only come from another cell Each living thing begins life as a cell Some things like bacteria live their entire life as a single cell Other things become multi-cellular like us Each of us have trillions of cells inside our body

Homeostasis Definition of Homeostasis - refers to the ability of the body or a cell to seek and maintain a condition of equilibrium or stability within its internal environment when dealing with external changes. Example - Human Internal Body Temperature

Evolution Definition of Evolution - the change in the characteristics of living things over certain periods of time Stayed by Charles Darwin His theory states that Evolution occurs by a process called Natural Selection This theory states that organisms adapt to their environment to survive and produce more offspring in the future

Adaption Adaptation is when an animal's gains an advantage to better help it survive in the environment The difference between adaptation and evolution is that adaptation can happen without evolution

Questions (Prize is candy) About how many cells does one person have in them? What two things does the cell theory state? Two people answer What do each of us start out as? What are the 4 main principles of Biology? Four people answer What is a gene? Where are Genes located? What is adaptation? Who invented evolution? What is evolution? What is homeostasis? What is DNA?

THANK YOU FOR LISTENING !!!!!!!!!!!!!!!!