The Science of Biology Biology Key aspect of Biology
Organisms = Living things
How do we know that something is a living thing?
Characteristics of Living Things Have a cellular organization Contain similar chemicals Use energy Respond to their surroundings Grow and develop Reproduce
A trip to the beach One day at the beach, Zeke picked up one of many rocks that were covered in white bumps. He thought the rock would look nice in his marine aquarium so he brought it home and dropped it into his tank. One day, while watching the fish in his tank, Zeke got a surprise. The white bumps on the rock had sprouted tiny legs and were waving back and forth in the water. The rock was alive! (Actually, the white bumps were alive.) Barnacles Zeke s rock was covered with tiny organisms called barnacles. These creatures live in tide pools along the seacoast where waves crash and tides cause water to flow in and out. Inside its shell the barnacle can hold seawater to survive the many hours of drought at low tide. At high tide the shell opens and the barnacle begins to feed. Its long, comb-like legs sweep back and forth to catch tiny organisms called plankton. Is a barnacle alive?
Have a cellular organization
Cells A cell is a basic unit of structure and function in an organism How many cells are in this picture?
Unicellular Multicellular Single celled organism. Bacteria Amoeba Organisms composed of many cells. These cells are specific and programmed for specific jobs.
Contain similar chemicals
Carbohydrates Proteins Lipids Nucleic Acids
Water is necessary for life. If there is no water there is NO life.
Main source of energy. Starches Get broken down into sugar (glucose).
Help cells to build things. Muscle is made of protein. Protein is found in eggs and meat.
Help cells to build things. Fats and oils are lipids sounds gross but you really need it!
Create genetic material DNA (deoxyribonucleic acid). The blueprint instructions for cells to direct all activity.
Use energy
Cells in organisms use energy to function. The students in this photo are using energy to learn. Even on the cellular level that we can t see!
Respond to their surroundings
Clearly, this cat is responding to something that has scared it. All living things can respond to their environment A stimulus is what causes the organism to react. A response is what action happens as a result of a stimulus.
Grow and Develop
Living things can grow an develop. Development is the process of change that occurs during and organism life to produce a more complex organism.
Reproduce
All living things can produce offspring similar to themselves.
Spontaneous generation The idea that life can come from a non-living source. This was a very popular idea during the time of Francesco Redi. He created a controlled experiment to test if spontaneous generation was real.
What is the independent variable? What is the dependent variable? Redi s Experiment This is a controlled experiment.
Life does not occur spontaneously. LIFE COMES FROM LIFE.
Louis Pasteur Wanted to re-test to see if spontaneous generation was true. (Most people still believed in it)
What is the independent variable? What is the dependent variable? Pasteur s Experiment This is also a controlled experiment.
The Needs of Living Things Food Autotroph make their own food Heterotrph must consume others All organisms need water to survive. Water Living All organisms need a place to live there is limited space on Earth. Space
Homeostasis Homeostasis = Balance The maintaining of a stable internal condition.
How does this frog maintain homeostasis?
How are organisms classified into Domains & Kingdoms? Organisms are placed into domains and kingdoms based on:
Three-domain system of classification used:
Within the domains are kingdoms