Characteristics of Life Biology 9

Characteristics of all Living Things Are made up of units called cells Reproduce Are based on a universal genetic code Grow and develop Obtain and use of materials and energy Respond to their environment Maintain a stable internal environment Change over time

Life Defined Living things exhibit ALL of these characteristics. Dead things USED to exhibit all of these characteristics Non-living things do not exhibit ALL of the characteristics. Anything that exhibits all the characteristics is called an organism and is classified/categorized in the biological system by taxonomy. (scientific name, place in taxonomy comes from its attributes.

1. Made up of Cells Small self contained units. A collection of living matter enclosed by a membrane (barrier) that separates the inside of the cell from the surroundings. Cells are alive they exhibit all characteristics of life. Unicellular Organism- basic organism consisting of one cell. (bacteria, protists) Multicellular Organism- complex oragnism consisting of many cells, those cell will usually have specialized functions. More diverse. (animals, plants) Multicellular organisms can have thousands or even trillions of cells. Humans have over 85 different cell types!

2. Reproduction All organisms produce new organisms through reproduction Sexual- cells from two different parents combine to create a new organism. Asexual- new organism arises from a single parent. Two ways- Selfing and Binary fission. Selfing occurs when an adult grows the new organism off of its self (ex. Hydra) Binary fission- the organism copies all of its parts and splits into two organisms.

3. Based on Genetic Code The genetic code carries instructions for producing and maintaining an organism. It allows for continuity of life. Parents and offspring share the same or similar traits. Dogs produce dogs not cats! Traits are inherited from the parents to offspring. The universal genetic code is carried in a molecule called a nucleic acid for all known life. DNA- deoxyribonucleic acid RNA viruses?? alive?

4. Growth and Development All living things grow for at least a portion of their lives. Growth- size increase All Multicellular organisms go through a process of development in addition of growth. Development- increase in cell number, size, differentiations, changes in structure, Ex. Butterfly, humans, plants. Differentiation- cells specialize in their structure and function (ex. Muscle cells, brain cells, etc.)

5. Need for materials and Energy Organisms must get energy and the building blocks of life for growth and development. Organisms need building blocks of life and energy to maintain life. All organisms take in selected materials from their surroundings. They must be broken down into their basic building blocks and used to build molecules for the organism. This process is called metabolism. Producers use the sun as an energy source. Consumers use other organisms as an energy source.

6. Response to Environment Stimulus Response- response to immediate changes Examples : Plants bending toward sunlight, animals moving away from perceived danger Adaptation Response- response to long-term changes Change in fur color to match environment, switching to a new food source

7. Maintaining Internal Balance All living organisms, unicellular and multicellular are able to maintain an internal balance because they cell separates in internal from the external. This balance is called Homeostasis. Conditions in the internal environment remain stable even with the changing outside environment. Often involves internal feedback mechanisms and external feedback mechanisms Example: Need for water and thirst, increase in temperature and sweating.

8. Change over time All living organisms as a whole population change over time based on their environment. This process is called evolution. It does not involve and organism changing from one to another. It does involve an organism population changing in types, number, and ability of traits in the organism. Example: Cave organisms Every known organism has been observed to evolve over time.